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Chapter 1-17

       Operations Management



Roberta Russell & Bernard W. Taylor, III
Organization of This Text:
Part I – Operations Management
Intro. to Operations and
Supply Chain Management:       Chapter 1 (Slide 5)
Quality Management:            Chapter 2 (Slide 67)
Statistical Quality Control:   Chapter 3 (Slide 120)
Product Design:                Chapter 4 (Slide 186)
Service Design:                Chapter 5 (Slide 231)
Processes and Technology:      Chapter 6 (Slide 276)
Facilities:                    Chapter 7 (Slide 321)
Human Resources:               Chapter 8 (Slide 402)
Project Management:            Chapter 9 (Slide 450)

                                                   1 -2
Organization of This Text:
Part II – Supply Chain Management
Supply Chain
Strategy and Design:            Chapter 10 (Slide 507)
Global Supply Chain
Procurement and Distribution:   Chapter 11 (Slide 534)
Forecasting:                    Chapter 12 (Slide 575)
Inventory Management:           Chapter 13 (Slide 641)
Sales and
Operations Planning:            Chapter 14 (Slide 703)
Resource Planning:              Chapter 15 (Slide 767)
Lean Systems:                   Chapter 16 (Slide 827)
Scheduling:                     Chapter 17 (Slide 878)
                                                    1 -3
Learning Objectives of
  this Course
Gain an appreciation of strategic importance
of operations and supply chain management
in a global business environment
Understand how operations relates to other
business functions
Develop a working knowledge of concepts
and methods related to designing and
managing operations and supply chains
Develop a skill set for quality and process
improvement
                                               1 -4
Chapter 1
Introduction to Operations and
  Supply Chain Management
        Operations Management

 Roberta Russell & Bernard W. Taylor, III
Lecture Outline

What Operations and Supply Chain
Managers Do
Operations Function
Evolution of Operations and Supply Chain
Management
Globalization and Competitiveness
Operations
Strategy and Organization of the Text
Learning Objectives for This Course

                                           1 -6
What Operations and
   Supply Chain Managers Do
What is Operations Management?
  design, operation, and improvement of productive
  systems
What is Operations?
  a function or system that transforms inputs into outputs of
  greater value
What is a Transformation Process?
  a series of activities along a value chain extending from
  supplier to customer
  activities that do not add value are superfluous and
  should be eliminated


                                                                1 -7
Transformation Process

Physical: as in manufacturing operations
Locational: as in transportation or
warehouse operations
Exchange: as in retail operations
Physiological: as in health care
Psychological: as in entertainment
Informational: as in communication


                                           1 -8
Operations as a
    Transformation Process

INPUT
•Material
              TRANSFORMATION             OUTPUT
•Machines
                 PROCESS                 •Goods
•Labor
                                         •Services
•Management
•Capital




                         Feedback & Requirements


                                                     1 -9
Operations Function

Operations
Marketing
Finance and
Accounting
Human
Resources
Outside
Suppliers

                        1-10
How is Operations Relevant to my
 Major?
              “As an auditor you must
Accounting    understand the fundamentals of
              operations management.”
Information   “IT is a tool, and there’s no better
Technology    place to apply it than in
              operations.”
              “We use so many things you
Management    learn in an operations class—
                                       class—
              scheduling, lean production,
              theory of constraints, and tons of
              quality tools.”
                                                1-11
How is Operations Relevant to my
 Major? (cont.)
            “It’s all about processes. I live
Economics   by flowcharts and Pareto
            analysis.”
Marketing   “How can you do a good job
            marketing a product if you’re
            unsure of its quality or delivery
            status?”
Finance     “Most of our capital budgeting
            requests are from operations,
            and most of our cost savings,
            too.”

                                                1-12
Evolution of Operations and
Supply Chain Management
Craft production
  process of handcrafting products or
  services for individual customers
Division of labor
  dividing a job into a series of small tasks
  each performed by a different worker
Interchangeable parts
  standardization of parts initially as
  replacement parts; enabled mass
  production


                                                1-13
Evolution of Operations and
 Supply Chain Management (cont.)

Scientific management
  systematic analysis of work methods
Mass production
  high-
  high-volume production of a standardized
  product for a mass market
Lean production
  adaptation of mass production that prizes
  quality and flexibility

                                              1-14
Historical Events in
      Operations Management
Era          Events/Concepts            Dates   Originator
             Steam engine               1769    James Watt
Industrial
             Division of labor          1776    Adam Smith
Revolution
             Interchangeable parts      1790    Eli Whitney
             Principles of scientific
                                        1911    Frederick W. Taylor
             management
                                                Frank and Lillian
Scientific Time and motion studies      1911    Gilbreth
Management Activity scheduling chart    1912    Henry Gantt
           Moving assembly line         1913    Henry Ford




                                                                    1-15
Historical Events in
      Operations Management (cont.)
Era          Events/Concepts         Dates    Originator
             Hawthorne studies       1930     Elton Mayo
Human                                1940s    Abraham Maslow
Relations    Motivation theories     1950s    Frederick Herzberg
                                     1960s    Douglas McGregor
             Linear programming      1947     George Dantzig
             Digital computer        1951     Remington Rand
             Simulation, waiting
Operations                                    Operations research
             line theory, decision   1950s
Research                                      groups
             theory, PERT/CPM
                                     1960s,   Joseph Orlicky, IBM
             MRP, EDI, EFT, CIM
                                     1970s    and others

                                                               1-16
Historical Events in
       Operations Management (cont.)
Era         Events/Concepts Dates Originator
           JIT (just-in-time)   1970s   Taiichi Ohno (Toyota)
           TQM (total quality           W. Edwards Deming,
                                1980s
           management)                  Joseph Juran
Quality    Strategy and                 Wickham Skinner,
                                1980s
Revolution operations                   Robert Hayes
           Business process             Michael Hammer,
                                1990s
           reengineering                James Champy
            Six Sigma           1990s   GE, Motorola




                                                                1-17
Historical Events in
       Operations Management (cont.)
Era           Events/Concepts          Dates Originator
Internet      Internet, WWW, ERP,     1990s     ARPANET, Tim
Revolution    supply chain management           Berners-Lee SAP,
                                                i2 Technologies,
                                                ORACLE
              E-commerce               2000s    Amazon, Yahoo,
                                                eBay, Google, and
                                                others
Globalization WTO, European Union,      1990s   Numerous countries
              and other trade           2000s   and companies
              agreements, global supply
              chains, outsourcing, BPO,
              Services Science
                                                               1-18
Evolution of Operations and
  Supply Chain Management (cont.)
Supply chain management
   management of the flow of information, products, and services across
   a network of customers, enterprises, and supply chain partners




                                                                      1-19
Globalization and
Competitiveness
Why “go global”?
  favorable cost
  access to international markets
  response to changes in demand
  reliable sources of supply
  latest trends and technologies
Increased globalization
  results from the Internet and falling trade
  barriers

                                                1-20
Globalization and
Competitiveness (cont.)




   Hourly Compensation Costs for Production Workers
       Source: U.S. Bureau of Labor Statistics, 2005.
                                                        1-21
Globalization and
Competitiveness (cont.)




        World Population Distribution
       Source: U.S. Census Bureau, 2006.
                                           1-22
Globalization and
   Competitiveness (cont.)




                       Trade in Goods as % of GDP
(sum of merchandise exports and imports divided by GDP, valued in U.S. dollars)
                                                                             1-23
Productivity and
 Competitiveness
Competitiveness
  degree to which a nation can produce goods and
  services that meet the test of international
  markets
Productivity
  ratio of output to input
Output
  sales made, products produced, customers
  served, meals delivered, or calls answered
Input
  labor hours, investment in equipment, material
  usage, or square footage


                                                   1-24
Productivity and
Competitiveness (cont.)




      Measures of Productivity


                                 1-25
Productivity and
Competitiveness (cont.)




  Average Annual Growth Rates in Productivity, 1995-2005.
                                                   1995-
       Source: Bureau of Labor Statistics. A Chartbook of
     International Labor Comparisons. January 2007, p. 28.
                                                             1-26
Productivity and
        Competitiveness (cont.)




Average Annual Growth Rates in Output and Input, 1995-2005
                                                       1995-       Dramatic Increase in
Source: Bureau of Labor Statistics. A Chartbook of International   Output w/ Decrease in
   Labor Comparisons, January 2007, p. 26.
                                                                       Labor Hours
                                                                                    1-27
Productivity and
 Competitiveness (cont.)

Retrenching
  productivity is increasing, but both output and input
  decrease with input decreasing at a faster rate
Assumption that more input would cause
output to increase at the same rate
  certain limits to the amount of output may not be
  considered
  output produced is emphasized, not output sold;
                                              sold;
  increased inventories

                                                      1-28
Strategy and Operations

Strategy
  Provides direction for achieving a mission
Five Steps for Strategy Formulation
  Defining a primary task
     What is the firm in the business of doing?
  Assessing core competencies
     What does the firm do better than anyone else?
  Determining order winners and order qualifiers
     What qualifies an item to be considered for purchase?
     What wins the order?
  Positioning the firm
     How will the firm compete?
  Deploying the strategy

                                                             1-29
Strategic Planning
             Mission
            and Vision


            Corporate
             Strategy



Marketing   Operations   Financial
Strategy     Strategy    Strategy
                                     1-30
Order Winners
and Order Qualifiers




Source: Adapted from Nigel Slack, Stuart Chambers, Robert Johnston, and Alan
      Betts, Operations and Process Management, Prentice Hall, 2006, p. 47
                                     Management,

                                                                               1-31
Positioning the Firm

Cost
Speed
Quality
Flexibility




                       1-32
Positioning the Firm:
 Cost
Waste elimination
  relentlessly pursuing the removal of all waste
Examination of cost structure
  looking at the entire cost structure for
  reduction potential
Lean production
  providing low costs through disciplined
  operations




                                                   1-33
Positioning the Firm:
 Speed
fast moves, fast adaptations, tight linkages
Internet
   conditioned customers to expect immediate responses
Service organizations
   always competed on speed (McDonald’s, LensCrafters, and
   Federal Express)
Manufacturers
   time-
   time-based competition: build-to-order production and
                           build-to-
   efficient supply chains
Fashion industry
   two-
   two-week design-to-rack lead time of Spanish retailer, Zara
            design-to-



                                                                 1-34
Positioning the Firm:
  Quality
Minimizing defect rates or conforming to
design specifications; please the customer
Ritz-
Ritz-Carlton - one customer at a time
  Service system is designed to “move heaven
  and earth” to satisfy customer
  Every employee is empowered to satisfy a
  guest’s wish
  Teams at all levels set objectives and devise
  quality action plans
  Each hotel has a quality leader

                                                  1-35
Positioning the Firm:
 Flexibility
ability to adjust to changes in product mix,
production volume, or design
National Bicycle Industrial Company
  offers 11,231,862 variations
  delivers within two weeks at costs only 10%
  above standard models
  mass customization: the mass production of
         customization:
  customized parts




                                                1-36
Policy Deployment

Policy deployment
  translates corporate strategy into measurable
  objectives
Hoshins
  action plans generated from the policy
  deployment process




                                                  1-37
Policy Deployment




  Derivation of an Action Plan Using Policy Deployment
                                                         1-38
Balanced Scorecard

Balanced scorecard
  measuring more than financial performance
    finances
    customers
    processes
    learning and growing
Key performance indicators
  a set of measures that help managers evaluate
  performance in critical areas

                                                  1-39
Balanced Scorecard
Balanced Scorecard Worksheet




                                 1-40
Balanced Scorecard




Radar Chart      Dashboard


                             1-41
Operations Strategy

                  Services      Process
                                  and
      Products
                               Technology

                   Human
                   Resources      Quality
   Capacity




  Facilities     Sourcing         Operating
                                  Systems




                                              1-42
Chapter 1 Supplement

        Decision Analysis

          Operations Management

 Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Decision Analysis
Decision Making without Probabilities
Decision Analysis with Excel
Decision Analysis with OM Tools
Decision Making with Probabilities
Expected Value of Perfect Information
Sequential Decision Tree

                                        Supplement 1-44
                                                   1-
Decision Analysis

Quantitative methods
  a set of tools for operations manager
Decision analysis
  a set of quantitative decision-making
                        decision-
  techniques for decision situations in which
  uncertainty exists
  Example of an uncertain situation
    demand for a product may vary between 0 and 200
    units, depending on the state of market


                                                Supplement 1-45
                                                           1-
Decision Making
Without Probabilities
States of nature
  Events that may occur in the future
  Examples of states of nature:
     high or low demand for a product
     good or bad economic conditions
Decision making under risk
  probabilities can be assigned to the occurrence of
  states of nature in the future
Decision making under uncertainty
  probabilities can NOT be assigned to the
  occurrence of states of nature in the future

                                                   Supplement 1-46
                                                              1-
Payoff Table
Payoff table
  method for organizing and illustrating payoffs from different
  decisions given various states of nature
Payoff
  outcome of a decision

                States Of Nature
   Decision    a             b
      1     Payoff 1a     Payoff 1b
      2     Payoff 2a     Payoff 2b

                                                        Supplement 1-47
                                                                   1-
Decision Making Criteria Under
Uncertainty

 Maximax
   choose decision with the maximum of the
   maximum payoffs
 Maximin
   choose decision with the maximum of the
   minimum payoffs
 Minimax regret
   choose decision with the minimum of the
   maximum regrets for each alternative

                                        Supplement 1-48
                                                   1-
Decision Making Criteria Under
 Uncertainty (cont.)

Hurwicz
  choose decision in which decision payoffs are
  weighted by a coefficient of optimism, alpha
  coefficient of optimism is a measure of a
  decision maker’s optimism, from 0 (completely
  pessimistic) to 1 (completely optimistic)
Equal likelihood (La Place)
  choose decision in which each state of nature is
  weighted equally

                                             Supplement 1-49
                                                        1-
Southern Textile
        Company

                                   STATES OF NATURE
                          Good Foreign             Poor Foreign
DECISION              Competitive Conditions   Competitive Conditions

Expand                    $ 800,000                $ 500,000
Maintain status quo       1,300,000                 -150,000
Sell now                    320,000                  320,000




                                                          Supplement 1-50
                                                                     1-
Maximax Solution
                                   STATES OF NATURE
                          Good Foreign              Poor Foreign
DECISION              Competitive Conditions    Competitive Conditions

Expand                    $ 800,000                 $ 500,000
Maintain status quo       1,300,000                  -150,000
Sell now                    320,000                   320,000


   Expand:               $800,000
   Status quo:           1,300,000     ← Maximum
   Sell:                   320,000
                                      Decision: Maintain status quo

                                                         Supplement 1-51
                                                                    1-
Maximin Solution
                                   STATES OF NATURE
                          Good Foreign             Poor Foreign
DECISION              Competitive Conditions   Competitive Conditions

Expand                    $ 800,000                $ 500,000
Maintain status quo       1,300,000                 -150,000
Sell now                    320,000                  320,000


   Expand:                $500,000     ← Maximum
   Status quo:            -150,000
   Sell:                   320,000
                                                Decision: Expand

                                                        Supplement 1-52
                                                                   1-
Minimax Regret Solution
Good Foreign                    Poor Foreign
Competitive Conditions           Competitive Conditions


$1,300,000 - 800,000 = 500,000     $500,000 - 500,000 = 0
1,300,000 - 1,300,000 = 0     500,000 - (-150,000)= 650,000
1,300,000 - 320,000 = 980,000     500,000 - 320,000= 180,000



    Expand:                 $500,000   ← Minimum
    Status quo:              650,000
    Sell:                    980,000
                                               Decision: Expand

                                                       Supplement 1-53
                                                                  1-
Hurwicz Criteria
                                   STATES OF NATURE
                          Good Foreign             Poor Foreign
DECISION              Competitive Conditions   Competitive Conditions

Expand                    $ 800,000                $ 500,000
Maintain status quo       1,300,000                 -150,000
Sell now                    320,000                  320,000
   α = 0.3               1 - α = 0.7

   Expand: $800,000(0.3) + 500,000(0.7) = $590,000 ← Maximum
   Status quo: 1,300,000(0.3) -150,000(0.7) = 285,000
   Sell: 320,000(0.3) + 320,000(0.7) = 320,000
                                                  Decision: Expand

                                                        Supplement 1-54
                                                                   1-
Equal Likelihood Criteria
                                   STATES OF NATURE
                          Good Foreign             Poor Foreign
DECISION              Competitive Conditions   Competitive Conditions

Expand                    $ 800,000                $ 500,000
Maintain status quo       1,300,000                 -150,000
Sell now                    320,000                  320,000

   Two states of nature each weighted 0.50
   Expand: $800,000(0.5) + 500,000(0.5) = $650,000 ← Maximum
   Status quo: 1,300,000(0.5) -150,000(0.5) = 575,000
   Sell: 320,000(0.5) + 320,000(0.5) = 320,000
                                                  Decision: Expand

                                                        Supplement 1-55
                                                                   1-
Decision Analysis with
Excel




                         Supplement 1-56
                                    1-
Decision Analysis with
OM Tools




                         Supplement 1-57
                                    1-
Decision Making with
 Probabilities

Risk involves assigning probabilities to
states of nature
Expected value
  a weighted average of decision outcomes in
  which each future state of nature is
  assigned a probability of occurrence




                                           Supplement 1-58
                                                      1-
Expected value

                           n
         EV (x) =
             (x
         p(xi)xi          ∑
                          i =1

where

           xi = outcome i
        p(xi) = probability of outcome i




                                           Supplement 1-59
                                                      1-
Decision Making with
     Probabilities: Example
                                    STATES OF NATURE
                           Good Foreign                  Poor Foreign
DECISION               Competitive Conditions     Competitive Conditions

Expand                      $ 800,000                    $ 500,000
Maintain status quo         1,300,000                     -150,000
Sell now                      320,000                      320,000

                   p(good) = 0.70       p(poor) = 0.30
      EV(expand): $800,000(0.7) + 500,000(0.3) = $710,000
      EV(status quo): 1,300,000(0.7) -150,000(0.3) = 865,000 ← Maximum
      EV(sell):   320,000(0.7) + 320,000(0.3) = 320,000

                                                Decision: Status quo

                                                             Supplement 1-60
                                                                        1-
Decision Making with
Probabilities: Excel




                       Supplement 1-61
                                  1-
Expected Value of
Perfect Information
EVPI
 maximum value of perfect information to
 the decision maker
 maximum amount that would be paid to
 gain information that would result in a
 decision better than the one made
 without perfect information


                                    Supplement 1-62
                                               1-
EVPI Example
Good conditions will exist 70% of the time
    choose maintain status quo with payoff of $1,300,000
Poor conditions will exist 30% of the time
    choose expand with payoff of $500,000
Expected value given perfect information
       = $1,300,000 (0.70) + 500,000 (0.30)
       = $1,060,000
Recall that expected value without perfect
information was $865,000 (maintain status quo)

EVPI=
EVPI= $1,060,000 - 865,000 = $195,000


                                                     Supplement 1-63
                                                                1-
Sequential
Decision Trees
A graphical method for analyzing
decision situations that require a
sequence of decisions over time
Decision tree consists of
   Square nodes - indicating decision points
   Circles nodes - indicating states of nature
   Arcs - connecting nodes



                                       Supplement 1-64
                                                  1-
Evaluations at Nodes

Compute EV at nodes 6 & 7
    EV(node 6)= 0.80($3,000,000) + 0.20($700,000) = $2,540,000
    EV(     6)=
    EV(node 7)= 0.30($2,300,000) + 0.70($1,000,000)= $1,390,000
    EV(     7)=
Decision at node 4 is between
            $2,540,000 for Expand and
            $450,000 for Sell land
Choose Expand
Repeat expected value calculations and decisions at
remaining nodes



                                                      Supplement 1-65
                                                                 1-
Decision Tree Analysis
      $1,290,000                                                               $2,000,000
                     0.60            Market growth
                 2
                       0.40
                                               $225,000
                                                                               $3,000,000
                                                           $2,540,000
                                                                   0.80
                              $1,740,000                      6
                                                                                 $700,000
                                                                   0.20
1   $1,160,000                             4


                                                              $450,000
                          0.60                                                 $2,300,000
                                                          $1,390,000
                 3
                          0.40
                                                                  0.30
                                   $790,000                   7
          $1,360,000
                                                                   0.70        $1,000,000
                                           5


                                                               $210,000
                                                                          Supplement 1-66
                                                                                     1-
Chapter 2

     Quality Management

         Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

What Is Quality?       Quality in Service
Evolution of Quality   Companies
Management             Six Sigma
Quality Tools          Cost of Quality
TQM and QMS            Effect of Quality
Focus of Quality       Management on
Management—
Management—            Productivity
Customers              Quality Awards
Role of Employees in   ISO 9000
Quality Improvement
                                            2-68
What Is Quality?

Oxford American Dictionary
  a degree or level of excellence
American Society for Quality
  totality of features and characteristics
  that satisfy needs without deficiencies
Consumer’s and producer’s
perspective


                                             2-69
What Is Quality:
  Customer’s Perspective
Fitness for use
   how well product or
   service does what it is
   supposed to
Quality of design
    designing quality
    characteristics into a
    product or service
A Mercedes and a Ford are
equally “fit for use,” but with
different design dimensions.


                                  2-70
Dimensions of Quality:
  Manufactured Products
Performance
  basic operating characteristics of a product; how
  well a car handles or its gas mileage
Features
  “extra” items added to basic features, such as a
  stereo CD or a leather interior in a car
Reliability
  probability that a product will operate properly
  within an expected time frame; that is, a TV will
  work without repair for about seven years


                                                      2-71
Dimensions of Quality:
Manufactured Products (cont.)
Conformance
  degree to which a product meets pre–established
                                  pre–
  standards
Durability
  how long product lasts before replacement; with
  care, L.L.Bean boots may last a lifetime
Serviceability
  ease of getting repairs, speed of repairs, courtesy
  and competence of repair person


                                                   2-72
Dimensions of Quality:
Manufactured Products (cont.)
Aesthetics
  how a product looks, feels, sounds,
  smells, or tastes
Safety
  assurance that customer will not suffer
  injury or harm from a product; an
  especially important consideration for
  automobiles
Perceptions
  subjective perceptions based on brand
  name, advertising, and like

                                            2-73
Dimensions of Quality:
Services

Time and timeliness
  how long must a customer wait for service,
  and is it completed on time?
  is an overnight package delivered overnight?
Completeness:
  is everything customer asked for provided?
  is a mail order from a catalogue company
  complete when delivered?


                                                 2-74
Dimensions of Quality:
Service (cont.)
Courtesy:
  how are customers treated by employees?
  are catalogue phone operators nice and are
  their voices pleasant?
Consistency
  is same level of service provided to each
  customer each time?
  is your newspaper delivered on time every
  morning?


                                               2-75
Dimensions of Quality:
 Service (cont.)
Accessibility and convenience
  how easy is it to obtain service?
  does service representative answer you calls quickly?
Accuracy
  is service performed right every time?
  is your bank or credit card statement correct every month?
Responsiveness
  how well does company react to unusual situations?
  how well is a telephone operator able to respond to a
  customer’s questions?



                                                               2-76
What Is Quality:
 Producer’s Perspective

Quality of conformance
  making sure product or service is produced
  according to design
    if new tires do not conform to specifications, they
    wobble
    if a hotel room is not clean when a guest checks
    in, hotel is not functioning according to
    specifications of its design


                                                     2-77
Meaning of Quality




                     2-78
What Is Quality:
 A Final Perspective

Customer’s and producer’s perspectives
depend on each other
Producer’s perspective:
  production process and COST
Customer’s perspective:
  fitness for use and PRICE
Customer’s view must dominate


                                         2-79
Evolution of Quality Management:
Quality Gurus
Walter Shewart
  In 1920s, developed control charts
  Introduced term “quality assurance”
                  “quality
W. Edwards Deming
  Developed courses during World War II to teach
  statistical quality-control techniques to engineers and
              quality-
  executives of companies that were military suppliers
  After war, began teaching statistical quality control to
  Japanese companies
Joseph M. Juran
  Followed Deming to Japan in 1954
  Focused on strategic quality planning
  Quality improvement achieved by focusing on projects
  to solve problems and securing breakthrough solutions
                                                             2-80
Evolution of Quality Management:
 Quality Gurus (cont.)
Armand V. Feigenbaum
  In 1951, introduced concepts of total quality control
  and continuous quality improvement
Philip Crosby
  In 1979, emphasized that costs of poor quality far
  outweigh cost of preventing poor quality
  In 1984, defined absolutes of quality management—
                                        management—
  conformance to requirements, prevention, and “zero
  defects”
Kaoru Ishikawa
  Promoted use of quality circles
  Developed “fishbone” diagram
  Emphasized importance of internal customer

                                                          2-81
Deming’s 14 Points

 1. Create constancy of purpose
2. Adopt philosophy of prevention
    3. Cease mass inspection
4. Select a few suppliers based on
                quality
5. Constantly improve system and
               workers
                                     2-82
Deming’s 14 Points (cont.)

6. Institute worker training
7. Instill leadership among
    supervisors
8. Eliminate fear among employees
9. Eliminate barriers between
    departments
10. Eliminate slogans
                                    2-83
Deming’s 14 Points (cont.)

11. Remove numerical quotas
12. Enhance worker pride
13. Institute vigorous training and
    education programs
14. Develop a commitment from top
    management to implement
    above 13 points
                                      2-84
Deming Wheel: PDCA Cycle




                           2-85
Quality Tools


Process Flow      Histogram
Chart             Scatter Diagram
Cause-and-
Cause-and-        Statistical Process
Effect Diagram    Control Chart
Check Sheet
Pareto Analysis


                                        2-86
Flow Chart




             2-87
Cause-and-
  Cause-and-Effect Diagram
Cause-and-
Cause-and-effect diagram (“fishbone” diagram)
  chart showing different categories of problem causes




                                                         2-88
Cause-and-
 Cause-and-Effect Matrix
Cause-and-
Cause-and-effect matrix
  grid used to prioritize causes of quality problems




                                                       2-89
Check Sheets and Histograms




                              2-90
Pareto Analysis

Pareto analysis
  most quality problems result from a few causes




                                                   2-91
Pareto Chart




               2-92
Scatter Diagram




                  2-93
Control Chart




                2-94
TQM and QMS

Total Quality Management (TQM)
 customer-
 customer-oriented, leadership, strategic
 planning, employee responsibility,
 continuous improvement, cooperation,
 statistical methods, and training and
 education
Quality Management System (QMS)
 system to achieve customer satisfaction
 that complements other company
 systems
                                        2-95
Focus of Quality Management—
                  Management—
 Customers
TQM and QMSs
 serve to achieve customer satisfaction
Partnering
 a relationship between a company and
 its supplier based on mutual quality
 standards
Measuring customer satisfaction
 important component of any QMS
 customer surveys, telephone interviews

                                          2-96
Role of Employees in
 Quality Improvement
Participative
problem solving
  employees involved in
  quality-
  quality-management
  every employee has
  undergone extensive
  training to provide quality
  service to Disney’s guests
Kaizen
  involves everyone in
  process of continuous
  improvement

                                2-97
Quality Circles
     and QITs
                                               Organization
                                               8-10 members
                                                 Same area
Quality circle                              Supervisor/moderator

   group of workers
                                                                      Training
   and supervisors        Presentation                             Group processes
                          Implementation                            Data collection
   from same area           Monitoring                             Problem analysis
   who address
   quality problems
Process/Quality                                                      Problem
improvement teams           Solution
                          Problem results
                                                                   Identification
                                                                   List alternatives
(QITs)                                                               Consensus
                                                                    Brainstorming
                                                 Problem
   focus attention on                            Analysis
   business processes                         Cause and effect
                                               Data collection
   rather than separate                         and analysis

   company functions
                                                                                 2-98
Quality in Services

Service defects are not always easy
to measure because service output
is not usually a tangible item
Services tend to be labor intensive
Services and manufacturing
companies have similar inputs but
different processes and outputs


                                      2-99
Quality Attributes in
 Services
Principles of TQM apply
equally well to services
and manufacturing
Timeliness
  how quickly a service is
  provided?
Benchmark
  “best” level of quality     “quickest, friendliest, most
  achievement in one                    accurate service
  company that other                           available.”
  companies seek to achieve

                                                   2-100
Six Sigma

A process for developing and delivering
virtually perfect products and services
Measure of how much a process
deviates from perfection
3.4 defects per million opportunities
Six Sigma Process
  four basic steps of Six Sigma—align,
                          Sigma—
  mobilize, accelerate, and govern
Champion
  an executive responsible for project success

                                                 2-101
Six Sigma:
         Breakthrough Strategy—DMAIC
                      Strategy—
DEFINE      MEASURE   ANALYZE    IMPROVE   CONTROL




                                              3.4 DPMO




                 67,000 DPMO
                 cost = 25% of
                     sales
                                                  2-102
Six Sigma:
 Black Belts and
 Green Belts

Black Belt
  project leader
Master Black Belt
  a teacher and mentor
  for Black Belts
Green Belts
  project team
  members


                         2-103
Six Sigma

Design for Six Sigma (DFSS)
  a systematic approach to designing products and
  processes that will achieve Six Sigma
Profitability
  typical criterion for selection Six Sigma project
  one of the factors distinguishing Six Sigma from
  TQM
  “Quality is not only free, it is an
  honest-to-
  honest-to-everything profit maker.”

                                                      2-104
Cost of Quality

Cost of Achieving Good Quality
 Prevention costs
    costs incurred during product design
 Appraisal costs
    costs of measuring, testing, and analyzing
Cost of Poor Quality
 Internal failure costs
    include scrap, rework, process failure, downtime,
    and price reductions
 External failure costs
    include complaints, returns, warranty claims,
    liability, and lost sales

                                                        2-105
Prevention Costs

Quality planning costs      Training costs
  costs of developing and     costs of developing and
  implementing quality        putting on quality training
  management program
                              programs for employees
Product-
Product-design costs          and management
  costs of designing        Information costs
  products with quality
  characteristics             costs of acquiring
Process costs                 and maintaining data
                              related to quality, and
  costs expended to make
  sure productive process     development and
  conforms to quality         analysis of reports on
  specifications              quality performance


                                                        2-106
Appraisal Costs

Inspection and testing
  costs of testing and inspecting materials, parts, and
  product at various stages and at end of process
Test equipment costs
  costs of maintaining equipment used in testing
  quality characteristics of products
Operator costs
  costs of time spent by operators to gather data for
  testing product quality, to make equipment
  adjustments to maintain quality, and to stop work to
  assess quality



                                                          2-107
Internal Failure Costs

Scrap costs                      Process downtime costs
  costs of poor-quality
           poor-
  products that must be            costs of shutting down
  discarded, including labor,      productive process to fix
  material, and indirect costs     problem
Rework costs                     Price-
                                 Price-downgrading costs
  costs of fixing defective
  products to conform to           costs of discounting poor-
                                                        poor-
  quality specifications           quality products—that is,
                                           products—
Process failure costs              selling products as
  costs of determining why         “seconds”
  production process is
  producing poor-quality
             poor-
  products

                                                          2-108
External Failure Costs

Customer complaint costs            Product liability costs
  costs of investigating and           litigation costs
  satisfactorily responding to a       resulting from product
  customer complaint resulting
  from a poor-quality product
         poor-                         liability and customer
                                       injury
Product return costs
  costs of handling and replacing   Lost sales costs
  poor-
  poor-quality products returned       costs incurred
  by customer                          because customers
Warranty claims costs                  are dissatisfied with
  costs of complying with              poor-
                                       poor-quality products
  product warranties                   and do not make
                                       additional purchases


                                                          2-109
Measuring and
Reporting Quality Costs
Index numbers
  ratios that measure quality costs against a
  base value
  labor index
     ratio of quality cost to labor hours
  cost index
     ratio of quality cost to manufacturing cost
  sales index
     ratio of quality cost to sales
  production index
     ratio of quality cost to units of final product


                                                       2-110
Quality–
Quality–Cost Relationship

Cost of quality
  difference between price of
  nonconformance and conformance
  cost of doing things wrong
    20 to 35% of revenues
  cost of doing things right
    3 to 4% of revenues


                                   2-111
Effect of Quality
         Management on Productivity
       Productivity
           ratio of output to input
       Quality impact on productivity
          fewer defects increase output, and quality
          improvement reduces inputs
       Yield
          a measure of productivity
Yield=(total input)(% good units) + (total input)(1-%good units)(% reworked)


                                     or
                         Y=(I)(%G)+(I)(1-
                         Y=(I)(%G)+(I)(1-%G)(%R)

                                                                        2-112
Computing Product
Cost per Unit

                    (Kd )(I) +(Kr )(R)
 Product Cost
                  =
                            Y
                         where:
        Kd = direct manufacturing cost per unit
                        I = input
                Kr = rework cost per unit
                   R = reworked units
                        Y = yield



                                                  2-113
Computing Product Yield
for Multistage Processes

        Y = (I)(%g1)(%g2) … (%gn)


                             where:
  I = input of items to the production process that will
                 result in finished products
 gi = good-quality, work-in-process products at stage i




                                                           2-114
Quality–
        Quality–Productivity Ratio

   QPR
         productivity index that includes productivity and
         quality costs


                          (good-quality units)
QPR =                                                                (100)
        (input) (processing cost) + (reworked units) (rework cost)




                                                                     2-115
Malcolm Baldrige Award

Created in 1987 to stimulate growth of
quality management in United States
Categories
  Leadership
  Information and analysis
  Strategic planning
  Human resource focus
  Process management
  Business results
  Customer and market focus
                                         2-116
Other Awards for Quality

National individual          International awards
awards                         European Quality Award
   Armand V. Feigenbaum        Canadian Quality Award
   Medal                       Australian Business
   Deming Medal                Excellence Award
   E. Jack Lancaster Medal     Deming Prize from Japan
   Edwards Medal
   Shewart Medal
   Ishikawa Medal




                                                    2-117
ISO 9000

A set of procedures and        ISO 9001:2000
policies for international       Quality Management
quality certification of         Systems—
                                 Systems—Requirements
suppliers                        standard to assess ability to
Standards                        achieve customer satisfaction
   ISO 9000:2000               ISO 9004:2000
     Quality Management          Quality Management
     Systems—Fundamentals
     Systems—                    Systems—
                                 Systems—Guidelines for
     and Vocabulary              Performance Improvements
     defines fundamental         guidance to a company for
     terms and definitions       continual improvement of its
     used in ISO 9000 family     quality-
                                 quality-management system



                                                         2-118
ISO 9000 Certification,
 Implications, and Registrars

ISO 9001:2000—only
      9001:2000—
standard that carries third-
                      third-
party certification
Many overseas companies
will not do business with a
supplier unless it has ISO
9000 certification
ISO 9000 accreditation
ISO registrars


                                2-119
Chapter 3

 Statistical Process Control

         Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Basics of Statistical Process Control
Control Charts
Control Charts for Attributes
Control Charts for Variables
Control Chart Patterns
SPC with Excel and OM Tools
Process Capability

                                        3-121
Basics of Statistical
    Process Control
Statistical Process Control
(SPC)
   monitoring production process
   to detect and prevent poor      UCL
   quality
Sample
   subset of items produced to
   use for inspection              LCL
Control Charts
   process is within statistical
   control limits


                                         3-122
Basics of Statistical
  Process Control (cont.)
Random                    Non-
                          Non-Random
 inherent in a process     special causes
 depends on equipment      identifiable and
 and machinery,            correctable
 engineering, operator,    include equipment out of
 and system of             adjustment, defective
 measurement               materials, changes in
 natural occurrences       parts or materials, broken
                           machinery or equipment,
                           operator fatigue or poor
                           work methods, or errors
                           due to lack of training
                                                 3-123
SPC in Quality Management

SPC
 tool for identifying problems in
 order to make improvements
 contributes to the TQM goal of
 continuous improvements




                                    3-124
Quality Measures:
 Attributes and Variables

Attribute
  a product characteristic that can be
  evaluated with a discrete response
  good – bad; yes - no
Variable measure
  a product characteristic that is continuous
  and can be measured
  weight - length

                                                3-125
SPC Applied to
  Services

Nature of defect is different in services
Service defect is a failure to meet
customer requirements
Monitor time and customer satisfaction




                                            3-126
SPC Applied to
 Services (cont.)
Hospitals
   timeliness and quickness of care, staff responses to requests,
   accuracy of lab tests, cleanliness, courtesy, accuracy of
   paperwork, speed of admittance and checkouts
Grocery stores
   waiting time to check out, frequency of out-of-stock items,
                                            out-of-
   quality of food items, cleanliness, customer complaints,
   checkout register errors
Airlines
   flight delays, lost luggage and luggage handling, waiting time
   at ticket counters and check-in, agent and flight attendant
                           check-
   courtesy, accurate flight information, passenger cabin
   cleanliness and maintenance


                                                                 3-127
SPC Applied to
 Services (cont.)
Fast-
Fast-food restaurants
  waiting time for service, customer complaints,
  cleanliness, food quality, order accuracy, employee
  courtesy
Catalogue-
Catalogue-order companies
  order accuracy, operator knowledge and courtesy,
  packaging, delivery time, phone order waiting time
Insurance companies
  billing accuracy, timeliness of claims processing,
  agent availability and response time



                                                        3-128
Where to Use Control Charts

Process has a tendency to go out of control
Process is particularly harmful and costly if it
goes out of control
Examples
   at the beginning of a process because it is a waste of
   time and money to begin production process with bad
   supplies
   before a costly or irreversible point, after which
   product is difficult to rework or correct
   before and after assembly or painting operations that
   might cover defects
   before the outgoing final product or service is
   delivered

                                                            3-129
Control Charts

A graph that establishes     Types of charts
control limits of a
process                        Attributes
Control limits                   p-chart
  upper and lower bands of       c-chart
  a control chart
                               Variables
                                 mean (x bar – chart)
                                 range (R-chart)
                                       (R-



                                                  3-130
Process Control Chart
                               Out of control
 Upper
control
  limit

Process
average

 Lower
control
  limit


          1   2   3    4   5      6     7       8   9   10
                      Sample number

                                                        3-131
Normal Distribution




                       95%
                      99.74%
 - 3σ   - 2σ   - 1σ    µ=0     1σ   2σ   3σ


                                              3-132
A Process Is in
   Control If …

1. … no sample points outside limits
2. … most points near process average
3. … about equal number of points above
   and below centerline
4. … points appear randomly distributed




                                          3-133
Control Charts for
 Attributes

p-chart
  uses portion defective in a sample
c-chart
  uses number of defective items in
  a sample


                                       3-134
p-Chart

             UCL = p + zσp
             LCL = p - zσp
      z = number of standard deviations from
          process average
      p = sample proportion defective; an estimate
          of process average
     σp = standard deviation of sample proportion

                                 p(1 - p)
                       σp =
                                    n
                                                 3-135
Construction of p-Chart
                p-

               NUMBER OF       PROPORTION
    SAMPLE     DEFECTIVES       DEFECTIVE
       1             6              .06
       2             0              .00
       3             4              .04
       :             :                :
       :             :                :
      20            18              .18
                   200


     20 samples of 100 pairs of jeans

                                            3-136
Construction of p-Chart (cont.)
                p-

          total defectives
p=                                  = 200 / 20(100) = 0.10
     total sample observations

                p(1 - p)                  0.10(1 - 0.10)
 UCL = p + z                = 0.10 + 3
                   n                            100
 UCL = 0.190

               p(1 - p)                  0.10(1 - 0.10)
 LCL = p - z               = 0.10 - 3
                  n                           100
 LCL = 0.010


                                                             3-137
0.20

                                      0.18              UCL = 0.190

                                      0.16

Construction                          0.14




               Proportion defective
of p-Chart
   p-                                 0.12
                                             p = 0.10

(cont.)                               0.10

                                      0.08

                                      0.06

                                      0.04

                                      0.02              LCL = 0.010


                                                2       4    6     8   10   12 14   16   18     20
                                                                  Sample number


                                                                                              3-138
c-Chart


UCL = c + zσc
                           σc =     c
LCL = c - zσc

where

        c = number of defects per sample




                                           3-139
c-Chart (cont.)
Number of defects in 15 sample rooms
         NUMBER
           OF
SAMPLE
         DEFECTS                            190
 1       12                            c=         = 12.67
                                            15
 2        8
 3       16                   UCL = c + zσc
                                  = 12.67 + 3         12.67
 :             :                  = 23.35
 :             :
                              LCL      = c - zσ c
 15       15
                                       = 12.67 - 3   12.67
         190
                                       = 1.99


                                                              3-140
24
                                           UCL = 23.35
                              21


                              18




          Number of defects
                                       c = 12.67

                              15
c-Chart                       12
(cont.)                       9


                              6


                              3            LCL = 1.99



                                   2        4      6     8    10   12   14   16
                                                   Sample number



                                                                                  3-141
Control Charts for
Variables
Range chart ( R-Chart )
              R-
   uses amount of dispersion in a
   sample
Mean chart ( x -Chart )
   uses process average of a
   sample



                                    3-142
x-bar Chart:
Standard Deviation Known
         =
   UCL = x + zσx               LCL = = - zσx
                                     x

  =         x1 + x2 + ... xn
  x =              n

where
        =
    x = average of sample means

                                               3-143
x-bar Chart Example:
Standard Deviation Known (cont.)




                               3-144
x-bar Chart Example:
Standard Deviation Known (cont.)




                               3-145
x-bar Chart Example:
Standard Deviation Unknown


      =
UCL = x + A2R             =
                    LCL = x - A2R



where

    x = average of sample means


                                    3-146
Control
Limits




          3-147
x-bar Chart Example:
         Standard Deviation Unknown
                 OBSERVATIONS (SLIP- RING DIAMETER, CM)
                              (SLIP-
      SAMPLE k    1      2      3      4      5      x       R
           1     5.02   5.01   4.94   4.99   4.96   4.98    0.08
           2     5.01   5.03   5.07   4.95   4.96   5.00    0.12
           3     4.99   5.00   4.93   4.92   4.99   4.97    0.08
           4     5.03   4.91   5.01   4.98   4.89   4.96    0.14
           5     4.95   4.92   5.03   5.05   5.01   4.99    0.13
           6     4.97   5.06   5.06   4.96   5.03   5.01    0.10
           7     5.05   5.01   5.10   4.96   4.99   5.02    0.14
           8     5.09   5.10   5.00   4.99   5.08   5.05    0.11
           9     5.14   5.10   4.99   5.08   5.09   5.08    0.15
          10     5.01   4.98   5.08   5.07   4.99   5.03    0.10
Example 15.4                                        50.09   1.15
                                                                   3-148
x-bar Chart Example:
Standard Deviation Unknown (cont.)
               ∑R               1.15
     R=            k     =       10      = 0.115


    =     ∑x           50.09 5.01 cm
    x=         =           =
           k            10


         =
 UCL = x + A2R = 5.01 + (0.58)(0.115) = 5.08

 LCL = x = A2R = 5.01 - (0.58)(0.115) = 4.94
         -

                   Retrieve Factor Value A2
                                                   3-149
5.10 –

                 5.08 –
                              UCL = 5.08

                 5.06 –

                 5.04 –
                              =
          Mean   5.02 –       x = 5.01

                 5.00 –

x- bar           4.98 –
Chart
                 4.96 –       LCL = 4.94
Example
(cont.)          4.94 –

                 4.92 –   |    |    |      |   |   |   |   |   |    |
                          1    2    3      4   5   6   7   8   9   10
                                         Sample number



                                                                        3-150
R- Chart

  UCL = D4R      LCL = D3R

                ∑R
           R=
                k
 where
     R = range of each sample
     k = number of samples

                                3-151
R-Chart Example
                OBSERVATIONS (SLIP-RING DIAMETER, CM)
                             (SLIP-
     SAMPLE k    1      2      3      4      5      x       R
          1     5.02   5.01   4.94   4.99   4.96   4.98    0.08
          2     5.01   5.03   5.07   4.95   4.96   5.00    0.12
          3     4.99   5.00   4.93   4.92   4.99   4.97    0.08
          4     5.03   4.91   5.01   4.98   4.89   4.96    0.14
          5     4.95   4.92   5.03   5.05   5.01   4.99    0.13
          6     4.97   5.06   5.06   4.96   5.03   5.01    0.10
          7     5.05   5.01   5.10   4.96   4.99   5.02    0.14
          8     5.09   5.10   5.00   4.99   5.08   5.05    0.11
          9     5.14   5.10   4.99   5.08   5.09   5.08    0.15
         10     5.01   4.98   5.08   5.07   4.99   5.03    0.10
Example 15.3                                       50.09   1.15
                                                                  3-152
R-Chart Example (cont.)


               UCL = D4R = 2.11(0.115) = 0.243

                  LCL = D3R = 0(0.115) = 0

                   Retrieve Factor Values D3 and D4




Example 15.3
                                                      3-153
R-Chart Example (cont.)
        0.28 –

        0.24 –   UCL = 0.243
        0.20 –
Range




        0.16 –     R = 0.115

        0.12 –

        0.08 –
                 LCL = 0
        0.04 –   |  |    |      |   |  |   |   |   |    |
                 1 2     3     4    5  6   7   8   9   10
           0–                Sample number

                                                            3-154
Using x- bar and R-Charts
        x-         R-
  Together


Process average and process variability must be in control
It is possible for samples to have very narrow ranges, but
their averages might be beyond control limits
It is possible for sample averages to be in control, but
ranges might be very large
It is possible for an R-chart to exhibit a distinct downward
                      R-
trend, suggesting some nonrandom cause is reducing
variation




                                                               3-155
Control Chart Patterns

Run
    sequence of sample values that display same characteristic
Pattern test
    determines if observations within limits of a control chart display a
    nonrandom pattern
To identify a pattern:
    8 consecutive points on one side of the center line
    8 consecutive points up or down
    14 points alternating up or down
    2 out of 3 consecutive points in zone A (on one side of center line)
    4 out of 5 consecutive points in zone A or B (on one side of center
    line)


                                                                  3-156
Control Chart Patterns (cont.)
UCL



                               UCL

LCL


      Sample observations
                               LCL
      consistently below the
      center line
                                     Sample observations
                                     consistently above the
                                     center line
                                                              3-157
Control Chart Patterns (cont.)
UCL



                                UCL

LCL


      Sample observations
      consistently increasing   LCL


                                      Sample observations
                                      consistently decreasing


                                                                3-158
Zones for Pattern Tests
   UCL                                                                       =
                                                                   3 sigma = x + A2R
                              Zone A
                                                                             = 2
                                                                   2 sigma = x +   (A2R)
                                                                                   (A
                                                                                 3
                              Zone B
                                                                             = 1
                                                                   1 sigma = x +   (A2R)
                                                                                   (A
                                                                                 3
                              Zone C
Process                                                            =
                                                                   x
average
                              Zone C
                                                                             = 1
                                                                   1 sigma = x - (A2R)
                                                                                3
                              Zone B
                                                                             = 2
                                                                   2 sigma = x - (A2R)
                                                                                3
                              Zone A
                                                                             =
   LCL                                                             3 sigma = x - A2R
          |   |   |   |   |   |   |    |   |    |    |    |    |
          1   2   3   4   5   6   7    8   9   10   11   12   13
                          Sample number
                                                                                       3-159
Performing a Pattern Test
SAMPLE    x     ABOVE/BELOW   UP/DOWN   ZONE

  1      4.98       B           —        B
  2      5.00       B           U        C
  3      4.95       B           D        A
  4      4.96       B           D        A
  5      4.99       B           U        C
  6      5.01       —           U        C
  7      5.02       A           U        C
  8      5.05       A           U        B
  9      5.08       A           U        A
 10      5.03       A           D        B




                                               3-160
Sample Size Determination



Attribute charts require larger sample sizes
     50 to 100 parts in a sample
Variable charts require smaller samples
     2 to 10 parts in a sample




                                               3-161
SPC with Excel




                 3-162
SPC with Excel and OM Tools




                              3-163
Process Capability

Tolerances
  design specifications reflecting product
  requirements
Process capability
  range of natural variability in a process—
                                    process—
  what we measure with control charts



                                               3-164
Process Capability (cont.)
                                      Design
                                   Specifications

(a) Natural variation
exceeds design
specifications; process
is not capable of
meeting specifications
all the time.
                                       Process
                                                       Design
                                                    Specifications

               (b) Design specifications
               and natural variation the
               same; process is capable
               of meeting specifications
               most of the time.

                                                       Process

                                                                     3-165
Process Capability (cont.)
                                       Design
                                    Specifications

(c) Design specifications
greater than natural
variation; process is
capable of always
conforming to
specifications.
                                        Process
                                                        Design
                                                     Specifications

               (d) Specifications greater
               than natural variation,
               but process off center;
               capable but some output
               will not meet upper
               specification.
                                                        Process

                                                                      3-166
Process Capability Measures

    Process Capability Ratio

            tolerance range
     Cp =
             process range

            upper specification limit -
               lower specification limit
        =
                          6σ

                                           3-167
Computing Cp
Net weight specification = 9.0 oz ± 0.5 oz
Process mean = 8.80 oz
Process standard deviation = 0.12 oz


            upper specification limit -
                     lower specification limit
   Cp =
                                 6σ


        =    9.5 - 8.5 = 1.39
             6(0.12)



                                                 3-168
Process Capability Measures

        Process Capability Index

                =
                    x - lower specification limit
                                 3σ
                                                    ,
Cpk = minimum
                                                         =
                         upper specification limit - x
                                      3σ




                                                             3-169
Computing Cpk
 Net weight specification = 9.0 oz ± 0.5 oz
 Process mean = 8.80 oz
 Process standard deviation = 0.12 oz

                   =
                    x - lower specification limit
                                                    ,
Cpk = minimum                   3σ                     =
                         upper specification limit - x
                                      3σ

                  8.80 - 8.50    9.50 - 8.80
   = minimum        3(0.12) ,      3(0.12)     = 0.83


                                                           3-170
Process Capability
with Excel




                     3-171
Process Capability
with Excel and OM Tools




                          3-172
Chapter 3 Supplement

     Acceptance Sampling

          Operations Management

 Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Single-
Single-Sample Attribute Plan
Operating Characteristic Curve
Developing a Sampling Plan with Excel
Average Outgoing Quality
Double - and Multiple-Sampling Plans
             Multiple-


                                Supplement 3-174
                                           3-
Acceptance Sampling

Accepting or rejecting a production lot based
on the number of defects in a sample
Not consistent with TQM or Zero Defects
philosophy
  producer and customer agree on the number of
  acceptable defects
  a means of identifying not preventing poor quality
  percent of defective parts versus PPM
Sampling plan
  provides guidelines for accepting a lot
                                            Supplement 3-175
                                                       3-
Single–
  Single–Sample
  Attribute Plan
Single sampling plan
  N = lot size
  n = sample size (random)
  c = acceptance number
  d = number of defective items in sample
If d ≤ c, accept lot; else reject



                                      Supplement 3-176
                                                 3-
Producer’s and
   Consumer’s Risk
AQL or acceptable quality level
  proportion of defects consumer will accept in
  a given lot
α or producer’s risk
  probability of rejecting a good lot
LTPD or lot tolerance percent defective
  limit on the number of defectives the
  customer will accept
β or consumer’s risk
  probability of accepting a bad lot

                                              Supplement 3-177
                                                         3-
Producer’s and
Consumer’s Risk (cont.)
              Accept                     Reject
Good Lot



                                   Type I Error
              No Error
                                  Producer’ Risk
Bad Lot




             Type II Error
                                    No Error
           Consumer’s Risk


                       Sampling Errors


                                                   Supplement 3-178
                                                              3-
Operating Characteristic
 (OC) Curve
shows probability of accepting lots of
different quality levels with a specific
sampling plan
assists management to discriminate
between good and bad lots
exact shape and location of the curve is
defined by the sample size (n) and
                              (n
acceptance level (c) for the sampling
                    (c
plan

                                      Supplement 3-179
                                                 3-
OC Curve (cont.)
     1.00 –
α = 0.05


                           0.80 –

   Probability of acceptance, Pa

                           0.60 –                                     OC curve for n and c



                           0.40 –




                           0.20 –

β = 0.10
                                        |         |     |    |    |    |     |   |   |   |
                                   –   0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20
                                                      Proportion defective
                                            AQL                              LTPD

                                                                                             Supplement 3-180
                                                                                                        3-
Developing a Sampling Plan
   with OM Tools

ABC Company produces mugs
in lots of 10,000. Performance
measures for quality of mugs
sent to stores call for a
producer’s risk of 0.05 with an
AQL of 1% defective and a
consumer’s risk of 0.10 with a    N = 10,000   n=?
LTPD of 5% defective. What        α = 0.05             c=
size sample and what              ?
acceptance number should
ABC use to achieve                β = 0.10
performance measures called       AQL = 1%
for in the sampling plan?         LTPD = 5%

                                                Supplement 3-181
                                                           3-
Average Outgoing
 Quality (AOQ)

Expected number of defective
items that will pass on to
customer with a sampling plan
Average outgoing quality limit
(AOQL)
  maximum point on the curve
  worst level of outgoing quality

                                    Supplement 3-182
                                               3-
AOQ Curve




            Supplement 3-183
                       3-
Double-
 Double-Sampling Plans

Take small initial sample
   If # defective ≤ lower limit, accept
   If # defective > upper limit, reject
   If # defective between limits, take second
   sample
Accept or reject based on 2 samples
Less costly than single-sampling plans
                 single-


                                       Supplement 3-184
                                                  3-
Multiple-
 Multiple-Sampling Plans

Uses smaller sample sizes
Take initial sample
   If # defective ≤ lower limit, accept
   If # defective > upper limit, reject
   If # defective between limits, resample
Continue sampling until accept or reject
lot based on all sample data

                                       Supplement 3-185
                                                  3-
Chapter 4

        Product Design
         Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Design Process
Concurrent Design
Technology in Design
Design Reviews
Design for Environment
Design for Robustness
Quality Function Deployment

                              4-187
Design Process

Effective design can provide a competitive
edge
   matches product or service characteristics with
   customer requirements
   ensures that customer requirements are met in the
   simplest and least costly manner
   reduces time required to design a new product or
   service
   minimizes revisions necessary to make a design
   workable

Copyright 2009 John Wiley & Sons, Inc.            4-188
Design Process (cont.)

Product design
  defines appearance of product
  sets standards for performance
  specifies which materials are to be used
  determines dimensions and tolerances




                                             4-189
Design Process (cont.)




                         4-190
Idea Generation

Company’s own         Salespersons in the
R&D department        field
Customer complaints   Factory workers
or suggestions        New technological
Marketing research    developments
Suppliers             Competitors



                                       4-191
Idea Generation (cont.)

Perceptual Maps
  Visual comparison of
  customer perceptions
Benchmarking
  Comparing product/process
  against best-in-class
          best-in-
Reverse engineering
  Dismantling competitor’s product to
  improve your own product


                                        4-192
Perceptual Map of
Breakfast Cereals




                    4-193
Feasibility Study


Market analysis
Economic analysis
Technical/strategic analyses
Performance specifications



                               4-194
Rapid Prototyping

 testing and revising a
 preliminary design model
 Build a prototype
   form design
   functional design
   production design
 Test prototype
 Revise design
 Retest

                            4-195
Form and Functional Design

                Form Design
                  how product will
                  look?
                Functional Design
                  how product will
                  perform?
                    reliability
                    maintainability
                    usability


                                      4-196
Computing Reliability


Components in series


  0.90           0.90   0.90 x 0.90 = 0.81




                                             4-197
Computing Reliability (cont.)

Components in parallel


          0.90
                 R2


          0.95           0.95 + 0.90(1-0.95) = 0.995
                                0.90(1-
                 R1




                                                       4-198
System Reliability

                         0.90



         0.98            0.92          0.98




  0.98          0.92+(1-
                0.92+(1-0.92)(0.90)=0.99      0.98



            0.98 x 0.99 x 0.98 = 0.951

                                                     4-199
System Availability (SA)


                     MTBF
      SA =
                MTBF + MTTR

      where:
      MTBF = mean time between failures
      MTTR = mean time to repair




                                          4-200
System Availability
(cont.)

PROVIDER         MTBF (HR)            MTTR (HR)
   A                 60                  4.0
   B                 36                  2.0
   C                 24                  1.0

 SAA = 60 / (60 + 4) = .9375 or 94%
 SAB = 36 / (36 + 2) = .9473 or 95%
 SAC = 24 / (24 + 1) = .96 or 96%




                                                  4-201
Usability

Ease of use of a product or service
  ease of learning
  ease of use
  ease of remembering how to use
  frequency and severity of errors
  user satisfaction with experience



                                      4-202
Production Design

How the product will be made
  Simplification
    reducing number of parts, assemblies, or options in a
    product
  Standardization
    using commonly available and interchangeable parts
  Modular Design
    combining standardized building blocks, or modules, to
    create unique finished products
  Design for Manufacture (DFM)
  • Designing a product so that it can be produced easily and
    economically
                                                             4-203
Design                          Source: Adapted from G. Boothroyd and
                                        P. Dewhurst, “Product Design…. Key to
                                      Successful Robotic Assembly.” Assembly
       Simplification                   Engineering (September 1986), pp. 90-
                                                                          90-
                                                                          93.

(a) Original design   (b) Revised design         (c) Final design




 Assembly using       One-
                      One-piece base &           Design for
 common fasteners     elimination of             push-and-
                                                 push-and-snap
                      fasteners                  assembly

                                                                    4-204
Final Design and Process Plans

Final design           Process plans
  detailed drawings      workable instructions
  and specifications       necessary equipment
  for new product or       and tooling
  service                  component sourcing
                           recommendations
                           job descriptions and
                           procedures
                           computer programs for
                           automated machines


                                               4-205
Design Team




              4-206
Concurrent Design

A new approach to           Involves suppliers
design that involves        Incorporates production
simultaneous design of      process
products and processes      Uses a price-minus
                                   price-
by design teams             system
                            Scheduling and
Improves quality of early   management can be
design decisions            complex as tasks are
                            done in parallel
                            Uses technology to aid
                            design


                                                 4-207
Technology in Design
Computer Aided Design (CAD)
  assists in creation, modification, and analysis of
  a design
  computer-
  computer-aided engineering (CAE)
    tests and analyzes designs on computer screen
  computer-
  computer-aided manufacturing (CAD/CAM)
    ultimate design-to-manufacture connection
             design-to-
  product life cycle management (PLM)
    managing entire lifecycle of a product
  collaborative product design (CPD)

                                                       4-208
Collaborative Product Design
 (CPD)
A software system for collaborative design and
development among trading partners
With PML, manages product data, sets up project
workspaces, and follows life cycle of the product
Accelerates product development, helps to resolve
product launch issues, and improves quality of design
Designers can
  conduct virtual review sessions
  test “what if” scenarios
  assign and track design issues
  communicate with multiple tiers of suppliers
  create, store, and manage project documents
                                                   4-209
Design Review

Review designs to prevent failures and
ensure value
  Failure mode and effects analysis (FMEA)
    a systematic method of analyzing product
    failures
  Fault tree analysis (FTA)
    a visual method for analyzing interrelationships
    among failures
  Value analysis (VA)
    helps eliminate unnecessary features and
    functions
                                                       4-210
FMEA for Potato Chips
  Failure           Cause of                 Effect of              Corrective
  Mode               Failure                 Failure                 Action
Stale        low moisture content          tastes bad         add moisture
             expired shelf life            won’t crunch        cure longer
             poor packaging                thrown out         better package seal
                                           lost sales         shorter shelf life
Broken       too thin                      can’t dip          change recipe
             too brittle                   poor display       change process
             rough handling                injures mouth      change packaging
             rough use                     chocking
             poor packaging                perceived as old
                                           lost sales
Too Salty    outdated receipt              eat less           experiment with recipe
             process not in control        drink more         experiment with process
             uneven distribution of salt   health hazard      introduce low salt version
                                           lost sales

                                                                                    4-211
Fault tree analysis (FTA)




                            4-212
Value analysis (VA)

Can we do without it?
Does it do more than is required?
Does it cost more than it is worth?
Can something else do a better job?
Can it be made by
  a less costly method?
  with less costly tooling?
  with less costly material?
Can it be made cheaper, better, or faster by
someone else?

                                               4-213
Value analysis (VA) (cont.)

Updated versions also include:
  Is it recyclable or biodegradable?
  Is the process sustainable?
  Will it use more energy than it is worth?
  Does the item or its by-product harm the
                         by-
  environment?



                                              4-214
Design for Environment and
   Extended Producer Responsibility
Design for environment
  designing a product from material that can be recycled
  design from recycled material
  design for ease of repair
  minimize packaging
  minimize material and energy used during manufacture,
  consumption and disposal
Extended producer responsibility
  holds companies responsible for their product even after its
  useful life



                                                                 4-215
Design for Environment




                         4-216
Sustainability

Ability to meet present needs without compromising
those of future generations
Green product design
  Use fewer materials
  Use recycled materials or recovered components
  Don’t assume natural materials are always better
  Don’t forget energy consumption
  Extend useful life of product
  Involve entire supply chain
  Change paradigm of design

                              Source: Adapted from the Business
                                Social Responsibility Web site,
                              www.bsr.org,
                              www.bsr.org, accessed April 1, 2007.   4-217
Quality Function
  Deployment (QFD)

Translates voice of customer into technical
design requirements
Displays requirements in matrix diagrams
  first matrix called “house of quality”
  series of connected houses




                                              4-218
House of Quality
                                                5




                   Importance
                                       Trade-
                                       Trade-off matrix

                                              3
                                           Design
                                        characteristics


           1                                    4             2

        Customer                         Relationship     Competitive
      requirements                          matrix        assessment




               6                Target values



                                                                        4-219
Competitive Assessment
 of Customer
 Requirements
                                               Competitive Assessment
              Customer Requirements            1     2      3        4      5
              Presses quickly              9       B A           X
              Removes wrinkles             8         AB              X
Irons
 well




              Doesn’t stick to fabric      6         X               BA
              Provides enough steam        8               AB               X
              Doesn’t spot fabric          6              X AB
              Doesn’t scorch fabric        9              A XB
safe to use




              Heats quickly                6         X      B        A
 Easy and




              Automatic shut-off
                        shut-              3                              ABX
                                                                          ABX
              Quick cool-down
                    cool-                  3         X      A B
              Doesn’t break when dropped   5         AB              X
              Doesn’t burn when touched    5       AB X
                                                                          4-220
              Not too heavy                8         X               A      B
Protective cover for soleplate
                                                                                                                                                                                                                                        Time required to reach 450º F
From Customer




                                                                                                                                                                                                                                                                        Time to go from 450º to 100º
                                                                                                                                      Material used in soleplate




                                                                                                                                                                                                             Flow of water from holes
                                               Energy needed to press
Requirements




                                                                                                             Thickness of soleplate




                                                                                                                                                                                                                                                                                                                                        Automatic shutoff
to Design




                                                                                                                                                                   Number of holes
                                                                                         Size of soleplate
                                                                        Weight of iron




                                                                                                                                                                                         Size of holes
Characteristics
                  Customer Requirements
                  Presses quickly                                 -             - + + +                                                                                                                                            -
                  Removes wrinkles                                            +                              +                                                     + + +
    Irons
     well




                  Doesn’t stick to fabric                                       -                                                     +                                                                  +                                            + +
                  Provides enough steam                                                     +                                                                      + + +
                  Doesn’t spot fabric                                                                                                 + -                                            -                   -
                  Doesn’t scorch fabric                                                                      + +                                                                                         + - +
    safe to use




                  Heats quickly                                                                -              -                                                                                                                +                                                   -
     Easy and




                  Automatic shut-off
                            shut-                                                                                                                                                                                                                                                                      +
                  Quick cool-down
                        cool-                                                                  -              - +                                                                                                                                     +
                  Doesn’t break when dropped                                  + + +                                                                                                                                                                                           +
                  Doesn’t burn when touched                                                                  +                                                                                                                                        + + +
                  Not too heavy                               + -                              -              - +                                                                                                                                                                  -4-221
Tradeoff Matrix




        Energy needed to press
        Weight of iron
                                             -
                                         +




        Size of soleplate
        Thickness of soleplate
        Material used in soleplate
                                             -
                                                 +




        Number of holes
                                                 +




        Size of holes
        Flow of water from holes
        Time required to reach 450º
        Time to go from 450º to 100º
        Protective cover for soleplate
4-222




        Automatic shutoff
Targeted Changes in
Design




                                                                                                                                                                                                                                                                                                  Protective cover for soleplate
                                                                                                                                                                                                                                                                   Time to go from 450º to 100º
                                                                                                                                                                                                                                     Time required to reach 450º
                                                                                                                                  Material used in soleplate




                                                                                                                                                                                                          Flow of water from holes
                                Energy needed to press




                                                                                                    Thickness of soleplate




                                                                                                                                                                                                                                                                                                                                   Automatic shutoff
                                                                                                                                                                    Number of holes
                                                                            Size of soleplate
                                                          Weight of iron




                                                                                                                                                                                          Size of holes
            Units of measure   ft-lb
                               ft-                       lb                in.                  cm                           ty                                ea             mm oz/s sec sec Y/N Y/N
measures
Objective




            Iron A                   3                   1.4               8x4                  2                            SS                                27                 15             0.5                45               500                             N                            Y

            Iron B                   4                   1.2               8x4                  1                            MG                                27                 15             0.3                35               350                             N                            Y

            Our Iron (X)             2                   1.7               9x5                  4                            T                                 35                 15             0.7                50               600                             N                            Y

Estimated impact                     3                   4                  4                   4                            5                                 4                      3               2                    5                   5                        3                         0

Estimated cost                       3                   3                  3                   3                            4                                 3                      3               3                    4                   4                        5                         2

Targets                                                  1.2               8x5                  3                            SS                                30                                                   30               500

Design changes                                            *                 *                   *                            *                                 *                                                            *                    *
                                                                                                                                                                                                                                                                   4-223
Completed
House of Quality




                   SS = Silverstone
                   MG = Mirorrglide
                   T = Titanium




                             4-224
A Series of Connected
                    QFD Houses
                  Product
               characteristics
requirements
  Customer




                                                        Part
                   A-1                             characteristics

                                 characteristics
                                    Product


                                                                                          Process
                 House                                A-2                              characteristics
                   of




                                                                     characteristics
                 quality
                                                      Parts                                                                Operations




                                                                          Part
                                                                                           A-3
                                                   deployment




                                                                                                         characteristics
                                                                                                            Process
                                                                                       Process                              A-4
                                                                                       planning

                                                                                                                         Operating
                                                                                                                       requirements

                                                                                                                                  4-225
Benefits of QFD

Promotes better understanding of
customer demands
Promotes better understanding of
design interactions
Involves manufacturing in design
process
Provides documentation of design
process



                                   4-226
Design for Robustness

Robust product
   designed to withstand variations in environmental and
   operating conditions
Robust design
   yields a product or service designed to withstand
   variations
Controllable factors
   design parameters such as material used, dimensions,
   and form of processing
Uncontrollable factors
   user’s control (length of use, maintenance, settings, etc.)



                                                                 4-227
Design for Robustness (cont.)

Tolerance
  allowable ranges of variation in the dimension of a
  part
Consistency
  consistent errors are easier to correct than random
  errors
  parts within tolerances may yield assemblies that
  are not within limits
  consumers prefer product characteristics near their
  ideal values

                                                   4-228
Taguchi’s Quality Loss
 Function
Quantifies customer
preferences toward
quality




                        Quality Loss
Emphasizes that
customer preferences
are strongly oriented
toward consistently                      Lower     Target     Upper
                                       tolerance            tolerance
Design for Six Sigma                      limit                limit
(DFSS)


                                                                        4-229
Copyright 2009 John Wiley & Sons, Inc.
All rights reserved. Reproduction or translation of this work beyond
that permitted in section 117 of the 1976 United States Copyright
Act without express permission of the copyright owner is unlawful.
Request for further information should be addressed to the
Permission Department, John Wiley & Sons, Inc. The purchaser
may make back-up copies for his/her own use only and not for
             back-
distribution or resale. The Publisher assumes no responsibility for
errors, omissions, or damages caused by the use of these
programs or from the use of the information herein.




                                                                  4-230
Chapter 5

         Service Design
       Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Service Economy
Characteristics of Services
Service Design Process
Tools for Service Design
Waiting Line Analysis for
Service Improvement

                              5-232
Service Economy




 Source: U.S. Bureau of Labor Statistics, IBM Almaden Research Center
                                                                        5-233
5-234
Characteristics of Services

Services
  acts, deeds, or performances
Goods
  tangible objects
Facilitating services
  accompany almost all purchases of goods
Facilitating goods
  accompany almost all service purchases

                                            5-235
Continuum from
Goods to Services




 Source: Adapted from Earl W. Sasser, R.P. Olsen, and D. Daryl Wyckoff,
  Management of Service Operations (Boston: Allyn Bacon, 1978), p.11.
                                                                          5-236
Characteristics
of Services (cont.)
Services are           Service inseparable
intangible             from delivery
Service output is      Services tend to be
variable               decentralized and
Services have higher   dispersed
customer contact       Services are
Services are           consumed more often
perishable             than products
                       Services can be easily
                       emulated


                                          5-237
Service
Design
Process




          5-238
Service Design
Process (cont.)
Service concept
  purpose of a service; it defines target
  market and customer experience
Service package
  mixture of physical items, sensual
  benefits, and psychological benefits
Service specifications
  performance specifications
  design specifications
  delivery specifications

                                            5-239
Service Process Matrix




                         5-240
High v. Low Contact
  Services
Design           High-Contact Service                      Low-Contact Service
Decision
 Facility           Convenient to                                  Near labor or
 location           customer                                    transportation source

 Facility         Must look presentable,                     Designed for efficiency
   layout               accommodate
                   customer needs, and
                    facilitate interaction
                        with customer

   Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Compensative
                               Advantage (New York:McGraw-Hill, 2001), p. 210

                                                                                               5-241
High v. Low Contact
    Services (cont.)
Design             High-Contact Service                             Low-Contact
Decision                                                              Service

 Quality               More variable since                        Measured against
 control               customer is involved in                        established
                       process; customer                           standards; testing
                       expectations and                           and rework possible
                       perceptions of quality
                       may differ; customer                        to correct defects
                       present when defects
                       occur
Capacity           Excess capacity required                     Planned for average
                       to handle peaks in                             demand
                            demand
Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Compensative
                            Advantage (New York:McGraw-Hill, 2001), p. 210


                                                                                               5-242
High v. Low Contact
 Services (cont.)
   Design                   High-Contact Service                         Low-Contact
   Decision                                                                Service
  Worker skills                 Must be able to                          Technical skills
                                interact well with
                                customers and use
                                judgment in decision
                                making
  Scheduling                    Must accommodate                            Customer
                                 customer schedule                         concerned only
                                                                           with completion
                                                                                 date


Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Compensative
                            Advantage (New York:McGraw-Hill, 2001), p. 210

                                                                                            5-243
High v. Low Contact
  Services (cont.)
    Design                   High-Contact Service                         Low-Contact
    Decision                                                                Service
   Service                       Mostly front-room                      Mostly back-room
   process                       activities; service may                     activities;
                                 change during delivery                    planned and
                                 in response to                           executed with
                                 customer
                                                                              minimal
                                                                           interference

Service package                 Varies with customer;                        Fixed, less
                                 includes environment                          extensive
                                    as well as actual
                                        service

 Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Compensative
                             Advantage (New York:McGraw-Hill, 2001), p. 210

                                                                                             5-244
Tools for Service Design

Service blueprinting    Servicescapes
  line of influence       space and function
  line of interaction     ambient conditions
  line of visibility      signs, symbols, and
  line of support         artifacts
Front-office/Back-
Front-office/Back-      Quantitative
office activities       techniques



                                            5-245
Service Blueprinting




                       5-246
Service Blueprinting (Con’t)




                               5-247
Elements of
 Waiting Line Analysis
Operating characteristics
  average values for characteristics that describe
  performance of waiting line system
Queue
  a single waiting line
Waiting line system
  consists of arrivals, servers, and waiting line
  structure
Calling population
  source of customers; infinite or finite

                                                     5-248
5-249
Elements of
 Waiting Line Analysis (cont.)
Arrival rate (λ)
             (λ
   frequency at which customers arrive at a waiting line
   according to a probability distribution, usually Poisson
Service time (µ)
             (µ
   time required to serve a customer, usually described by
   negative exponential distribution
Service rate must be shorter than arrival rate (λ < µ)
                                               (λ
Queue discipline
   order in which customers are served
Infinite queue
   can be of any length; length of a finite queue is limited



                                                               5-250
Elements of
Waiting Line Analysis (cont.)

                           Channels
                                number of
                                parallel
                                servers for
                                servicing
                                customers
                           Phases
                                number of
                                servers in
                                sequence a
                                customer
                                must go
                                through

                                      5-251
Operating Characteristics
Operating characteristics are assumed to
approach a steady state




                                           5-252
Traditional Cost Relationships
 as service improves, cost increases




                                       5-253
Psychology of Waiting

Waiting rooms           Disney
  magazines and           costumed characters
  newspapers              mobile vendors
  televisions             accurate wait times
Bank of America           special passes
  mirrors
Supermarkets
  magazines
  “impulse purchases”

                                           5-254
Psychology of Waiting (cont.)

Preferential treatment
  Grocery stores: express lanes for customers with
  few purchases
  Airlines/Car rental agencies: special cards
  available to frequent-users or for an additional fee
               frequent-
  Phone retailers: route calls to more or less
  experienced salespeople based on customer’s
  sales history
Critical service providers
  services of police department, fire department, etc.
  waiting is unacceptable; cost is not important

                                                     5-255
Waiting Line Models

Single-
Single-server model
  simplest, most basic waiting line structure
Frequent variations (all with Poisson arrival rate)
  exponential service times
  general (unknown) distribution of service times
  constant service times
  exponential service times with finite queue
  exponential service times with finite calling population


                                                     5-256
Basic Single-Server Model
       Single-

Assumptions               Computations
  Poisson arrival rate      λ = mean arrival rate
  exponential service       µ = mean service rate
  times                     n = number of
  first-
  first-come, first-
                first-      customers in line
  served queue
  discipline
  infinite queue length
  infinite calling
  population

                                              5-257
Basic Single-Server Model (cont.)
             Single-

  probability that no customers            average number of customers
  are in queuing system                    in queuing system

            P0 =  ( ) λ
                     1–
                      µ
                                                  L=
                                                   µ–λ
                                                       λ




  probability of n customers in            average number of customers
  queuing system                           in waiting line


   ( ) ( )( )
        λ   n             λ   n        λ                        λ2
Pn =            · P0 =            1–            Lq =
        µ                 µ            µ                   µ ( µ – λ)


                                                                        5-258
Basic Single-Server Model (cont.)
       Single-

average time customer      probability that server is busy
spends in queuing system   and a customer has to wait
            1        L     (utilization factor)
    W=           =                         λ
           µ–λ       λ                ρ=
                                           µ

average time customer      probability that server is idle
spends waiting in line     and customer can be served
                λ                    I=1– ρ
          Wq =
          µ ( µ – λ)                     λ
                                   =1–        = P0
                                         µ

                                                       5-259
Basic Single-Server Model
      Single-
Example




                            5-260
Basic Single-Server Model
      Single-
Example (cont.)




                            5-261
Service Improvement Analysis

waiting time (8 min.) is too long
  hire assistant for cashier?
    increased service rate
  hire another cashier?
    reduced arrival rate
Is improved service worth the cost?


                                      5-262
Basic Single-Server Model
      Single-
Example: Excel




                            5-263
Advanced Single-Server Models
          Single-

Constant service times
  occur most often when automated equipment or
  machinery performs service
Finite queue lengths
  occur when there is a physical limitation to length of
  waiting line
Finite calling population
  number of “customers” that can arrive is limited


                                                     5-264
Advanced Single-Server
          Single-
Models (cont.)




                         5-265
Basic Multiple-Server Model
       Multiple-

single waiting line and service facility with
several independent servers in parallel
same assumptions as single-server model
                        single-
sµ > λ
  s = number of servers
  servers must be able to serve customers faster than
  they arrive



                                                  5-266
Basic Multiple-Server Model
       Multiple-
 (cont.)
probability that there are no customers in system
                          1
 P0 = n = s – 1
                        1 λ n      1 λ s
           ∑
         n=0
                  () n!
                          +
                          µ    ( )( )
                                 s!   µ
                                                sµ
                                            sµ - λ

probability of n customers in system
                                λ n
                      ()
                       1

       Pn = {        ()
                       s!sn–s    µ

                             1 λ n
                                   P0, for n > s


                             P0, for n ≤ s
                              n! µ
                                                     5-267
Basic Multiple-Server Model
        Multiple-
  (cont.)
probability that customer must wait

             ()
          1     λ   s    sµ                          λ
Pw =                          P0         Lq = L –
        s!    µ     sµ – λ                           µ


             λµ (λ/µ)s               λ                   1       Lq
L=                            P0 +          Wq = W –         =
       (s – 1)! (sµ – λ)2
                (s                   µ                   µ       λ


        L                                     λ
        W=                                      ρ=
        λ                                    sµ

                                                                 5-268
Basic Multiple-Server Model
      Multiple-
Example




                              5-269
Basic Multiple-Server Model
      Multiple-
Example (cont.)




                              5-270
Basic Multiple-Server Model
      Multiple-
Example (cont.)




                              5-271
Basic Multiple-Server Model
      Multiple-
Example (cont.)




                              5-272
Basic Multiple-Server Model
      Multiple-
Example (cont.)




                              5-273
Basic Multiple-Server Model
       Multiple-
 Example (cont.)
To cut wait time, add another service
representative
  now, s = 4
Therefore:




                                        5-274
Multiple-
Multiple-Server Waiting Line
in Excel




                               5-275
Chapter 6
 Processes and Technology
         Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Process Planning
Process Analysis
Process Innovation
Technology Decisions




                       6-277
Process Planning

Process
  a group of related tasks with specific inputs and outputs
Process design
  what tasks need to be done and how they are
  coordinated among functions, people, and
  organizations
Process strategy
  an organization’s overall approach for physically
  producing goods and services
Process planning
  converts designs into workable instructions for
  manufacture or delivery

                                                              6-278
Process Strategy

Vertical integration
   extent to which firm will produce inputs and control outputs of
   each stage of production process
Capital intensity
   mix of capital (i.e., equipment, automation) and labor
   resources used in production process
Process flexibility
   ease with which resources can be adjusted in response to
   changes in demand, technology, products or services, and
   resource availability
Customer involvement
   role of customer in production process


                                                               6-279
Outsourcing

Cost           Speed
Capacity       Reliability
Quality        Expertise




                             6-280
Process Selection

Projects
  one-of-a-kind production of a product to customer order
Batch production
  processes many different jobs at the same time in groups or
  batches
Mass production
  produces large volumes of a standard product for a mass
  market
Continuous production
  used for very-high volume commodity products



                                                            6-281
Sourcing Continuum




                     6-282
Product-
 Product-Process Matrix




Source: Adapted from Robert Hayes and Steven Wheelwright, Restoring the Competitive Edge
      Competing through Manufacturing (New York, John Wiley & Sons, 1984), p. 209.

                                                                                           6-283
Types of Processes
                  PROJECT                 BATCH                  MASS                   CONT.
                                                                                        CONT.


                                        Made-to-
                                        Made-to-               Made-to-
                                                               Made-to-
Type of
                    Unique               order                  stock                Commodity
product
                                      (customized)           (standardized )

                  One-at-
                  One-at-a-               Few
 Type of                                                         Mass                   Mass
                    time               individual
customer                                                         market                 market
                                       customers


Product
demand          Infrequent             Fluctuates                Stable              Very stable

    Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Competitive
        Advantage (New York:McGraw-Hill, 2001), p. 210
                         York:McGraw-

                                                                                                 6-284
Types of Processes (cont.)
                   PROJECT                 BATCH                  MASS                   CONT.
                                                                                         CONT.


 Demand                                   Low to
                    Very low                                        High               Very high
 volume                                   medium


 No. of               Infinite
different                              Many, varied                 Few                 Very few
products              variety


                                                               Repetitive,           Continuous,
Production         Long-
                   Long-term           Discrete, job
  system                                                       assembly                process
                    project               shops
                                                                 lines                industries
     Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Competitive
         Advantage (New York:McGraw-Hill, 2001), p. 210
                          York:McGraw-

                                                                                                  6-285
Types of Processes (cont.)
                  PROJECT                 BATCH                  MASS                   CONT.
                                                                                        CONT.



                     Varied              General-
                                         General-               Special-
                                                                Special-               Highly
Equipment
                                         purpose                purpose              automated


 Primary                                                                                Mixing,
 type of         Specialized
                                       Fabrication            Assembly                 treating,
  work            contracts
                                                                                        refining

                   Experts,                                      Limited
 Worker                               Wide range                                     Equipment
  skills            crafts-
                    crafts-                                     range of
                                       of skills                                      monitors
                   persons                                        skills
    Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Competitive
        Advantage (New York:McGraw-Hill, 2001), p. 210
                         York:McGraw-

                                                                                                 6-286
Types of Processes (cont.)
                        PROJECT                   BATCH                  MASS                     CONT.
                                                                                                  CONT.


                                                                        Efficiency,           Highly efficient,
                        Custom work,              Flexibility,
Advantages            latest technology            quality
                                                                          speed,              large capacity,
                                                                         low cost             ease of control

                                                                         Capital
                       Non-
                       Non-repetitive,          Costly, slow,                               Difficult to change,
   Dis-
   Dis-               small customer             difficult to
                                                                       investment;
                                                                                           far-reaching errors,
                                                                                           far-
advantages            base, expensive                                     lack of
                                                  manage                                      limited variety
                                                                     responsiveness

                                              Machine shops,          Automobiles,
                        Construction,          print shops,            televisions,          Paint, chemicals,
Examples                shipbuilding,
                                                                                                foodstuffs
                         spacecraft             bakeries,              computers,
                                                education                fast food
 Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Competitive Advantage (New
     York:McGraw-
     York:McGraw-Hill, 2001), p. 210


                                                                                                           6-287
Process Selection with
   Break-
   Break-Even Analysis
examines cost trade-offs associated with demand volume
Cost
  Fixed costs
     constant regardless of the number of units produced
  Variable costs
     vary with the volume of units produced
Revenue
   price at which an item is sold
Total revenue
   is price times volume sold
Profit
   difference between total revenue and total cost
                                                           6-288
Process Selection with
    Break-
    Break-Even Analysis (cont.)

Total cost = fixed cost + total variable cost
       TC = cf + vcv
Total revenue = volume x price
       TR = vp
Profit = total revenue - total cost
       Z = TR – TC = vp - (cf + vcv)


                                                6-289
Process Selection with
Break-
Break-Even Analysis (cont.)

                TR = TC
                 vp = cf + vcv
          vp - vcv = cf
         v ( p - c v) = c f
                              cf
                        p - cv
                   v=
    Solving for Break-Even Point (Volume)
                Break-

                                            6-290
Break-
Break-Even Analysis: Example

    Fixed cost = cf = $2,000
  Variable cost = cv = $5 per raft
          Price = p = $10 per raft

        Break-
        Break-even point is
          cf         2000
   v=            =            = 400 rafts
        p - cv       10 - 5


                                            6-291
Break-
Break-Even Analysis: Graph
  Dollars



   $3,000 —                       Total
                                  cost
                                   line

   $2,000 —



   $1,000 —
                Total
              revenue
                 line
                    400               Units
               Break-
               Break-even point


                                              6-292
Process Plans

Set of documents that detail manufacturing
and service delivery specifications
  assembly charts
  operations sheets
  quality-control check-sheets




                                             6-293
Process Selection

     Process A    Process B
   $2,000 + $5v = $10,000 + $3v
            $5v             $3v
           $2v = $8,000
           $2v
              v = 4,000 rafts

Below or equal to 4,000, choose A
Above or equal to 4,000, choose B

                                    6-294
Process Analysis


                   •
                   systematic
                   examinatio
                   n of all
                   aspects of
                   process to
                   improve
                   operation




                      6-295
An Operations Sheet for a Plastic Part

     Part name         Crevice Tool
     Part No.          52074
     Usage             Hand-Vac
                       Hand-
     Assembly No. 520

Oper. No.    Description                Dept.   Machine/Tools        Time
   10        Pour in plastic bits       041     Injection molding    2 min
   20        Insert mold                041     #076                 2 min
   30        Check settings             041     113, 67, 650         20 min
             & start machine
   40        Collect parts & lay flat   051     Plastics finishing   10 min
   50        Remove & clean mold        042     Parts washer         15 min
   60        Break off rough edges      051     Plastics finishing   10 min




                                                                        6-296
Process Analysis

Building a flowchart
  Determine objectives
  Define process boundaries
  Define units of flow
  Choose type of chart
  Observe process and collect data
  Map out process
  Validate chart

                                     6-297
Process Flowcharts

look at manufacture of product or delivery
of service from broad perspective
Incorporate
  nonproductive activities (inspection,
  transportation, delay, storage)
  productive activities (operations)



                                          6-298
Process Flowchart
Symbols

       Operations
       Inspection
       Transportation
       Delay
       Storage

                        6-299
Process
Flowchart
of Apple
Processin
g
            6-300
6-301
Simple Value Chain Flowchart




                           6-302
Process Innovation
                                       Continuous improvement
                                       refines the breakthrough




                   Breakthrough
                   Improvement




 Total redesign                   Continuous improvement activities
                                  peak; time to reengineer process
of a process for
   breakthrough
 improvements



                                                                      6-303
From Function to Process


                                                     Product Development
                           Manufacturing
              Purchasing
Accounting




                                                       Order Fulfillment

                                           Sales
                                                   Supply Chain Management

                                                      Customer Service

              Function                                     Process



                                                                           6-304
Process Innovation
                            Strategic
                            Directives

                                                Baseline Data
  Customer            Goals for Process                 Benchmark
                        Performance
 Requirements                                             Data

                           High - level          Innovative
                          Process map                            Design
                                                   Ideas
                                                                Principles
                            Detailed              Model
                          Process Map                             Key
                                                 Validation
                                                              Performance
                                                               Measures
                            Pilot Study
                          of New Design



                              Goals                  Full Scale
                     No       Met?        Yes      Implementation



                                                                        6-305
High-
High-Level Process Map




                         6-306
Principles for Redesigning
 Processes
Remove waste, simplify, and consolidate
similar activities
Link processes to create value
Let the swiftest and most capable enterprise
execute the process
Flex process for any time, any place, any way
Capture information digitally at the source and
propagate it through process

                                             6-307
Principles for Redesigning
 Processes (cont.)
Provide visibility through fresher and richer
information about process status
Fit process with sensors and feedback loops
that can prompt action
Add analytic capabilities to process
Connect, collect, and create knowledge around
process through all who touch it
Personalize process with preferences and
habits of participants


                                          6-308
Techniques for Generating
 Innovative Ideas

Vary the entry point to a problem
  in trying to untangle fishing lines, it’s best to start
  from the fish, not the poles
Draw analogies
  a previous solution to an old problem might work
Change your perspective
  think like a customer
  bring in persons who have no knowledge of
  process


                                                            6-309
Techniques for Generating
 Innovative Ideas (cont.)
Try inverse brainstorming
  what would increase cost
  what would displease the customer
Chain forward as far as possible
  if I solve this problem, what is the next problem
Use attribute brainstorming
  how would this process operate if. . .
    our workers were mobile and flexible
    there were no monetary constraints
    we had perfect knowledge


                                                      6-310
Technology Decisions

 Financial justification of technology
   Purchase cost
   Operating Costs
   Annual Savings
   Revenue Enhancement
   Replacement Analysis
   Risk and Uncertainty
   Piecemeal Analysis


                                         6-311
Components of e-Manufacturing
              e-




                                6-312
A Technology Primer
               Product Technology
Computer-aided      Creates and communicates designs
design (CAD)        electronically
Group technology    Classifies designs into families for easy
(GT)                retrieval and modification
Computer-aided      Tests functionality of CAD designs
engineering (CAE)   electronically
Collaborative
product commerce    Facilitates electronic communication and
(CPC)               exchange of information among designers
                    and suppliers




                                                           6-313
A Technology Primer (cont.)
                     Product Technology
Product data             Keeps track of design specs and revisions
management               for the life of the product
(PDM)
                         Integrates decisions of those involved in
Product life cycle       product development, manufacturing, sales,
management               customer service, recycling, and disposal
(PLM)
Product                  Defines products “configured” by customers
configuration            who have selected among various options,
                         usually from a Web site




                                                               6-314
A Technology Primer (cont.)
                Process Technology
Standard for         Set standards for communication among
exchange of          different CAD vendors; translates CAD data
product model data   into requirements for automated inspection
(STEP)               and manufacture
Computer-aided       Electronic link between automated design
design and           (CAD) and automated manufacture (CAM)
manufacture
(CAD/CAM)
Computer aided       Generates process plans based on
process (CAPP)       database of similar requirements
E-procurement        Electronic purchasing of items from e-
                                                         e-
                     marketplaces, auctions, or company
                     websites


                                                              6-315
A Technology Primer (cont.)
             Manufacturing Technology
Computer              Machines controlled by software code to perform a
numerically control   variety of operations with the help of automated
(CNC)                 tool changers; also collects processing information
                      and quality data
Flexible              A collection of CNC machines connected by an
manufacturing         automated material handling system to produce a
system (FMS)          wide variety of parts
                      Manipulators that can be programmed to perform
Robots                repetitive tasks; more consistent than workers but
                      less flexible
                      Fixed-
                      Fixed-path material handling; moves items along a
Conveyors             belt or overhead chain; “reads” packages and
                      diverts them to different directions; can be very fast



                                                                     6-316
A Technology Primer (cont.)
              Manufacturing Technology
Automatic guided       A driverless truck that moves material along a
vehicle (AGV)          specified path; directed by wire or tape embedded
                       in floor or by radio frequencies; very flexible
                       An automated warehouse—some 26 stores high—
                                      warehouse—                    high—
Automated storage      in which items are placed in a carousel-type
                                                      carousel-
and retrieval system   storage system and retrieved by fast-moving
                                                        fast-
(ASRS)                 stacker cranes; controlled by computer
                       Continuous monitoring of automated equipment;
                       makes real-time decisions on ongoing operation,
                              real-
Process Control        maintenance, and quality
                       Automated manufacturing systems integrated
Computer-integrated    through computer technology; also called e-
                                                                e-
                       manufacturing
manufacturing (CIM)


                                                                     6-317
A Technology Primer (cont.)
             Information Technology
Business – to –   Electronic transactions between businesses
Business (B2B)    usually over the Internet
Business – to –   Electronic transactions between businesses and
Consumer (B2C)    their customers usually over the Internet
Internet          A global information system of computer networks
                  that facilitates communication and data transfer

Intranet          Communication networks internal to an
                  organization; can be password (i.e., firewall)
                  protected sites on the Internet
                  Intranets connected to the Internet for shared
Extranet          access with select suppliers, customers, and
                  trading partners


                                                                   6-318
A Technology Primer (cont.)
                Information Technology
Bar Codes             A series of vertical lines printed on most packages that
                      identifies item and other information when read by a
                      scanner
Radio Frequency       An integrated circuit embedded in a tag that can send
Identification tags   and receive information; a twenty-first century bar code
                                                    twenty-
(RFID)                with read/write capabilities
                      A computer-to-computer exchange of business
                        computer-to-
Electronic data       documents over a proprietary network; very expensive
                      and inflexible
interchange (EDI)
                      A programming language that enables computer – to -
                      computer communication over the Internet by tagging
Extensive markup      data before its is sent
language (XML)        Software for managing basic requirements of an
                      enterprise, including sales & marketing, finance and
                      accounting, production & materials management, and
Enterprise            human resources
resource planning
(ERP)
                                                                           6-319
A Technology Primer (cont.)
                      Information Technology
                          Software for managing flow of goods and information
Supply chain              among a network of suppliers, manufacturers and
management (SCM)          distributors
                          Software for managing interactions with customers and
Customer relationship     compiling and analyzing customer data
management (CRM)          An information system that helps managers make
                          decisions; includes a quantitative modeling component
Decision support          and an interactive component for what-if analysis
                                                              what-
systems (DSS)
                          A computer system that uses an expert knowledge base
                          to diagnose or solve a problem
Expert systems (ES)
                          A field of study that attempts to replicate elements of
                          human thought in computer processes; includes expert
Artificial intelligence   systems, genetic algorithms, neural networks, and fuzzy
(AI)                      logic




                                                                              6-320
Chapter 7

Capacity and Facilities
           Operations Management

  Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Capacity Planning
Basic Layouts
Designing Process Layouts
Designing Service Layouts
Designing Product Layouts
Hybrid Layouts
Capacity

Maximum capability to produce
Capacity planning
  establishes overall level of productive
  resources for a firm
3 basic strategies for timing of capacity
expansion in relation to steady growth in
demand (lead, lag, and average)
Capacity Expansion Strategies
Capacity (cont.)
Capacity increase depends on
  volume and certainty of anticipated demand
  strategic objectives
  costs of expansion and operation
Best operating level
  % of capacity utilization that minimizes unit costs
Capacity cushion
  % of capacity held in reserve for unexpected
  occurrences
Economies of Scale

it costs less per unit to produce high levels of
output
  fixed costs can be spread over a larger number of
  units
  production or operating costs do not increase
  linearly with output levels
  quantity discounts are available for material
  purchases
  operating efficiency increases as workers gain
  experience
Best Operating Level for a Hotel
Machine Objectives of
     Facility Layout
    Arrangement of areas within a facility to:
Minimize material-handling      Facilitate entry, exit, and
costs                           placement of material, products,
Utilize space efficiently       and people
Utilize labor efficiently       Incorporate safety and security
Eliminate bottlenecks           measures
Facilitate communication and    Promote product and service
interaction                     quality
Reduce manufacturing cycle      Encourage proper maintenance
time                            activities
Reduce customer service time    Provide a visual control of
                                activities
Eliminate wasted or redundant   Provide flexibility to adapt to
movement                        changing conditions
Increase capacity
BASIC LAYOUTS

Process layouts
  group similar activities together
  according to process or function they
  perform
Product layouts
  arrange activities in line according to
  sequence of operations for a particular
  product or service
Fixed-position layouts
  are used for projects in which product
  cannot be moved
Process Layout in Services

  Women’s
                 Shoes        Housewares
  lingerie


  Women’s      Cosmetics      Children’s
  dresses      and jewelry    department



   Women’s      Entry and       Men’s
  sportswear   display area   department
Manufacturing Process Layout
A Product Layout
In




                        Out
Comparison of Product
  and Process Layouts
                    Product              Process
Description       Sequential           Functional
                  arrangement of       grouping of
                  activities           activities
                  Continuous, mass     Intermittent, job
Type of process   production, mainly   shop, batch
                  assembly             production, mainly
                                       fabrication
                  Standardized, made   Varied, made to
Product                                order
                  to stock
Demand            Stable               Fluctuating
Volume            High                 Low
Equipment         Special purpose      General purpose
Comparison of Product
       and Process Layouts
                       Product                 Process
Workers             Limited skills          Varied skills
Inventory           Low in-process, high
                          in-               High in-process, low
                                                  in-
                    finished goods          finished goods
Storage space       Small                   Large
Material handling   Fixed path (conveyor)   Variable path (forklift)
Aisles              Narrow                  Wide
Scheduling          Part of balancing       Dynamic
Layout decision     Line balancing          Machine location
Goal
                    Equalize work at each   Minimize material
                    station                 handling cost
Advantage
                    Efficiency              Flexibility
Fixed-
        Fixed-Position Layouts
   Typical of projects in
   which product produced
   is too fragile, bulky, or
   heavy to move
   Equipment, workers,
   materials, other
   resources brought to the
   site
   Low equipment utilization
   Highly skilled labor
   Typically low fixed cost
   Often high variable costs
7-335
Designing Process Layouts

Goal: minimize material handling costs
Block Diagramming
  minimize nonadjacent loads
  use when quantitative data is available
Relationship Diagramming
  based on location preference between areas
  use when quantitative data is not available
Block Diagramming

Unit load                STEPS
  quantity in which        create load summary chart
  material is normally     calculate composite (two
  moved                    way) movements
Nonadjacent load           develop trial layouts
  distance farther         minimizing number of
  than the next block      nonadjacent loads
Block Diagramming: Example
            Load Summary Chart
            FROM/TO          DEPARTMENT
1   2   3
            Department 1     2     3    4    5

               1       —    100    50
               2             —    200   50
4   5          3       60          —    40   50
               4            100         —    60
               5                  50         —
Block Diagramming:
    Example (cont.)
                              Nonadjacent Loads:
2    3   200 loads
                                 110+40=150
                                      0
2    4   150 loads
1    3   110 loads
                                     110
1    2   100 loads
4    5    60 loads
                               100         150
                                           200
3    5    50 loads        1           2           3
                                                  4
2    5    50 loads
                              150 200 50
                                   50  50 40 60
3    4    40 loads            110
1    4     0 loads              60       50
                          4           3
                                      5           5
1    5     0 loads
                                             40
                     Grid 1
                          2
Block Diagramming:
     Example (cont.)
 Block Diagram
     type of schematic layout diagram; includes space requirements
(a) Initial block diagram             (b) Final block diagram




                                           1                    4
     1         2            4                       2


               3            5               3               5
Relationship Diagramming


Schematic diagram that
uses weighted lines to
denote location preference
Muther’s grid
   format for displaying
  manager preferences for
  department locations
Relationship Diagramming: Excel
Relationship A Absolutely necessary
              E Especially important
 Diagramming: Example
              I Important
                       O Okay
                       U Unimportant
Production             X Undesirable
               O
Offices            A
               U       I
Stockroom          O       E
               A       X       A
Shipping and       U       U
receiving
               U       O
Locker room        O
               O
Toolroom
Relationship Diagrams: Example (cont.)
      (a) Relationship diagram of original layout




    Offices            Locker       Shipping
                        room           and
                                    receiving

                                               Key: A
                                                    E
Stockroom          Toolroom         Production      I
                                                    O
                                                    U
                                                    X
Relationship Diagrams: Example (cont.)
           (b) Relationship diagram of revised layout



                   Stockroom


   Offices                           Shipping
                                        and
                                     receiving



                                     Locker      Key: A
Toolroom           Production
                                      room            E
                                                      I
                                                      O
                                                      U
                                                      X
Computerized layout
 Solutions
CRAFT
  Computerized Relative Allocation of Facilities
  Technique
CORELAP
  Computerized Relationship Layout Planning
PROMODEL and EXTEND
  visual feedback
  allow user to quickly test a variety of scenarios
Three-D modeling and CAD
  integrated layout analysis
  available in VisFactory and similar software
Designing Service
    Layouts
Must be both attractive and functional
Types
  Free flow layouts
     encourage browsing, increase impulse purchasing, are flexible
     and visually appealing
   Grid layouts
     encourage customer familiarity, are low cost, easy to clean and
     secure, and good for repeat customers
   Loop and Spine layouts
     both increase customer sightlines and exposure to products,
     while encouraging customer to circulate through the entire
     store
Types of Store Layouts
Designing Product
 Layouts
Objective
  Balance the assembly line
Line balancing
  tries to equalize the amount of work at each
  workstation
Precedence requirements
  physical restrictions on the order in which operations
  are performed
Cycle time
  maximum amount of time a product is allowed to
  spend at each workstation
Cycle Time Example

            production time available
   Cd =         desired units of output

           (8 hours x 60 minutes / hour)
  Cd =                 (120 units)

                 480
         Cd =    120
                         = 4 minutes
Flow Time vs Cycle Time

Cycle time = max time spent at any station
Flow time = time to complete all stations

           1             2             3

       4 minutes     4 minutes    4 minutes

        Flow time = 4 + 4 + 4 = 12 minutes
       Cycle time = max (4, 4, 4) = 4 minutes
Efficiency of Line and Balance Delay
                                Minimum number of
        Efficiency                 workstations

                 i                         i

            ∑        ti
                                         ∑     ti   Balance
                                                    delay
            i=1                          i=1
  E=        nCa
                                  N=      Cd
                                                      total idle
                                                      time of line
                                                      calculated
where
                                                      as (1 -
            ti   = completion time for element i      efficiency)
             j   = number of work elements
            n    = actual number of workstations
           Ca    = actual cycle time
           Cd    = desired cycle time
Line Balancing Procedure

1. Draw and label a precedence diagram
2. Calculate desired cycle time required for line
3. Calculate theoretical minimum number of
   workstations
4. Group elements into workstations, recognizing cycle
   time and precedence constraints
5. Calculate efficiency of line
6. Determine if theoretical minimum number of
   workstations or an acceptable efficiency level has
   been reached. If not, go back to step 4.
Line Balancing: Example
    WORK ELEMENT                   PRECEDENCE      TIME (MIN)
A   Press out sheet of fruit              —           0.1
B   Cut into strips                       A           0.2
C   Outline fun shapes                    A           0.4
D   Roll up and package                  B, C         0.3


                                   0.2
                               B


               0.1 A                     D   0.3


                               C
                                   0.4
Line Balancing: Example (cont.)
      WORK ELEMENT                      PRECEDENCE            TIME (MIN)
A     Press out sheet of fruit                  —                 0.1
B     Cut into strips                           A                 0.2
C     Outline fun shapes                        A                 0.4
D     Roll up and package                      B, C               0.3



           40 hours x 60 minutes / hour              2400
    Cd =                                       =            = 0.4 minute
                    6,000 units                      6000

           0.1 + 0.2 + 0.3 + 0.4       1.0
    N=                             =         = 2.5     3 workstations
                   0.4                 0.4
Line Balancing: Example (cont.)
                          REMAINING       REMAINING
WORKSTATION    ELEMENT      TIME          ELEMENTS
    1             A          0.3             B, C
                  B          0.1             C, D
     2            C          0.0              D
     3            D          0.1            none
                          0.2             Cd = 0.4
                      B
                                          N = 2.5

              0.1 A             D   0.3


                      C
                          0.4
Line Balancing: Example (cont.)

       Work          Work        Work
     station 1     station 2   station 3
                                                       Cd = 0.4
                                                       N = 2.5
      A, B            C           D
      0.3            0.4        0.3
     minute         minute     minute




      0.1 + 0.2 + 0.3 + 0.4           1.0
E=                               =          = 0.833 = 83.3%
                 3(0.4)               1.2
Computerized Line
 Balancing
Use heuristics to assign tasks to
workstations
  Longest operation time
  Shortest operation time
  Most number of following tasks
  Least number of following tasks
  Ranked positional weight
Hybrid Layouts

Cellular layouts
   group dissimilar machines into work centers (called cells)
   that process families of parts with similar shapes or
   processing requirements
Production flow analysis (PFA)
   reorders part routing matrices to identify families of parts
   with similar processing requirements
Flexible manufacturing system
   automated machining and material handling systems
   which can produce an enormous variety of items
Mixed-model assembly line
   processes more than one product model in one line
Cellular Layouts

1. Identify families of parts with similar
   flow paths
2. Group machines into cells based on
   part families
3. Arrange cells so material movement
   is minimized
4. Locate large shared machines at
   point of use
Parts Families




  A family of    A family of related
 similar parts     grocery items
Original Process Layout
              Assembly



  4       6            7           9


      5                       8

      2                10          12

  1       3                   11


  A   B   C   Raw materials
Part Routing Matrix
                               Machines
        Parts     1   2   3   4 5 6 7         8   9   10 11 12
             A    x   x       x               x       x
             B                    x       x               x   x
             C            x           x           x
             D    x   x       x               x       x
             E                x   x                           x
             F    x           x               x
             G            x           x           x           x
             H                            x               x   x




Figure 5.8
Revised Cellular Layout
                     Assembly


           8     10           9   12


                                           11
    4   Cell 1       Cell 2   6   Cell 3
                                           7

           2     1            3   5

                      A B C
                 Raw materials
Reordered Routing Matrix
                     Machines
Parts   1   2   4   8 10 3 6        9   5   7   11 12
 A      x   x   x   x   x
 D      x   x   x   x   x
 F      x       x   x
 C                          x   x   x
 G                          x   x   x               x
 B                                      x   x   x   x
 H                                          x   x   x
 E                              x       x           x
Operationsmanagement 919slidespresentation-090928145353-phpapp01
Advantages and Disadvantages
 of Cellular Layouts
Advantages                    Disadvantages
  Reduced material              Inadequate part families
  handling and transit time     Poorly balanced cells
  Reduced setup time            Expanded training and
  Reduced work-in-
            work-in-            scheduling of workers
  process inventory             Increased capital
  Better use of human           investment
  resources
  Easier to control
  Easier to automate
Automated Manufacturing Cell




Source: J. T. Black, “Cellular
Manufacturing Systems Reduce
Setup Time, Make Small Lot
Production Economical.” Industrial
Engineering (November 1983)
Flexible Manufacturing
Systems (FMS)
FMS consists of numerous programmable
machine tools connected by an automated
material handling system and controlled by
a common computer network
FMS combines flexibility with efficiency
FMS layouts differ based on
  variety of parts that the system can process
  size of parts processed
  average processing time required for part
  completion
Full-Blown FMS
Mixed Model
 Assembly Lines
Produce multiple models in any order
on one assembly line
Issues in mixed model lines
   Line balancing
   U-shaped lines
   Flexible workforce
   Model sequencing
Balancing U-Shaped Lines
                U-
           Precedence diagram:

                                        A             B           C



                   Cycle time = 12 min
                                                      D           E


(a) Balanced for a straight line                          (b) Balanced for a U-shaped line
                                                                             U-

         A,B          C,D           E
                                                                   A,B
        9 min      12 min         3 min
                 24         24
 Efficiency =           =        = .6666 = 66.7 %                               C,D
                3(12)       36


                                                                      E

                                        24       24
                  Efficiency =               =        = 100 % 12 min           12 min
                                    2(12)        24
Chapter 7 Supplement

   Facility Location Models

          Operations Management

 Roberta Russell & Bernard W. Taylor, III
Lecture Outline


Types of Facilities
Site Selection: Where to Locate
Location Analysis Techniques




                                  Supplement 7-374
                                             7-
Types of Facilities

Heavy-
Heavy-manufacturing facilities
  large, require a lot of space, and are
  expensive
Light-
Light-industry facilities
  smaller, cleaner plants and usually less
  costly
Retail and service facilities
  smallest and least costly

                                           Supplement 7-375
                                                      7-
Factors in Heavy Manufacturing
Location
 Construction costs
 Land costs
 Raw material and finished goods
 shipment modes
 Proximity to raw materials
 Utilities
 Means of waste disposal
 Labor availability
                              Supplement 7-376
                                         7-
Factors in Light Industry
Location

 Land costs
 Transportation costs
 Proximity to markets
   depending on delivery requirements
   including frequency of delivery
   required by customer


                                  Supplement 7-377
                                             7-
Factors in Retail Location


Proximity to customers
Location is everything




                              Supplement 7-378
                                         7-
Site Selection: Where to Locate

Infrequent but important              Location criteria for
   being “in the right place at the   manufacturing facility
   right time”                           nature of labor force
Must consider other factors,             labor costs
especially financial                     proximity to suppliers and
considerations                           markets
Location decisions made more             distribution and
often for service operations             transportation costs
than manufacturing facilities            energy availability and cost
Location criteria for service            community infrastructure
   access to customers                   quality of life in community
                                         government regulations and
                                         taxes


                                                         Supplement 7-379
                                                                    7-
Global Location Factors

Government stability            Raw material availability
Government regulations          Number and proximity of
                                suppliers
Political and economic
systems                         Transportation and
                                distribution system
Economic stability and growth   Labor cost and education
Exchange rates                  Available technology
Culture                         Commercial travel
Climate                         Technical expertise
Export/import regulations,      Cross-
                                Cross-border trade
duties and tariffs              regulations
                                Group trade agreements


                                                  Supplement 7-380
                                                             7-
Regional and Community
   Location Factors in U.S.
Labor (availability,     Modes and quality of
education, cost, and     transportation
unions)                  Transportation costs
Proximity of customers   Community government
Number of customers      Local business
Construction/leasing     regulations
costs                    Government services
Land cost                (e.g., Chamber of
                         Commerce)



                                      Supplement 7-381
                                                 7-
Regional and Community
  Location Factors in U.S. (cont.)
Business climate            Infrastructure (e.g.,
Community services          roads, water, sewers)
Incentive packages          Quality of life
Government regulations      Taxes
Environmental               Availability of sites
regulations                 Financial services
Raw material availability   Community inducements
Commercial travel           Proximity of suppliers
Climate                     Education system


                                         Supplement 7-382
                                                    7-
Location Incentives
Tax credits
Relaxed government regulation
Job training
Infrastructure improvement
Money




                                Supplement 7-383
                                           7-
Geographic Information
 Systems (GIS)
Computerized system for storing, managing,
creating, analyzing, integrating, and digitally
displaying geographic, i.e., spatial, data
Specifically used for site selection
enables users to integrate large quantities of
information about potential sites and analyze these
data with many different, powerful analytical tools



                                          Supplement 7-384
                                                     7-
GIS Diagram




              Supplement 7-385
                         7-
Location Analysis Techniques

Location factor rating

Center-of-
Center-of-gravity

Load-
Load-distance



                          Supplement 7-386
                                     7-
Location Factor Rating

Identify important factors
Weight factors (0.00 - 1.00)
Subjectively score each factor (0 - 100)
Sum weighted scores




                                           Supplement 7-387
                                                      7-
Location Factor Rating: Example
                                   SCORES (0 TO 100)
LOCATION FACTOR           WEIGHT     Site 1   Site 2      Site 3
Labor pool and climate      .30        80       65           90
Proximity to suppliers      .20       100       91           75
Wage rates                  .15        60       95           72
Community environment       .15        75       80           80
Proximity to customers      .10        65       90           95
Shipping modes              .05        85       92           65
Air service                 .05        50       65           90
     Weighted Score for “Labor pool and climate” for
                 Site 1 = (0.30)(80) = 24



                                                     Supplement 7-388
                                                                7-
Location Factor Rating: Example
  (cont.)
 WEIGHTED SCORES
Site 1   Site 2   Site 3
24.00    19.50    27.00
                              Site 3 has the
20.00    18.20    15.00    highest factor rating
 9.00    14.25    10.80
11.25    12.00    12.00
 6.50     9.00     9.50
 4.25     4.60     3.25
 2.50     3.25     4.50
77.50    80.80    82.05



                                            Supplement 7-389
                                                       7-
Location Factor Rating
with Excel and OM Tools




                          Supplement 7-390
                                     7-
Center-of-
 Center-of-Gravity
 Technique
Locate facility at center of movement
in geographic area
Based on weight and distance
traveled; establishes grid-map of
                       grid-
area
Identify coordinates and weights
shipped for each location



                                        Supplement 7-391
                                                   7-
Grid-
       Grid-Map Coordinates
y                                                   n                   n
                                                   ∑ xiWi              ∑ yiWi
                       2 (x2, y2), W2
                         (x                       i=1                 i=1
y2                                          x=      n         y=        n
                                                    ∑ Wi               ∑ Wi
     1 (x1, y1), W1
       (x                                          i=1                i=1
y1
                                            where,
                                              x, y = coordinates of new facility
                           3 (x3, y3), W3
                             (x                       at center of gravity
y3
                                             xi, yi = coordinates of existing
                                                      facility i
                                               Wi = annual weight shipped from
                                                      facility i

             x1       x2     x3         x

                                                                   Supplement 7-392
                                                                              7-
Center-of-
              Center-of-Gravity Technique:
              Example
          y                                        A     B     C         D
        700                                   x    200   100   250      500
                       C
        600
                                              y    200   500   600      300
                           (135)
               B                              Wt    75   105   135      60
        500        (105)
Miles




        400
                                   D
        300
                   A                   (60)
        200            (75)
        100

          0   100 200 300 400 500 600 700 x
                        Miles


                                                                Supplement 7-393
                                                                           7-
Center-of-
      Center-of-Gravity Technique:
      Example (cont.)
      n
     ∑ xiWi
     i=1          (200)(75) + (100)(105) + (250)(135) + (500)(60)
x=            =                                                       = 238
         n                     75 + 105 + 135 + 60
      ∑ Wi
     i=1


     n
     ∑ yiWi
     i=1          (200)(75) + (500)(105) + (600)(135) + (300)(60)
y=            =                                                      = 444
      n                        75 + 105 + 135 + 60
      ∑ Wi
     i=1




                                                                    Supplement 7-394
                                                                               7-
Center-of-
              Center-of-Gravity Technique:
              Example (cont.)
          y                                     A          B     C         D
        700                              x     200         100   250      500
                        C
        600
                                         y     200         500   600      300
                            (135)
                B                        Wt     75         105   135      60
        500         (105)
                            Center of gravity (238, 444)
Miles




        400
                                 D
        300
                    A               (60)
        200             (75)
        100

          0    100 200 300 400 500 600 700 x
                         Miles


                                                                  Supplement 7-395
                                                                             7-
Center-of-
Center-of-Gravity Technique
with Excel and OM Tools




                          Supplement 7-396
                                     7-
Load-
 Load-Distance Technique


Compute (Load x Distance) for each site
Choose site with lowest (Load x Distance)
Distance can be actual or straight-line
                          straight-




                                      Supplement 7-397
                                                 7-
Load-
     Load-Distance Calculations
                                   n
                      LD =        ∑ ld   i     i

                                  i=1
where,
LD =      load-
          load-distance value
li   =   load expressed as a weight, number of trips or units
         being shipped from proposed site and location i
di   =   distance between proposed site and location i
di   =    (xi - x)2 + (yi - y)2
                      (y
where,
(x,y) = coordinates of proposed site
 x,y)
(xi , yi) = coordinates of existing facility

                                                       Supplement 7-398
                                                                  7-
Load-
        Load-Distance: Example
     Potential Sites                               Suppliers
     Site   X          Y                    A      B      C        D
     1      360        180        X         200    100    250      500
     2      420        450        Y         200    500    600      300
     3      250        400        Wt        75     105    135      60

   Compute distance from each site to each supplier

Site 1 dA =   (xA - x1)2 + (yA - y1)2   =   (200-360)2 + (200-180)2 = 161.2
                                            (200-        (200-

      dB =    (xB - x1)2 + (yB - y1)2 =     (100-360)2 + (500-180)2 = 412.3
                                            (100-        (500-

      dC = 434.2                  dD = 184.4


                                                                Supplement 7-399
                                                                           7-
Load-
         Load-Distance: Example (cont.)
        Site 2 dA = 333    dB = 323.9 dC = 226.7 dD = 170
        Site 3 dA = 206.2 dB = 180.3 dC = 200      dD = 269.3

  Compute load-distance
          load-
                                     n
                          LD =     ∑ ld   i   i
                                   i=1
Site 1 = (75)(161.2) + (105)(412.3) + (135)(434.2) + (60)(434.4) = 125,063
Site 2 = (75)(333) + (105)(323.9) + (135)(226.7) + (60)(170) = 99,789
Site 3 = (75)(206.2) + (105)(180.3) + (135)(200) + (60)(269.3) = 77,555*

                                * Choose site 3
                                                             Supplement 7-400
                                                                        7-
Load-
Load-Distance Technique
with Excel and OM Tools




                          Supplement 7-401
                                     7-
Chapter 8

  Human Resources
         Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

 Human Resources and Quality Management
 Changing Nature of Human Resources
 Management
 Contemporary Trends in Human Resources
 Management
 Employee Compensation
 Managing Diversity in Workplace
 Job Design
 Job Analysis
 Learning Curves

                                          8-403
Human Resources and Quality
 Management
Employees play important       Employees have power to
role in quality management     make decisions that will
Malcolm Baldrige National      improve quality and customer
Quality Award winners have a   service
pervasive human resource       Strategic goals for quality and
focus                          customer satisfaction require
Employee training and          teamwork and group
education are recognized as    participation
necessary long-term
investments




                                                          8-404
Changing Nature of Human
 Resources Management
Scientific management         Assembly-line
  Breaking down jobs into       Production meshed with
  elemental activities and      principles of scientific
  simplifying job design        management
Jobs                          Advantages of task
  Comprise a set of tasks,    specialization
  elements, and job motions     High output, low costs,
  (basic physical               and minimal training
  movements)
                              Disadvantages of task
In a piece-rate wage          specialization
system, pay is based on         Boredom, lack of
output                          motivation, and physical
                                and mental fatigue

                                                          8-405
Employee Motivation
Motivation                            Improving Motivation
 willingness to work hard because    (cont.)
 that effort satisfies an employee    design of jobs to fit employee
 need                                 work responsibility
Improving Motivation                  empowerment
 positive reinforcement and           restructuring of jobs when
 feedback                             necessary
 effective organization and           rewards based on company as
 discipline                           well as individual performance
 fair treatment of people             achievement of company goals
 satisfaction of employee needs
 setting of work-related goals


                                                                8-406
Evolution of Theories of
          Employee Motivation
 Abraham Maslow’s            Douglas McGregor’s          Frederick Herzberg’s
 Pyramid of Human           Theory X and Theory Y         Hygiene/Motivation
      Needs                                                    Theories
                            •Theory X Employee          •Hygiene Factors
                             • Dislikes work              • Company policies
                             • Must be coerced            • Supervision
                             • Shirks responsibility      • Working conditions
         Self-
         Self-               • Little ambition            • Interpersonal relations
     actualization           • Security top motivator     • Salary, status, security
                            •Theory Y Employee          •Motivation Factors
        Esteem                                            • Achievement
                             • Work is natural
        Social               • Self-directed
                               Self-                      • Recognition
                             • Controlled                 • Job interest
   Safety/Security                                        • Responsibility
                             • Accepts responsibility
Physiological (financial)    • Makes good decisions       • Growth
                                                          • Advancement

                                                                             8-407
Contemporary Trends in
 Human Resources Management
Job training                   Empowerment
   extensive and varied
                                 giving employees
   two of Deming’s 14 points
   refer to employee             authority to make
   education and training        decisions
Cross Training                 Teams
   an employee learns more       group of employees work
   than one job
                                 on problems in their
Job rotation                     immediate work area
   horizontal movement
   between two or more jobs
   according to a plan



                                                     8-408
Contemporary Trends in Human
 Resources Management (cont.)
Job enrichment                    Alternative workplace
   vertical enlargement             nontraditional work location
     allows employees control
     over their work              Telecommuting
   horizontal enlargement           employees work
     an employee is assigned a
                                    electronically from a
     complete unit of work with     location they choose
     defined start and end        Temporary and part-time
Flexible time                     employees
   part of a daily work             mostly in fast-food and
   schedule in which                restaurant chains, retail
   employees can choose             companies, package delivery
   time of arrival and              services, and financial firms
   departure

                                                             8-409
Employee Compensation
Types of pay
  hourly wage
    the longer someone works, the more s/he is paid
  individual incentive or piece rate
    employees are paid for the number of units they produce
    during the workday
  straight salary
    common form of payment for management
  commissions
    usually applied to sales and salespeople


                                                          8-410
Employee Compensation (cont.)

 Gainsharing
   an incentive plan joins employees
   in a common effort to achieve
   company goals in which they
   share in the gains
 Profit sharing
   sets aside a portion of profits for
   employees at year’s end


                                         8-411
Managing Diversity in
 Workplace
Workforce has become more diverse
  4 out of every 10 people entering workforce during
  the decade from 1998 to 2008 will be members of
  minority groups
  In 2000 U.S. Census showed that some minorities,
  primarily Hispanic and Asian, are becoming
  majorities
Companies must develop a strategic approach
to managing diversity

                                                  8-412
Affirmative Actions vs.
 Managing Diversity
Affirmative action            Managing diversity
   an outgrowth of laws and     process of creating a work
   regulations                  environment in which all
   government initiated and     employees can contribute
   mandated                     to their full potential in
   contains goals and           order to achieve a
   timetables designed to       company’s goals
   increase level of            voluntary in nature, not
   participation by women       mandated
   and minorities to attain     seeks to improve internal
   parity levels in a           communications and
   company’s workforce          interpersonal
   not directly concerned       relationships, resolve
   with increasing company      conflict, and increase
   success or increasing        product quality,
   profits                      productivity, and efficiency
                                                        8-413
Diversity Management Programs


Education
Awareness
Communication
Fairness
Commitment



                                8-414
Global Diversity Issues

Cultural, language, geography
   significant barriers to managing a globally diverse workforce
E-mails, faxes, Internet, phones, air travel
   make managing a global workforce possible but not
   necessarily effective
How to deal with diversity?
   identify critical cultural elements
   learn informal rules of communication
   use a third party who is better able to bridge cultural gap
   become culturally aware and learn foreign language
   teach employees cultural norm of organization


                                                                 8-415
Attributes of Good Job Design

An appropriate degree of   Goals and achievement
repetitiveness             feedback
An appropriate degree of   A perceived contribution
attention and mental       to a useful product or
absorption                 service
Some employee              Opportunities for
responsibility for         personal relationships
decisions and discretion   and friendships
Employee control over      Some influence over the
their own job              way work is carried out
                           in groups
                           Use of skills

                                                8-416
Factors in Job Design

Task analysis
  how tasks fit together to form a job
Worker analysis
  determining worker capabilities and responsibilities for a
  job
Environment analysis
  physical characteristics and location of a job
Ergonomics
  fitting task to person in a work environment
Technology and automation
  broadened scope of job design


                                                               8-417
Elements of Job Design




                         8-418
Job Analysis

Method Analysis (work methods)
  Study methods used in the work included in
  the job to see how it should be done
  Primary tools are a variety of charts that
  illustrate in different ways how a job or work
  process is done




                                              8-419
Process Flowchart Symbols
 Operation:
 An activity directly contributing to product or service
  Transportation:
  Moving the product or service from one location to another
  Inspection:
  Examining the product or service for completeness,
  irregularities, or quality
  Delay:
  Process having to wait
  Storage:
  Store of the product or service



                                                           8-420
Process Flowchart




                    8-421
Job Photo-Id Cards
                Photo-                                              Date   10/14
          Time                                Time
          (min)          Operator             (min)      Photo Machine


          –1
                  Key in customer data         2.6    Idle
                  on card
          –2
Worker-
Worker-           Feed data card in            0.4    Accept card
Machine   –3      Position customer for photo 1.0     Idle
  Chart
                  Take picture                 0.6    Begin photo process
          –4

          –5
                  Idle                         3.4    Photo/card processed

          –6

          –7
                  Inspect card & trim edges    1.2    Idle

          –8

                                                                               8-422
          –9
Worker-
        Worker-Machine Chart: Summary


                              Summary
         Operator Time   %              Photo Machine Time   %

Work     5.8             63             4.8                  52

Idle     3.4             37             4.4                  48

Total    9.2 min         100%           9.2 Min              100%




                                                                    8-423
Motion Study

Used to ensure efficiency of motion in
a job
Frank & Lillian Gilbreth
Find one “best way” to do task
Use videotape to study motions




                                         8-424
General Guidelines for
  Motion Study
Efficient Use Of Human Body
   Work
     simplified, rhythmic and symmetric
   Hand/arm motions
     coordinated and simultaneous
   Employ full extent of physical capabilities
   Conserve energy
     use machines, minimize distances, use momentum
   Tasks
     simple, minimal eye contact and muscular effort, no
    unnecessary motions, delays or idleness

                                                           8-425
General Guidelines for
   Motion Study
Efficient Arrangement of Workplace
   Tools, material, equipment - designated, easily accessible
   location
   Comfortable and healthy seating and work area
Efficient Use of Equipment
   Equipment and mechanized tools enhance worker abilities
   Use foot-operated equipment to relieve hand/arm stress
       foot-
   Construct and arrange equipment to fit worker use




                                                                8-426
Learning Curves

Illustrates




                      Processing time per unit
improvement rate of
workers as a job is
repeated
Processing time per
unit decreases by a
constant percentage
each time output
doubles                                          Units produced



                                                              8-427
Learning Curves (cont.)

            Time required for the nth unit =

                                       tn = t1n b
where:
     tn =   time required for nth unit produced
     t1 =   time required for first unit produced
     n=     cumulative number of units produced
     b=       ln r where r is the learning curve percentage
              ln 2 (decimal coefficient)



                                                              8-428
Learning Curve Effect

Contract to produce 36 computers.
t1 = 18 hours, learning rate = 80%
What is time for 9th, 18th, 36th units?

 t9 = (18)(9)ln(0.8)/ln 2 = (18)(9)-0.322
    = (18)/(9)0.322 = (18)(0.493) = 8.874hrs
t18 = (18)(18)ln(0.8)/ln 2 = (18)(0.394) = 7.092hrs
t36 = (18)(36)ln(0.8)/ln 2 = (18)(0.315) = 5.674hrs


                                                8-429
Learning Curve for Mass
 Production Job
    Processing time per unit




                               End of improvement

Standard
  time




                                 Units produced


                                                    8-430
Learning Curves (cont.)

Advantages          Limitations
  planning labor      product modifications
  planning budget     negate learning curve
  determining         effect
  scheduling          improvement can derive
  requirements        from sources besides
                      learning
                      industry-derived learning
                      curve rates may be
                      inappropriate


                                            8-431
Chapter 8 Supplement

   Work Measurement
          Operations Management

 Roberta Russell & Bernard W. Taylor, III
Lecture Outline
Time Studies
Work Sampling




                   Supplement 8-433
                              8-
Work Measurement

Determining how long it takes to do a job
Growing importance in service sector
  Services tend to be labor-intensive
                      labor-
  Service jobs are often repetitive
Time studies
  Standard time
    is time required by an average worker to perform a job once
  Incentive piece-rate wage system based on time
            piece-
  study


                                                   Supplement 8-434
                                                              8-
Stopwatch Time
     Study Basic Steps

1.   Establish standard job method
2.   Break down job into elements
3.   Study job
4.   Rate worker’s performance (RF)
5.   Compute average time (t)


                                      Supplement 8-435
                                                 8-
Stopwatch Time Study
     Basic Steps (cont.)
6. Compute normal time
      Normal Time = (Elemental average) x (rating factor)

                            Nt = (t )(RF)
                                    )(RF)

                 Normal Cycle Time = NT = ΣNt

7. Compute standard time
 Standard Time = (normal cycle time) x (1 + allowance factor)

                       ST = (NT)(1 + AF)

                                                       Supplement 8-436
                                                                  8-
Performing a Time Study
                                       Time Study Observation Sheet

Identification of operation                 Sandwich Assembly                                Date       5/17
                                      Operator                      Approval                   Observer
                                       Smith                         Jones                      Russell
                                                        Cycles                                    Summary
                                  1    2     3     4     5     6      7     8     9    10    Σt     t   RF     Nt
  Grasp and lay               t   .04 .05 .05 .04 .06 .05 .06 .06 .07 .05                    .53 .053 1.05 .056
1 out bread slices
                              R .04   .38 .72 1.05 1.40 1.76 2.13 2.50 2.89 3.29
    Spread mayonnaise         t .07   .06   .07 .08 .07 .07         .08    .10   .09   .08   .77 .077 1.00 .077
2
    on both slices            R .11   .44 .79 1.13 1.47 1.83 2.21 2.60 2.98 3.37

    Place ham, cheese,        t .12   .11   .14   .12   .13   .13    .13   .12   .14   .14 1.28 1.28 1.10 .141
3
    and lettuce on bread      R .23 .55     .93 1.25 1.60 1.96 2.34 2.72 3.12 3.51
    Place top on sandwich, t .10 .12 .08 .09 .11 .11 .10 .10 .12 .10 1.03 1.03 1.10 .113
4
    Slice, and stack       R .33 .67 1.01 1.34 1.71 2.07 2.44 2.82 3.24 3.61



                                                                                               Supplement 8-437
                                                                                                          8-
Performing a Time
Study (cont.)
                               Σt   0.53
  Average element time = t =      =      = 0.053
                               10    10


  Normal time = (Elemental average)(rating factor)
       Nt = ( t )(RF) = (0.053)(1.05) = 0.056
                )(RF)


       Normal Cycle Time = NT = Σ Nt = 0.387


  ST = (NT) (1 + AF) = (0.387)(1+0.15) = 0.445 min




                                               Supplement 8-438
                                                          8-
Performing a Time
         Study (cont.)

     How many sandwiches can be made in 2 hours?


             120 min
                            = 269.7 or 270 sandwiches
       0.445 min/sandwich




Example 17.3
                                                        Supplement 8-439
                                                                   8-
Number of Cycles
To determine sample size:
                                       2
                                 zs
                            n=
                                 eT
 where
      z = number of standard deviations from the mean in a
          normal distribution reflecting a level of statistical
          confidence

      s=     Σ(xi - x)2 = sample standard deviation from sample
                          time study
               n-1
      T = average job cycle time from the sample time study
      e = degree of error from true mean of distribution


                                                           Supplement 8-440
                                                                      8-
Number of Cycles: Example
• Average cycle time = 0.361
• Computed standard deviation = 0.03
• Company wants to be 95% confident that computed time is
  within 5% of true average time




                 2                      2
            zs           (1.96)(0.03)
      n=         =                 = 10.61 or 11
            eT          (0.05)(0.361)




                                                     Supplement 8-441
                                                                8-
Number of Cycles: Example
(cont.)




                            Supplement 8-442
                                       8-
Developing Time Standards
 without a Time Study
Elemental standard time     Advantages
files                         worker cooperation
  predetermined job           unnecessary
  element times
                              workplace uninterrupted
Predetermined motion          performance ratings
times                         unnecessary
  predetermined times for     consistent
  basic micro-motions
        micro-
Time measurement units      Disadvantages
  TMUs = 0.0006 minute        ignores job context
  100,000 TMU = 1 hour        may not reflect skills and
                              abilities of local workers


                                             Supplement 8-443
                                                        8-
MTM Table for MOVE
            TIME (TMU) WEIGHT ALLOWANCE
DISTANCE                                    Hand in      Weight                     Static
MOVED                                       motion        (lb)      Dynamic        constant
(INCHES)     A             B         C        B          up to:      factor          TMU
3/4 or less  2.0           2.0       2.0
1            2.5           2.9       3.4       2.3          2.5       1.00               0
2            3.6           4.6       5.2       2.9
3            4.9           5.7       6.7       3.6          7.5       1.06             2.2
4            6.1           6.9       8.0       4.3
…
20          19.2          18.2      22.1      15.6        37.5        1.39           12.5

A. Move object to other hand or against stop
B. Move object to approximate or indefinite location
C. Move object to exact location            Source: MTM Association for Standards and Research.



                                                                               Supplement 8-444
                                                                                          8-
Work Sampling

Determines the proportion of time a worker
spends on activities
Primary uses of work sampling are to
determine
  ratio delay
    percentage of time a worker or machine is delayed or idle
  analyze jobs that have non-repetitive tasks
                         non-
Cheaper, easier approach to work
measurement

                                                   Supplement 8-445
                                                              8-
Steps of Work Sampling
1.    Define job activities
2.    Determine number of observations in work sample
                                  2
                              z
                      n=      e p(1 - p)
where
     n = sample size (number of sample observations)
     z = number of standard deviations from mean for desired
         level of confidence
     e = degree of allowable error in sample estimate
     p = proportion of time spent on a work activity estimated
         prior to calculating work sample

                                                          Supplement 8-446
                                                                     8-
Steps of Work Sampling
   (cont.)
3. Determine length of sampling
   period
4. Conduct work sampling study;
   record observations
5. Periodically re-compute number
                re-
   of observations


                                    Supplement 8-447
                                               8-
Work Sampling: Example
What percent of time is spent looking up
information? Current estimate is p = 30%
Estimate within +/- 2%, with 95% confidence
                +/-


               2                      2
           z                  1.96
     n=        p(1 - p) =             (0.3)(0.7) = 2016.84 or 2017
           e                  0.02

After 280 observations, p = 38%

                       2                    2
                   z                 1.96
          n=           p(1 - p) =           (0.38)(0.62) = 2263
                   e                 0.02

                                                          Supplement 8-448
                                                                     8-
Supplement 8-449
           8-
Chapter 9

Project Management
         Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

 Project Planning
 Project Scheduling
 Project Control
 CPM/PERT
 Probabilistic Activity Times
 Microsoft Project
 Project Crashing and Time-Cost
 Trade-off
                                  9-451
Project Management Process
Project
  unique, one-time operational activity or effort




                                                    9-452
Project Management Process
(cont.)




                             9-453
Project Management Process
(cont.)




                             9-454
Project Elements

Objective
Scope
Contract requirements
Schedules
Resources
Personnel
Control
Risk and problem analysis

                            9-455
Project Team and Project Manager

Project team
  made up of individuals from various areas and
  departments within a company
Matrix organization
  a team structure with members from functional
  areas, depending on skills required
Project manager
  most important member of project team


                                                  9-456
Scope Statement and Work
 Breakdown Structure

Scope statement
  a document that provides an understanding,
  justification, and expected result of a project
Statement of work
  written description of objectives of a project
Work breakdown structure (WBS)
  breaks down a project into components,
  subcomponents, activities, and tasks

                                              9-457
Work Breakdown Structure for Computer Order
         Processing System Project



                                              9-458
Responsibility Assignment Matrix
                        Organizational
                        Breakdown
                        Structure (OBS)
                          a chart that
                          shows which
                          organizational
                          units are
                          responsible for
                          work items
                        Responsibility
                        Assignment
                        Matrix (RAM)
                          shows who is
                          responsible for
                          work in a
                          project
                                   9-459
Global and Diversity Issues in
 Project Management
In existing global business environment,
project teams are formed from different
genders, cultures, ethnicities, etc.
In global projects diversity among team
members can add an extra dimension to
project planning
Cultural research and communication are
important elements in planning process


                                           9-460
Project Scheduling

Steps                Techniques
 Define activities    Gantt chart
 Sequence             CPM/PERT
 activities           Microsoft Project
 Estimate time
 Develop schedule



                                      9-461
Gantt Chart

Graph or bar chart with a bar for each
project activity that shows passage of
time
Provides visual display of project
schedule
Slack
  amount of time an activity can be delayed
  without delaying the project


                                              9-462
Example of Gantt Chart
                                 Month
                 0   |   2   |    4      |   6   |   8   |   10
Activity

Design house
and obtain
financing

Lay foundation

Order and
receive
materials

Build house


Select paint


Select carpet
                     1       3           5       7       9
                                 Month
Finish work
                                                             9-463
Project Control
Time management
Cost management
Quality management
Performance management
  Earned Value Analysis
    a standard procedure for numerically measuring a
    project’s progress, forecasting its completion date and
    cost and measuring schedule and budget variation
Communication
Enterprise project management


                                                              9-464
CPM/PERT

Critical Path Method (CPM)
  DuPont & Remington-Rand (1956)
             Remington-
  Deterministic task times
  Activity-on-
  Activity-on-node network construction
Project Evaluation and Review Technique
(PERT)
  US Navy, Booz, Allen & Hamilton
  Multiple task time estimates; probabilistic
  Activity-on-
  Activity-on-arrow network construction

                                                9-465
Project Network
Activity-on-node (AON)
  nodes represent activities,
  and arrows show                      Node
  precedence relationships
Activity-on-arrow (AOA)
  arrows represent activities   1            2    3
  and nodes are events for
  points in time
Event                               Branch
  completion or beginning
  of an activity in a project
Dummy
  two or more activities
  cannot share same start
  and end nodes
                                                 9-466
AOA Project Network for
    a House

                              3
            Lay                       Dummy
            foundation
                          2       0             Build                Finish
        3                     1                 house                work
1                  2                     4          3
                                                             6          1
                                                                              7
    Design house       Order and
    and obtain         receive                  1       1
                                       Select               Select
    financing          materials       paint                carpet
                                                    5




                                                                                  9-467
Concurrent Activities

                                             3
    Lay foundation         Lay
                                                     Dummy
                           foundation
                                         2       0
   2               3
                                             1
     Order material               2                    4
                                      Order material


(a) Incorrect precedence        (b) Correct precedence
    relationship                    relationship




                                                             9-468
AON Network for House
  Building Project
                   Lay foundations         Build house

                          2                  4
                                                              Finish work
                          2                  3
                                                                    7
Start      1                                                        1
           3
    Design house                                       6
     and obtain          3
      financing          1             5               1
                                       1            Select carpet
               Order and receive
                  materials          Select paint




                                                                        9-469
Critical Path
                                 2         4
                                 2         3
                                                           7
     Start        1                                        1
                  3

                                3                6
                                1     5          1
                                      1

A:     1-2-4-7
       3 + 2 + 3 + 1 = 9 months           Critical path
B:     1-2-5-6-7                              Longest path
       3 + 2 + 1 + 1 + 1 = 8 months           through a network
C:     1-3-4-7                                Minimum project
       3 + 1 + 3 + 1 = 8 months
D:     1-3-5-6-7
                                              completion time
       3 + 1 + 1 + 1 + 1 = 7 months
                                                               9-470
Activity Start Times

                                  Start at 5 months

                      2                4
                                                    Finish at 9 months
                      2                3
                                                               7     Finish
Start     1                                                    1
          3

                      3                         6
                      1           5             1
                                  1        Start at 6 months
              Start at 3 months




                                                                         9-471
Node Configuration
Activity number             Earliest start


                                               Earliest finish
                    1   0   3


                    3   0   3
                                               Latest finish


Activity duration               Latest start


                                                           9-472
Activity Scheduling

Earliest start time (ES)
   earliest time an activity can start
   ES = maximum EF of immediate predecessors
Forward pass
   starts at beginning of CPM/PERT network to
   determine earliest activity times
Earliest finish time (EF)
   earliest time an activity can finish
   earliest start time plus activity time
   EF= ES + t



                                                9-473
Earliest Activity Start and
         Finish Times
                               Lay foundations
                                                             Build house
                               2       3   5
 Start                                                   4       5   8
                               2
                                                         3

         1   0     3                                                                 7   8    9
         1                                                                           1
Design house
 and obtain                                                          6   6   7       Finish work
  financing            3   3       4
                                                                     1
                       1                         5   5       6
                                                                     Select carpet
                 Order and receive               1
                    materials                    Select pain


                                                                                             9-474
Activity Scheduling (cont.)

Latest start time (LS)
   Latest time an activity can start without delaying
   critical path time
   LS= LF - t
Latest finish time (LF)
   latest time an activity can be completed without
   delaying critical path time
   LF = minimum LS of immediate predecessors
Backward pass
   Determines latest activity times by starting at the end
   of CPM/PERT network and working forward


                                                             9-475
Latest Activity Start and
         Finish Times
                               Lay foundations
                                                             Build house
                               2       3   5
 Start                                                   4       5   8
                               2       3   5
                                                         3       5   8

         1   0     3                                                                 7   8    9
         1   0     3                                                                 1   8    9
Design house
 and obtain                                                          6   6   7       Finish work
  financing            3   3       4
                                                                     1   7   8
                       1   4       5             5   5       6
                                                                     Select carpet
                 Order and receive               1   6       7
                    materials                    Select pain



                                                                                             9-476
Activity Slack

 Activity     LS      ES   LF   EF   Slack S
   *1             0   0    3    3      0
   *2             3   3    5    5      0
    3             4   3    5    4      1
   *4             5   5    8    8      0
    5             6   5    7    6      1
    6             7   6    8    7      1
   *7             8   8    9    9      0
* Critical Path



                                               9-477
Probabilistic Time Estimates
Beta distribution
  a probability distribution traditionally used in
  CPM/PERT
                                         a + 4m + b
                                             4m
    Mean (expected time):    t=
                                               6
                                                   2
                                         b-a
                 Variance:        σ =
                                   2
                                          6
     where
              a = optimistic estimate
              m = most likely time estimate
              b = pessimistic time estimate

                                                       9-478
P(time)
              Examples of Beta Distributions




                                        P(time)
          a     m       t           b             a          t   m     b
                    Time                              Time
                      P(time)




                                a   m=t               b
                                        Time

                                                                     9-479
Project Network with Probabilistic
        Time Estimates: Example
         Equipment
         installation                  Equipment testing
                                        and modification
             1                     4
           6,8,10               2,4,12            System       Final
                                                  training   debugging
           System                                               10
         development                               8
                         Manual                   3,7,11       1,4,7
Start        2           testing                                          Finish
            3,6,9
                           5                                    11
           Position       2,3,4                    9          1,10,13
          recruiting                              2,4,6
                        Job Training                           System
             3              6                    System      changeover
            1,3,5          3,4,5                 testing

                        Orientation
                            7
                           2,2,2


                                                                             9-480
Activity Time Estimates
           TIME ESTIMATES (WKS)   MEAN TIME   VARIANCE

ACTIVITY   a       m         b        t          б2
  1        6        8        10       8         0.44
  2        3        6         9       6         1.00
  3        1        3         5       3         0.44
  4        2        4        12       5         2.78
  5        2        3         4       3         0.11
  6        3        4         5       4         0.11
  7        2        2         2       2         0.00
  8        3        7        11       7         1.78
  9        2        4         6       4         0.44
 10        1        4         7       4         1.00
 11        1       10        13       9         4.00

                                                         9-481
Activity Early, Late Times,
 and Slack
ACTIVITY   t   б2     ES   EF   LS   LF   S
  1        8   0.44    0    8    1    9    1
  2        6   1.00    0    6    0    6    0
  3        3   0.44    0    3    2    5    2
  4        5   2.78    8   13   16   21    8
  5        3   0.11    6    9    6    9    0
  6        4   0.11    3    7    5    9    2
  7        2   0.00    3    5   14   16   11
  8        7   1.78    9   16    9   16    0
  9        4   0.44    9   13   12   16    3
 10        4   1.00   13   17   21   25    8
 11        9   4.00   16   25   16   25    0

                                               9-482
Earliest, Latest, and Slack
                                              Critical Path
        1 0   8     4 8     13
        8 1   9     5 16 21
                                            10 13 17

                                       16
                                            1 0   3
                                 8 9
Start   2 0   6                                          Finish
                                 7 9   16
        6 0   6         9
                  5 6                        11 16 25
                  3 6   9        9 9   13
                                             9 16 25
                                 4 12 16
        3 0   3   6 3   7
        3 2   5   4 5   9

                  7 3 5
                  2 14 16



                                                              9-483
Total project variance


σ2 = б22 + б52 + б82 + б112

σ   = 1.00 + 0.11 + 1.78 + 4.00

    = 6.89 weeks




                                  9-484
9-485
Probabilistic Network Analysis
Determine probability that project is
completed within specified time
                    x-µ
               Z=
                     σ
where
     µ = tp = project mean time
     σ = project standard deviation
     x = proposed project time
     Z = number of standard deviations x
         is from mean
                                        9-486
Normal Distribution of
Project Time
                            Probability




                       Zσ




              µ = tp        x             Time


                                            9-487
Southern Textile Example
   What is the probability that the project is completed within 30
   weeks?


P(x ≤ 30 weeks)                                                   x-µ
                                     σ   2   = 6.89 weeks   Z =
                                                                   σ
                                     σ       =   6.89        =    30 - 25
                                                                   2.62
                                     σ       = 2.62 weeks
                                                             = 1.91
                  µ = 25 x = 30   Time (weeks)



From Table A.1, (appendix A) a Z score of 1.91 corresponds to a
probability of 0.4719. Thus P(30) = 0.4719 + 0.5000 = 0.9719

                                                                        9-488
Southern Textile Example
 What is the probability that the project is completed within 22
 weeks?
                                                                   x-µ
     P(x ≤ 22 weeks)
                                σ   2   = 6.89 weeks     Z =
                                                                    σ
                                σ       =   6.89            =      22 - 25
                                                                    2.62
                                σ       = 2.62 weeks
                                                            = -1.14


              x = 22 µ = 25   Time
                              (weeks)

From Table A.1 (appendix A) a Z score of -1.14 corresponds to a
probability of 0.3729. Thus P(22) = 0.5000 - 0.3729 = 0.1271

                                                                         9-489
Microsoft Project

Popular software package for project
management and CPM/PERT analysis
Relatively easy to use




                                       9-490
Microsoft Project (cont.)




                            9-491
Microsoft Project (cont.)




                            9-492
Microsoft Project (cont.)




                            9-493
Microsoft Project (cont.)




                            9-494
Microsoft Project (cont.)




                            9-495
Microsoft Project (cont.)




                            9-496
PERT Analysis with
Microsoft Project




                     9-497
PERT Analysis with
Microsoft Project (cont.)




                            9-498
PERT Analysis with
Microsoft Project (cont.)




                            9-499
Project Crashing

Crashing
  reducing project time by expending additional
  resources
Crash time
  an amount of time an activity is reduced
Crash cost
  cost of reducing activity time
Goal
  reduce project duration at minimum cost

                                                  9-500
Project Network for Building
a House

         2         4
                   12
         8
                            7
   1                        4
   12


        3               6
        4      5        4
               4




                                9-501
Normal Time and Cost
vs. Crash Time and Cost
$7,000 –


$6,000 –
           Crash cost

$5,000 –                          Crashed activity

                                                Slope = crash cost per week
$4,000 –

                                                      Normal activity
$3,000 –
           Normal cost

$2,000 –

                 Crash time                             Normal time
$1,000 –
             |      |         |     |      |      |        |
      0      2      4         6     8     10     12       14            Weeks
      –

                                                                              9-502
Project Crashing: Example

                                                       TOTAL
            NORMAL     CRASH                         ALLOWABLE     CRASH
              TIME      TIME     NORMAL     CRASH    CRASH TIME   COST PER
ACTIVITY    (WEEKS)   (WEEKS)     COST       COST     (WEEKS)      WEEK

  1           12         7       $3,000     $5,000       5          $400
  2            8         5        2,000      3,500       3           500
  3            4         3        4,000      7,000       1          3,000
  4           12         9       50,000     71,000       3          7,000
  5            4         1         500       1,100       3           200
  6            4         1         500       1,100       3           200
  7            4         3       15,000     22,000       1          7,000

                                $75,000   $110,700
                                                                      9-503
$500               $7000
                                                                 Project Duration:
               2                   4
                                                    $700             36 weeks
               8                  12
                                                      7
     1                                                4                  FROM …
    12

   $400       3                               6
              4             5                 4
                            4                $200
            $3000
                          $200

                                       $500                $7000

                                         2                   4
                                         8                  12              $700
                                                                              7
     TO…              1                                                       4
                      7

Project Duration:    $400                3                           6
    31 weeks                             4           5               4
Additional Cost:                                     4             $200
                                   $3000
     $2000                                          $200

                                                                                   9-504
Time-
   Time-Cost Relationship

Crashing costs increase as project
duration decreases
Indirect costs increase as project
duration increases
Reduce project length as long as
crashing costs are less than indirect
costs


                                        9-505
Time-
           Time-Cost Tradeoff
           Minimum cost = optimal project time
                                                 Total project cost

                                                  Indirect cost
Cost ($)




                                                  Direct cost

                           Crashing                         Time
                              Project duration

                                                                      9-506
Chapter 10
Supply Chain Management
   Strategy and Design
       Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

The Management of Supply Chains
Information Technology: A Supply Chain
Enabler
Supply Chain Integration
Supply Chain Management (SCM)
Software
Measuring Supply Chain Performance

                                    10-508
                                    10-
Supply Chains

  All facilities, functions, and activities
 associated with flow and transformation
of goods and services from raw materials
  to customer, as well as the associated
                information flows
  An integrated group of processes to
 “source,” “make,” and “deliver” products



                                              10-509
                                              10-
Supply Chain Illustration
                            10-510
                            10-
Supply
 Chain
   for
Denim
 Jeans


         10-511
         10-
Supply
Chain
for
Denim
Jeans
(cont.)

    10-512
    10-
Supply Chain Processes




                         10-513
                         10-
Supply Chain for Service
  Providers

More difficult than manufacturing
Does not focus on the flow of physical goods
Focuses on human resources and support
services
More compact and less extended



                                               10-514
                                               10-
Value Chains
Value chain
  every step from raw materials to the eventual end user
  ultimate goal is delivery of maximum value to the end user
Supply chain
  activities that get raw materials and subassemblies into
  manufacturing operation
  ultimate goal is same as that of value chain
Demand chain
  increase value for any part or all of chain
Terms are used interchangeably
Value
  creation of value for customer is important aspect of supply
  chain management

                                                             10-515
                                                             10-
Supply Chain
 Management (SCM)
Managing flow of information through supply
chain in order to attain the level of
synchronization that will make it more
responsive to customer needs while lowering
costs
Keys to effective SCM
  information
  communication
  cooperation
  trust


                                          10-516
                                          10-
Supply Chain
   Uncertainty and Inventory
One goal in SCM:               Factors that contribute to
   respond to uncertainty in   uncertainty
   customer demand                inaccurate demand
   without creating costly        forecasting
   excess inventory               long variable lead times
Negative effects of               late deliveries
uncertainty                       incomplete shipments
   lateness                       product changes
   incomplete orders              batch ordering
Inventory                         price fluctuations and
                                  discounts
   insurance against supply
   chain uncertainty              inflated orders



                                                             10-517
                                                             10-
Bullwhip Effect

Occurs when slight demand variability is magnified as information
                      moves back upstream




                                                              10-518
                                                              10-
Risk Pooling

Risks are aggregated to reduce the
impact of individual risks
  Combine inventories from multiple locations
  into one
  Reduce parts and product variability,
  thereby reducing the number of product
  components
  Create flexible capacity


                                          10-519
                                          10-
Information Technology:
 A Supply Chain Enabler
Information links all aspects of supply chain
E-business
   replacement of physical business processes with electronic
   ones
Electronic data interchange (EDI)
   a computer-to-computer exchange of business documents
Bar code and point-of-sale
   data creates an instantaneous computer record of a sale




                                                             10-520
                                                             10-
Information Technology:
 A Supply Chain Enabler (cont.)
Radio frequency identification (RFID)
   technology can send product data from an item to a reader
   via radio waves
Internet
   allows companies to communicate with suppliers,
   customers, shippers and other businesses around the world
   instantaneously
Build-to-order (BTO)
   direct-sell-to-customers model via the Internet; extensive
   communication with suppliers and customer




                                                                10-521
                                                                10-
Supply Chain Enablers




                        10-522
                        10-
RFID Capabilities




                    10-523
                    10-
RFID Capabilities (cont.)




                            10-524
                            10-
Supply Chain Integration

Information sharing among supply chain
members
   Reduced bullwhip effect
   Early problem detection
   Faster response
   Builds trust and confidence
Collaborative planning, forecasting,
replenishment, and design
   Reduced bullwhip effect
   Lower costs (material, logistics, operating, etc.)
   Higher capacity utilization
   Improved customer service levels


                                                        10-525
                                                        10-
Supply Chain Integration (cont.)

Coordinated workflow, production and
operations, procurement
  Production efficiencies
  Fast response
  Improved service
  Quicker to market
Adopt new business models and
technologies
  Penetration of new markets
  Creation of new products
  Improved efficiency
  Mass customization


                                       10-526
                                       10-
Collaborative Planning, Forecasting,
and Replenishment (CPFR)
Process for two or more companies in
a supply chain to synchronize their
demand forecasts into a single plan to
meet customer demand
Parties electronically exchange
  past sales trends
  point-of-sale data
  on-hand inventory
  scheduled promotions
  forecasts


                                         10-527
                                         10-
Supply Chain Management
 (SCM) Software

Enterprise resource planning (ERP)
  software that integrates the components of a
  company by sharing and organizing
  information and data




                                          10-528
                                          10-
Key Performance Indicators

Metrics used to measure supply chain performance
    Inventory turnover
                                                Cost of goods sold
                   Inventory turns =
                                        Average aggregate value of inventory
    Total value (at cost) of inventory

  Average aggregate value of inventory = ∑ (average inventory for item i ) × (unit value item i )

    Days of supply
                                      Average aggregate value of inventory
                 Days of supply =
                                        (Cost of goods sold)/(365 days)
    Fill rate: fraction of orders filled by a distribution center within a
    specific time period


                                                                                                    10-529
                                                                                                    10-
Computing
Key
Performance
Indicators

              10-530
              10-
Process Control and SCOR

Process Control
  not only for manufacturing operations
  can be used in any processes of supply chain
Supply Chain Operations Reference (SCOR)
  a cross industry supply chain diagnostic tool
  maintained by the Supply Chain Council




                                                  10-531
                                                  10-
SCOR




       10-532
       10-
SCOR
(cont.)




          10-533
          10-
Chapter 11
    Global Supply Chain
Procurement and Distribution
         Operations Management

  Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Procurement
E-Procurement
Distribution
Transportation
The Global Supply Chain



                          11-535
                          11-
Procurement

The purchase of goods and services from suppliers
Cross enterprise teams
  coordinate processes between a company and its supplier
On-
On-demand (direct-response) delivery
          (direct-
  requires the supplier to deliver goods when demanded by the
  customer
Continuous replenishment
  supplying orders in a short period of time according to a
  predetermined schedule




                                                              11-536
                                                              11-
Outsourcing
Sourcing
  selection of suppliers
Outsourcing
  purchase of goods and services from an
  outside supplier
Core competencies
  what a company does best
Single sourcing
  a company purchases goods and services
  from only a few (or one) suppliers

                                           11-537
                                           11-
Categories of Goods and
Services...




                          11-538
                          11-
E-Procurement

Direct purchase from suppliers over the
Internet, by using software packages or
through e-marketplaces, e-hubs, and
         e-               e-
trading exchanges
Can streamline and speed up the
purchase order and transaction process


                                     11-539
                                     11-
E-Procurement (cont.)

What can companies buy over the
Internet?
  Manufacturing inputs
    the raw materials and components that go
    directly into the production process of the product
  Operating inputs
    maintenance, repair, and operation goods and
    services


                                                   11-540
                                                   11-
E-Procurement (cont.)

E-marketplaces (e-hubs)
               (e-
  Websites where companies and suppliers
  conduct business-to-business activities
          business-to-
Reverse auction
  process used by e-marketplaces for buyers
                     e-
  to purchase items; company posts orders on
  the internet for suppliers to bid on


                                         11-541
                                         11-
Distribution

Encompasses all channels, processes, and functions,
   including warehousing and transportation, that a
      product passes on its way to final customer
                    Order fulfillment
    process of ensuring on-time delivery of an order
                          on-
                       Logistics
       transportation and distribution of goods and
                          services
             Driving force today is speed
     Particularly important for Internet dot-coms
                                         dot-



                                                  11-542
                                                  11-
Distribution Centers (DC)
  and Warehousing
   DCs are some of the largest business
          facilities in the United States
Trend is for more frequent orders in smaller
                      quantities
   Flow-
   Flow-through facilities and automated
                  material handling
                  Postponement
   final assembly and product configuration
               may be done at the DC

                                               11-543
                                               11-
Warehouse Management
 Systems
Highly automated system that runs day-to-day
                                  day-to-
               operations of a DC
Controls item putaway, picking, packing, and
                    shipping
                   Features
           transportation management
               order management
                yard management
               labor management
             warehouse optimization



                                               11-544
                                               11-
A WMS
        11-545
        11-
Vendor-
 Vendor-Managed Inventory

Manufacturers generate orders, not distributors or
                       retailers
   Stocking information is accessed using EDI
  A first step towards supply chain collaboration
 Increased speed, reduced errors, and improved
                        service




                                                     11-546
                                                     11-
Collaborative Logistics and
 Distribution Outsourcing

  Collaborative planning, forecasting, and
 replenishment create greater economies of
                     scale
   Internet-
   Internet-based exchange of data and
                  information
Significant decrease in inventory levels and
       costs and more efficient logistics
 Companies focus on core competencies


                                           11-547
                                           11-
Transportation
Rail
   low-value, high-density, bulk
   products, raw materials,
   intermodal containers
   not as economical for small
   loads, slower, less flexible
   than trucking
Trucking
   main mode of freight
   transport in U.S.
   small loads, point-to-point
   service, flexible
   More reliable, less damage
   than rails; more expensive
   than rails for long distance


                                   11-548
                                   11-
Transportation (cont.)

Air
  most expensive and fastest, mode of
  freight transport
  lightweight, small packages <500 lbs
  high-value, perishable and critical
  goods
  less theft
Package Delivery
  small packages
  fast and reliable
  increased with e-Business
  primary shipping mode for Internet
  companies

                                         11-549
                                         11-
Transportation (cont.)
Water
  low-cost shipping mode
  primary means of international shipping
  U.S. waterways
  slowest shipping mode
Intermodal
  combines several modes of shipping-
  truck, water and rail
  key component is containers
Pipeline
  transport oil and products in liquid form
  high capital cost, economical use
  long life and low operating cost


                                              11-550
                                              11-
Internet Transportation
Exchanges
  Bring together shippers and carriers
  Initial contact, negotiations, auctions
                 Examples
                  www.nte.com
             www.freightquote.com




                                            11-551
                                            11-
Global Supply Chain

        International trade barriers have fallen
                New trade agreements
To compete globally requires an effective supply chain
 Information technology is an “enabler” of global trade




                                                          11-552
                                                          11-
Obstacles to Global Chain
 Transactions
Increased documentation for invoices, cargo
insurance, letters of credit, ocean bills of lading or air
waybills, and inspections
Ever changing regulations that vary from country to
country that govern the import and export of goods
Trade groups, tariffs, duties, and landing costs
Limited shipping modes
Differences in communication technology and
availability




                                                        11-553
                                                        11-
Obstacles to Global Chain
 Transactions (cont.)
Different business practices as well as language
barriers
Government codes and reporting requirements that
vary from country to country
Numerous players, including forwarding agents,
custom house brokers, financial institutions, insurance
providers, multiple transportation carriers, and
government agencies
Since 9/11, numerous security regulations and
requirements


                                                    11-554
                                                    11-
Duties and Tariffs
      Proliferation of trade agreements
        Nations form trading groups
             no tariffs or duties within group
          charge uniform tariffs to nonmembers
Member nations have a competitive advantage
               within the group
             Trade specialists
    include freight forwarders, customs house brokers,
   export packers, and export management and trading
                         companies




                                                         11-555
                                                         11-
Duties and Tariffs (cont.)




                             11-556
                             11-
Landed Cost
Total cost of producing, storing, and
transporting a product to the site of
consumption or another port
Value added tax (VAT)
  an indirect tax assessed on the increase in value of
  a good at any stage of production process from
  raw material to final product
Clicker shock
  occurs when an ordered is placed with a company
  that does not have the capability to calculate landed
  cost

                                                   11-557
                                                   11-
Web-
 Web-based International Trade
 Logistic Systems
International trade logistics web-based software
systems reduce obstacles to global trade
  convert language and currency
  provide information on tariffs, duties, and customs processes
  attach appropriate weights, measurements, and unit prices to
  individual products ordered over the Web
  incorporate transportation costs and conversion rates
  calculate shipping costs online while a company enters an
  order
  track global shipments




                                                           11-558
                                                           11-
Recent Trends in Globalization for
 U.S. Companies
Two significant changes
  passage of NAFTA
  admission of China in WTO
Mexico
  cheap labor and relatively short shipping time
China
  cheaper labor and longer work week, but lengthy
  shipping time
  Major supply chains have moved to China

                                                   11-559
                                                   11-
China’s Increasing Role
 in the Global Supply Chain

World’s premier sources of supply
Abundance of low-wage labor
               low-
World’s fastest growing market
Regulatory changes have liberalized its
market
Increased exporting of higher technology
products

                                     11-560
                                     11-
Models in Doing Business in China

Employ local third-party trading agents
             third-
Wholly-
Wholly-owned foreign enterprise
Develop your own international
procurement offices




                                          11-561
                                          11-
Challenges Sourcing from China

Getting reliable information in more
difficult than in the U.S.
Information technology is much less
advanced and sophisticated than in the
U.S.
Work turnover rates among low-skilled
                              low-
workers is extremely high

                                     11-562
                                     11-
Effects of 9/11 on Global Chains

Increase security measures
   added time to supply chain schedules
   Increased supply chain costs
24 hours rules for “risk screening”
   extended documentation
   extend time by 3-4 days
                  3-
Inventory levels have increased 5%
Other costs include:
   new people, technologies, equipment, surveillance,
   communication, and security systems, and training necessary
   for screening at airports and seaports around the world


                                                          11-563
                                                          11-
Chapter 11 Supplement
     Transportation and
    Transshipment Models
          Operations Management

 Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Transportation Model
Transshipment Model




                       Supplement 11-565
                                  11-
Transportation Model

A transportation model is formulated for a class of
problems with the following characteristics
   a product is transported from a number of sources to a
   number of destinations at the minimum possible cost
   each source is able to supply a fixed number of units of
   product
   each destination has a fixed demand for product
Solution Methods
   stepping-
   stepping-stone
   modified distribution
   Excel’s Solver


                                                      Supplement 11-566
                                                                 11-
Transportation Method: Example




                           Supplement 11-567
                                      11-
Transportation Method: Example




                           Supplement 11-568
                                      11-
Problem
Formulation
Using Excel




Total Cost
 Formula




              Supplement 11-569
                         11-
Using Solver
 from Tools
    Menu




    Supplement 11-570
               11-
Solution




           Supplement 11-571
                      11-
Modified
Problem
Solution


           Supplement 11-572
                      11-
Transshipment
Model




                Supplement 11-573
                           11-
Transshipment Model: Solution




                          Supplement 11-574
                                     11-
Chapter 12
         Forecasting

       Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Strategic Role of Forecasting in Supply
Chain Management
Components of Forecasting Demand
Time Series Methods
Forecast Accuracy
Time Series Forecasting Using Excel
Regression Methods

                                      12-576
                                      12-
Forecasting

Predicting the future
Qualitative forecast methods
   subjective
Quantitative forecast
methods
   based on mathematical
   formulas




                               12-577
                               12-
Forecasting and Supply Chain
Management
Accurate forecasting determines how much
inventory a company must keep at various points
along its supply chain
Continuous replenishment
  supplier and customer share continuously updated data
  typically managed by the supplier
  reduces inventory for the company
  speeds customer delivery
Variations of continuous replenishment
  quick response
  JIT (just-in-time)
      (just-in-
  VMI (vendor-managed inventory)
       (vendor-
  stockless inventory

                                                          12-578
                                                          12-
Forecasting

Quality Management
  Accurately forecasting customer demand is
  a key to providing good quality service
Strategic Planning
  Successful strategic planning requires
  accurate forecasts of future products and
  markets


                                              12-579
                                              12-
Types of Forecasting Methods

  Depend on
    time frame
    demand behavior
    causes of behavior




                           12-580
                           12-
Time Frame

Indicates how far into the future is
forecast
  Short- mid-
  Short- to mid-range forecast
    typically encompasses the immediate future
    daily up to two years
  Long-
  Long-range forecast
    usually encompasses a period of time longer
    than two years

                                                  12-581
                                                  12-
Demand Behavior

Trend
  a gradual, long-term up or down movement of
             long-
  demand
Random variations
  movements in demand that do not follow a pattern
Cycle
  an up-and-down repetitive movement in demand
     up-and-
Seasonal pattern
  an up-and-down repetitive movement in demand
     up-and-
  occurring periodically

                                                12-582
                                                12-
Forms of Forecast Movement




                                        Demand
Demand




                              Random
                             movement

                 Time                                        Time
               (a) Trend                                   (b) Cycle




                                        Demand
Demand




                  Time                                        Time
          (c) Seasonal pattern                   (d) Trend with seasonal pattern

                                                                                   12-583
                                                                                   12-
Forecasting Methods
Time series
  statistical techniques that use historical demand data
  to predict future demand
Regression methods
  attempt to develop a mathematical relationship
  between demand and factors that cause its behavior
Qualitative
  use management judgment, expertise, and opinion to
  predict future demand


                                                      12-584
                                                      12-
Qualitative Methods

Management, marketing, purchasing,
and engineering are sources for internal
qualitative forecasts
Delphi method
  involves soliciting forecasts about
  technological advances from experts



                                        12-585
                                        12-
Forecasting Process
   1. Identify the           2. Collect historical      3. Plot data and identify
purpose of forecast                  data                        patterns



 6. Check forecast          5. Develop/compute          4. Select a forecast
accuracy with one or        forecast for period of       model that seems
  more measures                 historical data         appropriate for data


           7.
    Is accuracy of     No      8b. Select new
        forecast
                             forecast model or
     acceptable?
                            adjust parameters of
                               existing model

           Yes
                            9. Adjust forecast based       10. Monitor results
   8a. Forecast over
                            on additional qualitative     and measure forecast
   planning horizon
                             information and insight            accuracy




                                                                          12-586
                                                                          12-
Time Series

Assume that what has occurred in the past will
continue to occur in the future
Relate the forecast to only one factor - time
Include
  moving average
  exponential smoothing
  linear trend line



                                           12-587
                                           12-
Moving Average

Naive forecast
  demand in current period is used as next period’s
  forecast
Simple moving average
  uses average demand for a fixed sequence of
  periods
  stable demand with no pronounced behavioral
  patterns
Weighted moving average
  weights are assigned to most recent data


                                                  12-588
                                                  12-
Moving Average:
Naïve Approach
         ORDERS
MONTH   PER MONTH     FORECAST

        Jan         120 -
        Feb          90
                     120
        Mar         100
                      90
        Apr          75
                     100
        May         110
                      75
        June         50
                     110
        July         75
                      50
        Aug         130
                      75
        Sept        110
                     130
        Oct          90
                     110
                      90
Nov            -
                                 12-589
                                 12-
Simple Moving Average

               n
               Σ D
                  i
              i=1
      MAn =
                   n
   where

   n = number of periods in
         the moving average
    Di = demand in period i




                              12-590
                              12-
3-month Simple Moving Average

                                        3

MONTH
         ORDERS
        PER MONTH
                     MOVING
                    AVERAGE
                                       Σ        Di
                                       i=1
                               MA3 =
Jan        120             –                3
Feb         90             –
Mar        100             –            90 + 110 + 130
Apr         75         103.3       =           3
May        110          88.3
June        50          95.0
July        75          78.3       = 110 orders
Aug        130          78.3          for Nov
Sept       110          85.0
 Oct         90        105.0
 Nov           -       110.0



                                                     12-591
                                                     12-
5-month Simple Moving Average

         ORDERS      MOVING
MONTH   PER MONTH   AVERAGE            5
                                      Σ        Di
Jan        120            –           i=1
Feb         90            –   MA5 =
Mar        100            –                5
Apr         75            –
May        110            –        90 + 110 + 130+75+50
June        50         99.0    =             5
July        75         85.0
Aug        130         82.0
Sept       110         88.0        = 91 orders
 Oct         90        95.0          for Nov
 Nov           -       91.0



                                                    12-592
                                                    12-
Smoothing Effects
         150 –

                                             5-month
         125 –


         100 –
Orders




          75 –


          50 –                                                      3-month

                                    Actual
          25 –


           0–       |     |     |      |   |    |   |      |   |        |       |
                  Jan   Feb   Mar    Apr May June July   Aug Sept     Oct     Nov
                                          Month

                                                                              12-593
                                                                              12-
Weighted Moving Average

                                    Σ Wi Di
                                    n
Adjusts moving average     WMAn =
      method to more                i=1
    closely reflect data
        fluctuations
                           where
                             Wi = the weight for period i,
                                     between 0 and 100
                                          percent

                                        Σ Wi = 1.00

                                                       12-594
                                                       12-
Weighted Moving Average Example

   MONTH            WEIGHT            DATA
   August              17%             130
   September           33%             110
   October             50%              90
                                  3
 November Forecast WMA3 =         Σ1 Wi Di
                                 i=

  = (0.50)(90) + (0.33)(110) + (0.17)(130)

              = 103.4 orders

                                             12-595
                                             12-
Exponential Smoothing


         Averaging method
Weights most recent data more strongly
   Reacts more to recent changes
    Widely used, accurate method




                                         12-596
                                         12-
Exponential Smoothing (cont.)

           Ft +1 = α Dt + (1 - α)Ft
                   where:
         Ft +1 = forecast for next period
    Dt = actual demand for present period
    Ft = previously determined forecast for
                  present period
   α = weighting factor, smoothing constant




                                              12-597
                                              12-
Effect of Smoothing Constant

                   0.0 ≤ α ≤ 1.0
    If α = 0.20, then Ft +1 = 0.20 Dt + 0.80 Ft

      If α = 0, then Ft +1 = 0 Dt + 1 Ft = Ft
  Forecast does not reflect recent data
      If α = 1, then Ft +1 = 1 Dt + 0 Ft = Dt
 Forecast based only on most recent data




                                                  12-598
                                                  12-
Exponential Smoothing (α=0.30)
                               (α

PERIOD    MONTH   DEMAND    F2 = αD1 + (1 - α)F1
   1       Jan      37      = (0.30)(37) + (0.70)(37)
   2       Feb      40                = 37
   3       Mar      41
   4       Apr      37     F3 = αD2 + (1 - α)F2
   5       May      45     = (0.30)(40) + (0.70)(37)
   6       Jun      50              = 37.9
   7       Jul      43
   8       Aug      47
                            F13 = αD12 + (1 - α)F12
   9       Sep      56
                           = (0.30)(54) + (0.70)(50.84)
  10       Oct      52
  11       Nov      55               = 51.79
  12       Dec      54

                                                        12-599
                                                        12-
Exponential Smoothing (cont.)
                               FORECAST, Ft + 1
PERIOD   MONTH   DEMAND   (α = 0.3)  (α = 0.5)
    1      Jan      37         –            –
   2      Feb      40       37.00        37.00
   3      Mar      41       37.90        38.50
   4      Apr      37       38.83        39.75
   5      May      45       38.28        38.37
   6      Jun      50       40.29        41.68
   7      Jul      43       43.20        45.84
   8      Aug      47       43.14        44.42
   9      Sep      56       44.30        45.71
  10      Oct      52       47.81        50.85
  11      Nov      55       49.06        51.42
  12      Dec      54       50.84        53.21
  13      Jan       –       51.79        53.61

                                                  12-600
                                                  12-
Exponential Smoothing (cont.)
         70 –

         60 –                  Actual        α = 0.50

         50 –

         40 –
Orders




                                                                                 α = 0.30
         30 –

         20 –

         10 –

          0–     |    |    |      |      |        |      |    |    |    |    |     |     |
                1    2    3      4      5        6      7    8    9    10   11    12    13
                                              Month

                                                                                       12-601
                                                                                       12-
Adjusted Exponential Smoothing

          AFt +1 = Ft +1 + Tt +1
                where
   T = an exponentially smoothed trend factor

       Tt +1 = β(Ft +1 - Ft) + (1 - β) Tt
                    where
          Tt = the last period trend factor
       β = a smoothing constant for trend




                                                12-602
                                                12-
Adjusted Exponential
         Smoothing (β=0.30)
                   (β
PERIOD   MONTH   DEMAND       T3 = β(F3 - F2) + (1 - β) T2
                              = (0.30)(38.5 - 37.0) + (0.70)(0)
   1      Jan      37
   2      Feb      40                      = 0.45
   3      Mar      41
   4      Apr      37       AF3 = F3 + T3 = 38.5 + 0.45
   5      May      45                   = 38.95
   6      Jun      50
   7      Jul      43           T13 = β(F13 - F12) + (1 - β) T12
   8      Aug      47          = (0.30)(53.61 - 53.21) + (0.70)(1.77)
   9      Sep      56                          = 1.36
  10      Oct      52
  11      Nov      55
  12      Dec      54     AF13 = F13 + T13 = 53.61 + 1.36 = 54.97

                                                             12-603
                                                             12-
Adjusted Exponential Smoothing:
         Example
                              FORECAST    TREND    ADJUSTED
PERIOD    MONTH     DEMAND      Ft +1     Tt +1 FORECAST AFt +1

      1       Jan        37       37.00        –           –
     2       Feb        40       37.00      0.00        37.00
     3       Mar        41       38.50      0.45        38.95
     4       Apr        37       39.75      0.69        40.44
     5       May        45       38.37      0.07        38.44
     6       Jun        50       38.37      0.07        38.44
     7       Jul        43       45.84      1.97        47.82
     8       Aug        47       44.42      0.95        45.37
     9       Sep        56       45.71      1.05        46.76
    10       Oct        52       50.85      2.28        58.13
    11       Nov        55       51.42      1.76        53.19
    12       Dec        54       53.21      1.77        54.98
    13       Jan         –       53.61      1.36        54.96
                                                         12-604
                                                         12-
Adjusted Exponential Smoothing
                     Forecasts
         70 –
                                       Adjusted forecast (β = 0.30)
                                                         (β
         60 –
                                Actual
         50 –
Demand




         40 –

         30 –                                   Forecast (α = 0.50)
                                                         (α


         20 –

         10 –

          0–     |     |    |      |      |     |     |     |     |    |    |    |     |
                1     2    3      4      5     6     7     8     9    10   11   12    13
                                               Period

                                                                                     12-605
                                                                                     12-
Linear Trend Line

                             Σ xy - nxy
      y = a + bx                        b =
                             Σx 2 - nx2


        where                       a = y-bx
    a = intercept
b = slope of the line               where
                             n = number of periods
   x = time period
  y = forecast for          Σx
demand for period x      x = n   = mean of the x values
                            Σy
                        y = n = mean of the y values


                                                    12-606
                                                    12-
Least Squares Example
 x(PERIOD)   y(DEMAND)     xy       x2
        1            73       37          1
        2            40       80          4
        3            41      123          9
        4            37      148         16
        5            45      225         25
        6            50      300         36
    7           43        301      49
         8           47      376     64
         9           56      504     81
        10           52      520    100
        11           55      605    121
        12           54      648    144
        78       557       3867     650



                                              12-607
                                              12-
Least Squares Example
(cont.)
 78
 12                x =      = 6.5
 557
  12              y =      = 46.42
  ∑xy - nxy       3867 - (12)(6.5)(46.42)
b = 2            =                           =1.72
  ∑x - nx2            650 - 12(6.5)2

                     a = y - bx
              = 46.42 - (1.72)(6.5) = 35.2


                                                 12-608
                                                 12-
Linear trend line y = 35.2 + 1.72x
         Forecast for period 13 y = 35.2 + 1.72(13) = 57.56 units

         70 –

         60 –
                               Actual

         50 –
Demand




         40 –
                                              Linear trend line
         30 –

         20 –

         10 –    |    |    |      |      |    |     |     |        |    |    |    |    |
                1    2    3      4      5    6     7     8        9    10   11   12   13
          0–                                 Period


                                                                                      12-609
                                                                                      12-
Seasonal Adjustments

Repetitive increase/ decrease in demand
 Use seasonal factor to adjust forecast


                             Di
    Seasonal factor = Si =
                             ∑D




                                          12-610
                                          12-
Seasonal Adjustment (cont.)
                  DEMAND (1000’S PER QUARTER)
       YEAR     1     2        3      4    Total
       2002    12.6      8.6     6.3   17.5    45.0
       2003    14.1     10.3     7.5   18.2    50.1
       2004    15.3     10.6     8.1   19.6    53.6
       Total   42.0     29.5    21.9   55.3   148.7



     D1   42.0                      D3   21.9
S1 =    =      = 0.28          S3 =    =      = 0.15
     ∑D 148.7                       ∑D 148.7
     D2   29.5                      D4   55.3
S2 =    =      = 0.20          S4 =    =      = 0.37
     ∑D 148.7                       ∑D 148.7

                                                      12-611
                                                      12-
Seasonal Adjustment (cont.)


For 2005

  y = 40.97 + 4.30x = 40.97 + 4.30(4) = 58.17
              4.30x

     SF1 = (S1) (F5) = (0.28)(58.17) = 16.28
           (S (F
     SF2 = (S2) (F5) = (0.20)(58.17) = 11.63
           (S (F
      SF3 = (S3) (F5) = (0.15)(58.17) = 8.73
            (S (F
     SF4 = (S4) (F5) = (0.37)(58.17) = 21.53
           (S (F


                                                12-612
                                                12-
Forecast Accuracy

Forecast error
  difference between forecast and actual demand
  MAD
    mean absolute deviation
  MAPD
    mean absolute percent deviation
  Cumulative error
  Average error or bias



                                                  12-613
                                                  12-
Mean Absolute Deviation
(MAD)

             Σ| Dt - Ft |
       MAD =     n

             where
           t = period number
       Dt = demand in period t
       Ft = forecast for period t
      n = total number of periods
           = absolute value

                                    12-614
                                    12-
MAD Example
PERIOD   DEMAND, Dt   Ft (α =0.3)   (Dt - Ft)   |Dt - Ft|
   1        37        37.00        –                   –
   2        40        37.00     3.00                3.00
   3        41
                  Σ| D37.90 t | 3.10
                       t - F
                                                    3.10
   4
   5
            MAD = 38.28 -6.72
            37
            45
                      38.83
                       n
                                1.83                1.83
                                                    6.72
   6        50        40.29     9.69                9.69
   7        43
                   53.39
                 = 43.20 -0.20                      0.20
   8        47       11
                      43.14     3.86                3.86
   9        56
  10        52
               = 4.85 44.30 11.70
                      47.81     4.19
                                                   11.70
                                                    4.19
  11        55        49.06     5.94                5.94
  12        54        50.84     3.15                3.15
            557                       49.31        53.39


                                                            12-615
                                                            12-
Other Accuracy Measures

Mean absolute percent deviation (MAPD)
                   ∑|Dt - Ft|
            MAPD =
                     ∑Dt
 Cumulative error
                    E = ∑et
 Average error
                          ∑et
                     E=
                          n
                                         12-616
                                         12-
Comparison of Forecasts


FORECAST                          MAD     MAPD      E     (E)
Exponential smoothing (α = 0.30) 4.85
                      (α                     9.6% 49.31   4.48
Exponential smoothing (α = 0.50) 4.04
                      (α                     8.5% 33.21   3.02
Adjusted exponential smoothing      3.81     7.5% 21.14   1.92
                        (α = 0.50, β = 0.30)
 Linear trend line                   2.29     4.9%   –      –




                                                           12-617
                                                           12-
Forecast Control

Tracking signal
  monitors the forecast to see if it is biased
  high or low
                     ∑(Dt - Ft)    E
Tracking signal =               =
                       MAD        MAD
  1 MAD ≈ 0.8 б
  Control limits of 2 to 5 MADs are used most
  frequently

                                                 12-618
                                                 12-
Tracking Signal Values
         DEMAND     FORECAST,   ERROR       ∑E =           TRACKING
PERIOD     Dt          Ft        Dt - Ft   ∑(Dt - Ft)   MAD SIGNAL

  1       37          37.00        –          –            –    –
  2       40          37.00     3.00       3.00         3.00 1.00
  3       41          37.90     3.10       6.10         3.05 2.00
  4       37          38.83    -1.83       4.27         2.64 1.62
  5       45          38.28     6.72      10.99
                  Tracking signal for period 3          3.66 3.00
  6       50          40.29     9.69      20.68         4.87 4.25
  7       43          43.20    -0.20      20.48         4.09 5.01
                              6.10
  8       47          43.14 =
                      TS3       3.86 = 2.00
                                          24.34         4.06 6.00
  9       56          44.30   3.05
                               11.70      36.04         5.01 7.19
 10       52          47.81     4.19      40.23         4.92 8.18
 11       55          49.06     5.94      46.17         5.02 9.20
 12       54          50.84     3.15      49.32         4.85 10.17



                                                                     12-619
                                                                     12-
Tracking Signal Plot
                        3σ –
Tracking signal (MAD)




                        2σ –
                                                                                  α
                                                           Exponential smoothing (α = 0.30)
                        1σ –

                        0σ –

                        -1σ –

                        -2σ –                              Linear trend line

                        -3σ –
                            |    |    |    |    |    |       |     |    |       |    |    |    |
                           0    1    2    3    4    5       6     7    8       9    10   11   12
                                                         Period


                                                                                              12-620
                                                                                              12-
Statistical Control Charts

                   ∑(Dt - Ft)2
          σ=         n-1


Using σ we can calculate statistical control
         limits for the forecast error
  Control limits are typically set at ± 3σ



                                               12-621
                                               12-
Statistical Control Charts

         18.39 –
                           σ
                   UCL = +3σ
         12.24 –

          6.12 –
Errors




             0–

         -6.12 –

     -12.24 –
                           σ
                   LCL = -3σ
     -18.39 –

               |      |    |    |    |    |       |     |    |    |    |    |    |
              0      1    2    3    4    5       6     7    8    9    10   11   12
                                              Period


                                                                                12-622
                                                                                12-
Time Series Forecasting using Excel

Excel can be used to develop forecasts:
  Moving average
  Exponential smoothing
  Adjusted exponential smoothing
  Linear trend line




                                       12-623
                                       12-
Exponentially Smoothed and Adjusted
Exponentially Smoothed Forecasts




                                      12-624
                                      12-
Demand and exponentially
smoothed forecast




                           12-625
                           12-
Data Analysis option




                       12-626
                       12-
Computing a Forecast with
Seasonal Adjustment




                            12-627
                            12-
OM Tools




           12-628
           12-
Regression Methods

Linear regression
  a mathematical technique that relates a
  dependent variable to an independent
  variable in the form of a linear equation
Correlation
  a measure of the strength of the relationship
  between independent and dependent
  variables


                                              12-629
                                              12-
Linear Regression

y = a + bx              a = y-bx
                Σ xy - nxy
                Σx 2 - nx2 b =

                     where
                     a = intercept
                  b = slope of the line
                Σx
              x =n    = mean of the x data
                 Σy
              y =n    = mean of the y data

                                          12-630
                                          12-
Linear Regression Example
           x            y
(WINS)   (ATTENDANCE)       xy    x2
  4          36.3       145.2    16
  6          40.1       240.6    36
  6          41.2       247.2    36
  8          53.0       424.0    64
  6          44.0       264.0    36
  7          45.6       319.2    49
  5          39.0       195.0    25
  7          47.5       332.5    49
 49         346.7       2167.7   311



                                       12-631
                                       12-
Linear Regression Example (cont.)
     49
     8      x=       = 6.125
     346.9y =          = 43.36
       8

     ∑xy - nxy2 b =
     ∑x2 - nx2
                      =
     (2,167.7) - (8)(6.125)(43.36)
          (311) - (8)(6.125)2
                   = 4.06

               a = y - bx
          = 43.36 - (4.06)(6.125)
                 = 18.46


                                     12-632
                                     12-
Linear Regression Example (cont.)
Regression equation                  Attendance forecast for 7 wins
  y = 18.46 + 4.06x                       y = 18.46 + 4.06(7)
                     60,000 –              = 46.88, or 46,880


                     50,000 –


                     40,000 –
     Attendance, y




                     30,000 –

                                                      Linear regression line,
                     20,000 –                            y = 18.46 + 4.06x
                                                                     4.06x

                     10,000 –

                            |    |    |     |    |       |    |    |    |    |    |
                           0    1    2     3    4       5    6    7    8    9    10
                                                     Wins, x
                                                                                      12-633
                                                                                      12-
Correlation and Coefficient of
Determination
                Correlation, r
   Measure of strength of relationship
    Varies between -1.00 and +1.00
       Coefficient of determination, r2
  Percentage of variation in dependent
   variable resulting from changes in the
            independent variable



                                            12-634
                                            12-
Computing Correlation
                    n∑ xy - ∑ x∑ y
     r=
            [n∑ x2 - (∑ x)2] [n∑ y2 - (∑ y)2]
                             [n

              (8)(2,167.7) - (49)(346.9)
r=
     [(8)(311) - (49)2] [(8)(15,224.7) - (346.9)2]

                   r = 0.947

          Coefficient of determination
             r2 = (0.947)2 = 0.897
                                                 12-635
                                                 12-
Regression Analysis with Excel




                            12-636
                            12-
Regression Analysis with Excel
(cont.)




                                 12-637
                                 12-
Regression Analysis with Excel
(cont.)




                                 12-638
                                 12-
Multiple Regression
Study the relationship of demand to two or more independent
                           variables


        y = β0 + β1x1 + β2x2 … + βkxk
                    where
                    β0 = the intercept
   β1, … , βk = parameters for the
                   independent variables
       x1, … , xk = independent variables



                                                              12-639
                                                              12-
Multiple Regression with Excel




                            12-640
                            12-
Chapter 13
Inventory Management

 Operations Management - 6th Edition

Roberta Russell & Bernard W. Taylor, III




                                                       Beni Asllani
                           University of Tennessee at Chattanooga
Lecture Outline

Elements of Inventory Management
Inventory Control Systems
Economic Order Quantity Models
Quantity Discounts
Reorder Point
Order Quantity for a Periodic Inventory
System

                                      13-642
                                      13-
What Is Inventory?

Stock of items kept to meet future
demand
Purpose of inventory management
  how many units to order
  when to order




                                     13-643
                                     13-
Inventory and Supply Chain
 Management
Bullwhip effect
  demand information is distorted as it moves away
  from the end-use customer
           end-
  higher safety stock inventories to are stored to
  compensate
Seasonal or cyclical demand
Inventory provides independence from vendors
Take advantage of price discounts
Inventory provides independence between
stages and avoids work stoppages

                                                 13-644
                                                 13-
Inventory and Quality
 Management in the Supply Chain

Customers usually perceive quality
service as availability of goods they want
when they want them
Inventory must be sufficient to provide
high-quality customer service in QM




                                       13-645
                                       13-
Types of Inventory

Raw materials
Purchased parts and supplies
Work-in-process (partially completed)
products (WIP)
Items being transported
Tools and equipment


                                        13-646
                                        13-
Two Forms of Demand
          Dependent
 Demand for items used to produce final
                   products
 Tires stored at a Goodyear plant are an
    example of a dependent demand item
         Independent
  Demand for items used by external
                 customers
Cars, appliances, computers, and houses
   are examples of independent demand
                  inventory




                                           13-647
                                           13-
Inventory Costs
             Carrying cost
   cost of holding an item in inventory
             Ordering cost
     cost of replenishing inventory
             Shortage cost
  temporary or permanent loss of sales
      when demand cannot be met




                                          13-648
                                          13-
Inventory Control Systems

Continuous system (fixed-order-
                   (fixed-order-
            quantity)
     constant amount ordered when
           inventory declines to
            predetermined level
  Periodic system (fixed-time-
                   (fixed-time-
              period)
    order placed for variable amount
        after fixed passage of time




                                       13-649
                                       13-
ABC Classification
Class A
  5 – 15 % of units
  70 – 80 % of value
Class B
  30 % of units
  15 % of value
Class C
  50 – 60 % of units
  5 – 10 % of value


                        13-650
                        13-
ABC Classification: Example
PART    UNIT COST   ANNUAL USAGE
    1        $ 60           90
    2         350           40
    3          30          130
    4          80           60
    5          30          100
    6          20          180
    7          10          170
    8         320           50
    9         510           60
   10          20          120


                                   13-651
                                   13-
ABC Classification:
   Example (cont.)
                   TOTAL
PART
       PART
       VALUE
                    UNIT COSTQUANTITY OF% CUMMULATIVE
                     VALUE
                           % OF TOTAL %  TOTAL
                                   ANNUAL USAGE
   9   $30,6001          35.9 $ 60      6.0      90 6.0
   8    16,0002          18.7 350       5.0      40 11.0
   2    14,000           16.4           4.0   A
   1     5,400
               3          6.3
                                 30     9.0
                                                130 15.0
                                                     24.0
   4     4,8004           5.6    80     6.0      60 30.0
                                              B 100 40.0
   3     3,9005           4.6 30       10.0
   6     3,6006                  20
                          4.2 % OF TOTAL
                                       18.0    %180TOTAL
                                                 OF 58.0
   5     3,000
       CLASS 7       ITEMS3.5 10VALUE  13.0     170 71.0
                                                QUANTITY
  10     2,400            2.8          12.0          83.0
   7       A 8
         1,700        9, 8, 2
                          2.0
                               320 71.017.0
                                              C 50 100.0
                                                    15.0
           B 9        1, 4, 3 510 16.5
                                $85,400
                                                 60 25.0
           C 10       6, 5, 10, 720 12.5        120 60.0
                                                    Example 10.1

                                                            13-652
                                                            13-
Economic Order Quantity
 (EOQ) Models

EOQ
  optimal order quantity that will
  minimize total inventory costs
Basic EOQ model
Production quantity model



                                     13-653
                                     13-
Assumptions of Basic
EOQ Model

Demand is known with certainty and is constant over time
              No shortages are allowed
    Lead time for the receipt of orders is constant
         Order quantity is received all at once




                                                           13-654
                                                           13-
Inventory Order Cycle
Order quantity, Q
                                     Demand             Average
                                       rate              inventory
           Inventory Level




                             Q
                             2


Reorder point, R




                                 0         Lead                  Lead         Time
                                            time                  time
                                       Order Order           Order Order
                                       placed receipt        placed receipt


                                                                              13-655
                                                                              13-
EOQ Cost Model
Co - cost of placing order               D - annual demand
 Cc - annual per-unit carrying cost
              per-                        Q - order quantity

                                         CoD
               Annual ordering cost =
                                          Q
                                         CcQ
               Annual carrying cost =
                                          2
                                CoD     CcQ
                 Total cost =       +
                                 Q       2




                                                               13-656
                                                               13-
EOQ Cost Model

Deriving Qopt           Proving equality of
                       costs at optimal point
         CoD   CcQ
    TC =     +
          Q     2           CoD   CcQ
                                =
  ∂TC   CoD  Cc              Q     2
      =– 2 +
   ∂Q   Q    2
                                    2CoD
        C0D                  Q2   =
             Cc                      Cc
     0=– 2 +
        Q    2
                                      2CoD
                2CoD         Qopt =
   Qopt =                              Cc
                 Cc



                                             13-657
                                             13-
EOQ Cost Model (cont.)
  Annual
  cost ($)                       Total Cost
                     Slope = 0
                                                 CcQ
Minimum                          Carrying Cost =
                                                  2
total cost




                                                 CoD
                                 Ordering Cost = Q


               Optimal order      Order Quantity, Q
                     Qopt


                                                 13-658
                                                 13-
EOQ Example
Cc = $0.75 per gallon      Co = $150         D = 10,000 gallons

          2CoD                         CoD   CcQ
Qopt =                         TCmin =     +
           Cc                           Q     2
          2(150)(10,000)                 (150)(10,000) (0.75)(2,000)
Qopt =                         TCmin   =              +
              (0.75)                         2,000           2

Qopt = 2,000 gallons           TCmin = $750 + $750 = $1,500

 Orders per year = D/Qopt       Order cycle time = 311 days/(D/Qopt)
                                                       days/(D
             = 10,000/2,000                           = 311/5
             = 5 orders/year                      = 62.2 store days
                                                               13-659
                                                               13-
Production Quantity
 Model

An inventory system in which an order is
received gradually, as inventory is
simultaneously being depleted
  AKA non-instantaneous receipt model
  assumption that Q is received all at once is relaxed
p - daily rate at which an order is received over
time, a.k.a. production rate
d - daily rate at which inventory is demanded

                                                   13-660
                                                   13-
Production Quantity Model
            (cont.)
Inventory
  level


                                          Maximum
 Q(1-d/p)
  (1-d/p)                                 inventory
                                            level

                                           Average
Q                                         inventory
  (1-d/p)
  (1-d/p)
2                                           level


       0
                         Begin    End     Time
                         order order
           Order        receipt receipt
       receipt period


                                                 13-661
                                                 13-
Production Quantity Model
    (cont.)
        p = production rate         d = demand rate

                              Q
Maximum inventory level = Q - p d

                                d
                         = Q 1 -p                2CoD
                                      Qopt =
                          Q    d               Cc 1 - d
Average inventory level =   1-                        p
                          2    p

          CoD CcQ   d
     TC = Q + 2 1 - p


                                                      13-662
                                                      13-
Production Quantity Model:
      Example
  Cc = $0.75 per gallon      Co = $150        D = 10,000 gallons
d = 10,000/311 = 32.2 gallons per day       p = 150 gallons per day

            2C o D           2(150)(10,000)
 Qopt =                =                       = 2,256.8 gallons
          Cc 1 - d          0.75 1 - 32.2
                 p                   150


      CoD CcQ   d
 TC = Q + 2 1 - p          = $1,329


                  Q   2,256.8
 Production run = p =         = 15.05 days per order
                        150

                                                                   13-663
                                                                   13-
Production Quantity Model:
   Example (cont.)


                            D   10,000
Number of production runs = Q = 2,256.8 = 4.43 runs/year


                                  d                   32.2
  Maximum inventory level = Q 1 - p   = 2,256.8 1 -
                                                      150
                              = 1,772 gallons




                                                             13-664
                                                             13-
Solution of EOQ Models with
Excel




                              13-665
                              13-
Solution of EOQ Models with
Excel (Con’t)




                              13-666
                              13-
Solution of EOQ Models with OM
Tools




                            13-667
                            13-
Quantity Discounts

  Price per unit decreases as order
           quantity increases

               CoD   CcQ
          TC =     +     + PD
                Q     2

where

        P = per unit price of the item
            D = annual demand


                                         13-668
                                         13-
Quantity Discount Model (cont.)
                            ORDER SIZE    PRICE
                             0 - 99        $10           TC = ($10 )
                            100 – 199      8 (d1)
                            200+           6 (d2)        TC (d1 = $8 )

                                                         TC (d2 = $6 )
Inventory cost ($)




                                                         Carrying cost




                                                         Ordering cost


                      Q(d1 ) = 100 Qopt   Q(d2 ) = 200
                                                                  13-669
                                                                  13-
Quantity Discount: Example
     QUANTITY        PRICE
                                         Co = $2,500
       1 - 49        $1,400           Cc = $190 per TV
       50 - 89        1,100          D = 200 TVs per year
        90+             900

                   2C o D     2(2500)(200)
         Qopt =           =                = 72.5 TVs
                    Cc            190

For Q = 72.5
                    CoD    CcQopt
               TC =      +        + PD = $233,784
                    Qopt     2

For Q = 90
                    CoD   CcQ
               TC =     +     + PD = $194,105
                     Q     2

                                                            13-670
                                                            13-
Quantity-
Quantity-Discount Model Solution
with Excel




                              13-671
                              13-
Reorder Point
  Level of inventory at which a new order is placed



                     R = dL

                    where
             d = demand rate per period
                   L = lead time




                                                      13-672
                                                      13-
Reorder Point: Example

    Demand = 10,000 gallons/year
       Store open 311 days/year
Daily demand = 10,000 / 311 = 32.154
              gallons/day
        Lead time = L = 10 days

R = dL = (32.154)(10) = 321.54 gallons


                                         13-673
                                         13-
Safety Stocks
               Safety stock
  buffer added to on hand inventory during lead
                       time
                  Stockout
              an inventory shortage
               Service level
probability that the inventory available during lead
                time will meet demand



                                                   13-674
                                                   13-
Variable Demand with
                      a Reorder Point
                       Q
Inventory level




                  Reorder
                  point, R


                        0
                              LT             LT
                                   Time


                                                  13-675
                                                  13-
Reorder Point with
                         a Safety Stock
Inventory level




                             Q
                  Reorder
                  point, R




                                        Safety Stock
                             0
                                   LT                  LT
                                          Time
                                                            13-676
                                                            13-
Reorder Point With
Variable Demand
          R = dL + zσd L
                  where
            d = average daily demand
                   L = lead time
   σd = the standard deviation of daily demand
        z = number of standard deviations
           corresponding to the service level
                      probability
            zσd L = safety stock


                                                 13-677
                                                 13-
Reorder Point for
a Service Level
                              Probability of
                         meeting demand during
                         lead time = service level




                                     Probability of
                                      a stockout


                 Safety stock
                       σ
                      zσd L

               dL               R
             Demand

                                               13-678
                                               13-
Reorder Point for
Variable Demand
The paint store wants a reorder point with a 95%
  service level and a 5% stockout probability
                  d = 30 gallons per day
                       L = 10 days
                  σd = 5 gallons per day

           For a 95% service level, z = 1.65

   R = dL + z σd L                  Safety stock = z σd L
= 30(10) + (1.65)(5)( 10)                      = (1.65)(5)( 10)
    = 326.1 gallons                             = 26.1 gallons


                                                            13-679
                                                            13-
Determining Reorder Point with
Excel




                                 13-680
                                 13-
Order Quantity for a
Periodic Inventory System

    Q = d(tb + L) + zσd   tb + L - I

               where
           d = average demand rate
      tb = the fixed time between orders
                  L = lead time
     σd = standard deviation of demand
     zσd   tb + L = safety stock
               I = inventory level


                                           13-681
                                           13-
Periodic Inventory System




                            13-682
                            13-
Fixed-
Fixed-Period Model with
Variable Demand
         d = 6 packages per day
           σd = 1.2 packages
               tb = 60 days
                L = 5 days
              I = 8 packages
    z = 1.65 (for a 95% service level)

     Q = d(tb + L) + zσd    tb + L - I
   = (6)(60 + 5) + (1.65)(1.2)   60 + 5 - 8
            = 397.96 packages


                                              13-683
                                              13-
Fixed-
Fixed-Period Model with Excel




                           13-684
                           13-
Chapter 13 Supplement

            Simulation
          Operations Management

 Roberta Russell & Bernard W. Taylor, III
Lecture Outline


Monte Carlo Simulation
Computer Simulation with Excel
Areas of Simulation Application




                                  Supplement 13-686
                                             13-
Simulation

Mathematical and computer modeling technique for
replicating real-world problem situations
Modeling approach primarily used to analyze
probabilistic problems
  It does not normally provide a solution; instead it provides
  information that is used to make a decision
Physical simulation
  Space flights, wind tunnels, treadmills for tires
Mathematical-computerized simulation
  Computer-based replicated models



                                                      Supplement 13-687
                                                                 13-
Monte Carlo Simulation
Select numbers randomly from a
probability distribution
Use these values to observe how a
model performs over time
Random numbers each have an equal
likelihood of being selected at random



                                 Supplement 13-688
                                            13-
Distribution of Demand

LAPTOPS DEMANDED   FREQUENCY OF   PROBABILITY OF
   PER WEEK, x        DEMAND       DEMAND, P(x)
       0                 20            0.20
       1                 40            0.40
       2                 20            0.20
       3                 10            0.10
       4                 10            0.10
                       100             1.00




                                        Supplement 13-689
                                                   13-
Roulette Wheel of Demand
                     0
          90

               x=4
                         x=0
80    x=3                      20




      x=2


                         x=1

     60


                                    Supplement 13-690
                                               13-
Generating Demand
 from Random Numbers

DEMAND,   RANGES OF RANDOM NUMBERS,
   x                   r
   0                 0-19
   1                20-59
                    20-               r = 39
   2                60-79
                    60-
   3                80-89
                    80-
   4                90-99
                    90-




                                  Supplement 13-691
                                             13-
Random Number Table




                      Supplement 13-692
                                 13-
15 Weeks of Demand
WEEK      r    DEMAND (x)
                      (x    REVENUE (S)
 1        39        1          4,300
 2        73        2          8,600
 3        72        2          8,600
 4        75        2          8,600
 5        37        1          4,300
 6        02        0              0
 7        87        3         12,900
 8        98        4         17,200
 9        10        0              0
10        47        1          4,300
11        93        4         17,200 Average demand
12        21        1          4,300  = 31/15
13        95        4         17,200  = 2.07 laptops/week
14        97        4         17,200
15        69        2          8,600
                Σ = 31      $133,300
                                            Supplement 13-693
                                                       13-
Computing Expected Demand

E(x) = (0.20)(0) + (0.40)(1) + (0.20)(2)
     + (0.10)(3) + (0.10)(4)
     = 1.5 laptops per week

•Difference between 1.5 and 2.07 is due to small number of periods
analyzed (only 15 weeks)

•Steady-state result
 Steady-
    •an average result that remains constant after enough trials



                                                         Supplement 13-694
                                                                    13-
Random Numbers in Excel




                          Supplement 13-695
                                     13-
Simulation in Excel




                      Supplement 13-696
                                 13-
Simulation in Excel (cont.)




                              Supplement 13-697
                                         13-
Decision Making with
Simulation




                       Supplement 13-698
                                  13-
Decision Making with
Simulation (cont.)




                       Supplement 13-699
                                  13-
Areas of Simulation Application

Waiting Lines/Service
  Complex systems for which it is difficult to develop
  analytical formulas
  Determine how many registers and servers are
  needed to meet customer demand
Inventory Management
  Traditional models make the assumption that
  customer demand is certain
  Simulation is widely used to analyze JIT without
  having to implement it physically


                                              Supplement 13-700
                                                         13-
Areas of Simulation
 Application (cont.)

Production and Manufacturing Systems
  Examples: production scheduling, production sequencing,
  assembly line balancing, plant layout, and plant location
  analysis
  Machine breakdowns typically occur according to some
  probability distributions
Capital Investment and Budgeting
  Capital budgeting problems require estimates of cash flows,
  often resulting from many random variables
  Simulation has been used to generate values of cash flows,
  market size, selling price, growth rate, and market share




                                                    Supplement 13-701
                                                               13-
Areas of Simulation Application
 (cont.)
Logistics
   Typically include numerous random variables, such as
   distance, different modes of transport, shipping rates, and
   schedules to analyze different distribution channels
Service Operations
   Examples: police departments, fire departments, post offices,
   hospitals, court systems, airports
   Complex operations that no technique except simulation can
   be employed
Environmental and Resource Analysis
   Examples: impact of manufacturing plants, waste-disposal
   facilities, nuclear power plants, waste and population
   conditions, feasibility of alternative energy sources


                                                      Supplement 13-702
                                                                 13-
Chapter 14
Sales and Operations Planning

         Operations Management

  Roberta Russell & Bernard W. Taylor, III
Lecture Outline

The Sales and Operations Planning
Process
Strategies for Adjusting Capacity
Strategies for Managing Demand
Quantitative Techniques for Aggregate
Planning
Hierarchical Nature of Planning
Aggregate Planning for Services


                                        14-704
                                        14-
Sales and Operations Planning

Determines the resource capacity needed to
meet demand over an intermediate time
horizon
  Aggregate refers to sales and operations planning
  for product lines or families
  Sales and Operations planning (S&OP) matches
  supply and demand
Objectives
  Establish a company wide game plan for allocating
  resources
  Develop an economic strategy for meeting
  demand



                                                      14-705
                                                      14-
Sales and Operations Planning
Process




                                14-706
                                14-
The Monthly S&OP Planning
Process




                            14-707
                            14-
Meeting Demand Strategies
Adjusting capacity
  Resources necessary to meet demand
  are acquired and maintained over the
  time horizon of the plan
  Minor variations in demand are handled
  with overtime or under-time
                   under-
Managing demand
  Proactive demand management



                                           14-708
                                           14-
Strategies for Adjusting Capacity

Level production                 Overtime and under-time
                                              under-
  Producing at a constant rate     Increasing or decreasing
  and using inventory to           working hours
  absorb fluctuations in         Subcontracting
  demand
                                   Let outside companies
Chase demand                       complete the work
  Hiring and firing workers to   Part-
                                 Part-time workers
  match demand
                                   Hiring part time workers to
Peak demand                        complete the work
  Maintaining resources for      Backordering
  high-
  high-demand levels
                                   Providing the service or
                                   product at a later time period


                                                              14-709
                                                              14-
Level Production

            Demand

            Production
Units




            Time


                         14-710
                         14-
Chase Demand
            Demand

                  Production
Units




           Time


                               14-711
                               14-
Strategies for Managing Demand

Shifting demand into
other time periods
  Incentives
  Sales promotions
  Advertising campaigns
Offering products or
services with counter-
cyclical demand patterns
Partnering with suppliers
to reduce information
distortion along the
supply chain

                              14-712
                              14-
Quantitative Techniques For AP

Pure Strategies
Mixed Strategies
Linear Programming
Transportation Method
Other Quantitative
Techniques



                                  14-713
                                  14-
Pure Strategies
Example:
                QUARTER           SALES FORECAST (LB)
                    Spring                     80,000
                    Summer                     50,000
                    Fall                      120,000
                    Winter                    150,000

                        Hiring cost = $100 per worker
                        Firing cost = $500 per worker
        Inventory carrying cost = $0.50 pound per quarter
     Regular production cost per pound = $2.00
     Production per employee = 1,000 pounds per quarter
               Beginning work force = 100 workers


                                                        14-714
                                                        14-
Level Production Strategy
     Level production
     (50,000 + 120,000 + 150,000 + 80,000)
                                           = 100,000 pounds
                       4

                   SALES          PRODUCTION
QUARTER      FORECAST           PLAN    INVENTORY
Spring          80,000          100,000         20,000
Summer          50,000          100,000         70,000
Fall           120,000          100,000         50,000
Winter         150,000          100,000              0
                                400,000        140,000
         Cost of Level Production Strategy
   (400,000 X $2.00) + (140,00 X $.50) = $870,000

                                                         14-715
                                                         14-
Chase Demand Strategy
            SALES PRODUCTION   WORKERS WORKERS WORKERS
QUARTER    FORECAST   PLAN      NEEDED   HIRED   FIRED
 Spring     80,000    80,000       80          0       20
Summer     50,000    50,000       50          0       30
 Fall      120,000   120,000      120         70        0
 Winter    150,000   150,000      150         30        0
                                             100       50

              Cost of Chase Demand Strategy
 (400,000 X $2.00) + (100 x $100) + (50 x $500) = $835,000


                                                       14-716
                                                       14-
Level Production with Excel




                              14-717
                              14-
Chase Demand with Excel




                          14-718
                          14-
Mixed Strategy

Combination of Level Production and
Chase Demand strategies
Examples of management policies
  no more than x% of the workforce can be
  laid off in one quarter
  inventory levels cannot exceed x dollars
Many industries may simply shut down
manufacturing during the low demand
season and schedule employee
vacations during that time

                                             14-719
                                             14-
Mixed Strategies with Excel




                              14-720
                              14-
Mixed Strategies with Excel
(cont.)




                              14-721
                              14-
General Linear Programming (LP)
 Model
LP gives an optimal solution, but demand
and costs must be linear
Let
  Wt = workforce size for period t
  Pt =units produced in period t
  It =units in inventory at the end of period t
  Ft =number of workers fired for period t
  Ht = number of workers hired for period t

                                              14-722
                                              14-
LP MODEL
   Minimize Z = $100 (H1 + H2 + H3 + H4)
                + $500 (F1 + F2 + F3 + F4)
                 + $0.50 (I1 + I2 + I3 + I4)
                 + $2 (P1 + P2 + P3 + P4)
         Subject to
                      P1 - I1   = 80,000     (1)
Demand           I1 + P2 - I2   = 50,000     (2)
constraints      I2 + P3 - I3   = 120,000    (3)
                 I3 + P4 - I4   = 150,000    (4)
Production         1000 W1      = P1         (5)
constraints        1000 W2      = P2         (6)
                   1000 W3      = P3         (7)
                   1000 W4      = P4         (8)
              100 + H1 - F1     = W1         (9)
Work force     W1 + H2 - F2     = W2        (10)
constraints    W2 + H3 - F3     = W3        (11)
               W3 + H4 - F4     = W4        (12)



                                                   14-723
                                                   14-
Setting up the Spreadsheet




                             14-724
                             14-
The LP Solution




                  14-725
                  14-
Transportation Method

        EXPECTED      REGULAR   OVERTIME SUBCONTRACT
QUARTER   DEMAND       CAPACITY  CAPACITY   CAPACITY
  1          900         1000         100            500
  2         1500         1200         150            500
  3         1600         1300         200            500
  4         3000         1300         200            500

  Regular production cost per unit              $20
  Overtime production cost per unit             $25
  Subcontracting cost per unit                  $28
   Inventory holding cost per unit per period    $3
Beginning inventory                           300 units

                                                           14-726
                                                           14-
Transportation Tableau
                                           PERIOD OF USE

                                                                                               Unused
    PERIOD OF PRODUCTION      1            2               3               4            Capacity    Capacity

                Beginning                      0               3               6               9
    Inventory               300           —               —               —                              300
1   Regular                 600    20   300        23   100        26     —        29                    1000

    Overtime                       25              28              31   100        34                    100

    Subcontract                    28              31              34              37                    500

2   Regular                             1200       20     —        23     —        26                    1200

    Overtime                                       25              28   150        31                    150

                                                   28              31              34
    Subcontract                                                         250              250             500

3                                                                  20              23
    Regular                                             1300              —                              1300
                                                                   25              28
    Overtime                                            200               —                              200
                                                                   28              31
    Subcontract                                                         500                              500

4                                                                                  20
    Regular                                                             1300                             1300
                                                                                   25
    Overtime                                                            200                              200
                                                                                   28
    Subcontract                                                         500                              500

          Demand                  900          1500            1600            3000                250


                                                                                                                14-727
                                                                                                                14-
Burruss’ Production Plan

                REGULAR              SUB-
                                     SUB-     ENDING
PERIOD DEMAND PRODUCTION OVERTIME CONTRACT INVENTORY

  1      900    1000       100        0      500
  2     1500    1200       150      250      600
  3     1600    1300       200      500     1000
  4     3000    1300       200      500        0
Total   7000    4800       650     1250     2100




                                                14-728
                                                14-
Using Excel for the Transportation
Method of Aggregate Planning




                                14-729
                                14-
Other Quantitative Techniques

Linear decision rule (LDR)
Search decision rule (SDR)
Management coefficients model




                                14-730
                                14-
Hierarchical Nature of Planning
                   Production                   Capacity        Resource
      Items         Planning                    Planning          Level

   Product lines    Sales and                    Resource
                    Operations                 requirements       Plants
    or families
                      Plan                         plan



                      Master                    Rough-cut        Critical
     Individual
                    production                   capacity         work
      products
                     schedule                      plan          centers



                      Material                   Capacity          All
   Components      requirements                requirements       work
                       plan                        plan          centers



                       Shop                       Input/
   Manufacturing                                                Individual
                       floor                     output
    operations                                                  machines
                     schedule                    control




Disaggregation: process of breaking an aggregate plan into more detailed plans
                                                                            14-731
                                                                            14-
Collaborative Planning

Sharing information and synchronizing
production across supply chain
Part of CPFR (collaborative planning,
forecasting, and replenishment)
  involves selecting products to be jointly
  managed, creating a single forecast of
  customer demand, and synchronizing
  production across supply chain


                                              14-732
                                              14-
Available-to-Promise (ATP)
Quantity of items that can be promised to customer
Difference between planned production and customer
orders already received
  AT in period 1 = (On-hand quantity + MPS in period 1) –
               (CO until the next period of planned production)
           ATP in period n = (MPS in period n) –
               (CO until the next period of planned production)


Capable-to-promise
  quantity of items that can be produced and mad available at
  a later date
                                                            14-733
                                                            14-
ATP: Example




               14-734
               14-
ATP: Example (cont.)




                       14-735
                       14-
ATP: Example (cont.)



                       Take excess units from April

   ATP in April = (10+100) – 70 = 40
                               = 30
    ATP in May = 100 – 110 = -10
                               =0
     ATP in June = 100 – 50 = 50


                                              14-736
                                              14-
Rule Based ATP
                        Product
                        Request




              Yes    Is the product       Is an alternative     Yes
                                         product available                Available-
                       available at                                      to-promise
                     this location?        at an alternate
                                              location?

                               No                    No
                                                                           Allocate
                                                                          inventory
                                           Capable-to-
              Yes    Is an alternative    promise date
 Available-
to-promise          product available
                    at this location?



                               No                              Yes
 Allocate                                 Is the customer               Revise master
inventory                                willing to wait for              schedule
                                            the product?
              Yes    Is this product
                      available at a
                         different
                        location?                    No               Trigger production

                                            Lose sale
                               No


                                                                                       14-737
                                                                                       14-
Aggregate Planning for Services

  1. Most services cannot be inventoried
2. Demand for services is difficult to predict
    3. Capacity is also difficult to predict
4. Service capacity must be provided at the
          appropriate place and time
 5. Labor is usually the most constraining
             resource for services



                                             14-738
                                             14-
Yield Management




                   14-739
                   14-
Yield Management (cont.)




                           14-740
                           14-
Yield Management: Example
NO-SHOWS
NO-              PROBABILITY            P(N < X)
    0                     .15               .00
    1                     .25               .15
    2                     .30               .40    .517
    3                     .30               .70

         Optimal probability of no-shows
                                no-

        P(n < x) ≤
        P(n            Cu    =   75    = .517
                     Cu + Co   75 + 70



   Hotel should be overbooked by two rooms

                                                     14-741
                                                     14-
Chapter 14 Supplement

  Linear Programming
          Operations Management

 Roberta Russell & Bernard W. Taylor, III
Lecture Outline

 Model Formulation
 Graphical Solution Method
 Linear Programming Model Solution
 Solving Linear Programming Problems
 with Excel
 Sensitivity Analysis



                                Supplement 14-743
                                           14-
Linear Programming (LP)

        A model consisting of linear relationships
 representing a firm’s objective and resource constraints


LP is a mathematical modeling technique used to determine a
 level of operational activity in order to achieve an objective,
            subject to restrictions called constraints




                                                         Supplement 14-744
                                                                    14-
Types of LP




              Supplement 14-745
                         14-
Types of LP (cont.)




                      Supplement 14-746
                                 14-
Types of LP (cont.)




                      Supplement 14-747
                                 14-
LP Model Formulation

Decision variables
  mathematical symbols representing levels of activity of an
  operation
Objective function
  a linear relationship reflecting the objective of an operation
  most frequent objective of business firms is to maximize profit
  most frequent objective of individual operational units (such as
  a production or packaging department) is to minimize cost
Constraint
  a linear relationship representing a restriction on decision
  making


                                                      Supplement 14-748
                                                                 14-
LP Model Formulation (cont.)
Max/min          z = c1x1 + c2x2 + ... + cnxn

subject to:
                 a11x1 + a12x2 + ... + a1nxn (≤, =, ≥) b1
                 a21x1 + a22x2 + ... + a2nxn (≤, =, ≥) b2
                          :
                 an1x1 + an2x2 + ... + annxn (≤, =, ≥) bn

   xj = decision variables
   bi = constraint levels
   cj = objective function coefficients
   aij = constraint coefficients


                                                            Supplement 14-749
                                                                       14-
LP Model: Example

                   RESOURCE REQUIREMENTS
                    Labor        Clay      Revenue
PRODUCT            (hr/unit)   (lb/unit)    ($/unit)
Bowl                   1           4          40
Mug                    2           3          50
There are 40 hours of labor and 120 pounds of clay
available each day
Decision variables
            x1 = number of bowls to produce
            x2 = number of mugs to produce


                                                   Supplement 14-750
                                                              14-
LP Formulation: Example

Maximize Z = $40 x1 + 50 x2
Subject to
          x1 +      2x2 ≤ 40 hr    (labor constraint)
         4x1 +      3x2 ≤ 120 lb   (clay constraint)
                 x1 , x2 ≥ 0
Solution is x1 = 24 bowls          x2 = 8 mugs
Revenue = $1,360




                                                        Supplement 14-751
                                                                   14-
Graphical Solution Method

1. Plot model constraint on a set of coordinates
   in a plane
2. Identify the feasible solution space on the
   graph where all constraints are satisfied
   simultaneously
3. Plot objective function to find the point on
   boundary of this space that maximizes (or
   minimizes) value of objective function


                                          Supplement 14-752
                                                     14-
Graphical Solution: Example
x2
50 –


40 –
            4 x1 + 3 x2 ≤ 120 lb

30 –

                   Area common to
20 –               both constraints

10 –                           x1 + 2 x2 ≤ 40 hr

        |    |      |      |        |     |
 0–    10   20     30     40       50    60        x1

                                              Supplement 14-753
                                                         14-
Computing Optimal Values
                                                    x1 +   2x 2 =        40
x2
                                                   4x1 +   3x 2 =       120
40 – 4 x1 + 3 x2 = 120 lb                          4x1 +   8x 2 =       160
                                                  -4x1 -   3x 2 =      -120
30 –                                                       5x 2 =         40
                                                            x2 =           8

20 –            x1 + 2 x2 = 40 hr                   x1 + 2(8) =           40
                                                    x1        =           24
10 – 8
           |       | 24 |            | x1
 0–       10      20   30           40
                                    Z = $40(24) + $50(8) = $1,360

                                                             Supplement 14-754
                                                                        14-
Extreme Corner Points
           x1 = 0 bowls
x2         x2 = 20 mugs
           Z = $1,000      x1 = 224 bowls
                           x2 = 8 mugs
40 –
                           Z = $1,360     x1 = 30 bowls
30 –                                      x2 = 0 mugs
                                          Z = $1,200
       A
20 –

10 –               B
        |      |    | C|
 0–    10     20   30 40     x1



                                                     Supplement 14-755
                                                                14-
Objective Function
x2
  40 –
         4x1 + 3x2 = 120 lb
               3x

                    Z = 70x1 + 20x2
                        70x 20x
 30 –
                                                Optimal point:
                                                x1 = 30 bowls
     A                                          x2 = 0 mugs
 20 –                                           Z = $2,100


                              B
 10 –
                                       x1 + 2x2 = 40 hr
                                             2x
              |        |           | C     |
  0–         10       20          30      40      x1
                                                          Supplement 14-756
                                                                     14-
Minimization Problem

                     CHEMICAL CONTRIBUTION
Brand          Nitrogen (lb/bag)    Phosphate (lb/bag)
Gro-
Gro-plus               2                    4
Crop-
Crop-fast              4                    3


        Minimize Z = $6x1 + $3x2

        subject to
               2x1 + 4x2 ≥ 16 lb of nitrogen
               4x1 + 3x2 ≥ 24 lb of phosphate
                    x 1, x 2 ≥ 0

                                                 Supplement 14-757
                                                            14-
Graphical Solution
   x2

   14 –
        x1 = 0 bags of Gro-plus
                       Gro-
   12 – x2 = 8 bags of Crop-fast
                       Crop-
        Z = $24
   10 –
          A
    8–                            Z = 6x1 + 3x2
                                      6x 3x

    6–

    4–                B

    2–                        C
              |   |   |   |        |    |    |
              2   4   6   8       10   12   14    x1
    0–
                                                       Supplement 14-758
                                                                  14-
Simplex Method
A mathematical procedure for solving linear programming
problems according to a set of steps
Slack variables added to ≤ constraints to represent unused
resources
    x1 + 2x2 + s1 =40 hours of labor
                    40
   4x1 + 3x2 + s2 =120 lb of clay
                    120
Surplus variables subtracted from ≥ constraints to represent
excess above resource requirement. For example,
   2x1 + 4x2 ≥ 16 is transformed into
         4x     16
   2x1 + 4x2 - s1 = 16
         4x          16
Slack/surplus variables have a 0 coefficient in the objective
function
   Z = $40x1 + $50x2 + 0s1 + 0s2




                                                       Supplement 14-759
                                                                  14-
Solution
Points with
Slack
Variables



              Supplement 14-760
                         14-
Solution
Points with
Surplus
Variables


              Supplement 14-761
                         14-
Solving LP Problems with Excel




                          Supplement 14-762
                                     14-
Solving LP Problems with Excel
(cont.)




                          Supplement 14-763
                                     14-
Solving LP Problems with Excel
(cont.)




                          Supplement 14-764
                                     14-
Sensitivity Range for Labor
Hours




                         Supplement 14-765
                                    14-
Sensitivity Range for
Bowls




                        Supplement 14-766
                                   14-
Chapter 15
    Resource Planning

       Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Material Requirements Planning (MRP)
Capacity Requirements Planning (CRP)
Enterprise Resource Planning (ERP)
Customer Relationship Management (CRM)
Supply Chain Management (SCM)
Product Lifecycle Management (PLM)



                                     15-768
                                     15-
Resource
 Planning for
Manufacturing




                15-769
                15-
Material Requirements
 Planning (MRP)
Computerized inventory control and
production planning system
When to use MRP?
  Dependent demand items
  Discrete demand items
  Complex products
  Job shop production
  Assemble-to-order environments

                                     15-770
                                     15-
Demand Characteristics
                        Independent demand                                      Dependent demand




                                                                        100 x 1 =
                                                                      100 tabletops



                                     100 tables                                       100 x 4 = 400 table legs

                        Continuous demand
                                                                               Discrete demand
                400 –
                                                                      400 –
                300 –
No. of tables




                                                                      300 –


                                                      No. of tables
                200 –
                                                                      200 –
                100 –
                                                                      100 –

                        1   2    3       4        5
                                       Week                                   M T W Th F   M T W Th F



                                                                                                                 15-771
                                                                                                                 15-
Material               Master
                     production
Requirements          schedule

Planning
        Product        Material          Item
       structure    requirements        master
           file       planning            file




                      Planned
                        order
                      releases




            Work     Purchase      Rescheduling
           orders     orders         notices


                                             15-772
                                             15-
MRP Inputs and Outputs

Inputs                     Outputs
  Master production          Planned order
  schedule                   releases
  Product structure file       Work orders
                               Purchase orders
  Item master file
                               Rescheduling notices




                                                15-773
                                                15-
Master Production Schedule

Drives MRP process with a schedule of
finished products
Quantities represent production not demand
Quantities may consist of a combination of
customer orders and demand forecasts
Quantities represent what needs to be
produced, not what can be produced
Quantities represent end items that may or
may not be finished products


                                         15-774
                                         15-
Master Production Schedule
               (cont.)
                              PERIOD
MPS ITEM        1     2     3     4     5
Pencil Case   125   125   125   125    125
Clipboard      85    95   120   100    100
Lapboard       75   120    47    20     17
Lapdesk         0    50     0    50      0




                                             15-775
                                             15-
Product Structure File




                         15-776
                         15-
Product Structure
                            Clipboard




                                        Top clip (1)   Bottom clip (1)



                                          Pivot (1)       Spring (1)



                                                  Rivets (2)
Finished clipboard   Pressboard (1)




                                                                 15-777
                                                                 15-
Product Structure Tree
                      Clipboard                             Level 0




      Pressboard     Clip Ass’y           Rivets            Level 1
          (1)            (1)                (2)




Top Clip     Bottom Clip          Pivot            Spring   Level 2
  (1)            (1)               (1)              (1)



                                                             15-778
                                                             15-
Multilevel Indented BOM

LEVEL     ITEM          UNIT OF MEASURE   QUANTITY
0----   Clipboard             ea             1
-1---   Clip Assembly         ea             1
--2--   Top Clip              ea             1
--2--   Bottom Clip           ea             1
--2--   Pivot                 ea             1
--2--   Spring                ea             1
-1---   Rivet                 ea             2
-1---   Press Board           ea             1


                                              15-779
                                              15-
Specialized BOMs

Phantom bills
  Transient subassemblies
  Never stocked
  Immediately consumed in next stage
K-bills
  Group small, loose parts under pseudo-item
                                 pseudo-
  number
  Reduces paperwork, processing time, and file
  space


                                                 15-780
                                                 15-
Specialized BOMs (cont.)

Modular bills
  Product assembled from major subassemblies and
  customer options
  Modular bill kept for each major subassembly
  Simplifies forecasting and planning
  X10 automobile example
    3 x 8 x 3 x 8 x 4 = 2,304 configurations
    3 + 8 + 3 + 8 + 4 = 26 modular bills



                                               15-781
                                               15-
Modular BOMs
                                                                     X10
                                                                Automobile




Engines              Exterior color             Interior        Interior color             Body
(1 of 3)                (1 of 8)                (1 of 3)           (1 of 8)               (1 of 4)


4-Cylinder (.40)       Bright red (.10)         Leather (.20)     Grey (.10)             Sports coupe (.20)
  6-Cylinder (.50)       White linen (.10)        Tweed (.40)       Light blue (.10)       Two-door (.20)
                                                                                           Two-
 8-Cylinder (.10)       Sulphur yellow (.10)     Plush (.40)       Rose (.10)             Four-door (.30)
                                                                                          Four-
                      Neon orange (.10)                          Off-white (.20)
                                                                 Off-                   Station wagon (.30)
                                  Metallic blue (.10)                          Cool green (.10)
                                      Emerald green (.10)                          Black (.20)
                                     Jet black (.20)                              Brown (.10)
                                 Champagne (.20)                               B/W checked (.10)



                                                                                                     15-782
                                                                                                     15-
Time-phased Bills
               an assembly chart shown against a time
                               scale




Forward scheduling: start at today‘s date and schedule forward to determine
  the earliest date the job can be finished. If each item takes one period to
           complete, the clipboards can be finished in three periods
   Backward scheduling: start at the due date and schedule backwards to
determine when to begin work. If an order for clipboards is due by period three,
                      we should start production now
                                                                          15-783
                                                                          15-
Item Master File
     DESCRIPTION                    INVENTORY POLICY

Item                Pressboard   Lead time                1
Item no.               7341      Annual demand         5000
Item type             Purch      Holding cost             1
Product/sales class   Comp       Ordering/setup cost     50
Value class             B        Safety stock             0
Buyer/planner          RSR       Reorder point           39
Vendor/drawing        07142      EOQ                    316
Phantom code            N        Minimum order qty      100
Unit price/cost        1.25      Maximum order qty      500
Pegging                 Y        Multiple order qty       1
LLC                      1       Policy code              3


                                                        15-784
                                                        15-
Item Master File (cont.)
   PHYSICAL INVENTORY           USAGE/SALES
On hand           150    YTD usage/sales       1100
Location          W142   MTD usage/sales          75
On order           100   YTD receipts          1200
Allocated          75    MTD receipts              0
Cycle               3    Last receipt           8/25
Last count         9/5   Last issue             10/5
Difference          -2                CODES


                         Cost acct.           00754
                         Routing              00326
                         Engr                 07142


                                                   15-785
                                                   15-
MRP Processes
Exploding the bill      Netting
of material                process of subtracting on-
                                                  on-
Netting out inventory      hand quantities and
                           scheduled receipts from
Lot sizing                 gross requirements to
Time-
Time-phasing               produce net requirements
requirements            Lot sizing
                           determining the quantities
                           in which items are usually
                           made or purchased



                                                 15-786
                                                 15-
MRP Matrix




             15-787
             15-
MRP: Example
               Master Production Schedule
                         1       2          3      4         5

Clipboard              85      95      120        100   100
Lapdesk                 0      60        0         60     0


                    Item Master File
             CLIPBOARD        LAPDESK           PRESSBOARD
On hand             25               20               150
On order       175 (Period 1)          0               0
                     (sch receipt)
 LLC                 0                 0                1
Lot size          L4L             Mult 50          Min 100
 Lead time           1                 1                1

                                                         15-788
                                                         15-
MRP: Example (cont.)
                 Product Structure Record


                            Clipboard                                Level 0



        Pressboard          Clip Ass’y             Rivets            Level 1
            (1)                 (1)                 (2)




                            Lapdesk                                  Level 0



Pressboard           Trim                Beanbag             Glue    Level 1
    (2)              (3’)                  (1)              (4 oz)


                                                                         15-789
                                                                         15-
MRP: Example (cont.)

    ITEM: CLIPBOARD      LLC: 0                       PERIOD
LOT SIZE: L4L         LT: 1       1         2     3      4      5

Gross Requirements                85        95   120    100    100
            Scheduled Receipts                   175
            Projected on Hand          25
            Net Requirements
      Planned Order Receipts
         Planned Order Releases




                                                                15-790
                                                                15-
MRP: Example (cont.)

    ITEM: CLIPBOARD      LLC: 0                          PERIOD
LOT SIZE: L4L         LT: 1        1     2           3      4      5

Gross Requirements                85     95         120    100    100
            Scheduled Receipts                      175
         Projected on Hand        25          115
            Net Requirements                          0
      Planned Order Receipts
         Planned Order Releases


                 (25 + 175) = 200 units available
         (200 - 85) = 115 on hand at the end of Period 1


                                                                   15-791
                                                                   15-
MRP: Example (cont.)

    ITEM: CLIPBOARD       LLC: 0                    PERIOD
LOT SIZE: L4L         LT: 1         1     2     3      4      5

Gross Requirements                  85   95    120    100    100
            Scheduled Receipts                 175
      Projected on Hand        25        115   20
      Net Requirements                    0      0
      Planned Order Receipts
         Planned Order Releases


                       115 units available
         (115 - 85) = 20 on hand at the end of Period 2


                                                              15-792
                                                              15-
MRP: Example (cont.)

    ITEM: CLIPBOARD         LLC: 0                             PERIOD
LOT SIZE: L4L          LT: 1         1          2          3           4     5

Gross Requirements                   85         95        120         100   100
            Scheduled Receipts                            175
   Projected on Hand           25         115        20           0
   Net Requirements                        0          0         100
   Planned Order Receipts                                       100
      Planned Order Releases                              100

                       20 units available
  (20 - 120) = -100 — 100 additional Clipboards are required
 Order must be placed in Period 2 to be received in Period 3

                                                                             15-793
                                                                             15-
MRP: Example (cont.)

     ITEM: CLIPBOARD        LLC: 0                         PERIOD
LOT SIZE: L4L            LT: 1        1    2           3           4           5

Gross Requirements                   85    95         120         100         100
            Scheduled Receipts                        175
Projected on Hand          25        115   20           0           0          0
Net Requirements                      0     0         100         100         100
Planned Order Receipts                                100         100         100
   Planned Order Releases                       100         100         100


  Following the same logic Gross Requirements in Periods 4
and 5 develop Net Requirements, Planned Order Receipts, and
                  Planned Order Releases

                                                                               15-794
                                                                               15-
MRP: Example (cont.)

    ITEM: LAPDESK        LLC: 0                     PERIOD
LOT SIZE: MULT 50     LT: 1       1        2    3      4     5

Gross Requirements                0        60   0      60    0
            Scheduled Receipts
            Projected on Hand         20
            Net Requirements
         Planned Order Receipts
         Planned Order Releases




                                                             15-795
                                                             15-
MRP: Example (cont.)

     ITEM: LAPDESK          LLC: 0                           PERIOD
LOT SIZE: MULT 50     LT: 1          1         2         3         4         5

Gross Requirements                    0        60         0        60        0
            Scheduled Receipts
Projected on Hand       20           20        10        10         0        0
   Net Requirements                        0        40                  50
   Planned Order Receipts                           50                  50
   Planned Order Releases                 50                  50


    Following the same logic, the Lapdesk MRP matrix is
                    completed as shown


                                                                             15-796
                                                                             15-
MRP: Example (cont.)
    ITEM: CLIPBOARD     LLC: 0                      PERIOD
LOT SIZE: L4L       LT: 1         1         2     3     4      5
Planned Order Releases                      100   100    100
    ITEM: LAPDESK        LLC: 0                     PERIOD
LOT SIZE: MULT 50    LT: 1        1         2     3     4      5
Planned Order Releases            50              50
    ITEM: PRESSBOARD LLC: 0                           PERIOD
LOT SIZE: MIN 100     LT: 1       1         2     3      4     5
            Gross Requirements
            Scheduled Receipts
            Projected on Hand         150
         Net Requirements
         Planned Order Receipts
         Planned Order Releases


                                                               15-797
                                                               15-
MRP: Example (cont.)
    ITEM: CLIPBOARD     LLC: 0                        PERIOD
LOT SIZE: L4L       LT: 1          1          2     3     4     5
Planned Order Releases                       100   100   100
    ITEM: LAPDESK        LLC: 0   x1                    x1
                                                      PERIOD   x1
LOT SIZE: MULT 50    LT: 1         1          2     3     4     5
Planned Order Releases             50               50
                           x2
     ITEM: PRESSBOARD LLC: 0             x2          PERIOD
LOT SIZE: MIN 100      LT: 1       1          2     3     4     5
Gross Requirements                100        100   200   100     0
             Scheduled Receipts
             Projected on Hand         150
         Net Requirements
         Planned Order Receipts
         Planned Order Releases


                                                                15-798
                                                                15-
MRP: Example (cont.)
    ITEM: CLIPBOARD     LLC: 0                                PERIOD
LOT SIZE: L4L       LT: 1           1           2           3     4             5
Planned Order Releases                         100         100      100
    ITEM: LAPDESK         LLC: 0                              PERIOD
LOT SIZE: MULT 50     LT: 1         1           2           3     4             5
Planned Order Releases              50                      50
     ITEM: PRESSBOARD LLC: 0                                 PERIOD
LOT SIZE: MIN 100     LT: 1         1           2           3        4          5
Gross Requirements                 100         100         200      100          0
             Scheduled Receipts
Projected on Hand      150         50          50            0        0          0
   Net Requirements                                   50      150         100
   Planned Order Receipts                            100      150         100
   Planned Order Releases                100         150      100


                                                                                15-799
                                                                                15-
MRP: Example (cont.)

                Planned Order Report
                                        PERIOD
ITEM                         1     2    3   4     5

Clipboard                           100 100 100
   Lapdesk                        50       50
   Pressboard                    100 150 100




                                                  15-800
                                                  15-
Lot Sizing in MRP Systems

 Lot-for-lot ordering policy
 Fixed-size lot ordering policy
   Minimum order quantities
   Maximum order quantities
   Multiple order quantities
   Economic order quantity
   Periodic order quantity

                                  15-801
                                  15-
Using Excel for MRP Calculations




                              15-802
                              15-
Advanced Lot Sizing Rules: L4L




 Total cost of L4L = (4 X $60) + (0 X $1) = $240

                                                   15-803
                                                   15-
Advanced Lot Sizing Rules: EOQ

                 2(30)(60
        EO Q =            = 60   minimum order quantity
                    1




Total cost of EOQ = (2 X $60) + [(10 + 50 + 40) X $1)] = $220

                                                          15-804
                                                          15-
Advanced Lot Sizing Rules: POQ

POQ = Q / d = 60 / 30 = 2 periods worth of requirements




 Total cost of POQ = (2 X $60) + [(20 + 40) X $1] = $180


                                                          15-805
                                                          15-
Planned Order Report
Item          #2740                                      Date            9 - 25 - 05
  On hand      100                                        Lead time       2 weeks
   On order      200                                        Lot size         200
    Allocated    50                                         Safety stock     50

                                           SCHEDULED PROJECTED
DATE    ORDER NO.      GROSS REQS.      RECEIPTS   ON HAND  ACTION
                                                                       50
          9-26      AL 4416            25                              25
          9-30      AL 4174            25                               0
          10-01
          10-       GR 6470            50                            - 50
10-08
10-      SR 7542                            200            150    Expedite SR 10-01
                                                                              10-
          10-10
          10-       CO 4471            75                              75
          10-15
          10-       GR 6471            50                              25
          10-23
          10-       GR 6471            25                               0
10-27
10-      GR 6473           50                              - 50   Release PO 10-13
                                                                              10-

   Key: AL = allocated            WO = work order
     CO = customer order        SR = scheduled receipt
     PO = purchase order        GR = gross requirement


                                                                              15-806
                                                                              15-
MRP Action Report

                   Current date 9-25-08
                                9-25-

   ITEM    DATE   ORDER NO. QTY.                   ACTION
#2740   10-08
        10-       7542      200    Expedite          SR     10-01
                                                            10-
#3616   10-09
        10-                        Move forward      PO     10-07
                                                            10-
#2412   10-10
        10-                        Move forward      PO     10-05
                                                            10-
#3427   10-15
        10-                        Move backward     PO     10-25
                                                            10-
#2516   10-20
        10-       7648      100    De-expedite
                                   De-               SR     10-30
                                                            10-
#2740   10-27
        10-                 200    Release           PO     10-13
                                                            10-
#3666   10-31
        10-                  50    Release           WO     10-24
                                                            10-




                                                             15-807
                                                             15-
Capacity Requirements
 Planning (CRP)

Creates a load profile
Identifies under-loads and over-loads
Inputs
  Planned order releases
  Routing file
  Open orders file


                                        15-808
                                        15-
CRP
           MRP planned
              order
            releases




             Capacity        Open
Routing
           requirements      orders
  file
             planning          file




          Load profile for
           each process

                                      15-809
                                      15-
Calculating Capacity

Maximum capability to produce
Rated Capacity
  Theoretical output that could be attained if a process were
  operating at full speed without interruption, exceptions, or
  downtime
Effective Capacity
  Takes into account the efficiency with which a particular
  product or customer can be processed and the utilization of
  the scheduled hours or work

    Effective Daily Capacity = (no. of machines or workers) x
     (hours per shift) x (no. of shifts) x (utilization) x ( efficiency)


                                                                           15-810
                                                                           15-
Calculating Capacity (cont.)

Utilization
   Percent of available time spent working
Efficiency
   How well a machine or worker performs compared to a
   standard output level
Load
   Standard hours of work assigned to a facility
Load Percent
   Ratio of load to capacity
                             load
                  Load Percent =          x 100%
                           capacity

                                                         15-811
                                                         15-
Load Profiles

graphical comparison of load versus
capacity
Leveling underloaded conditions:
  Acquire more work
  Pull work ahead that is scheduled for later
  time periods
  Reduce normal capacity

                                            15-812
                                            15-
Reducing Over-load Conditions
            Over-

1. Eliminating unnecessary requirements
2. Rerouting jobs to alternative machines,
   workers, or work centers
3. Splitting lots between two or more machines
4. Increasing normal capacity
5. Subcontracting
6. Increasing efficiency of the operation
7. Pushing work back to later time periods
8. Revising master schedule

                                            15-813
                                            15-
Initial Load Profile
                    120 –
                    110 –
                    100 –
Hours of capacity




                     90 –
                     80 –
                     70 –
                     60 –
                     50 –
                     40 –                                  Normal
                                                           capacity
                     30 –
                     20 –
                     10 –
                      0–
                            1   2      3           4   5   6
                                    Time (weeks)


                                                               15-814
                                                               15-
Adjusted Load Profile
                    120 –
                    110 –
                    100 –
Hours of capacity




                     90 –
                     80 –
                     70 –                         Work
                                                   an
                     60 –                         extra   Push back
                                     Pull ahead
                     50 –                         shift
                                      Overtime            Push back         Normal
                     40 –
                                                                            capacity
                     30 –
                     20 –
                     10 –
                      0–
                                 1         2          3          4    5     6
                                                  Time (weeks)
                        Load leveling
                            process of balancing underloads and overloads
                                                                                15-815
                                                                                15-
Relaxing MRP Assumptions
Material is not always the most constraining
resource
Lead times can vary
Not every transaction needs to be recorded
Shop floor may require a more sophisticated
scheduling system
Scheduling in advance may not be appropriate
for on-demand production.

                                         15-816
                                         15-
Enterprise Resource Planning
(ERP)
 Software that organizes and manages
 a company’s business processes by
   sharing information across functional
   areas
   integrating business processes
   facilitating customer interaction
   providing benefit to global companies




                                           15-817
                                           15-
Organizational Data Flows




Source: Adapted from Joseph Brady, Ellen Monk, and Bret Wagner, Concepts in
 Enterprise Resource Planning (Boston: Course Technology, 2001), pp. 7–12

                                                                        15-818
                                                                        15-
ERP’s Central Database




                         15-819
                         15-
Selected Enterprise Software
Vendors




                               15-820
                               15-
ERP Implementation

Analyze business processes
Choose modules to implement
  Which processes have the biggest impact on
  customer relations?
  Which process would benefit the most from
  integration?
  Which processes should be standardized?
Align level of sophistication
Finalize delivery and access
Link with external partners

                                               15-821
                                               15-
Customer Relationship
 Management (CRM)

Software that
  Plans and executes business processes
  Involves customer interaction
  Changes focus from managing products to
  managing customers
  Analyzes point-of-sale data for patterns
            point-of-
  used to predict future behavior


                                        15-822
                                        15-
Supply Chain Management

Software that plans and executes business
processes related to supply chains
Includes
  Supply chain planning
  Supply chain execution
  Supplier relationship management
Distinctions between ERP and SCM are
becoming increasingly blurred

                                            15-823
                                            15-
Product Lifecycle Management
 (PLM)

Software that
  Incorporates new product design and
  development and product life cycle
  management
  Integrates customers and suppliers in the
  design process though the entire product life
  cycle


                                           15-824
                                           15-
ERP and Software Systems




                           15-825
                           15-
Connectivity
Application programming interfaces (APIs)
   give other programs well-defined ways of speaking to
                       well-
   them
Enterprise Application Integration (EAI) solutions
EDI is being replaced by XML, business
language of Internet
Service-
Service-oriented architecture (SOA)
   collection of “services” that communicate with each
   other within software or between software




                                                          15-826
                                                          15-
Chapter 16
         Lean Systems

       Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Basic Elements of Lean Production
Benefits of Lean Production
Implementing Lean Production
Lean Services
Leaning the Supply Chain
Lean Six Sigma
Lean and the Environment
Lean Consumption


                                    16-828
                                    16-
Lean Production
Doing more with less inventory, fewer
workers, less space
Just-in-time (JIT)
  smoothing the flow of material to arrive
  just as it is needed
  “JIT” and “Lean Production” are used
  interchangeably
Muda
  waste, anything other than that which
  adds value to product or service


                                             16-829
                                             16-
Waste in Operations




                      16-830
                      16-
Waste in Operations (cont.)




                              16-831
                              16-
Waste in Operations (cont.)




                              16-832
                              16-
Basic Elements

1.    Flexible resources
2.    Cellular layouts
3.    Pull system
4.    Kanbans
5.    Small lots
6.    Quick setups
7.    Uniform production levels
8.    Quality at the source
9.    Total productive
      maintenance
10.   Supplier networks


                                  16-833
                                  16-
Flexible Resources
Multifunctional workers
  perform more than one job
  general-purpose machines perform
  several basic functions
Cycle time
  time required for the worker to complete
  one pass through the operations
  assigned
Takt time
  paces production to customer demand


                                             16-834
                                             16-
Standard Operating
Routine for a Worker




                       16-835
                       16-
Cellular Layouts

Manufacturing cells
  comprised of dissimilar machines brought
  together to manufacture a family of parts
Cycle time is adjusted to match takt time
by changing worker paths




                                              16-836
                                              16-
Cells with Worker Routes




                           16-837
                           16-
Worker Routes Lengthen as
Volume Decreases




                            16-838
                            16-
Pull System

Material is pulled through the system when
needed
Reversal of traditional push system where
material is pushed according to a schedule
Forces cooperation
Prevent over and underproduction
While push systems rely on a predetermined
schedule, pull systems rely on customer
requests


                                         16-839
                                         16-
Kanbans

Card which indicates standard quantity
of production
Derived from two-bin inventory system
              two-
Maintain discipline of pull production
Authorize production and movement of
goods



                                         16-840
                                         16-
Sample Kanban




                16-841
                16-
Origin of Kanban
    a) Two-bin inventory system
       Two-                              b) Kanban inventory system

           Bin 1
                                              Kanban
                           Bin 2
Reorder
  card      Q-R
                             R                             R



                         Q = order quantity
             R = reorder point - demand during lead time



                                                                16-842
                                                                16-
Types of Kanban

Production kanban            Signal kanban
  authorizes production of     a triangular kanban
  goods                        used to signal
Withdrawal kanban              production at the
                               previous workstation
  authorizes movement of
  goods                      Material kanban
Kanban square                  used to order material in
  a marked area designated     advance of a process
  to hold items              Supplier kanban
                               rotates between the
                               factory and suppliers
                                                 16-843
                                                 16-
16-844
16-
16-845
16-
16-846
16-
Determining Number of
                         Kanbans
                    average demand during lead time + safety stock
No. of Kanbans =
                                  container size

                                dL + S
                           N =
                                   C
                             where

                N = number of kanbans or containers
              d = average demand over some time period
                  L = lead time to replenish an order
                          S = safety stock
                         C = container size


                                                                16-847
                                                                16-
Determining Number of
  Kanbans: Example
      d = 150 bottles per hour
     L = 30 minutes = 0.5 hours
      S = 0.10(150 x 0.5) = 7.5
          C = 25 bottles


  dL + S     (150 x 0.5) + 7.5
          N=            =
    C               25
= 75 + 7.5 = 3.3 kanbans or containers
     25

Round up to 4 (to allow some slack) or
  down to 3 (to force improvement)


                                         16-848
                                         16-
Small Lots

Require less space and capital
investment
Move processes closer together
Make quality problems easier to
detect
Make processes more dependent
on each other

                                  16-849
                                  16-
Inventory Hides Problems




                           16-850
                           16-
Less Inventory Exposes Problems




                                  16-851
                                  16-
Components of Lead Time

Processing time
  Reduce number of items or improve efficiency
Move time
  Reduce distances, simplify movements, standardize
  routings
Waiting time
  Better scheduling, sufficient capacity
Setup time
  Generally the biggest bottleneck

                                                 16-852
                                                 16-
Quick Setups

Internal setup          SMED Principles
                          Separate internal setup from
   Can be performed
                          external setup
   only when a
   process is stopped     Convert internal setup to external
                          setup
External setup
                          Streamline all aspects of setup
   Can be performed
                          Perform setup activities in
   in advance
                          parallel or eliminate them entirely




                                                        16-853
                                                        16-
Common Techniques for Reducing
Setup Time




                            16-854
                            16-
Common Techniques for Reducing
Setup Time (cont.)




                            16-855
                            16-
Common Techniques for Reducing
Setup Time (cont.)




                            16-856
                            16-
Uniform Production Levels
 Result from smoothing production
 requirements on final assembly line
 Kanban systems can handle +/- 10%
                              +/-
 demand changes
 Reduce variability with more accurate
 forecasts
 Smooth demand across planning
 horizon
 Mixed-
 Mixed-model assembly steadies
 component production

                                         16-857
                                         16-
Mixed-
Mixed-Model Sequencing




                         16-858
                         16-
Quality at the Source

Visual control                Jidoka
   makes problems visible       authority to stop the
                                production line

Poka-yokes                    Andons
                                call lights that signal
   prevent defects from
                                quality problems
   occurring
Kaizen                        Under-capacity
   a system of continuous
                              scheduling
   improvement; “change for     leaves time for planning,
   the good of all”             problem solving, and
                                maintenance


                                                          16-859
                                                          16-
Examples of Visual
Control




                     16-860
                     16-
Examples of Visual
Control (cont.)




                     16-861
                     16-
Examples of Visual
Control (cont.)




                     16-862
                     16-
5 Whys

One of the keys to an effective Kaizen is
finding the root cause of a problem and
eliminating it
A practice of asking “why?” repeatedly
until the underlying cause is identified
(usually requiring five questions)
Simple, yet powerful technique for finding
the root cause of a problem

                                       16-863
                                       16-
Total Productive
 Maintenance (TPM)

Breakdown maintenance
  Repairs to make failed machine operational
Preventive maintenance
  System of periodic inspection and
  maintenance to keep machines operating
TPM combines preventive maintenance
and total quality concepts

                                           16-864
                                           16-
TPM Requirements

Design products that can be easily produced
on existing machines
Design machines for easier operation,
changeover, maintenance
Train and retrain workers to operate machines
Purchase machines that maximize productive
potential
Design preventive maintenance plan spanning
life of machine


                                          16-865
                                          16-
5S Scan                    Goal                  Eliminate or Correct
    Seiri(sort)        Keep only what you            Unneeded equipment, tools, furniture;
                              need                  unneeded items on walls, bulletins; items
                                                      blocking aisles or stacked in corners;
                                                   unneeded inventory, supplies, parts; safety
                                                                      hazards
                             A place for       Items not in their correct places; correct places
Seiton(set in order)       everything and       not obvious; aisles, workstations, & equipment
                           everything in its       locations not indicated; items not put away
                                place                          immediately after use
  Seisou (shine)       Cleaning, and looking   Floors, walls, stairs, equipment, & surfaces not
                          for ways to keep             clean; cleaning materials not easily
                        clean and organized         accessible; lines, labels, signs broken or
                                                         unclean; other cleaning problems
     Seiketsu            Maintaining and         Necessary information not visible; standards
                        monitoring the first     not known; checklists missing; quantities and
    (standardize)         three categories        limits not easily recognizable; items can’t be
                       Sticking to the rules                 located within 30 seconds
                                               Number of workers without 5S training; number
Shisuke (sustain)                                of daily 5S inspections not performed; number
                                                 of personal items not stored; number of times
                                                        job aids not available or up-to-date




                                                                                        16-866
                                                                                        16-
Supplier Networks

Long-term supplier contracts
Synchronized production
Supplier certification
Mixed loads and frequent deliveries
Precise delivery schedules
Standardized, sequenced delivery
Locating in close proximity to the customer


                                              16-867
                                              16-
Benefits of Lean
Production
    Reduced inventory
    Improved quality
    Lower costs
    Reduced space requirements
    Shorter lead time
    Increased productivity



                                 16-868
                                 16-
Benefits of Lean
Production (cont.)
  Greater flexibility
  Better relations with suppliers
  Simplified scheduling and control activities
  Increased capacity
  Better use of human resources
  More product variety




                                           16-869
                                           16-
Implementing Lean Production

Use lean production to finely tune an
operating system
Somewhat different in USA than Japan
Lean production is still evolving
Lean production is not for everyone


                                        16-870
                                        16-
Lean Services

 Basic elements of lean
 production apply equally to
 services
 Most prevalent applications
   lean retailing
   lean banking
   lean health care

                               16-871
                               16-
Leaning the Supply Chain

“pulling” a smooth flow of material through a
series of suppliers to support frequent
replenishment orders and changes in customer
demand
Firms need to share information and
coordinate demand forecasts, production
planning, and inventory replenishment with
suppliers and supplier’s suppliers throughout
supply chain

                                          16-872
                                          16-
Leaning the Supply Chain (cont.)

Steps in Leaning the Supply Chain:
  Build a highly collaborative business
  environment
  Adopt the technology to support your
  system




                                          16-873
                                          16-
Lean Six Sigma

Lean and Six Sigma are natural partners for
process improvement
Lean
  Eliminates waste and creates flow
  More continuous improvement
Six Sigma
  Reduces variability and enhances process
  capabilities
  Requires breakthrough improvements

                                              16-874
                                              16-
Lean and the Environment

Lean’s mandate to eliminate waste and
operate only with those resources that
are absolutely necessary aligns well with
environmental initiatives
Environmental waste is often an indicator
of poor process design and inefficient
production

                                      16-875
                                      16-
EPA Recommendations

Commit to eliminate environmental waste through lean
implementation
Recognize new improvement opportunities by
incorporating environmental, heath and safety (EHS)
icons and data into value stream maps
Involve staff with EHS expertise in planning
Find and drive out environmental wastes in specific
process by using lean process-improvement tools
                       process-
Empower and enable workers to eliminate
environmental wastes in their work areas


                                                 16-876
                                                 16-
Lean Consumption

Consumptions process involves locating,
buying, installing, using, maintaining, repairing,
and recycling.
Lean Consumption seeks to:
  Provide customers what they want, where and
  when they want it
  Resolve customer problems quickly and completely
  Reduce the number of problems customers need to
  solve


                                               16-877
                                               16-
Chapter 17
           Scheduling

       Operations Management

Roberta Russell & Bernard W. Taylor, III
Lecture Outline

Objectives in Scheduling
Loading
Sequencing
Monitoring
Advanced Planning and Scheduling Systems
Theory of Constraints
Employee Scheduling




                                           17-879
                                           17-
What is Scheduling?

Last stage of planning before production
occurs
Specifies when labor, equipment, and
facilities are needed to produce a
product or provide a service




                                      17-880
                                      17-
Scheduled Operations

Process Industry               Batch Production
  Linear programming
                                 Aggregate planning
  EOQ with non-instantaneous
            non-
  replenishment                  Master scheduling
Mass Production                  Material requirements
  Assembly line balancing        planning (MRP)
Project                          Capacity requirements
  Project -scheduling            planning (CRP)
  techniques (PERT, CPM)




                                                         17-881
                                                         17-
Objectives in Scheduling

Meet customer due        Minimize overtime
dates                    Maximize machine or
Minimize job lateness    labor utilization
Minimize response time   Minimize idle time
Minimize completion      Minimize work-in-
                                    work-in-
time                     process inventory
Minimize time in the
system



                                               17-882
                                               17-
Shop Floor Control (SFC)

scheduling and monitoring of day-to-day production
                              day-to-
in a job shop
also called production control and production
activity control (PAC)
usually performed by production control department
  Loading
     Check availability of material, machines, and labor
  Sequencing
     Release work orders to shop and issue dispatch lists for
     individual machines
  Monitoring
     Maintain progress reports on each job until it is complete

                                                                  17-883
                                                                  17-
Loading

Process of assigning work to limited
resources
Perform work with most efficient
resources
Use assignment method of linear
programming to determine allocation


                                       17-884
                                       17-
Assignment Method

1. Perform row reductions          4. If number of lines equals number
    subtract minimum value in each    of rows in matrix, then optimum
    row from all other row values     solution has been found. Make
2. Perform column reductions          assignments where zeros appear
    subtract minimum value in each       Else modify matrix
    column from all other column           subtract minimum uncrossed value
    values                                 from all uncrossed values
                                           add it to all cells where two lines
3. Cross out all zeros in matrix           intersect
    use minimum number of                  other values in matrix remain
    horizontal and vertical lines          unchanged
                                     5. Repeat steps 3 and 4 until
                                        optimum solution is reached


                                                                          17-885
                                                                          17-
Assignment Method: Example
         Initial                               PROJECT
        Matrix             1           2        3      4
        Bryan             10           5        6    10
        Kari               6           2        4      6
        Noah               7           6        5      6
        Chris              9           5        4    10

Row reduction         Column reduction             Cover all zeros
5   0    1      5     3        0   1       4      3    0    1    4
4   0    2      4     2        0   2       3      2    0    2    3
2   1    0      1     0        1   0       0      0    1    0    0
5   1    0      6     3        1   0       5      3    1    0    5

        Number lines ≠ number of rows so modify matrix


                                                                17-886
                                                                17-
Assignment Method: Example (cont.)
          Modify matrix           Cover all zeros
          1   0     1     2       1    0      1   2
          0   0     2     1       0    0      2   1
          0   3     2     0       0    3      2   0
          1   1     0     3       1    1      0   3
        Number of lines = number of rows so at optimal solution
                  PROJECT                                PROJECT
              1    2      3   4                      1    2   3     4
Bryan         1    0      1   2       Bryan         10    5   6    10
Kari          0    0      2   1       Kari           6    2   4     6
Noah          0    3      2   0       Noah           7    6   5     6
Chris         1    1      0   3       Chris          9    5   4    10

         Project Cost = (5 + 6 + 4 + 6) X $100 = $2,100

                                                                   17-887
                                                                   17-
Sequencing
         Prioritize jobs assigned to a resource
If no order specified use first-come first-served (FCFS)
                 Other Sequencing Rules
                    FCFS - first-come, first-served
                     LCFS - last come, first served
                      DDATE - earliest due date
                 CUSTPR - highest customer priority
                   SETUP - similar required setups
                        SLACK - smallest slack
                       CR - smallest critical ratio
                    SPT - shortest processing time
                     LPT - longest processing time

                                                           17-888
                                                           17-
Minimum Slack and
  Smallest Critical Ratio
SLACK considers both work and time remaining
    SLACK = (due date – today’s date) – (processing time)

   CR recalculates sequence as processing
 continues and arranges information in ratio form
           time remaining         due date - today’s date
         CR = remaining
          work                     =
                                remaining processing time

              If CR > 1, job ahead of schedule
                If CR < 1, job behind schedule
                   If CR = 1, job on schedule
                                                            17-889
                                                            17-
Sequencing Jobs through One Process

  Flow time (completion time)
    Time for a job to flow through system
  Makespan
    Time for a group of jobs to be completed
  Tardiness
    Difference between a late job’s due date
    and its completion time

                                               17-890
                                               17-
Simple Sequencing Rules


             PROCESSING    DUE
       JOB      TIME      DATE

        A        5        10
        B       10        15
        C        2         5
        D        8        12
        E        6         8




                                 17-891
                                 17-
Simple Sequencing
          Rules: FCFS

       FCFS   START PROCESSING COMPLETION      DUE
SEQUENCE TIME      TIME      TIME   DATE       TARDINESS
    A         0       5            5      10           0
    B         5      10           15      15           0
    C        15       2           17       5         12
    D        17       8           25      12         13
    E        25       6           31       8         23
 Total                            93                 48
Average                    93/5 = 18.60         48/5 = 9.6




                                                     17-892
                                                     17-
Simple Sequencing
       Rules: DDATE

       DDATE  START PROCESSING COMPLETION      DUE
SEQUENCE TIME      TIME      TIME   DATE       TARDINESS
     C       0        2            2       5          0
     E       2        6            8       8          0
     A       8        5           13      10          3
     D      13        8           21      12          9
     B      21       10           31      15         16
  Total                           75                 28
 Average                   75/5 = 15.00        28/5 = 5.6




                                                     17-893
                                                     17-
Simple Sequencing             A(10-0) – 5 = 5
                                         B(15-0) – 10 = 5
           Rules: SLACK                   C(5-0) – 2 = 3
                                         D(12-0) – 8 = 4
                                          E(8-0) – 6 = 2

       SLACK  START PROCESSING COMPLETION        DUE
SEQUENCE TIME      TIME      TIME   DATE         TARDINESS
     E        0       6           6          8           0
     C        6       2           8          5           3
     D        8       8          16         12           4
     A       16       5          21         10          11
     B       21      10          31         15         16
  Total                          82                    34
 Average                  82/5 = 16.40            34/5 = 6.8




                                                        17-894
                                                        17-
Simple Sequencing
           Rules: SPT


        SPT   START PROCESSING COMPLETION      DUE
SEQUENCE TIME      TIME      TIME   DATE       TARDINESS
     C        0       2            2       5          0
     A        2       5            7      10          0
     E        7       6           13       8          5
     D       13       8           21      12          9
     B       21      10           31      15         16
  Total                           74                 30
 Average                   74/5 = 14.80          30/5 = 6




                                                     17-895
                                                     17-
Simple Sequencing
       Rules: Summary

          AVERAGE         AVERAGE      NO. OF      MAXIMUM
RULE   COMPLETION TIME   TARDINESS   JOBS TARDY   TARDINESS

  FCFS         18.60           9.6          3          23
  DDATE        15.00           5.6          3          16
  SLACK        16.40           6.8          4          16
  SPT          14.80           6.0          3          16




                                                        17-896
                                                        17-
Sequencing Jobs Through
Two Serial Process
                   Johnson’s Rule
1. List time required to process each job at each machine.
     Set up a one-dimensional matrix to represent desired
               one-
           sequence with # of slots equal to # of jobs.
 2. Select smallest processing time at either machine. If
        that time is on machine 1, put the job as near to
               beginning of sequence as possible.
  3. If smallest time occurs on machine 2, put the job as
          near to the end of the sequence as possible.
                  4. Remove job from list.
5. Repeat steps 2-4 until all slots in matrix are filled and all
                   2-
                       jobs are sequenced.



                                                              17-897
                                                              17-
Johnson’s Rule


JOB   PROCESS 1   PROCESS 2
  A         6           8
  B        11           6
  C        7            3
  D         9           7
  E        5           10




                            E   A D   B   C


                                          17-898
                                          17-
Johnson’s Rule (cont.)

                       E   A    D        B       C

E        A         D                 B                   C                 Process 1
                                                                           (sanding)
    5        11            20                    31           38
                                             Idle time

             E             A             D               B        C        Process 2
                                                                           (painting)
    5             15            23              30           37       41


                                       Completion time = 41
                                     Idle time = 5+1+1+3=10


                                                                               17-899
                                                                               17-
Guidelines for Selecting a
     Sequencing Rule

1.   SPT most useful when shop is highly congested
2.   Use SLACK for periods of normal activity
3.   Use DDATE when only small tardiness values can
     be tolerated
4.   Use LPT if subcontracting is anticipated
5.   Use FCFS when operating at low-capacity levels
                                   low-
6.   Do not use SPT to sequence jobs that have to be
     assembled with other jobs at a later date



                                                   17-900
                                                   17-
Monitoring

Work package
  Shop paperwork that travels with a job
Gantt Chart
  Shows both planned and completed
  activities against a time scale
Input/Output Control
  Monitors the input and output from each
  work center

                                            17-901
                                            17-
Gantt Chart
                           Job 32B
           3                                          Behind schedule


                                     Job 23C
Facility




           2                                              Ahead of schedule


                           Job 11C                 Job 12A
           1                                                        On schedule




                1      2    3    4     5    6         8    9   10   11   12     Days
                                           Today’s Date
                Key:            Planned activity
                                                           Completed activity

                                                                                  17-902
                                                                                  17-
Input/Output Control
Input/Output Report

PERIOD                1         2        3        4        TOTAL
 Planned input        65        65       70       70         270
 Actual input                                                  0
 Deviation                                                     0
 Planned output       75        75       75       75         300
 Actual output                                                 0
 Deviation                                                     0
      Backlog         30
                           20       10        5        0


                                                               17-903
                                                               17-
Input/Output Control (cont.)
Input/Output Report

PERIOD                1     2    3     4     TOTAL
 Planned input         65   65    70    70       270
 Actual input          60   60    65    65       250
 Deviation             -5   -5    -5    -5       -20
 Planned output        75   75    75    75       300
 Actual output         75   75    65    65       280
 Deviation             -0   -0   -10   -10       -20
      Backlog         30    15     0     0   0



                                                   17-904
                                                   17-
Advanced Planning and
 Scheduling Systems
Infinite - assumes infinite capacity
  Loads without regard to capacity
  Then levels the load and sequences jobs
Finite - assumes finite (limited) capacity
  Sequences jobs as part of the loading
  decision
  Resources are never loaded beyond
  capacity

                                            17-905
                                            17-
Advanced Planning and
 Scheduling Systems (cont.)

Advanced planning and scheduling (APS)
  Add-ins to ERP systems
  Add-
  Constraint-
  Constraint-based programming (CBP) identifies a
  solution space and evaluates alternatives
  Genetic algorithms based on natural selection
  properties of genetics
  Manufacturing execution system (MES) monitors
  status, usage, availability, quality


                                                    17-906
                                                    17-
Theory of Constraints



Not all resources are used evenly
Concentrate on the” bottleneck” resource
Synchronize flow through the bottleneck
Use process and transfer batch sizes to
move product through facility


                                           17-907
                                           17-
Drum-Buffer-Rope

Drum
  Bottleneck, beating to set the pace of production for
  the rest of the system
Buffer
  Inventory placed in front of the bottleneck to ensure
  it is always kept busy
  Determines output or throughput of the system
Rope
  Communication signal; tells processes upstream
  when they should begin production


                                                    17-908
                                                    17-
TOC Scheduling Procedure

Identify bottleneck
Schedule job first whose lead time to
bottleneck is less than or equal to
bottleneck processing time
Forward schedule bottleneck machine
Backward schedule other machines to
sustain bottleneck schedule
Transfer in batch sizes smaller than
process batch size


                                        17-909
                                        17-
A




                          B              C             D


                   B3 1 7            C3 2 15       D3 3 5


                   B2 2 3           C2 1 10        D2 2 8


                   B1 1 5            C1 3 2        D1 3 10


                Key:      i     Item i
Synchronous            ij k l            Operation j of item i performed at
                                         machine center k takes l minutes
Manufacturing                                       to process



                                                                              17-910
                                                                              17-
Synchronous
Manufacturing (cont.)

            Demand = 100 A’s
      Machine setup time = 60 minutes

MACHINE 1 MACHINE 2 MACHINE 3
 B1       5    B2      3    C1      2
 B3       7    C3     15    D3      5
 C2      10    D2      8    D1     10
Sum      22          26*           17

* Bottleneck




                                        17-911
                                        17-
Synchronous Manufacturing (cont.)
 Machine 1                Setup               Setup

             C2                   B1                     B3
2                       1002              1562                  2322
      Idle
 Machine 2                                    Setup     Setup

                   C3                            B2              D2
12                                     1512           1872                   2732


 Machine 3
    Setup                         Setup

 C1               D1                       Idle                   D3
0 200                          1260                     1940
                                                                Completion   2737
                                                                  time




                                                                                17-912
                                                                                17-
Employee Scheduling

Labor is very flexible
resource
Scheduling workforce is
complicated, repetitive
task
Assignment method can
be used
Heuristics are commonly
used


                          17-913
                          17-
Employee Scheduling Heuristic
                1. Let N = no. of workers available
                      Di = demand for workers on day i
                               X = day working
                                 O = day off
 2. Assign the first N - D1 workers day 1 off. Assign the next N - D2
    workers day 2 off. Continue in a similar manner until all days are
                          have been scheduled
    3. If number of workdays for full time employee < 5, assign
        remaining workdays so consecutive days off are possible
       4. Assign any remaining work to part-time employees
                                         part-
5. If consecutive days off are desired, consider switching schedules
           among days with the same demand requirements



                                                                   17-914
                                                                   17-
Employee Scheduling
  DAY OF WEEK      M    T     W   TH   F   SA   SU
                     MIN NO. OF
WORKERS REQUIRED   3     3    4   3    4   5    3
    Taylor
    Smith
    Simpson
    Allen
    Dickerson




                                                 17-915
                                                 17-
Employee Scheduling (cont.)
  DAY OF WEEK          M     T     W   TH     F    SA     SU
                          MIN NO. OF
WORKERS REQUIRED        3     3    4    3     4     5     3
    Taylor            O     X     X    O     X     X      X
    Smith             O     X     X    O     X     X      X
    Simpson           X     O     X    X     O     X      X
    Allen             X     O     X    X     X     X      O
    Dickerson         X     X     O    X     X     X      O



   Completed schedule satisfies requirements but has no
                 consecutive days off




                                                              17-916
                                                              17-
Employee Scheduling (cont.)
  DAY OF WEEK          M     T     W    TH     F    SA   SU
                          MIN NO. OF
WORKERS REQUIRED        3     3    4     3     4     5       3
    Taylor             O     O    X     X     X     X    X
    Smith              O     O    X     X     X     X    X
    Simpson            X     X    O     O     X     X    X
    Allen              X     X    X     O     X     X    O
    Dickerson          X     X    X     X     O     X    O



  Revised schedule satisfies requirements with consecutive
               days off for most employees




                                                             17-917
                                                             17-
Automated Scheduling Systems


Staff Scheduling
Schedule Bidding
Schedule
Optimization




                          17-918
                          17-
Thank You
   www.bookfiesta4u.com




                          2-919

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Operationsmanagement 919slidespresentation-090928145353-phpapp01

  • 1. Chapter 1-17 Operations Management Roberta Russell & Bernard W. Taylor, III
  • 2. Organization of This Text: Part I – Operations Management Intro. to Operations and Supply Chain Management: Chapter 1 (Slide 5) Quality Management: Chapter 2 (Slide 67) Statistical Quality Control: Chapter 3 (Slide 120) Product Design: Chapter 4 (Slide 186) Service Design: Chapter 5 (Slide 231) Processes and Technology: Chapter 6 (Slide 276) Facilities: Chapter 7 (Slide 321) Human Resources: Chapter 8 (Slide 402) Project Management: Chapter 9 (Slide 450) 1 -2
  • 3. Organization of This Text: Part II – Supply Chain Management Supply Chain Strategy and Design: Chapter 10 (Slide 507) Global Supply Chain Procurement and Distribution: Chapter 11 (Slide 534) Forecasting: Chapter 12 (Slide 575) Inventory Management: Chapter 13 (Slide 641) Sales and Operations Planning: Chapter 14 (Slide 703) Resource Planning: Chapter 15 (Slide 767) Lean Systems: Chapter 16 (Slide 827) Scheduling: Chapter 17 (Slide 878) 1 -3
  • 4. Learning Objectives of this Course Gain an appreciation of strategic importance of operations and supply chain management in a global business environment Understand how operations relates to other business functions Develop a working knowledge of concepts and methods related to designing and managing operations and supply chains Develop a skill set for quality and process improvement 1 -4
  • 5. Chapter 1 Introduction to Operations and Supply Chain Management Operations Management Roberta Russell & Bernard W. Taylor, III
  • 6. Lecture Outline What Operations and Supply Chain Managers Do Operations Function Evolution of Operations and Supply Chain Management Globalization and Competitiveness Operations Strategy and Organization of the Text Learning Objectives for This Course 1 -6
  • 7. What Operations and Supply Chain Managers Do What is Operations Management? design, operation, and improvement of productive systems What is Operations? a function or system that transforms inputs into outputs of greater value What is a Transformation Process? a series of activities along a value chain extending from supplier to customer activities that do not add value are superfluous and should be eliminated 1 -7
  • 8. Transformation Process Physical: as in manufacturing operations Locational: as in transportation or warehouse operations Exchange: as in retail operations Physiological: as in health care Psychological: as in entertainment Informational: as in communication 1 -8
  • 9. Operations as a Transformation Process INPUT •Material TRANSFORMATION OUTPUT •Machines PROCESS •Goods •Labor •Services •Management •Capital Feedback & Requirements 1 -9
  • 11. How is Operations Relevant to my Major? “As an auditor you must Accounting understand the fundamentals of operations management.” Information “IT is a tool, and there’s no better Technology place to apply it than in operations.” “We use so many things you Management learn in an operations class— class— scheduling, lean production, theory of constraints, and tons of quality tools.” 1-11
  • 12. How is Operations Relevant to my Major? (cont.) “It’s all about processes. I live Economics by flowcharts and Pareto analysis.” Marketing “How can you do a good job marketing a product if you’re unsure of its quality or delivery status?” Finance “Most of our capital budgeting requests are from operations, and most of our cost savings, too.” 1-12
  • 13. Evolution of Operations and Supply Chain Management Craft production process of handcrafting products or services for individual customers Division of labor dividing a job into a series of small tasks each performed by a different worker Interchangeable parts standardization of parts initially as replacement parts; enabled mass production 1-13
  • 14. Evolution of Operations and Supply Chain Management (cont.) Scientific management systematic analysis of work methods Mass production high- high-volume production of a standardized product for a mass market Lean production adaptation of mass production that prizes quality and flexibility 1-14
  • 15. Historical Events in Operations Management Era Events/Concepts Dates Originator Steam engine 1769 James Watt Industrial Division of labor 1776 Adam Smith Revolution Interchangeable parts 1790 Eli Whitney Principles of scientific 1911 Frederick W. Taylor management Frank and Lillian Scientific Time and motion studies 1911 Gilbreth Management Activity scheduling chart 1912 Henry Gantt Moving assembly line 1913 Henry Ford 1-15
  • 16. Historical Events in Operations Management (cont.) Era Events/Concepts Dates Originator Hawthorne studies 1930 Elton Mayo Human 1940s Abraham Maslow Relations Motivation theories 1950s Frederick Herzberg 1960s Douglas McGregor Linear programming 1947 George Dantzig Digital computer 1951 Remington Rand Simulation, waiting Operations Operations research line theory, decision 1950s Research groups theory, PERT/CPM 1960s, Joseph Orlicky, IBM MRP, EDI, EFT, CIM 1970s and others 1-16
  • 17. Historical Events in Operations Management (cont.) Era Events/Concepts Dates Originator JIT (just-in-time) 1970s Taiichi Ohno (Toyota) TQM (total quality W. Edwards Deming, 1980s management) Joseph Juran Quality Strategy and Wickham Skinner, 1980s Revolution operations Robert Hayes Business process Michael Hammer, 1990s reengineering James Champy Six Sigma 1990s GE, Motorola 1-17
  • 18. Historical Events in Operations Management (cont.) Era Events/Concepts Dates Originator Internet Internet, WWW, ERP, 1990s ARPANET, Tim Revolution supply chain management Berners-Lee SAP, i2 Technologies, ORACLE E-commerce 2000s Amazon, Yahoo, eBay, Google, and others Globalization WTO, European Union, 1990s Numerous countries and other trade 2000s and companies agreements, global supply chains, outsourcing, BPO, Services Science 1-18
  • 19. Evolution of Operations and Supply Chain Management (cont.) Supply chain management management of the flow of information, products, and services across a network of customers, enterprises, and supply chain partners 1-19
  • 20. Globalization and Competitiveness Why “go global”? favorable cost access to international markets response to changes in demand reliable sources of supply latest trends and technologies Increased globalization results from the Internet and falling trade barriers 1-20
  • 21. Globalization and Competitiveness (cont.) Hourly Compensation Costs for Production Workers Source: U.S. Bureau of Labor Statistics, 2005. 1-21
  • 22. Globalization and Competitiveness (cont.) World Population Distribution Source: U.S. Census Bureau, 2006. 1-22
  • 23. Globalization and Competitiveness (cont.) Trade in Goods as % of GDP (sum of merchandise exports and imports divided by GDP, valued in U.S. dollars) 1-23
  • 24. Productivity and Competitiveness Competitiveness degree to which a nation can produce goods and services that meet the test of international markets Productivity ratio of output to input Output sales made, products produced, customers served, meals delivered, or calls answered Input labor hours, investment in equipment, material usage, or square footage 1-24
  • 25. Productivity and Competitiveness (cont.) Measures of Productivity 1-25
  • 26. Productivity and Competitiveness (cont.) Average Annual Growth Rates in Productivity, 1995-2005. 1995- Source: Bureau of Labor Statistics. A Chartbook of International Labor Comparisons. January 2007, p. 28. 1-26
  • 27. Productivity and Competitiveness (cont.) Average Annual Growth Rates in Output and Input, 1995-2005 1995- Dramatic Increase in Source: Bureau of Labor Statistics. A Chartbook of International Output w/ Decrease in Labor Comparisons, January 2007, p. 26. Labor Hours 1-27
  • 28. Productivity and Competitiveness (cont.) Retrenching productivity is increasing, but both output and input decrease with input decreasing at a faster rate Assumption that more input would cause output to increase at the same rate certain limits to the amount of output may not be considered output produced is emphasized, not output sold; sold; increased inventories 1-28
  • 29. Strategy and Operations Strategy Provides direction for achieving a mission Five Steps for Strategy Formulation Defining a primary task What is the firm in the business of doing? Assessing core competencies What does the firm do better than anyone else? Determining order winners and order qualifiers What qualifies an item to be considered for purchase? What wins the order? Positioning the firm How will the firm compete? Deploying the strategy 1-29
  • 30. Strategic Planning Mission and Vision Corporate Strategy Marketing Operations Financial Strategy Strategy Strategy 1-30
  • 31. Order Winners and Order Qualifiers Source: Adapted from Nigel Slack, Stuart Chambers, Robert Johnston, and Alan Betts, Operations and Process Management, Prentice Hall, 2006, p. 47 Management, 1-31
  • 33. Positioning the Firm: Cost Waste elimination relentlessly pursuing the removal of all waste Examination of cost structure looking at the entire cost structure for reduction potential Lean production providing low costs through disciplined operations 1-33
  • 34. Positioning the Firm: Speed fast moves, fast adaptations, tight linkages Internet conditioned customers to expect immediate responses Service organizations always competed on speed (McDonald’s, LensCrafters, and Federal Express) Manufacturers time- time-based competition: build-to-order production and build-to- efficient supply chains Fashion industry two- two-week design-to-rack lead time of Spanish retailer, Zara design-to- 1-34
  • 35. Positioning the Firm: Quality Minimizing defect rates or conforming to design specifications; please the customer Ritz- Ritz-Carlton - one customer at a time Service system is designed to “move heaven and earth” to satisfy customer Every employee is empowered to satisfy a guest’s wish Teams at all levels set objectives and devise quality action plans Each hotel has a quality leader 1-35
  • 36. Positioning the Firm: Flexibility ability to adjust to changes in product mix, production volume, or design National Bicycle Industrial Company offers 11,231,862 variations delivers within two weeks at costs only 10% above standard models mass customization: the mass production of customization: customized parts 1-36
  • 37. Policy Deployment Policy deployment translates corporate strategy into measurable objectives Hoshins action plans generated from the policy deployment process 1-37
  • 38. Policy Deployment Derivation of an Action Plan Using Policy Deployment 1-38
  • 39. Balanced Scorecard Balanced scorecard measuring more than financial performance finances customers processes learning and growing Key performance indicators a set of measures that help managers evaluate performance in critical areas 1-39
  • 42. Operations Strategy Services Process and Products Technology Human Resources Quality Capacity Facilities Sourcing Operating Systems 1-42
  • 43. Chapter 1 Supplement Decision Analysis Operations Management Roberta Russell & Bernard W. Taylor, III
  • 44. Lecture Outline Decision Analysis Decision Making without Probabilities Decision Analysis with Excel Decision Analysis with OM Tools Decision Making with Probabilities Expected Value of Perfect Information Sequential Decision Tree Supplement 1-44 1-
  • 45. Decision Analysis Quantitative methods a set of tools for operations manager Decision analysis a set of quantitative decision-making decision- techniques for decision situations in which uncertainty exists Example of an uncertain situation demand for a product may vary between 0 and 200 units, depending on the state of market Supplement 1-45 1-
  • 46. Decision Making Without Probabilities States of nature Events that may occur in the future Examples of states of nature: high or low demand for a product good or bad economic conditions Decision making under risk probabilities can be assigned to the occurrence of states of nature in the future Decision making under uncertainty probabilities can NOT be assigned to the occurrence of states of nature in the future Supplement 1-46 1-
  • 47. Payoff Table Payoff table method for organizing and illustrating payoffs from different decisions given various states of nature Payoff outcome of a decision States Of Nature Decision a b 1 Payoff 1a Payoff 1b 2 Payoff 2a Payoff 2b Supplement 1-47 1-
  • 48. Decision Making Criteria Under Uncertainty Maximax choose decision with the maximum of the maximum payoffs Maximin choose decision with the maximum of the minimum payoffs Minimax regret choose decision with the minimum of the maximum regrets for each alternative Supplement 1-48 1-
  • 49. Decision Making Criteria Under Uncertainty (cont.) Hurwicz choose decision in which decision payoffs are weighted by a coefficient of optimism, alpha coefficient of optimism is a measure of a decision maker’s optimism, from 0 (completely pessimistic) to 1 (completely optimistic) Equal likelihood (La Place) choose decision in which each state of nature is weighted equally Supplement 1-49 1-
  • 50. Southern Textile Company STATES OF NATURE Good Foreign Poor Foreign DECISION Competitive Conditions Competitive Conditions Expand $ 800,000 $ 500,000 Maintain status quo 1,300,000 -150,000 Sell now 320,000 320,000 Supplement 1-50 1-
  • 51. Maximax Solution STATES OF NATURE Good Foreign Poor Foreign DECISION Competitive Conditions Competitive Conditions Expand $ 800,000 $ 500,000 Maintain status quo 1,300,000 -150,000 Sell now 320,000 320,000 Expand: $800,000 Status quo: 1,300,000 ← Maximum Sell: 320,000 Decision: Maintain status quo Supplement 1-51 1-
  • 52. Maximin Solution STATES OF NATURE Good Foreign Poor Foreign DECISION Competitive Conditions Competitive Conditions Expand $ 800,000 $ 500,000 Maintain status quo 1,300,000 -150,000 Sell now 320,000 320,000 Expand: $500,000 ← Maximum Status quo: -150,000 Sell: 320,000 Decision: Expand Supplement 1-52 1-
  • 53. Minimax Regret Solution Good Foreign Poor Foreign Competitive Conditions Competitive Conditions $1,300,000 - 800,000 = 500,000 $500,000 - 500,000 = 0 1,300,000 - 1,300,000 = 0 500,000 - (-150,000)= 650,000 1,300,000 - 320,000 = 980,000 500,000 - 320,000= 180,000 Expand: $500,000 ← Minimum Status quo: 650,000 Sell: 980,000 Decision: Expand Supplement 1-53 1-
  • 54. Hurwicz Criteria STATES OF NATURE Good Foreign Poor Foreign DECISION Competitive Conditions Competitive Conditions Expand $ 800,000 $ 500,000 Maintain status quo 1,300,000 -150,000 Sell now 320,000 320,000 α = 0.3 1 - α = 0.7 Expand: $800,000(0.3) + 500,000(0.7) = $590,000 ← Maximum Status quo: 1,300,000(0.3) -150,000(0.7) = 285,000 Sell: 320,000(0.3) + 320,000(0.7) = 320,000 Decision: Expand Supplement 1-54 1-
  • 55. Equal Likelihood Criteria STATES OF NATURE Good Foreign Poor Foreign DECISION Competitive Conditions Competitive Conditions Expand $ 800,000 $ 500,000 Maintain status quo 1,300,000 -150,000 Sell now 320,000 320,000 Two states of nature each weighted 0.50 Expand: $800,000(0.5) + 500,000(0.5) = $650,000 ← Maximum Status quo: 1,300,000(0.5) -150,000(0.5) = 575,000 Sell: 320,000(0.5) + 320,000(0.5) = 320,000 Decision: Expand Supplement 1-55 1-
  • 56. Decision Analysis with Excel Supplement 1-56 1-
  • 57. Decision Analysis with OM Tools Supplement 1-57 1-
  • 58. Decision Making with Probabilities Risk involves assigning probabilities to states of nature Expected value a weighted average of decision outcomes in which each future state of nature is assigned a probability of occurrence Supplement 1-58 1-
  • 59. Expected value n EV (x) = (x p(xi)xi ∑ i =1 where xi = outcome i p(xi) = probability of outcome i Supplement 1-59 1-
  • 60. Decision Making with Probabilities: Example STATES OF NATURE Good Foreign Poor Foreign DECISION Competitive Conditions Competitive Conditions Expand $ 800,000 $ 500,000 Maintain status quo 1,300,000 -150,000 Sell now 320,000 320,000 p(good) = 0.70 p(poor) = 0.30 EV(expand): $800,000(0.7) + 500,000(0.3) = $710,000 EV(status quo): 1,300,000(0.7) -150,000(0.3) = 865,000 ← Maximum EV(sell): 320,000(0.7) + 320,000(0.3) = 320,000 Decision: Status quo Supplement 1-60 1-
  • 61. Decision Making with Probabilities: Excel Supplement 1-61 1-
  • 62. Expected Value of Perfect Information EVPI maximum value of perfect information to the decision maker maximum amount that would be paid to gain information that would result in a decision better than the one made without perfect information Supplement 1-62 1-
  • 63. EVPI Example Good conditions will exist 70% of the time choose maintain status quo with payoff of $1,300,000 Poor conditions will exist 30% of the time choose expand with payoff of $500,000 Expected value given perfect information = $1,300,000 (0.70) + 500,000 (0.30) = $1,060,000 Recall that expected value without perfect information was $865,000 (maintain status quo) EVPI= EVPI= $1,060,000 - 865,000 = $195,000 Supplement 1-63 1-
  • 64. Sequential Decision Trees A graphical method for analyzing decision situations that require a sequence of decisions over time Decision tree consists of Square nodes - indicating decision points Circles nodes - indicating states of nature Arcs - connecting nodes Supplement 1-64 1-
  • 65. Evaluations at Nodes Compute EV at nodes 6 & 7 EV(node 6)= 0.80($3,000,000) + 0.20($700,000) = $2,540,000 EV( 6)= EV(node 7)= 0.30($2,300,000) + 0.70($1,000,000)= $1,390,000 EV( 7)= Decision at node 4 is between $2,540,000 for Expand and $450,000 for Sell land Choose Expand Repeat expected value calculations and decisions at remaining nodes Supplement 1-65 1-
  • 66. Decision Tree Analysis $1,290,000 $2,000,000 0.60 Market growth 2 0.40 $225,000 $3,000,000 $2,540,000 0.80 $1,740,000 6 $700,000 0.20 1 $1,160,000 4 $450,000 0.60 $2,300,000 $1,390,000 3 0.40 0.30 $790,000 7 $1,360,000 0.70 $1,000,000 5 $210,000 Supplement 1-66 1-
  • 67. Chapter 2 Quality Management Operations Management Roberta Russell & Bernard W. Taylor, III
  • 68. Lecture Outline What Is Quality? Quality in Service Evolution of Quality Companies Management Six Sigma Quality Tools Cost of Quality TQM and QMS Effect of Quality Focus of Quality Management on Management— Management— Productivity Customers Quality Awards Role of Employees in ISO 9000 Quality Improvement 2-68
  • 69. What Is Quality? Oxford American Dictionary a degree or level of excellence American Society for Quality totality of features and characteristics that satisfy needs without deficiencies Consumer’s and producer’s perspective 2-69
  • 70. What Is Quality: Customer’s Perspective Fitness for use how well product or service does what it is supposed to Quality of design designing quality characteristics into a product or service A Mercedes and a Ford are equally “fit for use,” but with different design dimensions. 2-70
  • 71. Dimensions of Quality: Manufactured Products Performance basic operating characteristics of a product; how well a car handles or its gas mileage Features “extra” items added to basic features, such as a stereo CD or a leather interior in a car Reliability probability that a product will operate properly within an expected time frame; that is, a TV will work without repair for about seven years 2-71
  • 72. Dimensions of Quality: Manufactured Products (cont.) Conformance degree to which a product meets pre–established pre– standards Durability how long product lasts before replacement; with care, L.L.Bean boots may last a lifetime Serviceability ease of getting repairs, speed of repairs, courtesy and competence of repair person 2-72
  • 73. Dimensions of Quality: Manufactured Products (cont.) Aesthetics how a product looks, feels, sounds, smells, or tastes Safety assurance that customer will not suffer injury or harm from a product; an especially important consideration for automobiles Perceptions subjective perceptions based on brand name, advertising, and like 2-73
  • 74. Dimensions of Quality: Services Time and timeliness how long must a customer wait for service, and is it completed on time? is an overnight package delivered overnight? Completeness: is everything customer asked for provided? is a mail order from a catalogue company complete when delivered? 2-74
  • 75. Dimensions of Quality: Service (cont.) Courtesy: how are customers treated by employees? are catalogue phone operators nice and are their voices pleasant? Consistency is same level of service provided to each customer each time? is your newspaper delivered on time every morning? 2-75
  • 76. Dimensions of Quality: Service (cont.) Accessibility and convenience how easy is it to obtain service? does service representative answer you calls quickly? Accuracy is service performed right every time? is your bank or credit card statement correct every month? Responsiveness how well does company react to unusual situations? how well is a telephone operator able to respond to a customer’s questions? 2-76
  • 77. What Is Quality: Producer’s Perspective Quality of conformance making sure product or service is produced according to design if new tires do not conform to specifications, they wobble if a hotel room is not clean when a guest checks in, hotel is not functioning according to specifications of its design 2-77
  • 79. What Is Quality: A Final Perspective Customer’s and producer’s perspectives depend on each other Producer’s perspective: production process and COST Customer’s perspective: fitness for use and PRICE Customer’s view must dominate 2-79
  • 80. Evolution of Quality Management: Quality Gurus Walter Shewart In 1920s, developed control charts Introduced term “quality assurance” “quality W. Edwards Deming Developed courses during World War II to teach statistical quality-control techniques to engineers and quality- executives of companies that were military suppliers After war, began teaching statistical quality control to Japanese companies Joseph M. Juran Followed Deming to Japan in 1954 Focused on strategic quality planning Quality improvement achieved by focusing on projects to solve problems and securing breakthrough solutions 2-80
  • 81. Evolution of Quality Management: Quality Gurus (cont.) Armand V. Feigenbaum In 1951, introduced concepts of total quality control and continuous quality improvement Philip Crosby In 1979, emphasized that costs of poor quality far outweigh cost of preventing poor quality In 1984, defined absolutes of quality management— management— conformance to requirements, prevention, and “zero defects” Kaoru Ishikawa Promoted use of quality circles Developed “fishbone” diagram Emphasized importance of internal customer 2-81
  • 82. Deming’s 14 Points 1. Create constancy of purpose 2. Adopt philosophy of prevention 3. Cease mass inspection 4. Select a few suppliers based on quality 5. Constantly improve system and workers 2-82
  • 83. Deming’s 14 Points (cont.) 6. Institute worker training 7. Instill leadership among supervisors 8. Eliminate fear among employees 9. Eliminate barriers between departments 10. Eliminate slogans 2-83
  • 84. Deming’s 14 Points (cont.) 11. Remove numerical quotas 12. Enhance worker pride 13. Institute vigorous training and education programs 14. Develop a commitment from top management to implement above 13 points 2-84
  • 85. Deming Wheel: PDCA Cycle 2-85
  • 86. Quality Tools Process Flow Histogram Chart Scatter Diagram Cause-and- Cause-and- Statistical Process Effect Diagram Control Chart Check Sheet Pareto Analysis 2-86
  • 87. Flow Chart 2-87
  • 88. Cause-and- Cause-and-Effect Diagram Cause-and- Cause-and-effect diagram (“fishbone” diagram) chart showing different categories of problem causes 2-88
  • 89. Cause-and- Cause-and-Effect Matrix Cause-and- Cause-and-effect matrix grid used to prioritize causes of quality problems 2-89
  • 90. Check Sheets and Histograms 2-90
  • 91. Pareto Analysis Pareto analysis most quality problems result from a few causes 2-91
  • 92. Pareto Chart 2-92
  • 95. TQM and QMS Total Quality Management (TQM) customer- customer-oriented, leadership, strategic planning, employee responsibility, continuous improvement, cooperation, statistical methods, and training and education Quality Management System (QMS) system to achieve customer satisfaction that complements other company systems 2-95
  • 96. Focus of Quality Management— Management— Customers TQM and QMSs serve to achieve customer satisfaction Partnering a relationship between a company and its supplier based on mutual quality standards Measuring customer satisfaction important component of any QMS customer surveys, telephone interviews 2-96
  • 97. Role of Employees in Quality Improvement Participative problem solving employees involved in quality- quality-management every employee has undergone extensive training to provide quality service to Disney’s guests Kaizen involves everyone in process of continuous improvement 2-97
  • 98. Quality Circles and QITs Organization 8-10 members Same area Quality circle Supervisor/moderator group of workers Training and supervisors Presentation Group processes Implementation Data collection from same area Monitoring Problem analysis who address quality problems Process/Quality Problem improvement teams Solution Problem results Identification List alternatives (QITs) Consensus Brainstorming Problem focus attention on Analysis business processes Cause and effect Data collection rather than separate and analysis company functions 2-98
  • 99. Quality in Services Service defects are not always easy to measure because service output is not usually a tangible item Services tend to be labor intensive Services and manufacturing companies have similar inputs but different processes and outputs 2-99
  • 100. Quality Attributes in Services Principles of TQM apply equally well to services and manufacturing Timeliness how quickly a service is provided? Benchmark “best” level of quality “quickest, friendliest, most achievement in one accurate service company that other available.” companies seek to achieve 2-100
  • 101. Six Sigma A process for developing and delivering virtually perfect products and services Measure of how much a process deviates from perfection 3.4 defects per million opportunities Six Sigma Process four basic steps of Six Sigma—align, Sigma— mobilize, accelerate, and govern Champion an executive responsible for project success 2-101
  • 102. Six Sigma: Breakthrough Strategy—DMAIC Strategy— DEFINE MEASURE ANALYZE IMPROVE CONTROL 3.4 DPMO 67,000 DPMO cost = 25% of sales 2-102
  • 103. Six Sigma: Black Belts and Green Belts Black Belt project leader Master Black Belt a teacher and mentor for Black Belts Green Belts project team members 2-103
  • 104. Six Sigma Design for Six Sigma (DFSS) a systematic approach to designing products and processes that will achieve Six Sigma Profitability typical criterion for selection Six Sigma project one of the factors distinguishing Six Sigma from TQM “Quality is not only free, it is an honest-to- honest-to-everything profit maker.” 2-104
  • 105. Cost of Quality Cost of Achieving Good Quality Prevention costs costs incurred during product design Appraisal costs costs of measuring, testing, and analyzing Cost of Poor Quality Internal failure costs include scrap, rework, process failure, downtime, and price reductions External failure costs include complaints, returns, warranty claims, liability, and lost sales 2-105
  • 106. Prevention Costs Quality planning costs Training costs costs of developing and costs of developing and implementing quality putting on quality training management program programs for employees Product- Product-design costs and management costs of designing Information costs products with quality characteristics costs of acquiring Process costs and maintaining data related to quality, and costs expended to make sure productive process development and conforms to quality analysis of reports on specifications quality performance 2-106
  • 107. Appraisal Costs Inspection and testing costs of testing and inspecting materials, parts, and product at various stages and at end of process Test equipment costs costs of maintaining equipment used in testing quality characteristics of products Operator costs costs of time spent by operators to gather data for testing product quality, to make equipment adjustments to maintain quality, and to stop work to assess quality 2-107
  • 108. Internal Failure Costs Scrap costs Process downtime costs costs of poor-quality poor- products that must be costs of shutting down discarded, including labor, productive process to fix material, and indirect costs problem Rework costs Price- Price-downgrading costs costs of fixing defective products to conform to costs of discounting poor- poor- quality specifications quality products—that is, products— Process failure costs selling products as costs of determining why “seconds” production process is producing poor-quality poor- products 2-108
  • 109. External Failure Costs Customer complaint costs Product liability costs costs of investigating and litigation costs satisfactorily responding to a resulting from product customer complaint resulting from a poor-quality product poor- liability and customer injury Product return costs costs of handling and replacing Lost sales costs poor- poor-quality products returned costs incurred by customer because customers Warranty claims costs are dissatisfied with costs of complying with poor- poor-quality products product warranties and do not make additional purchases 2-109
  • 110. Measuring and Reporting Quality Costs Index numbers ratios that measure quality costs against a base value labor index ratio of quality cost to labor hours cost index ratio of quality cost to manufacturing cost sales index ratio of quality cost to sales production index ratio of quality cost to units of final product 2-110
  • 111. Quality– Quality–Cost Relationship Cost of quality difference between price of nonconformance and conformance cost of doing things wrong 20 to 35% of revenues cost of doing things right 3 to 4% of revenues 2-111
  • 112. Effect of Quality Management on Productivity Productivity ratio of output to input Quality impact on productivity fewer defects increase output, and quality improvement reduces inputs Yield a measure of productivity Yield=(total input)(% good units) + (total input)(1-%good units)(% reworked) or Y=(I)(%G)+(I)(1- Y=(I)(%G)+(I)(1-%G)(%R) 2-112
  • 113. Computing Product Cost per Unit (Kd )(I) +(Kr )(R) Product Cost = Y where: Kd = direct manufacturing cost per unit I = input Kr = rework cost per unit R = reworked units Y = yield 2-113
  • 114. Computing Product Yield for Multistage Processes Y = (I)(%g1)(%g2) … (%gn) where: I = input of items to the production process that will result in finished products gi = good-quality, work-in-process products at stage i 2-114
  • 115. Quality– Quality–Productivity Ratio QPR productivity index that includes productivity and quality costs (good-quality units) QPR = (100) (input) (processing cost) + (reworked units) (rework cost) 2-115
  • 116. Malcolm Baldrige Award Created in 1987 to stimulate growth of quality management in United States Categories Leadership Information and analysis Strategic planning Human resource focus Process management Business results Customer and market focus 2-116
  • 117. Other Awards for Quality National individual International awards awards European Quality Award Armand V. Feigenbaum Canadian Quality Award Medal Australian Business Deming Medal Excellence Award E. Jack Lancaster Medal Deming Prize from Japan Edwards Medal Shewart Medal Ishikawa Medal 2-117
  • 118. ISO 9000 A set of procedures and ISO 9001:2000 policies for international Quality Management quality certification of Systems— Systems—Requirements suppliers standard to assess ability to Standards achieve customer satisfaction ISO 9000:2000 ISO 9004:2000 Quality Management Quality Management Systems—Fundamentals Systems— Systems— Systems—Guidelines for and Vocabulary Performance Improvements defines fundamental guidance to a company for terms and definitions continual improvement of its used in ISO 9000 family quality- quality-management system 2-118
  • 119. ISO 9000 Certification, Implications, and Registrars ISO 9001:2000—only 9001:2000— standard that carries third- third- party certification Many overseas companies will not do business with a supplier unless it has ISO 9000 certification ISO 9000 accreditation ISO registrars 2-119
  • 120. Chapter 3 Statistical Process Control Operations Management Roberta Russell & Bernard W. Taylor, III
  • 121. Lecture Outline Basics of Statistical Process Control Control Charts Control Charts for Attributes Control Charts for Variables Control Chart Patterns SPC with Excel and OM Tools Process Capability 3-121
  • 122. Basics of Statistical Process Control Statistical Process Control (SPC) monitoring production process to detect and prevent poor UCL quality Sample subset of items produced to use for inspection LCL Control Charts process is within statistical control limits 3-122
  • 123. Basics of Statistical Process Control (cont.) Random Non- Non-Random inherent in a process special causes depends on equipment identifiable and and machinery, correctable engineering, operator, include equipment out of and system of adjustment, defective measurement materials, changes in natural occurrences parts or materials, broken machinery or equipment, operator fatigue or poor work methods, or errors due to lack of training 3-123
  • 124. SPC in Quality Management SPC tool for identifying problems in order to make improvements contributes to the TQM goal of continuous improvements 3-124
  • 125. Quality Measures: Attributes and Variables Attribute a product characteristic that can be evaluated with a discrete response good – bad; yes - no Variable measure a product characteristic that is continuous and can be measured weight - length 3-125
  • 126. SPC Applied to Services Nature of defect is different in services Service defect is a failure to meet customer requirements Monitor time and customer satisfaction 3-126
  • 127. SPC Applied to Services (cont.) Hospitals timeliness and quickness of care, staff responses to requests, accuracy of lab tests, cleanliness, courtesy, accuracy of paperwork, speed of admittance and checkouts Grocery stores waiting time to check out, frequency of out-of-stock items, out-of- quality of food items, cleanliness, customer complaints, checkout register errors Airlines flight delays, lost luggage and luggage handling, waiting time at ticket counters and check-in, agent and flight attendant check- courtesy, accurate flight information, passenger cabin cleanliness and maintenance 3-127
  • 128. SPC Applied to Services (cont.) Fast- Fast-food restaurants waiting time for service, customer complaints, cleanliness, food quality, order accuracy, employee courtesy Catalogue- Catalogue-order companies order accuracy, operator knowledge and courtesy, packaging, delivery time, phone order waiting time Insurance companies billing accuracy, timeliness of claims processing, agent availability and response time 3-128
  • 129. Where to Use Control Charts Process has a tendency to go out of control Process is particularly harmful and costly if it goes out of control Examples at the beginning of a process because it is a waste of time and money to begin production process with bad supplies before a costly or irreversible point, after which product is difficult to rework or correct before and after assembly or painting operations that might cover defects before the outgoing final product or service is delivered 3-129
  • 130. Control Charts A graph that establishes Types of charts control limits of a process Attributes Control limits p-chart upper and lower bands of c-chart a control chart Variables mean (x bar – chart) range (R-chart) (R- 3-130
  • 131. Process Control Chart Out of control Upper control limit Process average Lower control limit 1 2 3 4 5 6 7 8 9 10 Sample number 3-131
  • 132. Normal Distribution 95% 99.74% - 3σ - 2σ - 1σ µ=0 1σ 2σ 3σ 3-132
  • 133. A Process Is in Control If … 1. … no sample points outside limits 2. … most points near process average 3. … about equal number of points above and below centerline 4. … points appear randomly distributed 3-133
  • 134. Control Charts for Attributes p-chart uses portion defective in a sample c-chart uses number of defective items in a sample 3-134
  • 135. p-Chart UCL = p + zσp LCL = p - zσp z = number of standard deviations from process average p = sample proportion defective; an estimate of process average σp = standard deviation of sample proportion p(1 - p) σp = n 3-135
  • 136. Construction of p-Chart p- NUMBER OF PROPORTION SAMPLE DEFECTIVES DEFECTIVE 1 6 .06 2 0 .00 3 4 .04 : : : : : : 20 18 .18 200 20 samples of 100 pairs of jeans 3-136
  • 137. Construction of p-Chart (cont.) p- total defectives p= = 200 / 20(100) = 0.10 total sample observations p(1 - p) 0.10(1 - 0.10) UCL = p + z = 0.10 + 3 n 100 UCL = 0.190 p(1 - p) 0.10(1 - 0.10) LCL = p - z = 0.10 - 3 n 100 LCL = 0.010 3-137
  • 138. 0.20 0.18 UCL = 0.190 0.16 Construction 0.14 Proportion defective of p-Chart p- 0.12 p = 0.10 (cont.) 0.10 0.08 0.06 0.04 0.02 LCL = 0.010 2 4 6 8 10 12 14 16 18 20 Sample number 3-138
  • 139. c-Chart UCL = c + zσc σc = c LCL = c - zσc where c = number of defects per sample 3-139
  • 140. c-Chart (cont.) Number of defects in 15 sample rooms NUMBER OF SAMPLE DEFECTS 190 1 12 c= = 12.67 15 2 8 3 16 UCL = c + zσc = 12.67 + 3 12.67 : : = 23.35 : : LCL = c - zσ c 15 15 = 12.67 - 3 12.67 190 = 1.99 3-140
  • 141. 24 UCL = 23.35 21 18 Number of defects c = 12.67 15 c-Chart 12 (cont.) 9 6 3 LCL = 1.99 2 4 6 8 10 12 14 16 Sample number 3-141
  • 142. Control Charts for Variables Range chart ( R-Chart ) R- uses amount of dispersion in a sample Mean chart ( x -Chart ) uses process average of a sample 3-142
  • 143. x-bar Chart: Standard Deviation Known = UCL = x + zσx LCL = = - zσx x = x1 + x2 + ... xn x = n where = x = average of sample means 3-143
  • 144. x-bar Chart Example: Standard Deviation Known (cont.) 3-144
  • 145. x-bar Chart Example: Standard Deviation Known (cont.) 3-145
  • 146. x-bar Chart Example: Standard Deviation Unknown = UCL = x + A2R = LCL = x - A2R where x = average of sample means 3-146
  • 147. Control Limits 3-147
  • 148. x-bar Chart Example: Standard Deviation Unknown OBSERVATIONS (SLIP- RING DIAMETER, CM) (SLIP- SAMPLE k 1 2 3 4 5 x R 1 5.02 5.01 4.94 4.99 4.96 4.98 0.08 2 5.01 5.03 5.07 4.95 4.96 5.00 0.12 3 4.99 5.00 4.93 4.92 4.99 4.97 0.08 4 5.03 4.91 5.01 4.98 4.89 4.96 0.14 5 4.95 4.92 5.03 5.05 5.01 4.99 0.13 6 4.97 5.06 5.06 4.96 5.03 5.01 0.10 7 5.05 5.01 5.10 4.96 4.99 5.02 0.14 8 5.09 5.10 5.00 4.99 5.08 5.05 0.11 9 5.14 5.10 4.99 5.08 5.09 5.08 0.15 10 5.01 4.98 5.08 5.07 4.99 5.03 0.10 Example 15.4 50.09 1.15 3-148
  • 149. x-bar Chart Example: Standard Deviation Unknown (cont.) ∑R 1.15 R= k = 10 = 0.115 = ∑x 50.09 5.01 cm x= = = k 10 = UCL = x + A2R = 5.01 + (0.58)(0.115) = 5.08 LCL = x = A2R = 5.01 - (0.58)(0.115) = 4.94 - Retrieve Factor Value A2 3-149
  • 150. 5.10 – 5.08 – UCL = 5.08 5.06 – 5.04 – = Mean 5.02 – x = 5.01 5.00 – x- bar 4.98 – Chart 4.96 – LCL = 4.94 Example (cont.) 4.94 – 4.92 – | | | | | | | | | | 1 2 3 4 5 6 7 8 9 10 Sample number 3-150
  • 151. R- Chart UCL = D4R LCL = D3R ∑R R= k where R = range of each sample k = number of samples 3-151
  • 152. R-Chart Example OBSERVATIONS (SLIP-RING DIAMETER, CM) (SLIP- SAMPLE k 1 2 3 4 5 x R 1 5.02 5.01 4.94 4.99 4.96 4.98 0.08 2 5.01 5.03 5.07 4.95 4.96 5.00 0.12 3 4.99 5.00 4.93 4.92 4.99 4.97 0.08 4 5.03 4.91 5.01 4.98 4.89 4.96 0.14 5 4.95 4.92 5.03 5.05 5.01 4.99 0.13 6 4.97 5.06 5.06 4.96 5.03 5.01 0.10 7 5.05 5.01 5.10 4.96 4.99 5.02 0.14 8 5.09 5.10 5.00 4.99 5.08 5.05 0.11 9 5.14 5.10 4.99 5.08 5.09 5.08 0.15 10 5.01 4.98 5.08 5.07 4.99 5.03 0.10 Example 15.3 50.09 1.15 3-152
  • 153. R-Chart Example (cont.) UCL = D4R = 2.11(0.115) = 0.243 LCL = D3R = 0(0.115) = 0 Retrieve Factor Values D3 and D4 Example 15.3 3-153
  • 154. R-Chart Example (cont.) 0.28 – 0.24 – UCL = 0.243 0.20 – Range 0.16 – R = 0.115 0.12 – 0.08 – LCL = 0 0.04 – | | | | | | | | | | 1 2 3 4 5 6 7 8 9 10 0– Sample number 3-154
  • 155. Using x- bar and R-Charts x- R- Together Process average and process variability must be in control It is possible for samples to have very narrow ranges, but their averages might be beyond control limits It is possible for sample averages to be in control, but ranges might be very large It is possible for an R-chart to exhibit a distinct downward R- trend, suggesting some nonrandom cause is reducing variation 3-155
  • 156. Control Chart Patterns Run sequence of sample values that display same characteristic Pattern test determines if observations within limits of a control chart display a nonrandom pattern To identify a pattern: 8 consecutive points on one side of the center line 8 consecutive points up or down 14 points alternating up or down 2 out of 3 consecutive points in zone A (on one side of center line) 4 out of 5 consecutive points in zone A or B (on one side of center line) 3-156
  • 157. Control Chart Patterns (cont.) UCL UCL LCL Sample observations LCL consistently below the center line Sample observations consistently above the center line 3-157
  • 158. Control Chart Patterns (cont.) UCL UCL LCL Sample observations consistently increasing LCL Sample observations consistently decreasing 3-158
  • 159. Zones for Pattern Tests UCL = 3 sigma = x + A2R Zone A = 2 2 sigma = x + (A2R) (A 3 Zone B = 1 1 sigma = x + (A2R) (A 3 Zone C Process = x average Zone C = 1 1 sigma = x - (A2R) 3 Zone B = 2 2 sigma = x - (A2R) 3 Zone A = LCL 3 sigma = x - A2R | | | | | | | | | | | | | 1 2 3 4 5 6 7 8 9 10 11 12 13 Sample number 3-159
  • 160. Performing a Pattern Test SAMPLE x ABOVE/BELOW UP/DOWN ZONE 1 4.98 B — B 2 5.00 B U C 3 4.95 B D A 4 4.96 B D A 5 4.99 B U C 6 5.01 — U C 7 5.02 A U C 8 5.05 A U B 9 5.08 A U A 10 5.03 A D B 3-160
  • 161. Sample Size Determination Attribute charts require larger sample sizes 50 to 100 parts in a sample Variable charts require smaller samples 2 to 10 parts in a sample 3-161
  • 162. SPC with Excel 3-162
  • 163. SPC with Excel and OM Tools 3-163
  • 164. Process Capability Tolerances design specifications reflecting product requirements Process capability range of natural variability in a process— process— what we measure with control charts 3-164
  • 165. Process Capability (cont.) Design Specifications (a) Natural variation exceeds design specifications; process is not capable of meeting specifications all the time. Process Design Specifications (b) Design specifications and natural variation the same; process is capable of meeting specifications most of the time. Process 3-165
  • 166. Process Capability (cont.) Design Specifications (c) Design specifications greater than natural variation; process is capable of always conforming to specifications. Process Design Specifications (d) Specifications greater than natural variation, but process off center; capable but some output will not meet upper specification. Process 3-166
  • 167. Process Capability Measures Process Capability Ratio tolerance range Cp = process range upper specification limit - lower specification limit = 6σ 3-167
  • 168. Computing Cp Net weight specification = 9.0 oz ± 0.5 oz Process mean = 8.80 oz Process standard deviation = 0.12 oz upper specification limit - lower specification limit Cp = 6σ = 9.5 - 8.5 = 1.39 6(0.12) 3-168
  • 169. Process Capability Measures Process Capability Index = x - lower specification limit 3σ , Cpk = minimum = upper specification limit - x 3σ 3-169
  • 170. Computing Cpk Net weight specification = 9.0 oz ± 0.5 oz Process mean = 8.80 oz Process standard deviation = 0.12 oz = x - lower specification limit , Cpk = minimum 3σ = upper specification limit - x 3σ 8.80 - 8.50 9.50 - 8.80 = minimum 3(0.12) , 3(0.12) = 0.83 3-170
  • 172. Process Capability with Excel and OM Tools 3-172
  • 173. Chapter 3 Supplement Acceptance Sampling Operations Management Roberta Russell & Bernard W. Taylor, III
  • 174. Lecture Outline Single- Single-Sample Attribute Plan Operating Characteristic Curve Developing a Sampling Plan with Excel Average Outgoing Quality Double - and Multiple-Sampling Plans Multiple- Supplement 3-174 3-
  • 175. Acceptance Sampling Accepting or rejecting a production lot based on the number of defects in a sample Not consistent with TQM or Zero Defects philosophy producer and customer agree on the number of acceptable defects a means of identifying not preventing poor quality percent of defective parts versus PPM Sampling plan provides guidelines for accepting a lot Supplement 3-175 3-
  • 176. Single– Single–Sample Attribute Plan Single sampling plan N = lot size n = sample size (random) c = acceptance number d = number of defective items in sample If d ≤ c, accept lot; else reject Supplement 3-176 3-
  • 177. Producer’s and Consumer’s Risk AQL or acceptable quality level proportion of defects consumer will accept in a given lot α or producer’s risk probability of rejecting a good lot LTPD or lot tolerance percent defective limit on the number of defectives the customer will accept β or consumer’s risk probability of accepting a bad lot Supplement 3-177 3-
  • 178. Producer’s and Consumer’s Risk (cont.) Accept Reject Good Lot Type I Error No Error Producer’ Risk Bad Lot Type II Error No Error Consumer’s Risk Sampling Errors Supplement 3-178 3-
  • 179. Operating Characteristic (OC) Curve shows probability of accepting lots of different quality levels with a specific sampling plan assists management to discriminate between good and bad lots exact shape and location of the curve is defined by the sample size (n) and (n acceptance level (c) for the sampling (c plan Supplement 3-179 3-
  • 180. OC Curve (cont.) 1.00 – α = 0.05 0.80 – Probability of acceptance, Pa 0.60 – OC curve for n and c 0.40 – 0.20 – β = 0.10 | | | | | | | | | | – 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 Proportion defective AQL LTPD Supplement 3-180 3-
  • 181. Developing a Sampling Plan with OM Tools ABC Company produces mugs in lots of 10,000. Performance measures for quality of mugs sent to stores call for a producer’s risk of 0.05 with an AQL of 1% defective and a consumer’s risk of 0.10 with a N = 10,000 n=? LTPD of 5% defective. What α = 0.05 c= size sample and what ? acceptance number should ABC use to achieve β = 0.10 performance measures called AQL = 1% for in the sampling plan? LTPD = 5% Supplement 3-181 3-
  • 182. Average Outgoing Quality (AOQ) Expected number of defective items that will pass on to customer with a sampling plan Average outgoing quality limit (AOQL) maximum point on the curve worst level of outgoing quality Supplement 3-182 3-
  • 183. AOQ Curve Supplement 3-183 3-
  • 184. Double- Double-Sampling Plans Take small initial sample If # defective ≤ lower limit, accept If # defective > upper limit, reject If # defective between limits, take second sample Accept or reject based on 2 samples Less costly than single-sampling plans single- Supplement 3-184 3-
  • 185. Multiple- Multiple-Sampling Plans Uses smaller sample sizes Take initial sample If # defective ≤ lower limit, accept If # defective > upper limit, reject If # defective between limits, resample Continue sampling until accept or reject lot based on all sample data Supplement 3-185 3-
  • 186. Chapter 4 Product Design Operations Management Roberta Russell & Bernard W. Taylor, III
  • 187. Lecture Outline Design Process Concurrent Design Technology in Design Design Reviews Design for Environment Design for Robustness Quality Function Deployment 4-187
  • 188. Design Process Effective design can provide a competitive edge matches product or service characteristics with customer requirements ensures that customer requirements are met in the simplest and least costly manner reduces time required to design a new product or service minimizes revisions necessary to make a design workable Copyright 2009 John Wiley & Sons, Inc. 4-188
  • 189. Design Process (cont.) Product design defines appearance of product sets standards for performance specifies which materials are to be used determines dimensions and tolerances 4-189
  • 191. Idea Generation Company’s own Salespersons in the R&D department field Customer complaints Factory workers or suggestions New technological Marketing research developments Suppliers Competitors 4-191
  • 192. Idea Generation (cont.) Perceptual Maps Visual comparison of customer perceptions Benchmarking Comparing product/process against best-in-class best-in- Reverse engineering Dismantling competitor’s product to improve your own product 4-192
  • 193. Perceptual Map of Breakfast Cereals 4-193
  • 194. Feasibility Study Market analysis Economic analysis Technical/strategic analyses Performance specifications 4-194
  • 195. Rapid Prototyping testing and revising a preliminary design model Build a prototype form design functional design production design Test prototype Revise design Retest 4-195
  • 196. Form and Functional Design Form Design how product will look? Functional Design how product will perform? reliability maintainability usability 4-196
  • 197. Computing Reliability Components in series 0.90 0.90 0.90 x 0.90 = 0.81 4-197
  • 198. Computing Reliability (cont.) Components in parallel 0.90 R2 0.95 0.95 + 0.90(1-0.95) = 0.995 0.90(1- R1 4-198
  • 199. System Reliability 0.90 0.98 0.92 0.98 0.98 0.92+(1- 0.92+(1-0.92)(0.90)=0.99 0.98 0.98 x 0.99 x 0.98 = 0.951 4-199
  • 200. System Availability (SA) MTBF SA = MTBF + MTTR where: MTBF = mean time between failures MTTR = mean time to repair 4-200
  • 201. System Availability (cont.) PROVIDER MTBF (HR) MTTR (HR) A 60 4.0 B 36 2.0 C 24 1.0 SAA = 60 / (60 + 4) = .9375 or 94% SAB = 36 / (36 + 2) = .9473 or 95% SAC = 24 / (24 + 1) = .96 or 96% 4-201
  • 202. Usability Ease of use of a product or service ease of learning ease of use ease of remembering how to use frequency and severity of errors user satisfaction with experience 4-202
  • 203. Production Design How the product will be made Simplification reducing number of parts, assemblies, or options in a product Standardization using commonly available and interchangeable parts Modular Design combining standardized building blocks, or modules, to create unique finished products Design for Manufacture (DFM) • Designing a product so that it can be produced easily and economically 4-203
  • 204. Design Source: Adapted from G. Boothroyd and P. Dewhurst, “Product Design…. Key to Successful Robotic Assembly.” Assembly Simplification Engineering (September 1986), pp. 90- 90- 93. (a) Original design (b) Revised design (c) Final design Assembly using One- One-piece base & Design for common fasteners elimination of push-and- push-and-snap fasteners assembly 4-204
  • 205. Final Design and Process Plans Final design Process plans detailed drawings workable instructions and specifications necessary equipment for new product or and tooling service component sourcing recommendations job descriptions and procedures computer programs for automated machines 4-205
  • 206. Design Team 4-206
  • 207. Concurrent Design A new approach to Involves suppliers design that involves Incorporates production simultaneous design of process products and processes Uses a price-minus price- by design teams system Scheduling and Improves quality of early management can be design decisions complex as tasks are done in parallel Uses technology to aid design 4-207
  • 208. Technology in Design Computer Aided Design (CAD) assists in creation, modification, and analysis of a design computer- computer-aided engineering (CAE) tests and analyzes designs on computer screen computer- computer-aided manufacturing (CAD/CAM) ultimate design-to-manufacture connection design-to- product life cycle management (PLM) managing entire lifecycle of a product collaborative product design (CPD) 4-208
  • 209. Collaborative Product Design (CPD) A software system for collaborative design and development among trading partners With PML, manages product data, sets up project workspaces, and follows life cycle of the product Accelerates product development, helps to resolve product launch issues, and improves quality of design Designers can conduct virtual review sessions test “what if” scenarios assign and track design issues communicate with multiple tiers of suppliers create, store, and manage project documents 4-209
  • 210. Design Review Review designs to prevent failures and ensure value Failure mode and effects analysis (FMEA) a systematic method of analyzing product failures Fault tree analysis (FTA) a visual method for analyzing interrelationships among failures Value analysis (VA) helps eliminate unnecessary features and functions 4-210
  • 211. FMEA for Potato Chips Failure Cause of Effect of Corrective Mode Failure Failure Action Stale low moisture content tastes bad add moisture expired shelf life won’t crunch cure longer poor packaging thrown out better package seal lost sales shorter shelf life Broken too thin can’t dip change recipe too brittle poor display change process rough handling injures mouth change packaging rough use chocking poor packaging perceived as old lost sales Too Salty outdated receipt eat less experiment with recipe process not in control drink more experiment with process uneven distribution of salt health hazard introduce low salt version lost sales 4-211
  • 212. Fault tree analysis (FTA) 4-212
  • 213. Value analysis (VA) Can we do without it? Does it do more than is required? Does it cost more than it is worth? Can something else do a better job? Can it be made by a less costly method? with less costly tooling? with less costly material? Can it be made cheaper, better, or faster by someone else? 4-213
  • 214. Value analysis (VA) (cont.) Updated versions also include: Is it recyclable or biodegradable? Is the process sustainable? Will it use more energy than it is worth? Does the item or its by-product harm the by- environment? 4-214
  • 215. Design for Environment and Extended Producer Responsibility Design for environment designing a product from material that can be recycled design from recycled material design for ease of repair minimize packaging minimize material and energy used during manufacture, consumption and disposal Extended producer responsibility holds companies responsible for their product even after its useful life 4-215
  • 217. Sustainability Ability to meet present needs without compromising those of future generations Green product design Use fewer materials Use recycled materials or recovered components Don’t assume natural materials are always better Don’t forget energy consumption Extend useful life of product Involve entire supply chain Change paradigm of design Source: Adapted from the Business Social Responsibility Web site, www.bsr.org, www.bsr.org, accessed April 1, 2007. 4-217
  • 218. Quality Function Deployment (QFD) Translates voice of customer into technical design requirements Displays requirements in matrix diagrams first matrix called “house of quality” series of connected houses 4-218
  • 219. House of Quality 5 Importance Trade- Trade-off matrix 3 Design characteristics 1 4 2 Customer Relationship Competitive requirements matrix assessment 6 Target values 4-219
  • 220. Competitive Assessment of Customer Requirements Competitive Assessment Customer Requirements 1 2 3 4 5 Presses quickly 9 B A X Removes wrinkles 8 AB X Irons well Doesn’t stick to fabric 6 X BA Provides enough steam 8 AB X Doesn’t spot fabric 6 X AB Doesn’t scorch fabric 9 A XB safe to use Heats quickly 6 X B A Easy and Automatic shut-off shut- 3 ABX ABX Quick cool-down cool- 3 X A B Doesn’t break when dropped 5 AB X Doesn’t burn when touched 5 AB X 4-220 Not too heavy 8 X A B
  • 221. Protective cover for soleplate Time required to reach 450º F From Customer Time to go from 450º to 100º Material used in soleplate Flow of water from holes Energy needed to press Requirements Thickness of soleplate Automatic shutoff to Design Number of holes Size of soleplate Weight of iron Size of holes Characteristics Customer Requirements Presses quickly - - + + + - Removes wrinkles + + + + + Irons well Doesn’t stick to fabric - + + + + Provides enough steam + + + + Doesn’t spot fabric + - - - Doesn’t scorch fabric + + + - + safe to use Heats quickly - - + - Easy and Automatic shut-off shut- + Quick cool-down cool- - - + + Doesn’t break when dropped + + + + Doesn’t burn when touched + + + + Not too heavy + - - - + -4-221
  • 222. Tradeoff Matrix Energy needed to press Weight of iron - + Size of soleplate Thickness of soleplate Material used in soleplate - + Number of holes + Size of holes Flow of water from holes Time required to reach 450º Time to go from 450º to 100º Protective cover for soleplate 4-222 Automatic shutoff
  • 223. Targeted Changes in Design Protective cover for soleplate Time to go from 450º to 100º Time required to reach 450º Material used in soleplate Flow of water from holes Energy needed to press Thickness of soleplate Automatic shutoff Number of holes Size of soleplate Weight of iron Size of holes Units of measure ft-lb ft- lb in. cm ty ea mm oz/s sec sec Y/N Y/N measures Objective Iron A 3 1.4 8x4 2 SS 27 15 0.5 45 500 N Y Iron B 4 1.2 8x4 1 MG 27 15 0.3 35 350 N Y Our Iron (X) 2 1.7 9x5 4 T 35 15 0.7 50 600 N Y Estimated impact 3 4 4 4 5 4 3 2 5 5 3 0 Estimated cost 3 3 3 3 4 3 3 3 4 4 5 2 Targets 1.2 8x5 3 SS 30 30 500 Design changes * * * * * * * 4-223
  • 224. Completed House of Quality SS = Silverstone MG = Mirorrglide T = Titanium 4-224
  • 225. A Series of Connected QFD Houses Product characteristics requirements Customer Part A-1 characteristics characteristics Product Process House A-2 characteristics of characteristics quality Parts Operations Part A-3 deployment characteristics Process Process A-4 planning Operating requirements 4-225
  • 226. Benefits of QFD Promotes better understanding of customer demands Promotes better understanding of design interactions Involves manufacturing in design process Provides documentation of design process 4-226
  • 227. Design for Robustness Robust product designed to withstand variations in environmental and operating conditions Robust design yields a product or service designed to withstand variations Controllable factors design parameters such as material used, dimensions, and form of processing Uncontrollable factors user’s control (length of use, maintenance, settings, etc.) 4-227
  • 228. Design for Robustness (cont.) Tolerance allowable ranges of variation in the dimension of a part Consistency consistent errors are easier to correct than random errors parts within tolerances may yield assemblies that are not within limits consumers prefer product characteristics near their ideal values 4-228
  • 229. Taguchi’s Quality Loss Function Quantifies customer preferences toward quality Quality Loss Emphasizes that customer preferences are strongly oriented toward consistently Lower Target Upper tolerance tolerance Design for Six Sigma limit limit (DFSS) 4-229
  • 230. Copyright 2009 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for back- distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein. 4-230
  • 231. Chapter 5 Service Design Operations Management Roberta Russell & Bernard W. Taylor, III
  • 232. Lecture Outline Service Economy Characteristics of Services Service Design Process Tools for Service Design Waiting Line Analysis for Service Improvement 5-232
  • 233. Service Economy Source: U.S. Bureau of Labor Statistics, IBM Almaden Research Center 5-233
  • 234. 5-234
  • 235. Characteristics of Services Services acts, deeds, or performances Goods tangible objects Facilitating services accompany almost all purchases of goods Facilitating goods accompany almost all service purchases 5-235
  • 236. Continuum from Goods to Services Source: Adapted from Earl W. Sasser, R.P. Olsen, and D. Daryl Wyckoff, Management of Service Operations (Boston: Allyn Bacon, 1978), p.11. 5-236
  • 237. Characteristics of Services (cont.) Services are Service inseparable intangible from delivery Service output is Services tend to be variable decentralized and Services have higher dispersed customer contact Services are Services are consumed more often perishable than products Services can be easily emulated 5-237
  • 239. Service Design Process (cont.) Service concept purpose of a service; it defines target market and customer experience Service package mixture of physical items, sensual benefits, and psychological benefits Service specifications performance specifications design specifications delivery specifications 5-239
  • 241. High v. Low Contact Services Design High-Contact Service Low-Contact Service Decision Facility Convenient to Near labor or location customer transportation source Facility Must look presentable, Designed for efficiency layout accommodate customer needs, and facilitate interaction with customer Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Compensative Advantage (New York:McGraw-Hill, 2001), p. 210 5-241
  • 242. High v. Low Contact Services (cont.) Design High-Contact Service Low-Contact Decision Service Quality More variable since Measured against control customer is involved in established process; customer standards; testing expectations and and rework possible perceptions of quality may differ; customer to correct defects present when defects occur Capacity Excess capacity required Planned for average to handle peaks in demand demand Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Compensative Advantage (New York:McGraw-Hill, 2001), p. 210 5-242
  • 243. High v. Low Contact Services (cont.) Design High-Contact Service Low-Contact Decision Service Worker skills Must be able to Technical skills interact well with customers and use judgment in decision making Scheduling Must accommodate Customer customer schedule concerned only with completion date Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Compensative Advantage (New York:McGraw-Hill, 2001), p. 210 5-243
  • 244. High v. Low Contact Services (cont.) Design High-Contact Service Low-Contact Decision Service Service Mostly front-room Mostly back-room process activities; service may activities; change during delivery planned and in response to executed with customer minimal interference Service package Varies with customer; Fixed, less includes environment extensive as well as actual service Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Compensative Advantage (New York:McGraw-Hill, 2001), p. 210 5-244
  • 245. Tools for Service Design Service blueprinting Servicescapes line of influence space and function line of interaction ambient conditions line of visibility signs, symbols, and line of support artifacts Front-office/Back- Front-office/Back- Quantitative office activities techniques 5-245
  • 248. Elements of Waiting Line Analysis Operating characteristics average values for characteristics that describe performance of waiting line system Queue a single waiting line Waiting line system consists of arrivals, servers, and waiting line structure Calling population source of customers; infinite or finite 5-248
  • 249. 5-249
  • 250. Elements of Waiting Line Analysis (cont.) Arrival rate (λ) (λ frequency at which customers arrive at a waiting line according to a probability distribution, usually Poisson Service time (µ) (µ time required to serve a customer, usually described by negative exponential distribution Service rate must be shorter than arrival rate (λ < µ) (λ Queue discipline order in which customers are served Infinite queue can be of any length; length of a finite queue is limited 5-250
  • 251. Elements of Waiting Line Analysis (cont.) Channels number of parallel servers for servicing customers Phases number of servers in sequence a customer must go through 5-251
  • 252. Operating Characteristics Operating characteristics are assumed to approach a steady state 5-252
  • 253. Traditional Cost Relationships as service improves, cost increases 5-253
  • 254. Psychology of Waiting Waiting rooms Disney magazines and costumed characters newspapers mobile vendors televisions accurate wait times Bank of America special passes mirrors Supermarkets magazines “impulse purchases” 5-254
  • 255. Psychology of Waiting (cont.) Preferential treatment Grocery stores: express lanes for customers with few purchases Airlines/Car rental agencies: special cards available to frequent-users or for an additional fee frequent- Phone retailers: route calls to more or less experienced salespeople based on customer’s sales history Critical service providers services of police department, fire department, etc. waiting is unacceptable; cost is not important 5-255
  • 256. Waiting Line Models Single- Single-server model simplest, most basic waiting line structure Frequent variations (all with Poisson arrival rate) exponential service times general (unknown) distribution of service times constant service times exponential service times with finite queue exponential service times with finite calling population 5-256
  • 257. Basic Single-Server Model Single- Assumptions Computations Poisson arrival rate λ = mean arrival rate exponential service µ = mean service rate times n = number of first- first-come, first- first- customers in line served queue discipline infinite queue length infinite calling population 5-257
  • 258. Basic Single-Server Model (cont.) Single- probability that no customers average number of customers are in queuing system in queuing system P0 = ( ) λ 1– µ L= µ–λ λ probability of n customers in average number of customers queuing system in waiting line ( ) ( )( ) λ n λ n λ λ2 Pn = · P0 = 1– Lq = µ µ µ µ ( µ – λ) 5-258
  • 259. Basic Single-Server Model (cont.) Single- average time customer probability that server is busy spends in queuing system and a customer has to wait 1 L (utilization factor) W= = λ µ–λ λ ρ= µ average time customer probability that server is idle spends waiting in line and customer can be served λ I=1– ρ Wq = µ ( µ – λ) λ =1– = P0 µ 5-259
  • 260. Basic Single-Server Model Single- Example 5-260
  • 261. Basic Single-Server Model Single- Example (cont.) 5-261
  • 262. Service Improvement Analysis waiting time (8 min.) is too long hire assistant for cashier? increased service rate hire another cashier? reduced arrival rate Is improved service worth the cost? 5-262
  • 263. Basic Single-Server Model Single- Example: Excel 5-263
  • 264. Advanced Single-Server Models Single- Constant service times occur most often when automated equipment or machinery performs service Finite queue lengths occur when there is a physical limitation to length of waiting line Finite calling population number of “customers” that can arrive is limited 5-264
  • 265. Advanced Single-Server Single- Models (cont.) 5-265
  • 266. Basic Multiple-Server Model Multiple- single waiting line and service facility with several independent servers in parallel same assumptions as single-server model single- sµ > λ s = number of servers servers must be able to serve customers faster than they arrive 5-266
  • 267. Basic Multiple-Server Model Multiple- (cont.) probability that there are no customers in system 1 P0 = n = s – 1 1 λ n 1 λ s ∑ n=0 () n! + µ ( )( ) s! µ sµ sµ - λ probability of n customers in system λ n () 1 Pn = { () s!sn–s µ 1 λ n P0, for n > s P0, for n ≤ s n! µ 5-267
  • 268. Basic Multiple-Server Model Multiple- (cont.) probability that customer must wait () 1 λ s sµ λ Pw = P0 Lq = L – s! µ sµ – λ µ λµ (λ/µ)s λ 1 Lq L= P0 + Wq = W – = (s – 1)! (sµ – λ)2 (s µ µ λ L λ W= ρ= λ sµ 5-268
  • 269. Basic Multiple-Server Model Multiple- Example 5-269
  • 270. Basic Multiple-Server Model Multiple- Example (cont.) 5-270
  • 271. Basic Multiple-Server Model Multiple- Example (cont.) 5-271
  • 272. Basic Multiple-Server Model Multiple- Example (cont.) 5-272
  • 273. Basic Multiple-Server Model Multiple- Example (cont.) 5-273
  • 274. Basic Multiple-Server Model Multiple- Example (cont.) To cut wait time, add another service representative now, s = 4 Therefore: 5-274
  • 276. Chapter 6 Processes and Technology Operations Management Roberta Russell & Bernard W. Taylor, III
  • 277. Lecture Outline Process Planning Process Analysis Process Innovation Technology Decisions 6-277
  • 278. Process Planning Process a group of related tasks with specific inputs and outputs Process design what tasks need to be done and how they are coordinated among functions, people, and organizations Process strategy an organization’s overall approach for physically producing goods and services Process planning converts designs into workable instructions for manufacture or delivery 6-278
  • 279. Process Strategy Vertical integration extent to which firm will produce inputs and control outputs of each stage of production process Capital intensity mix of capital (i.e., equipment, automation) and labor resources used in production process Process flexibility ease with which resources can be adjusted in response to changes in demand, technology, products or services, and resource availability Customer involvement role of customer in production process 6-279
  • 280. Outsourcing Cost Speed Capacity Reliability Quality Expertise 6-280
  • 281. Process Selection Projects one-of-a-kind production of a product to customer order Batch production processes many different jobs at the same time in groups or batches Mass production produces large volumes of a standard product for a mass market Continuous production used for very-high volume commodity products 6-281
  • 283. Product- Product-Process Matrix Source: Adapted from Robert Hayes and Steven Wheelwright, Restoring the Competitive Edge Competing through Manufacturing (New York, John Wiley & Sons, 1984), p. 209. 6-283
  • 284. Types of Processes PROJECT BATCH MASS CONT. CONT. Made-to- Made-to- Made-to- Made-to- Type of Unique order stock Commodity product (customized) (standardized ) One-at- One-at-a- Few Type of Mass Mass time individual customer market market customers Product demand Infrequent Fluctuates Stable Very stable Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Competitive Advantage (New York:McGraw-Hill, 2001), p. 210 York:McGraw- 6-284
  • 285. Types of Processes (cont.) PROJECT BATCH MASS CONT. CONT. Demand Low to Very low High Very high volume medium No. of Infinite different Many, varied Few Very few products variety Repetitive, Continuous, Production Long- Long-term Discrete, job system assembly process project shops lines industries Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Competitive Advantage (New York:McGraw-Hill, 2001), p. 210 York:McGraw- 6-285
  • 286. Types of Processes (cont.) PROJECT BATCH MASS CONT. CONT. Varied General- General- Special- Special- Highly Equipment purpose purpose automated Primary Mixing, type of Specialized Fabrication Assembly treating, work contracts refining Experts, Limited Worker Wide range Equipment skills crafts- crafts- range of of skills monitors persons skills Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Competitive Advantage (New York:McGraw-Hill, 2001), p. 210 York:McGraw- 6-286
  • 287. Types of Processes (cont.) PROJECT BATCH MASS CONT. CONT. Efficiency, Highly efficient, Custom work, Flexibility, Advantages latest technology quality speed, large capacity, low cost ease of control Capital Non- Non-repetitive, Costly, slow, Difficult to change, Dis- Dis- small customer difficult to investment; far-reaching errors, far- advantages base, expensive lack of manage limited variety responsiveness Machine shops, Automobiles, Construction, print shops, televisions, Paint, chemicals, Examples shipbuilding, foodstuffs spacecraft bakeries, computers, education fast food Source: Adapted from R. Chase, N. Aquilano, and R. Jacobs, Operations Management for Competitive Advantage (New York:McGraw- York:McGraw-Hill, 2001), p. 210 6-287
  • 288. Process Selection with Break- Break-Even Analysis examines cost trade-offs associated with demand volume Cost Fixed costs constant regardless of the number of units produced Variable costs vary with the volume of units produced Revenue price at which an item is sold Total revenue is price times volume sold Profit difference between total revenue and total cost 6-288
  • 289. Process Selection with Break- Break-Even Analysis (cont.) Total cost = fixed cost + total variable cost TC = cf + vcv Total revenue = volume x price TR = vp Profit = total revenue - total cost Z = TR – TC = vp - (cf + vcv) 6-289
  • 290. Process Selection with Break- Break-Even Analysis (cont.) TR = TC vp = cf + vcv vp - vcv = cf v ( p - c v) = c f cf p - cv v= Solving for Break-Even Point (Volume) Break- 6-290
  • 291. Break- Break-Even Analysis: Example Fixed cost = cf = $2,000 Variable cost = cv = $5 per raft Price = p = $10 per raft Break- Break-even point is cf 2000 v= = = 400 rafts p - cv 10 - 5 6-291
  • 292. Break- Break-Even Analysis: Graph Dollars $3,000 — Total cost line $2,000 — $1,000 — Total revenue line 400 Units Break- Break-even point 6-292
  • 293. Process Plans Set of documents that detail manufacturing and service delivery specifications assembly charts operations sheets quality-control check-sheets 6-293
  • 294. Process Selection Process A Process B $2,000 + $5v = $10,000 + $3v $5v $3v $2v = $8,000 $2v v = 4,000 rafts Below or equal to 4,000, choose A Above or equal to 4,000, choose B 6-294
  • 295. Process Analysis • systematic examinatio n of all aspects of process to improve operation 6-295
  • 296. An Operations Sheet for a Plastic Part Part name Crevice Tool Part No. 52074 Usage Hand-Vac Hand- Assembly No. 520 Oper. No. Description Dept. Machine/Tools Time 10 Pour in plastic bits 041 Injection molding 2 min 20 Insert mold 041 #076 2 min 30 Check settings 041 113, 67, 650 20 min & start machine 40 Collect parts & lay flat 051 Plastics finishing 10 min 50 Remove & clean mold 042 Parts washer 15 min 60 Break off rough edges 051 Plastics finishing 10 min 6-296
  • 297. Process Analysis Building a flowchart Determine objectives Define process boundaries Define units of flow Choose type of chart Observe process and collect data Map out process Validate chart 6-297
  • 298. Process Flowcharts look at manufacture of product or delivery of service from broad perspective Incorporate nonproductive activities (inspection, transportation, delay, storage) productive activities (operations) 6-298
  • 299. Process Flowchart Symbols Operations Inspection Transportation Delay Storage 6-299
  • 301. 6-301
  • 302. Simple Value Chain Flowchart 6-302
  • 303. Process Innovation Continuous improvement refines the breakthrough Breakthrough Improvement Total redesign Continuous improvement activities peak; time to reengineer process of a process for breakthrough improvements 6-303
  • 304. From Function to Process Product Development Manufacturing Purchasing Accounting Order Fulfillment Sales Supply Chain Management Customer Service Function Process 6-304
  • 305. Process Innovation Strategic Directives Baseline Data Customer Goals for Process Benchmark Performance Requirements Data High - level Innovative Process map Design Ideas Principles Detailed Model Process Map Key Validation Performance Measures Pilot Study of New Design Goals Full Scale No Met? Yes Implementation 6-305
  • 307. Principles for Redesigning Processes Remove waste, simplify, and consolidate similar activities Link processes to create value Let the swiftest and most capable enterprise execute the process Flex process for any time, any place, any way Capture information digitally at the source and propagate it through process 6-307
  • 308. Principles for Redesigning Processes (cont.) Provide visibility through fresher and richer information about process status Fit process with sensors and feedback loops that can prompt action Add analytic capabilities to process Connect, collect, and create knowledge around process through all who touch it Personalize process with preferences and habits of participants 6-308
  • 309. Techniques for Generating Innovative Ideas Vary the entry point to a problem in trying to untangle fishing lines, it’s best to start from the fish, not the poles Draw analogies a previous solution to an old problem might work Change your perspective think like a customer bring in persons who have no knowledge of process 6-309
  • 310. Techniques for Generating Innovative Ideas (cont.) Try inverse brainstorming what would increase cost what would displease the customer Chain forward as far as possible if I solve this problem, what is the next problem Use attribute brainstorming how would this process operate if. . . our workers were mobile and flexible there were no monetary constraints we had perfect knowledge 6-310
  • 311. Technology Decisions Financial justification of technology Purchase cost Operating Costs Annual Savings Revenue Enhancement Replacement Analysis Risk and Uncertainty Piecemeal Analysis 6-311
  • 313. A Technology Primer Product Technology Computer-aided Creates and communicates designs design (CAD) electronically Group technology Classifies designs into families for easy (GT) retrieval and modification Computer-aided Tests functionality of CAD designs engineering (CAE) electronically Collaborative product commerce Facilitates electronic communication and (CPC) exchange of information among designers and suppliers 6-313
  • 314. A Technology Primer (cont.) Product Technology Product data Keeps track of design specs and revisions management for the life of the product (PDM) Integrates decisions of those involved in Product life cycle product development, manufacturing, sales, management customer service, recycling, and disposal (PLM) Product Defines products “configured” by customers configuration who have selected among various options, usually from a Web site 6-314
  • 315. A Technology Primer (cont.) Process Technology Standard for Set standards for communication among exchange of different CAD vendors; translates CAD data product model data into requirements for automated inspection (STEP) and manufacture Computer-aided Electronic link between automated design design and (CAD) and automated manufacture (CAM) manufacture (CAD/CAM) Computer aided Generates process plans based on process (CAPP) database of similar requirements E-procurement Electronic purchasing of items from e- e- marketplaces, auctions, or company websites 6-315
  • 316. A Technology Primer (cont.) Manufacturing Technology Computer Machines controlled by software code to perform a numerically control variety of operations with the help of automated (CNC) tool changers; also collects processing information and quality data Flexible A collection of CNC machines connected by an manufacturing automated material handling system to produce a system (FMS) wide variety of parts Manipulators that can be programmed to perform Robots repetitive tasks; more consistent than workers but less flexible Fixed- Fixed-path material handling; moves items along a Conveyors belt or overhead chain; “reads” packages and diverts them to different directions; can be very fast 6-316
  • 317. A Technology Primer (cont.) Manufacturing Technology Automatic guided A driverless truck that moves material along a vehicle (AGV) specified path; directed by wire or tape embedded in floor or by radio frequencies; very flexible An automated warehouse—some 26 stores high— warehouse— high— Automated storage in which items are placed in a carousel-type carousel- and retrieval system storage system and retrieved by fast-moving fast- (ASRS) stacker cranes; controlled by computer Continuous monitoring of automated equipment; makes real-time decisions on ongoing operation, real- Process Control maintenance, and quality Automated manufacturing systems integrated Computer-integrated through computer technology; also called e- e- manufacturing manufacturing (CIM) 6-317
  • 318. A Technology Primer (cont.) Information Technology Business – to – Electronic transactions between businesses Business (B2B) usually over the Internet Business – to – Electronic transactions between businesses and Consumer (B2C) their customers usually over the Internet Internet A global information system of computer networks that facilitates communication and data transfer Intranet Communication networks internal to an organization; can be password (i.e., firewall) protected sites on the Internet Intranets connected to the Internet for shared Extranet access with select suppliers, customers, and trading partners 6-318
  • 319. A Technology Primer (cont.) Information Technology Bar Codes A series of vertical lines printed on most packages that identifies item and other information when read by a scanner Radio Frequency An integrated circuit embedded in a tag that can send Identification tags and receive information; a twenty-first century bar code twenty- (RFID) with read/write capabilities A computer-to-computer exchange of business computer-to- Electronic data documents over a proprietary network; very expensive and inflexible interchange (EDI) A programming language that enables computer – to - computer communication over the Internet by tagging Extensive markup data before its is sent language (XML) Software for managing basic requirements of an enterprise, including sales & marketing, finance and accounting, production & materials management, and Enterprise human resources resource planning (ERP) 6-319
  • 320. A Technology Primer (cont.) Information Technology Software for managing flow of goods and information Supply chain among a network of suppliers, manufacturers and management (SCM) distributors Software for managing interactions with customers and Customer relationship compiling and analyzing customer data management (CRM) An information system that helps managers make decisions; includes a quantitative modeling component Decision support and an interactive component for what-if analysis what- systems (DSS) A computer system that uses an expert knowledge base to diagnose or solve a problem Expert systems (ES) A field of study that attempts to replicate elements of human thought in computer processes; includes expert Artificial intelligence systems, genetic algorithms, neural networks, and fuzzy (AI) logic 6-320
  • 321. Chapter 7 Capacity and Facilities Operations Management Roberta Russell & Bernard W. Taylor, III
  • 322. Lecture Outline Capacity Planning Basic Layouts Designing Process Layouts Designing Service Layouts Designing Product Layouts Hybrid Layouts
  • 323. Capacity Maximum capability to produce Capacity planning establishes overall level of productive resources for a firm 3 basic strategies for timing of capacity expansion in relation to steady growth in demand (lead, lag, and average)
  • 325. Capacity (cont.) Capacity increase depends on volume and certainty of anticipated demand strategic objectives costs of expansion and operation Best operating level % of capacity utilization that minimizes unit costs Capacity cushion % of capacity held in reserve for unexpected occurrences
  • 326. Economies of Scale it costs less per unit to produce high levels of output fixed costs can be spread over a larger number of units production or operating costs do not increase linearly with output levels quantity discounts are available for material purchases operating efficiency increases as workers gain experience
  • 327. Best Operating Level for a Hotel
  • 328. Machine Objectives of Facility Layout Arrangement of areas within a facility to: Minimize material-handling Facilitate entry, exit, and costs placement of material, products, Utilize space efficiently and people Utilize labor efficiently Incorporate safety and security Eliminate bottlenecks measures Facilitate communication and Promote product and service interaction quality Reduce manufacturing cycle Encourage proper maintenance time activities Reduce customer service time Provide a visual control of activities Eliminate wasted or redundant Provide flexibility to adapt to movement changing conditions Increase capacity
  • 329. BASIC LAYOUTS Process layouts group similar activities together according to process or function they perform Product layouts arrange activities in line according to sequence of operations for a particular product or service Fixed-position layouts are used for projects in which product cannot be moved
  • 330. Process Layout in Services Women’s Shoes Housewares lingerie Women’s Cosmetics Children’s dresses and jewelry department Women’s Entry and Men’s sportswear display area department
  • 333. Comparison of Product and Process Layouts Product Process Description Sequential Functional arrangement of grouping of activities activities Continuous, mass Intermittent, job Type of process production, mainly shop, batch assembly production, mainly fabrication Standardized, made Varied, made to Product order to stock Demand Stable Fluctuating Volume High Low Equipment Special purpose General purpose
  • 334. Comparison of Product and Process Layouts Product Process Workers Limited skills Varied skills Inventory Low in-process, high in- High in-process, low in- finished goods finished goods Storage space Small Large Material handling Fixed path (conveyor) Variable path (forklift) Aisles Narrow Wide Scheduling Part of balancing Dynamic Layout decision Line balancing Machine location Goal Equalize work at each Minimize material station handling cost Advantage Efficiency Flexibility
  • 335. Fixed- Fixed-Position Layouts Typical of projects in which product produced is too fragile, bulky, or heavy to move Equipment, workers, materials, other resources brought to the site Low equipment utilization Highly skilled labor Typically low fixed cost Often high variable costs 7-335
  • 336. Designing Process Layouts Goal: minimize material handling costs Block Diagramming minimize nonadjacent loads use when quantitative data is available Relationship Diagramming based on location preference between areas use when quantitative data is not available
  • 337. Block Diagramming Unit load STEPS quantity in which create load summary chart material is normally calculate composite (two moved way) movements Nonadjacent load develop trial layouts distance farther minimizing number of than the next block nonadjacent loads
  • 338. Block Diagramming: Example Load Summary Chart FROM/TO DEPARTMENT 1 2 3 Department 1 2 3 4 5 1 — 100 50 2 — 200 50 4 5 3 60 — 40 50 4 100 — 60 5 50 —
  • 339. Block Diagramming: Example (cont.) Nonadjacent Loads: 2 3 200 loads 110+40=150 0 2 4 150 loads 1 3 110 loads 110 1 2 100 loads 4 5 60 loads 100 150 200 3 5 50 loads 1 2 3 4 2 5 50 loads 150 200 50 50 50 40 60 3 4 40 loads 110 1 4 0 loads 60 50 4 3 5 5 1 5 0 loads 40 Grid 1 2
  • 340. Block Diagramming: Example (cont.) Block Diagram type of schematic layout diagram; includes space requirements (a) Initial block diagram (b) Final block diagram 1 4 1 2 4 2 3 5 3 5
  • 341. Relationship Diagramming Schematic diagram that uses weighted lines to denote location preference Muther’s grid format for displaying manager preferences for department locations
  • 343. Relationship A Absolutely necessary E Especially important Diagramming: Example I Important O Okay U Unimportant Production X Undesirable O Offices A U I Stockroom O E A X A Shipping and U U receiving U O Locker room O O Toolroom
  • 344. Relationship Diagrams: Example (cont.) (a) Relationship diagram of original layout Offices Locker Shipping room and receiving Key: A E Stockroom Toolroom Production I O U X
  • 345. Relationship Diagrams: Example (cont.) (b) Relationship diagram of revised layout Stockroom Offices Shipping and receiving Locker Key: A Toolroom Production room E I O U X
  • 346. Computerized layout Solutions CRAFT Computerized Relative Allocation of Facilities Technique CORELAP Computerized Relationship Layout Planning PROMODEL and EXTEND visual feedback allow user to quickly test a variety of scenarios Three-D modeling and CAD integrated layout analysis available in VisFactory and similar software
  • 347. Designing Service Layouts Must be both attractive and functional Types Free flow layouts encourage browsing, increase impulse purchasing, are flexible and visually appealing Grid layouts encourage customer familiarity, are low cost, easy to clean and secure, and good for repeat customers Loop and Spine layouts both increase customer sightlines and exposure to products, while encouraging customer to circulate through the entire store
  • 348. Types of Store Layouts
  • 349. Designing Product Layouts Objective Balance the assembly line Line balancing tries to equalize the amount of work at each workstation Precedence requirements physical restrictions on the order in which operations are performed Cycle time maximum amount of time a product is allowed to spend at each workstation
  • 350. Cycle Time Example production time available Cd = desired units of output (8 hours x 60 minutes / hour) Cd = (120 units) 480 Cd = 120 = 4 minutes
  • 351. Flow Time vs Cycle Time Cycle time = max time spent at any station Flow time = time to complete all stations 1 2 3 4 minutes 4 minutes 4 minutes Flow time = 4 + 4 + 4 = 12 minutes Cycle time = max (4, 4, 4) = 4 minutes
  • 352. Efficiency of Line and Balance Delay Minimum number of Efficiency workstations i i ∑ ti ∑ ti Balance delay i=1 i=1 E= nCa N= Cd total idle time of line calculated where as (1 - ti = completion time for element i efficiency) j = number of work elements n = actual number of workstations Ca = actual cycle time Cd = desired cycle time
  • 353. Line Balancing Procedure 1. Draw and label a precedence diagram 2. Calculate desired cycle time required for line 3. Calculate theoretical minimum number of workstations 4. Group elements into workstations, recognizing cycle time and precedence constraints 5. Calculate efficiency of line 6. Determine if theoretical minimum number of workstations or an acceptable efficiency level has been reached. If not, go back to step 4.
  • 354. Line Balancing: Example WORK ELEMENT PRECEDENCE TIME (MIN) A Press out sheet of fruit — 0.1 B Cut into strips A 0.2 C Outline fun shapes A 0.4 D Roll up and package B, C 0.3 0.2 B 0.1 A D 0.3 C 0.4
  • 355. Line Balancing: Example (cont.) WORK ELEMENT PRECEDENCE TIME (MIN) A Press out sheet of fruit — 0.1 B Cut into strips A 0.2 C Outline fun shapes A 0.4 D Roll up and package B, C 0.3 40 hours x 60 minutes / hour 2400 Cd = = = 0.4 minute 6,000 units 6000 0.1 + 0.2 + 0.3 + 0.4 1.0 N= = = 2.5 3 workstations 0.4 0.4
  • 356. Line Balancing: Example (cont.) REMAINING REMAINING WORKSTATION ELEMENT TIME ELEMENTS 1 A 0.3 B, C B 0.1 C, D 2 C 0.0 D 3 D 0.1 none 0.2 Cd = 0.4 B N = 2.5 0.1 A D 0.3 C 0.4
  • 357. Line Balancing: Example (cont.) Work Work Work station 1 station 2 station 3 Cd = 0.4 N = 2.5 A, B C D 0.3 0.4 0.3 minute minute minute 0.1 + 0.2 + 0.3 + 0.4 1.0 E= = = 0.833 = 83.3% 3(0.4) 1.2
  • 358. Computerized Line Balancing Use heuristics to assign tasks to workstations Longest operation time Shortest operation time Most number of following tasks Least number of following tasks Ranked positional weight
  • 359. Hybrid Layouts Cellular layouts group dissimilar machines into work centers (called cells) that process families of parts with similar shapes or processing requirements Production flow analysis (PFA) reorders part routing matrices to identify families of parts with similar processing requirements Flexible manufacturing system automated machining and material handling systems which can produce an enormous variety of items Mixed-model assembly line processes more than one product model in one line
  • 360. Cellular Layouts 1. Identify families of parts with similar flow paths 2. Group machines into cells based on part families 3. Arrange cells so material movement is minimized 4. Locate large shared machines at point of use
  • 361. Parts Families A family of A family of related similar parts grocery items
  • 362. Original Process Layout Assembly 4 6 7 9 5 8 2 10 12 1 3 11 A B C Raw materials
  • 363. Part Routing Matrix Machines Parts 1 2 3 4 5 6 7 8 9 10 11 12 A x x x x x B x x x x C x x x D x x x x x E x x x F x x x G x x x x H x x x Figure 5.8
  • 364. Revised Cellular Layout Assembly 8 10 9 12 11 4 Cell 1 Cell 2 6 Cell 3 7 2 1 3 5 A B C Raw materials
  • 365. Reordered Routing Matrix Machines Parts 1 2 4 8 10 3 6 9 5 7 11 12 A x x x x x D x x x x x F x x x C x x x G x x x x B x x x x H x x x E x x x
  • 367. Advantages and Disadvantages of Cellular Layouts Advantages Disadvantages Reduced material Inadequate part families handling and transit time Poorly balanced cells Reduced setup time Expanded training and Reduced work-in- work-in- scheduling of workers process inventory Increased capital Better use of human investment resources Easier to control Easier to automate
  • 368. Automated Manufacturing Cell Source: J. T. Black, “Cellular Manufacturing Systems Reduce Setup Time, Make Small Lot Production Economical.” Industrial Engineering (November 1983)
  • 369. Flexible Manufacturing Systems (FMS) FMS consists of numerous programmable machine tools connected by an automated material handling system and controlled by a common computer network FMS combines flexibility with efficiency FMS layouts differ based on variety of parts that the system can process size of parts processed average processing time required for part completion
  • 371. Mixed Model Assembly Lines Produce multiple models in any order on one assembly line Issues in mixed model lines Line balancing U-shaped lines Flexible workforce Model sequencing
  • 372. Balancing U-Shaped Lines U- Precedence diagram: A B C Cycle time = 12 min D E (a) Balanced for a straight line (b) Balanced for a U-shaped line U- A,B C,D E A,B 9 min 12 min 3 min 24 24 Efficiency = = = .6666 = 66.7 % C,D 3(12) 36 E 24 24 Efficiency = = = 100 % 12 min 12 min 2(12) 24
  • 373. Chapter 7 Supplement Facility Location Models Operations Management Roberta Russell & Bernard W. Taylor, III
  • 374. Lecture Outline Types of Facilities Site Selection: Where to Locate Location Analysis Techniques Supplement 7-374 7-
  • 375. Types of Facilities Heavy- Heavy-manufacturing facilities large, require a lot of space, and are expensive Light- Light-industry facilities smaller, cleaner plants and usually less costly Retail and service facilities smallest and least costly Supplement 7-375 7-
  • 376. Factors in Heavy Manufacturing Location Construction costs Land costs Raw material and finished goods shipment modes Proximity to raw materials Utilities Means of waste disposal Labor availability Supplement 7-376 7-
  • 377. Factors in Light Industry Location Land costs Transportation costs Proximity to markets depending on delivery requirements including frequency of delivery required by customer Supplement 7-377 7-
  • 378. Factors in Retail Location Proximity to customers Location is everything Supplement 7-378 7-
  • 379. Site Selection: Where to Locate Infrequent but important Location criteria for being “in the right place at the manufacturing facility right time” nature of labor force Must consider other factors, labor costs especially financial proximity to suppliers and considerations markets Location decisions made more distribution and often for service operations transportation costs than manufacturing facilities energy availability and cost Location criteria for service community infrastructure access to customers quality of life in community government regulations and taxes Supplement 7-379 7-
  • 380. Global Location Factors Government stability Raw material availability Government regulations Number and proximity of suppliers Political and economic systems Transportation and distribution system Economic stability and growth Labor cost and education Exchange rates Available technology Culture Commercial travel Climate Technical expertise Export/import regulations, Cross- Cross-border trade duties and tariffs regulations Group trade agreements Supplement 7-380 7-
  • 381. Regional and Community Location Factors in U.S. Labor (availability, Modes and quality of education, cost, and transportation unions) Transportation costs Proximity of customers Community government Number of customers Local business Construction/leasing regulations costs Government services Land cost (e.g., Chamber of Commerce) Supplement 7-381 7-
  • 382. Regional and Community Location Factors in U.S. (cont.) Business climate Infrastructure (e.g., Community services roads, water, sewers) Incentive packages Quality of life Government regulations Taxes Environmental Availability of sites regulations Financial services Raw material availability Community inducements Commercial travel Proximity of suppliers Climate Education system Supplement 7-382 7-
  • 383. Location Incentives Tax credits Relaxed government regulation Job training Infrastructure improvement Money Supplement 7-383 7-
  • 384. Geographic Information Systems (GIS) Computerized system for storing, managing, creating, analyzing, integrating, and digitally displaying geographic, i.e., spatial, data Specifically used for site selection enables users to integrate large quantities of information about potential sites and analyze these data with many different, powerful analytical tools Supplement 7-384 7-
  • 385. GIS Diagram Supplement 7-385 7-
  • 386. Location Analysis Techniques Location factor rating Center-of- Center-of-gravity Load- Load-distance Supplement 7-386 7-
  • 387. Location Factor Rating Identify important factors Weight factors (0.00 - 1.00) Subjectively score each factor (0 - 100) Sum weighted scores Supplement 7-387 7-
  • 388. Location Factor Rating: Example SCORES (0 TO 100) LOCATION FACTOR WEIGHT Site 1 Site 2 Site 3 Labor pool and climate .30 80 65 90 Proximity to suppliers .20 100 91 75 Wage rates .15 60 95 72 Community environment .15 75 80 80 Proximity to customers .10 65 90 95 Shipping modes .05 85 92 65 Air service .05 50 65 90 Weighted Score for “Labor pool and climate” for Site 1 = (0.30)(80) = 24 Supplement 7-388 7-
  • 389. Location Factor Rating: Example (cont.) WEIGHTED SCORES Site 1 Site 2 Site 3 24.00 19.50 27.00 Site 3 has the 20.00 18.20 15.00 highest factor rating 9.00 14.25 10.80 11.25 12.00 12.00 6.50 9.00 9.50 4.25 4.60 3.25 2.50 3.25 4.50 77.50 80.80 82.05 Supplement 7-389 7-
  • 390. Location Factor Rating with Excel and OM Tools Supplement 7-390 7-
  • 391. Center-of- Center-of-Gravity Technique Locate facility at center of movement in geographic area Based on weight and distance traveled; establishes grid-map of grid- area Identify coordinates and weights shipped for each location Supplement 7-391 7-
  • 392. Grid- Grid-Map Coordinates y n n ∑ xiWi ∑ yiWi 2 (x2, y2), W2 (x i=1 i=1 y2 x= n y= n ∑ Wi ∑ Wi 1 (x1, y1), W1 (x i=1 i=1 y1 where, x, y = coordinates of new facility 3 (x3, y3), W3 (x at center of gravity y3 xi, yi = coordinates of existing facility i Wi = annual weight shipped from facility i x1 x2 x3 x Supplement 7-392 7-
  • 393. Center-of- Center-of-Gravity Technique: Example y A B C D 700 x 200 100 250 500 C 600 y 200 500 600 300 (135) B Wt 75 105 135 60 500 (105) Miles 400 D 300 A (60) 200 (75) 100 0 100 200 300 400 500 600 700 x Miles Supplement 7-393 7-
  • 394. Center-of- Center-of-Gravity Technique: Example (cont.) n ∑ xiWi i=1 (200)(75) + (100)(105) + (250)(135) + (500)(60) x= = = 238 n 75 + 105 + 135 + 60 ∑ Wi i=1 n ∑ yiWi i=1 (200)(75) + (500)(105) + (600)(135) + (300)(60) y= = = 444 n 75 + 105 + 135 + 60 ∑ Wi i=1 Supplement 7-394 7-
  • 395. Center-of- Center-of-Gravity Technique: Example (cont.) y A B C D 700 x 200 100 250 500 C 600 y 200 500 600 300 (135) B Wt 75 105 135 60 500 (105) Center of gravity (238, 444) Miles 400 D 300 A (60) 200 (75) 100 0 100 200 300 400 500 600 700 x Miles Supplement 7-395 7-
  • 396. Center-of- Center-of-Gravity Technique with Excel and OM Tools Supplement 7-396 7-
  • 397. Load- Load-Distance Technique Compute (Load x Distance) for each site Choose site with lowest (Load x Distance) Distance can be actual or straight-line straight- Supplement 7-397 7-
  • 398. Load- Load-Distance Calculations n LD = ∑ ld i i i=1 where, LD = load- load-distance value li = load expressed as a weight, number of trips or units being shipped from proposed site and location i di = distance between proposed site and location i di = (xi - x)2 + (yi - y)2 (y where, (x,y) = coordinates of proposed site x,y) (xi , yi) = coordinates of existing facility Supplement 7-398 7-
  • 399. Load- Load-Distance: Example Potential Sites Suppliers Site X Y A B C D 1 360 180 X 200 100 250 500 2 420 450 Y 200 500 600 300 3 250 400 Wt 75 105 135 60 Compute distance from each site to each supplier Site 1 dA = (xA - x1)2 + (yA - y1)2 = (200-360)2 + (200-180)2 = 161.2 (200- (200- dB = (xB - x1)2 + (yB - y1)2 = (100-360)2 + (500-180)2 = 412.3 (100- (500- dC = 434.2 dD = 184.4 Supplement 7-399 7-
  • 400. Load- Load-Distance: Example (cont.) Site 2 dA = 333 dB = 323.9 dC = 226.7 dD = 170 Site 3 dA = 206.2 dB = 180.3 dC = 200 dD = 269.3 Compute load-distance load- n LD = ∑ ld i i i=1 Site 1 = (75)(161.2) + (105)(412.3) + (135)(434.2) + (60)(434.4) = 125,063 Site 2 = (75)(333) + (105)(323.9) + (135)(226.7) + (60)(170) = 99,789 Site 3 = (75)(206.2) + (105)(180.3) + (135)(200) + (60)(269.3) = 77,555* * Choose site 3 Supplement 7-400 7-
  • 401. Load- Load-Distance Technique with Excel and OM Tools Supplement 7-401 7-
  • 402. Chapter 8 Human Resources Operations Management Roberta Russell & Bernard W. Taylor, III
  • 403. Lecture Outline Human Resources and Quality Management Changing Nature of Human Resources Management Contemporary Trends in Human Resources Management Employee Compensation Managing Diversity in Workplace Job Design Job Analysis Learning Curves 8-403
  • 404. Human Resources and Quality Management Employees play important Employees have power to role in quality management make decisions that will Malcolm Baldrige National improve quality and customer Quality Award winners have a service pervasive human resource Strategic goals for quality and focus customer satisfaction require Employee training and teamwork and group education are recognized as participation necessary long-term investments 8-404
  • 405. Changing Nature of Human Resources Management Scientific management Assembly-line Breaking down jobs into Production meshed with elemental activities and principles of scientific simplifying job design management Jobs Advantages of task Comprise a set of tasks, specialization elements, and job motions High output, low costs, (basic physical and minimal training movements) Disadvantages of task In a piece-rate wage specialization system, pay is based on Boredom, lack of output motivation, and physical and mental fatigue 8-405
  • 406. Employee Motivation Motivation Improving Motivation willingness to work hard because (cont.) that effort satisfies an employee design of jobs to fit employee need work responsibility Improving Motivation empowerment positive reinforcement and restructuring of jobs when feedback necessary effective organization and rewards based on company as discipline well as individual performance fair treatment of people achievement of company goals satisfaction of employee needs setting of work-related goals 8-406
  • 407. Evolution of Theories of Employee Motivation Abraham Maslow’s Douglas McGregor’s Frederick Herzberg’s Pyramid of Human Theory X and Theory Y Hygiene/Motivation Needs Theories •Theory X Employee •Hygiene Factors • Dislikes work • Company policies • Must be coerced • Supervision • Shirks responsibility • Working conditions Self- Self- • Little ambition • Interpersonal relations actualization • Security top motivator • Salary, status, security •Theory Y Employee •Motivation Factors Esteem • Achievement • Work is natural Social • Self-directed Self- • Recognition • Controlled • Job interest Safety/Security • Responsibility • Accepts responsibility Physiological (financial) • Makes good decisions • Growth • Advancement 8-407
  • 408. Contemporary Trends in Human Resources Management Job training Empowerment extensive and varied giving employees two of Deming’s 14 points refer to employee authority to make education and training decisions Cross Training Teams an employee learns more group of employees work than one job on problems in their Job rotation immediate work area horizontal movement between two or more jobs according to a plan 8-408
  • 409. Contemporary Trends in Human Resources Management (cont.) Job enrichment Alternative workplace vertical enlargement nontraditional work location allows employees control over their work Telecommuting horizontal enlargement employees work an employee is assigned a electronically from a complete unit of work with location they choose defined start and end Temporary and part-time Flexible time employees part of a daily work mostly in fast-food and schedule in which restaurant chains, retail employees can choose companies, package delivery time of arrival and services, and financial firms departure 8-409
  • 410. Employee Compensation Types of pay hourly wage the longer someone works, the more s/he is paid individual incentive or piece rate employees are paid for the number of units they produce during the workday straight salary common form of payment for management commissions usually applied to sales and salespeople 8-410
  • 411. Employee Compensation (cont.) Gainsharing an incentive plan joins employees in a common effort to achieve company goals in which they share in the gains Profit sharing sets aside a portion of profits for employees at year’s end 8-411
  • 412. Managing Diversity in Workplace Workforce has become more diverse 4 out of every 10 people entering workforce during the decade from 1998 to 2008 will be members of minority groups In 2000 U.S. Census showed that some minorities, primarily Hispanic and Asian, are becoming majorities Companies must develop a strategic approach to managing diversity 8-412
  • 413. Affirmative Actions vs. Managing Diversity Affirmative action Managing diversity an outgrowth of laws and process of creating a work regulations environment in which all government initiated and employees can contribute mandated to their full potential in contains goals and order to achieve a timetables designed to company’s goals increase level of voluntary in nature, not participation by women mandated and minorities to attain seeks to improve internal parity levels in a communications and company’s workforce interpersonal not directly concerned relationships, resolve with increasing company conflict, and increase success or increasing product quality, profits productivity, and efficiency 8-413
  • 415. Global Diversity Issues Cultural, language, geography significant barriers to managing a globally diverse workforce E-mails, faxes, Internet, phones, air travel make managing a global workforce possible but not necessarily effective How to deal with diversity? identify critical cultural elements learn informal rules of communication use a third party who is better able to bridge cultural gap become culturally aware and learn foreign language teach employees cultural norm of organization 8-415
  • 416. Attributes of Good Job Design An appropriate degree of Goals and achievement repetitiveness feedback An appropriate degree of A perceived contribution attention and mental to a useful product or absorption service Some employee Opportunities for responsibility for personal relationships decisions and discretion and friendships Employee control over Some influence over the their own job way work is carried out in groups Use of skills 8-416
  • 417. Factors in Job Design Task analysis how tasks fit together to form a job Worker analysis determining worker capabilities and responsibilities for a job Environment analysis physical characteristics and location of a job Ergonomics fitting task to person in a work environment Technology and automation broadened scope of job design 8-417
  • 418. Elements of Job Design 8-418
  • 419. Job Analysis Method Analysis (work methods) Study methods used in the work included in the job to see how it should be done Primary tools are a variety of charts that illustrate in different ways how a job or work process is done 8-419
  • 420. Process Flowchart Symbols Operation: An activity directly contributing to product or service Transportation: Moving the product or service from one location to another Inspection: Examining the product or service for completeness, irregularities, or quality Delay: Process having to wait Storage: Store of the product or service 8-420
  • 422. Job Photo-Id Cards Photo- Date 10/14 Time Time (min) Operator (min) Photo Machine –1 Key in customer data 2.6 Idle on card –2 Worker- Worker- Feed data card in 0.4 Accept card Machine –3 Position customer for photo 1.0 Idle Chart Take picture 0.6 Begin photo process –4 –5 Idle 3.4 Photo/card processed –6 –7 Inspect card & trim edges 1.2 Idle –8 8-422 –9
  • 423. Worker- Worker-Machine Chart: Summary Summary Operator Time % Photo Machine Time % Work 5.8 63 4.8 52 Idle 3.4 37 4.4 48 Total 9.2 min 100% 9.2 Min 100% 8-423
  • 424. Motion Study Used to ensure efficiency of motion in a job Frank & Lillian Gilbreth Find one “best way” to do task Use videotape to study motions 8-424
  • 425. General Guidelines for Motion Study Efficient Use Of Human Body Work simplified, rhythmic and symmetric Hand/arm motions coordinated and simultaneous Employ full extent of physical capabilities Conserve energy use machines, minimize distances, use momentum Tasks simple, minimal eye contact and muscular effort, no unnecessary motions, delays or idleness 8-425
  • 426. General Guidelines for Motion Study Efficient Arrangement of Workplace Tools, material, equipment - designated, easily accessible location Comfortable and healthy seating and work area Efficient Use of Equipment Equipment and mechanized tools enhance worker abilities Use foot-operated equipment to relieve hand/arm stress foot- Construct and arrange equipment to fit worker use 8-426
  • 427. Learning Curves Illustrates Processing time per unit improvement rate of workers as a job is repeated Processing time per unit decreases by a constant percentage each time output doubles Units produced 8-427
  • 428. Learning Curves (cont.) Time required for the nth unit = tn = t1n b where: tn = time required for nth unit produced t1 = time required for first unit produced n= cumulative number of units produced b= ln r where r is the learning curve percentage ln 2 (decimal coefficient) 8-428
  • 429. Learning Curve Effect Contract to produce 36 computers. t1 = 18 hours, learning rate = 80% What is time for 9th, 18th, 36th units? t9 = (18)(9)ln(0.8)/ln 2 = (18)(9)-0.322 = (18)/(9)0.322 = (18)(0.493) = 8.874hrs t18 = (18)(18)ln(0.8)/ln 2 = (18)(0.394) = 7.092hrs t36 = (18)(36)ln(0.8)/ln 2 = (18)(0.315) = 5.674hrs 8-429
  • 430. Learning Curve for Mass Production Job Processing time per unit End of improvement Standard time Units produced 8-430
  • 431. Learning Curves (cont.) Advantages Limitations planning labor product modifications planning budget negate learning curve determining effect scheduling improvement can derive requirements from sources besides learning industry-derived learning curve rates may be inappropriate 8-431
  • 432. Chapter 8 Supplement Work Measurement Operations Management Roberta Russell & Bernard W. Taylor, III
  • 433. Lecture Outline Time Studies Work Sampling Supplement 8-433 8-
  • 434. Work Measurement Determining how long it takes to do a job Growing importance in service sector Services tend to be labor-intensive labor- Service jobs are often repetitive Time studies Standard time is time required by an average worker to perform a job once Incentive piece-rate wage system based on time piece- study Supplement 8-434 8-
  • 435. Stopwatch Time Study Basic Steps 1. Establish standard job method 2. Break down job into elements 3. Study job 4. Rate worker’s performance (RF) 5. Compute average time (t) Supplement 8-435 8-
  • 436. Stopwatch Time Study Basic Steps (cont.) 6. Compute normal time Normal Time = (Elemental average) x (rating factor) Nt = (t )(RF) )(RF) Normal Cycle Time = NT = ΣNt 7. Compute standard time Standard Time = (normal cycle time) x (1 + allowance factor) ST = (NT)(1 + AF) Supplement 8-436 8-
  • 437. Performing a Time Study Time Study Observation Sheet Identification of operation Sandwich Assembly Date 5/17 Operator Approval Observer Smith Jones Russell Cycles Summary 1 2 3 4 5 6 7 8 9 10 Σt t RF Nt Grasp and lay t .04 .05 .05 .04 .06 .05 .06 .06 .07 .05 .53 .053 1.05 .056 1 out bread slices R .04 .38 .72 1.05 1.40 1.76 2.13 2.50 2.89 3.29 Spread mayonnaise t .07 .06 .07 .08 .07 .07 .08 .10 .09 .08 .77 .077 1.00 .077 2 on both slices R .11 .44 .79 1.13 1.47 1.83 2.21 2.60 2.98 3.37 Place ham, cheese, t .12 .11 .14 .12 .13 .13 .13 .12 .14 .14 1.28 1.28 1.10 .141 3 and lettuce on bread R .23 .55 .93 1.25 1.60 1.96 2.34 2.72 3.12 3.51 Place top on sandwich, t .10 .12 .08 .09 .11 .11 .10 .10 .12 .10 1.03 1.03 1.10 .113 4 Slice, and stack R .33 .67 1.01 1.34 1.71 2.07 2.44 2.82 3.24 3.61 Supplement 8-437 8-
  • 438. Performing a Time Study (cont.) Σt 0.53 Average element time = t = = = 0.053 10 10 Normal time = (Elemental average)(rating factor) Nt = ( t )(RF) = (0.053)(1.05) = 0.056 )(RF) Normal Cycle Time = NT = Σ Nt = 0.387 ST = (NT) (1 + AF) = (0.387)(1+0.15) = 0.445 min Supplement 8-438 8-
  • 439. Performing a Time Study (cont.) How many sandwiches can be made in 2 hours? 120 min = 269.7 or 270 sandwiches 0.445 min/sandwich Example 17.3 Supplement 8-439 8-
  • 440. Number of Cycles To determine sample size: 2 zs n= eT where z = number of standard deviations from the mean in a normal distribution reflecting a level of statistical confidence s= Σ(xi - x)2 = sample standard deviation from sample time study n-1 T = average job cycle time from the sample time study e = degree of error from true mean of distribution Supplement 8-440 8-
  • 441. Number of Cycles: Example • Average cycle time = 0.361 • Computed standard deviation = 0.03 • Company wants to be 95% confident that computed time is within 5% of true average time 2 2 zs (1.96)(0.03) n= = = 10.61 or 11 eT (0.05)(0.361) Supplement 8-441 8-
  • 442. Number of Cycles: Example (cont.) Supplement 8-442 8-
  • 443. Developing Time Standards without a Time Study Elemental standard time Advantages files worker cooperation predetermined job unnecessary element times workplace uninterrupted Predetermined motion performance ratings times unnecessary predetermined times for consistent basic micro-motions micro- Time measurement units Disadvantages TMUs = 0.0006 minute ignores job context 100,000 TMU = 1 hour may not reflect skills and abilities of local workers Supplement 8-443 8-
  • 444. MTM Table for MOVE TIME (TMU) WEIGHT ALLOWANCE DISTANCE Hand in Weight Static MOVED motion (lb) Dynamic constant (INCHES) A B C B up to: factor TMU 3/4 or less 2.0 2.0 2.0 1 2.5 2.9 3.4 2.3 2.5 1.00 0 2 3.6 4.6 5.2 2.9 3 4.9 5.7 6.7 3.6 7.5 1.06 2.2 4 6.1 6.9 8.0 4.3 … 20 19.2 18.2 22.1 15.6 37.5 1.39 12.5 A. Move object to other hand or against stop B. Move object to approximate or indefinite location C. Move object to exact location Source: MTM Association for Standards and Research. Supplement 8-444 8-
  • 445. Work Sampling Determines the proportion of time a worker spends on activities Primary uses of work sampling are to determine ratio delay percentage of time a worker or machine is delayed or idle analyze jobs that have non-repetitive tasks non- Cheaper, easier approach to work measurement Supplement 8-445 8-
  • 446. Steps of Work Sampling 1. Define job activities 2. Determine number of observations in work sample 2 z n= e p(1 - p) where n = sample size (number of sample observations) z = number of standard deviations from mean for desired level of confidence e = degree of allowable error in sample estimate p = proportion of time spent on a work activity estimated prior to calculating work sample Supplement 8-446 8-
  • 447. Steps of Work Sampling (cont.) 3. Determine length of sampling period 4. Conduct work sampling study; record observations 5. Periodically re-compute number re- of observations Supplement 8-447 8-
  • 448. Work Sampling: Example What percent of time is spent looking up information? Current estimate is p = 30% Estimate within +/- 2%, with 95% confidence +/- 2 2 z 1.96 n= p(1 - p) = (0.3)(0.7) = 2016.84 or 2017 e 0.02 After 280 observations, p = 38% 2 2 z 1.96 n= p(1 - p) = (0.38)(0.62) = 2263 e 0.02 Supplement 8-448 8-
  • 450. Chapter 9 Project Management Operations Management Roberta Russell & Bernard W. Taylor, III
  • 451. Lecture Outline Project Planning Project Scheduling Project Control CPM/PERT Probabilistic Activity Times Microsoft Project Project Crashing and Time-Cost Trade-off 9-451
  • 452. Project Management Process Project unique, one-time operational activity or effort 9-452
  • 456. Project Team and Project Manager Project team made up of individuals from various areas and departments within a company Matrix organization a team structure with members from functional areas, depending on skills required Project manager most important member of project team 9-456
  • 457. Scope Statement and Work Breakdown Structure Scope statement a document that provides an understanding, justification, and expected result of a project Statement of work written description of objectives of a project Work breakdown structure (WBS) breaks down a project into components, subcomponents, activities, and tasks 9-457
  • 458. Work Breakdown Structure for Computer Order Processing System Project 9-458
  • 459. Responsibility Assignment Matrix Organizational Breakdown Structure (OBS) a chart that shows which organizational units are responsible for work items Responsibility Assignment Matrix (RAM) shows who is responsible for work in a project 9-459
  • 460. Global and Diversity Issues in Project Management In existing global business environment, project teams are formed from different genders, cultures, ethnicities, etc. In global projects diversity among team members can add an extra dimension to project planning Cultural research and communication are important elements in planning process 9-460
  • 461. Project Scheduling Steps Techniques Define activities Gantt chart Sequence CPM/PERT activities Microsoft Project Estimate time Develop schedule 9-461
  • 462. Gantt Chart Graph or bar chart with a bar for each project activity that shows passage of time Provides visual display of project schedule Slack amount of time an activity can be delayed without delaying the project 9-462
  • 463. Example of Gantt Chart Month 0 | 2 | 4 | 6 | 8 | 10 Activity Design house and obtain financing Lay foundation Order and receive materials Build house Select paint Select carpet 1 3 5 7 9 Month Finish work 9-463
  • 464. Project Control Time management Cost management Quality management Performance management Earned Value Analysis a standard procedure for numerically measuring a project’s progress, forecasting its completion date and cost and measuring schedule and budget variation Communication Enterprise project management 9-464
  • 465. CPM/PERT Critical Path Method (CPM) DuPont & Remington-Rand (1956) Remington- Deterministic task times Activity-on- Activity-on-node network construction Project Evaluation and Review Technique (PERT) US Navy, Booz, Allen & Hamilton Multiple task time estimates; probabilistic Activity-on- Activity-on-arrow network construction 9-465
  • 466. Project Network Activity-on-node (AON) nodes represent activities, and arrows show Node precedence relationships Activity-on-arrow (AOA) arrows represent activities 1 2 3 and nodes are events for points in time Event Branch completion or beginning of an activity in a project Dummy two or more activities cannot share same start and end nodes 9-466
  • 467. AOA Project Network for a House 3 Lay Dummy foundation 2 0 Build Finish 3 1 house work 1 2 4 3 6 1 7 Design house Order and and obtain receive 1 1 Select Select financing materials paint carpet 5 9-467
  • 468. Concurrent Activities 3 Lay foundation Lay Dummy foundation 2 0 2 3 1 Order material 2 4 Order material (a) Incorrect precedence (b) Correct precedence relationship relationship 9-468
  • 469. AON Network for House Building Project Lay foundations Build house 2 4 Finish work 2 3 7 Start 1 1 3 Design house 6 and obtain 3 financing 1 5 1 1 Select carpet Order and receive materials Select paint 9-469
  • 470. Critical Path 2 4 2 3 7 Start 1 1 3 3 6 1 5 1 1 A: 1-2-4-7 3 + 2 + 3 + 1 = 9 months Critical path B: 1-2-5-6-7 Longest path 3 + 2 + 1 + 1 + 1 = 8 months through a network C: 1-3-4-7 Minimum project 3 + 1 + 3 + 1 = 8 months D: 1-3-5-6-7 completion time 3 + 1 + 1 + 1 + 1 = 7 months 9-470
  • 471. Activity Start Times Start at 5 months 2 4 Finish at 9 months 2 3 7 Finish Start 1 1 3 3 6 1 5 1 1 Start at 6 months Start at 3 months 9-471
  • 472. Node Configuration Activity number Earliest start Earliest finish 1 0 3 3 0 3 Latest finish Activity duration Latest start 9-472
  • 473. Activity Scheduling Earliest start time (ES) earliest time an activity can start ES = maximum EF of immediate predecessors Forward pass starts at beginning of CPM/PERT network to determine earliest activity times Earliest finish time (EF) earliest time an activity can finish earliest start time plus activity time EF= ES + t 9-473
  • 474. Earliest Activity Start and Finish Times Lay foundations Build house 2 3 5 Start 4 5 8 2 3 1 0 3 7 8 9 1 1 Design house and obtain 6 6 7 Finish work financing 3 3 4 1 1 5 5 6 Select carpet Order and receive 1 materials Select pain 9-474
  • 475. Activity Scheduling (cont.) Latest start time (LS) Latest time an activity can start without delaying critical path time LS= LF - t Latest finish time (LF) latest time an activity can be completed without delaying critical path time LF = minimum LS of immediate predecessors Backward pass Determines latest activity times by starting at the end of CPM/PERT network and working forward 9-475
  • 476. Latest Activity Start and Finish Times Lay foundations Build house 2 3 5 Start 4 5 8 2 3 5 3 5 8 1 0 3 7 8 9 1 0 3 1 8 9 Design house and obtain 6 6 7 Finish work financing 3 3 4 1 7 8 1 4 5 5 5 6 Select carpet Order and receive 1 6 7 materials Select pain 9-476
  • 477. Activity Slack Activity LS ES LF EF Slack S *1 0 0 3 3 0 *2 3 3 5 5 0 3 4 3 5 4 1 *4 5 5 8 8 0 5 6 5 7 6 1 6 7 6 8 7 1 *7 8 8 9 9 0 * Critical Path 9-477
  • 478. Probabilistic Time Estimates Beta distribution a probability distribution traditionally used in CPM/PERT a + 4m + b 4m Mean (expected time): t= 6 2 b-a Variance: σ = 2 6 where a = optimistic estimate m = most likely time estimate b = pessimistic time estimate 9-478
  • 479. P(time) Examples of Beta Distributions P(time) a m t b a t m b Time Time P(time) a m=t b Time 9-479
  • 480. Project Network with Probabilistic Time Estimates: Example Equipment installation Equipment testing and modification 1 4 6,8,10 2,4,12 System Final training debugging System 10 development 8 Manual 3,7,11 1,4,7 Start 2 testing Finish 3,6,9 5 11 Position 2,3,4 9 1,10,13 recruiting 2,4,6 Job Training System 3 6 System changeover 1,3,5 3,4,5 testing Orientation 7 2,2,2 9-480
  • 481. Activity Time Estimates TIME ESTIMATES (WKS) MEAN TIME VARIANCE ACTIVITY a m b t б2 1 6 8 10 8 0.44 2 3 6 9 6 1.00 3 1 3 5 3 0.44 4 2 4 12 5 2.78 5 2 3 4 3 0.11 6 3 4 5 4 0.11 7 2 2 2 2 0.00 8 3 7 11 7 1.78 9 2 4 6 4 0.44 10 1 4 7 4 1.00 11 1 10 13 9 4.00 9-481
  • 482. Activity Early, Late Times, and Slack ACTIVITY t б2 ES EF LS LF S 1 8 0.44 0 8 1 9 1 2 6 1.00 0 6 0 6 0 3 3 0.44 0 3 2 5 2 4 5 2.78 8 13 16 21 8 5 3 0.11 6 9 6 9 0 6 4 0.11 3 7 5 9 2 7 2 0.00 3 5 14 16 11 8 7 1.78 9 16 9 16 0 9 4 0.44 9 13 12 16 3 10 4 1.00 13 17 21 25 8 11 9 4.00 16 25 16 25 0 9-482
  • 483. Earliest, Latest, and Slack Critical Path 1 0 8 4 8 13 8 1 9 5 16 21 10 13 17 16 1 0 3 8 9 Start 2 0 6 Finish 7 9 16 6 0 6 9 5 6 11 16 25 3 6 9 9 9 13 9 16 25 4 12 16 3 0 3 6 3 7 3 2 5 4 5 9 7 3 5 2 14 16 9-483
  • 484. Total project variance σ2 = б22 + б52 + б82 + б112 σ = 1.00 + 0.11 + 1.78 + 4.00 = 6.89 weeks 9-484
  • 485. 9-485
  • 486. Probabilistic Network Analysis Determine probability that project is completed within specified time x-µ Z= σ where µ = tp = project mean time σ = project standard deviation x = proposed project time Z = number of standard deviations x is from mean 9-486
  • 487. Normal Distribution of Project Time Probability Zσ µ = tp x Time 9-487
  • 488. Southern Textile Example What is the probability that the project is completed within 30 weeks? P(x ≤ 30 weeks) x-µ σ 2 = 6.89 weeks Z = σ σ = 6.89 = 30 - 25 2.62 σ = 2.62 weeks = 1.91 µ = 25 x = 30 Time (weeks) From Table A.1, (appendix A) a Z score of 1.91 corresponds to a probability of 0.4719. Thus P(30) = 0.4719 + 0.5000 = 0.9719 9-488
  • 489. Southern Textile Example What is the probability that the project is completed within 22 weeks? x-µ P(x ≤ 22 weeks) σ 2 = 6.89 weeks Z = σ σ = 6.89 = 22 - 25 2.62 σ = 2.62 weeks = -1.14 x = 22 µ = 25 Time (weeks) From Table A.1 (appendix A) a Z score of -1.14 corresponds to a probability of 0.3729. Thus P(22) = 0.5000 - 0.3729 = 0.1271 9-489
  • 490. Microsoft Project Popular software package for project management and CPM/PERT analysis Relatively easy to use 9-490
  • 498. PERT Analysis with Microsoft Project (cont.) 9-498
  • 499. PERT Analysis with Microsoft Project (cont.) 9-499
  • 500. Project Crashing Crashing reducing project time by expending additional resources Crash time an amount of time an activity is reduced Crash cost cost of reducing activity time Goal reduce project duration at minimum cost 9-500
  • 501. Project Network for Building a House 2 4 12 8 7 1 4 12 3 6 4 5 4 4 9-501
  • 502. Normal Time and Cost vs. Crash Time and Cost $7,000 – $6,000 – Crash cost $5,000 – Crashed activity Slope = crash cost per week $4,000 – Normal activity $3,000 – Normal cost $2,000 – Crash time Normal time $1,000 – | | | | | | | 0 2 4 6 8 10 12 14 Weeks – 9-502
  • 503. Project Crashing: Example TOTAL NORMAL CRASH ALLOWABLE CRASH TIME TIME NORMAL CRASH CRASH TIME COST PER ACTIVITY (WEEKS) (WEEKS) COST COST (WEEKS) WEEK 1 12 7 $3,000 $5,000 5 $400 2 8 5 2,000 3,500 3 500 3 4 3 4,000 7,000 1 3,000 4 12 9 50,000 71,000 3 7,000 5 4 1 500 1,100 3 200 6 4 1 500 1,100 3 200 7 4 3 15,000 22,000 1 7,000 $75,000 $110,700 9-503
  • 504. $500 $7000 Project Duration: 2 4 $700 36 weeks 8 12 7 1 4 FROM … 12 $400 3 6 4 5 4 4 $200 $3000 $200 $500 $7000 2 4 8 12 $700 7 TO… 1 4 7 Project Duration: $400 3 6 31 weeks 4 5 4 Additional Cost: 4 $200 $3000 $2000 $200 9-504
  • 505. Time- Time-Cost Relationship Crashing costs increase as project duration decreases Indirect costs increase as project duration increases Reduce project length as long as crashing costs are less than indirect costs 9-505
  • 506. Time- Time-Cost Tradeoff Minimum cost = optimal project time Total project cost Indirect cost Cost ($) Direct cost Crashing Time Project duration 9-506
  • 507. Chapter 10 Supply Chain Management Strategy and Design Operations Management Roberta Russell & Bernard W. Taylor, III
  • 508. Lecture Outline The Management of Supply Chains Information Technology: A Supply Chain Enabler Supply Chain Integration Supply Chain Management (SCM) Software Measuring Supply Chain Performance 10-508 10-
  • 509. Supply Chains All facilities, functions, and activities associated with flow and transformation of goods and services from raw materials to customer, as well as the associated information flows An integrated group of processes to “source,” “make,” and “deliver” products 10-509 10-
  • 511. Supply Chain for Denim Jeans 10-511 10-
  • 513. Supply Chain Processes 10-513 10-
  • 514. Supply Chain for Service Providers More difficult than manufacturing Does not focus on the flow of physical goods Focuses on human resources and support services More compact and less extended 10-514 10-
  • 515. Value Chains Value chain every step from raw materials to the eventual end user ultimate goal is delivery of maximum value to the end user Supply chain activities that get raw materials and subassemblies into manufacturing operation ultimate goal is same as that of value chain Demand chain increase value for any part or all of chain Terms are used interchangeably Value creation of value for customer is important aspect of supply chain management 10-515 10-
  • 516. Supply Chain Management (SCM) Managing flow of information through supply chain in order to attain the level of synchronization that will make it more responsive to customer needs while lowering costs Keys to effective SCM information communication cooperation trust 10-516 10-
  • 517. Supply Chain Uncertainty and Inventory One goal in SCM: Factors that contribute to respond to uncertainty in uncertainty customer demand inaccurate demand without creating costly forecasting excess inventory long variable lead times Negative effects of late deliveries uncertainty incomplete shipments lateness product changes incomplete orders batch ordering Inventory price fluctuations and discounts insurance against supply chain uncertainty inflated orders 10-517 10-
  • 518. Bullwhip Effect Occurs when slight demand variability is magnified as information moves back upstream 10-518 10-
  • 519. Risk Pooling Risks are aggregated to reduce the impact of individual risks Combine inventories from multiple locations into one Reduce parts and product variability, thereby reducing the number of product components Create flexible capacity 10-519 10-
  • 520. Information Technology: A Supply Chain Enabler Information links all aspects of supply chain E-business replacement of physical business processes with electronic ones Electronic data interchange (EDI) a computer-to-computer exchange of business documents Bar code and point-of-sale data creates an instantaneous computer record of a sale 10-520 10-
  • 521. Information Technology: A Supply Chain Enabler (cont.) Radio frequency identification (RFID) technology can send product data from an item to a reader via radio waves Internet allows companies to communicate with suppliers, customers, shippers and other businesses around the world instantaneously Build-to-order (BTO) direct-sell-to-customers model via the Internet; extensive communication with suppliers and customer 10-521 10-
  • 522. Supply Chain Enablers 10-522 10-
  • 523. RFID Capabilities 10-523 10-
  • 525. Supply Chain Integration Information sharing among supply chain members Reduced bullwhip effect Early problem detection Faster response Builds trust and confidence Collaborative planning, forecasting, replenishment, and design Reduced bullwhip effect Lower costs (material, logistics, operating, etc.) Higher capacity utilization Improved customer service levels 10-525 10-
  • 526. Supply Chain Integration (cont.) Coordinated workflow, production and operations, procurement Production efficiencies Fast response Improved service Quicker to market Adopt new business models and technologies Penetration of new markets Creation of new products Improved efficiency Mass customization 10-526 10-
  • 527. Collaborative Planning, Forecasting, and Replenishment (CPFR) Process for two or more companies in a supply chain to synchronize their demand forecasts into a single plan to meet customer demand Parties electronically exchange past sales trends point-of-sale data on-hand inventory scheduled promotions forecasts 10-527 10-
  • 528. Supply Chain Management (SCM) Software Enterprise resource planning (ERP) software that integrates the components of a company by sharing and organizing information and data 10-528 10-
  • 529. Key Performance Indicators Metrics used to measure supply chain performance Inventory turnover Cost of goods sold Inventory turns = Average aggregate value of inventory Total value (at cost) of inventory Average aggregate value of inventory = ∑ (average inventory for item i ) × (unit value item i ) Days of supply Average aggregate value of inventory Days of supply = (Cost of goods sold)/(365 days) Fill rate: fraction of orders filled by a distribution center within a specific time period 10-529 10-
  • 531. Process Control and SCOR Process Control not only for manufacturing operations can be used in any processes of supply chain Supply Chain Operations Reference (SCOR) a cross industry supply chain diagnostic tool maintained by the Supply Chain Council 10-531 10-
  • 532. SCOR 10-532 10-
  • 533. SCOR (cont.) 10-533 10-
  • 534. Chapter 11 Global Supply Chain Procurement and Distribution Operations Management Roberta Russell & Bernard W. Taylor, III
  • 536. Procurement The purchase of goods and services from suppliers Cross enterprise teams coordinate processes between a company and its supplier On- On-demand (direct-response) delivery (direct- requires the supplier to deliver goods when demanded by the customer Continuous replenishment supplying orders in a short period of time according to a predetermined schedule 11-536 11-
  • 537. Outsourcing Sourcing selection of suppliers Outsourcing purchase of goods and services from an outside supplier Core competencies what a company does best Single sourcing a company purchases goods and services from only a few (or one) suppliers 11-537 11-
  • 538. Categories of Goods and Services... 11-538 11-
  • 539. E-Procurement Direct purchase from suppliers over the Internet, by using software packages or through e-marketplaces, e-hubs, and e- e- trading exchanges Can streamline and speed up the purchase order and transaction process 11-539 11-
  • 540. E-Procurement (cont.) What can companies buy over the Internet? Manufacturing inputs the raw materials and components that go directly into the production process of the product Operating inputs maintenance, repair, and operation goods and services 11-540 11-
  • 541. E-Procurement (cont.) E-marketplaces (e-hubs) (e- Websites where companies and suppliers conduct business-to-business activities business-to- Reverse auction process used by e-marketplaces for buyers e- to purchase items; company posts orders on the internet for suppliers to bid on 11-541 11-
  • 542. Distribution Encompasses all channels, processes, and functions, including warehousing and transportation, that a product passes on its way to final customer Order fulfillment process of ensuring on-time delivery of an order on- Logistics transportation and distribution of goods and services Driving force today is speed Particularly important for Internet dot-coms dot- 11-542 11-
  • 543. Distribution Centers (DC) and Warehousing DCs are some of the largest business facilities in the United States Trend is for more frequent orders in smaller quantities Flow- Flow-through facilities and automated material handling Postponement final assembly and product configuration may be done at the DC 11-543 11-
  • 544. Warehouse Management Systems Highly automated system that runs day-to-day day-to- operations of a DC Controls item putaway, picking, packing, and shipping Features transportation management order management yard management labor management warehouse optimization 11-544 11-
  • 545. A WMS 11-545 11-
  • 546. Vendor- Vendor-Managed Inventory Manufacturers generate orders, not distributors or retailers Stocking information is accessed using EDI A first step towards supply chain collaboration Increased speed, reduced errors, and improved service 11-546 11-
  • 547. Collaborative Logistics and Distribution Outsourcing Collaborative planning, forecasting, and replenishment create greater economies of scale Internet- Internet-based exchange of data and information Significant decrease in inventory levels and costs and more efficient logistics Companies focus on core competencies 11-547 11-
  • 548. Transportation Rail low-value, high-density, bulk products, raw materials, intermodal containers not as economical for small loads, slower, less flexible than trucking Trucking main mode of freight transport in U.S. small loads, point-to-point service, flexible More reliable, less damage than rails; more expensive than rails for long distance 11-548 11-
  • 549. Transportation (cont.) Air most expensive and fastest, mode of freight transport lightweight, small packages <500 lbs high-value, perishable and critical goods less theft Package Delivery small packages fast and reliable increased with e-Business primary shipping mode for Internet companies 11-549 11-
  • 550. Transportation (cont.) Water low-cost shipping mode primary means of international shipping U.S. waterways slowest shipping mode Intermodal combines several modes of shipping- truck, water and rail key component is containers Pipeline transport oil and products in liquid form high capital cost, economical use long life and low operating cost 11-550 11-
  • 551. Internet Transportation Exchanges Bring together shippers and carriers Initial contact, negotiations, auctions Examples www.nte.com www.freightquote.com 11-551 11-
  • 552. Global Supply Chain International trade barriers have fallen New trade agreements To compete globally requires an effective supply chain Information technology is an “enabler” of global trade 11-552 11-
  • 553. Obstacles to Global Chain Transactions Increased documentation for invoices, cargo insurance, letters of credit, ocean bills of lading or air waybills, and inspections Ever changing regulations that vary from country to country that govern the import and export of goods Trade groups, tariffs, duties, and landing costs Limited shipping modes Differences in communication technology and availability 11-553 11-
  • 554. Obstacles to Global Chain Transactions (cont.) Different business practices as well as language barriers Government codes and reporting requirements that vary from country to country Numerous players, including forwarding agents, custom house brokers, financial institutions, insurance providers, multiple transportation carriers, and government agencies Since 9/11, numerous security regulations and requirements 11-554 11-
  • 555. Duties and Tariffs Proliferation of trade agreements Nations form trading groups no tariffs or duties within group charge uniform tariffs to nonmembers Member nations have a competitive advantage within the group Trade specialists include freight forwarders, customs house brokers, export packers, and export management and trading companies 11-555 11-
  • 556. Duties and Tariffs (cont.) 11-556 11-
  • 557. Landed Cost Total cost of producing, storing, and transporting a product to the site of consumption or another port Value added tax (VAT) an indirect tax assessed on the increase in value of a good at any stage of production process from raw material to final product Clicker shock occurs when an ordered is placed with a company that does not have the capability to calculate landed cost 11-557 11-
  • 558. Web- Web-based International Trade Logistic Systems International trade logistics web-based software systems reduce obstacles to global trade convert language and currency provide information on tariffs, duties, and customs processes attach appropriate weights, measurements, and unit prices to individual products ordered over the Web incorporate transportation costs and conversion rates calculate shipping costs online while a company enters an order track global shipments 11-558 11-
  • 559. Recent Trends in Globalization for U.S. Companies Two significant changes passage of NAFTA admission of China in WTO Mexico cheap labor and relatively short shipping time China cheaper labor and longer work week, but lengthy shipping time Major supply chains have moved to China 11-559 11-
  • 560. China’s Increasing Role in the Global Supply Chain World’s premier sources of supply Abundance of low-wage labor low- World’s fastest growing market Regulatory changes have liberalized its market Increased exporting of higher technology products 11-560 11-
  • 561. Models in Doing Business in China Employ local third-party trading agents third- Wholly- Wholly-owned foreign enterprise Develop your own international procurement offices 11-561 11-
  • 562. Challenges Sourcing from China Getting reliable information in more difficult than in the U.S. Information technology is much less advanced and sophisticated than in the U.S. Work turnover rates among low-skilled low- workers is extremely high 11-562 11-
  • 563. Effects of 9/11 on Global Chains Increase security measures added time to supply chain schedules Increased supply chain costs 24 hours rules for “risk screening” extended documentation extend time by 3-4 days 3- Inventory levels have increased 5% Other costs include: new people, technologies, equipment, surveillance, communication, and security systems, and training necessary for screening at airports and seaports around the world 11-563 11-
  • 564. Chapter 11 Supplement Transportation and Transshipment Models Operations Management Roberta Russell & Bernard W. Taylor, III
  • 566. Transportation Model A transportation model is formulated for a class of problems with the following characteristics a product is transported from a number of sources to a number of destinations at the minimum possible cost each source is able to supply a fixed number of units of product each destination has a fixed demand for product Solution Methods stepping- stepping-stone modified distribution Excel’s Solver Supplement 11-566 11-
  • 567. Transportation Method: Example Supplement 11-567 11-
  • 568. Transportation Method: Example Supplement 11-568 11-
  • 569. Problem Formulation Using Excel Total Cost Formula Supplement 11-569 11-
  • 570. Using Solver from Tools Menu Supplement 11-570 11-
  • 571. Solution Supplement 11-571 11-
  • 572. Modified Problem Solution Supplement 11-572 11-
  • 573. Transshipment Model Supplement 11-573 11-
  • 574. Transshipment Model: Solution Supplement 11-574 11-
  • 575. Chapter 12 Forecasting Operations Management Roberta Russell & Bernard W. Taylor, III
  • 576. Lecture Outline Strategic Role of Forecasting in Supply Chain Management Components of Forecasting Demand Time Series Methods Forecast Accuracy Time Series Forecasting Using Excel Regression Methods 12-576 12-
  • 577. Forecasting Predicting the future Qualitative forecast methods subjective Quantitative forecast methods based on mathematical formulas 12-577 12-
  • 578. Forecasting and Supply Chain Management Accurate forecasting determines how much inventory a company must keep at various points along its supply chain Continuous replenishment supplier and customer share continuously updated data typically managed by the supplier reduces inventory for the company speeds customer delivery Variations of continuous replenishment quick response JIT (just-in-time) (just-in- VMI (vendor-managed inventory) (vendor- stockless inventory 12-578 12-
  • 579. Forecasting Quality Management Accurately forecasting customer demand is a key to providing good quality service Strategic Planning Successful strategic planning requires accurate forecasts of future products and markets 12-579 12-
  • 580. Types of Forecasting Methods Depend on time frame demand behavior causes of behavior 12-580 12-
  • 581. Time Frame Indicates how far into the future is forecast Short- mid- Short- to mid-range forecast typically encompasses the immediate future daily up to two years Long- Long-range forecast usually encompasses a period of time longer than two years 12-581 12-
  • 582. Demand Behavior Trend a gradual, long-term up or down movement of long- demand Random variations movements in demand that do not follow a pattern Cycle an up-and-down repetitive movement in demand up-and- Seasonal pattern an up-and-down repetitive movement in demand up-and- occurring periodically 12-582 12-
  • 583. Forms of Forecast Movement Demand Demand Random movement Time Time (a) Trend (b) Cycle Demand Demand Time Time (c) Seasonal pattern (d) Trend with seasonal pattern 12-583 12-
  • 584. Forecasting Methods Time series statistical techniques that use historical demand data to predict future demand Regression methods attempt to develop a mathematical relationship between demand and factors that cause its behavior Qualitative use management judgment, expertise, and opinion to predict future demand 12-584 12-
  • 585. Qualitative Methods Management, marketing, purchasing, and engineering are sources for internal qualitative forecasts Delphi method involves soliciting forecasts about technological advances from experts 12-585 12-
  • 586. Forecasting Process 1. Identify the 2. Collect historical 3. Plot data and identify purpose of forecast data patterns 6. Check forecast 5. Develop/compute 4. Select a forecast accuracy with one or forecast for period of model that seems more measures historical data appropriate for data 7. Is accuracy of No 8b. Select new forecast forecast model or acceptable? adjust parameters of existing model Yes 9. Adjust forecast based 10. Monitor results 8a. Forecast over on additional qualitative and measure forecast planning horizon information and insight accuracy 12-586 12-
  • 587. Time Series Assume that what has occurred in the past will continue to occur in the future Relate the forecast to only one factor - time Include moving average exponential smoothing linear trend line 12-587 12-
  • 588. Moving Average Naive forecast demand in current period is used as next period’s forecast Simple moving average uses average demand for a fixed sequence of periods stable demand with no pronounced behavioral patterns Weighted moving average weights are assigned to most recent data 12-588 12-
  • 589. Moving Average: Naïve Approach ORDERS MONTH PER MONTH FORECAST Jan 120 - Feb 90 120 Mar 100 90 Apr 75 100 May 110 75 June 50 110 July 75 50 Aug 130 75 Sept 110 130 Oct 90 110 90 Nov - 12-589 12-
  • 590. Simple Moving Average n Σ D i i=1 MAn = n where n = number of periods in the moving average Di = demand in period i 12-590 12-
  • 591. 3-month Simple Moving Average 3 MONTH ORDERS PER MONTH MOVING AVERAGE Σ Di i=1 MA3 = Jan 120 – 3 Feb 90 – Mar 100 – 90 + 110 + 130 Apr 75 103.3 = 3 May 110 88.3 June 50 95.0 July 75 78.3 = 110 orders Aug 130 78.3 for Nov Sept 110 85.0 Oct 90 105.0 Nov - 110.0 12-591 12-
  • 592. 5-month Simple Moving Average ORDERS MOVING MONTH PER MONTH AVERAGE 5 Σ Di Jan 120 – i=1 Feb 90 – MA5 = Mar 100 – 5 Apr 75 – May 110 – 90 + 110 + 130+75+50 June 50 99.0 = 5 July 75 85.0 Aug 130 82.0 Sept 110 88.0 = 91 orders Oct 90 95.0 for Nov Nov - 91.0 12-592 12-
  • 593. Smoothing Effects 150 – 5-month 125 – 100 – Orders 75 – 50 – 3-month Actual 25 – 0– | | | | | | | | | | | Jan Feb Mar Apr May June July Aug Sept Oct Nov Month 12-593 12-
  • 594. Weighted Moving Average Σ Wi Di n Adjusts moving average WMAn = method to more i=1 closely reflect data fluctuations where Wi = the weight for period i, between 0 and 100 percent Σ Wi = 1.00 12-594 12-
  • 595. Weighted Moving Average Example MONTH WEIGHT DATA August 17% 130 September 33% 110 October 50% 90 3 November Forecast WMA3 = Σ1 Wi Di i= = (0.50)(90) + (0.33)(110) + (0.17)(130) = 103.4 orders 12-595 12-
  • 596. Exponential Smoothing Averaging method Weights most recent data more strongly Reacts more to recent changes Widely used, accurate method 12-596 12-
  • 597. Exponential Smoothing (cont.) Ft +1 = α Dt + (1 - α)Ft where: Ft +1 = forecast for next period Dt = actual demand for present period Ft = previously determined forecast for present period α = weighting factor, smoothing constant 12-597 12-
  • 598. Effect of Smoothing Constant 0.0 ≤ α ≤ 1.0 If α = 0.20, then Ft +1 = 0.20 Dt + 0.80 Ft If α = 0, then Ft +1 = 0 Dt + 1 Ft = Ft Forecast does not reflect recent data If α = 1, then Ft +1 = 1 Dt + 0 Ft = Dt Forecast based only on most recent data 12-598 12-
  • 599. Exponential Smoothing (α=0.30) (α PERIOD MONTH DEMAND F2 = αD1 + (1 - α)F1 1 Jan 37 = (0.30)(37) + (0.70)(37) 2 Feb 40 = 37 3 Mar 41 4 Apr 37 F3 = αD2 + (1 - α)F2 5 May 45 = (0.30)(40) + (0.70)(37) 6 Jun 50 = 37.9 7 Jul 43 8 Aug 47 F13 = αD12 + (1 - α)F12 9 Sep 56 = (0.30)(54) + (0.70)(50.84) 10 Oct 52 11 Nov 55 = 51.79 12 Dec 54 12-599 12-
  • 600. Exponential Smoothing (cont.) FORECAST, Ft + 1 PERIOD MONTH DEMAND (α = 0.3) (α = 0.5) 1 Jan 37 – – 2 Feb 40 37.00 37.00 3 Mar 41 37.90 38.50 4 Apr 37 38.83 39.75 5 May 45 38.28 38.37 6 Jun 50 40.29 41.68 7 Jul 43 43.20 45.84 8 Aug 47 43.14 44.42 9 Sep 56 44.30 45.71 10 Oct 52 47.81 50.85 11 Nov 55 49.06 51.42 12 Dec 54 50.84 53.21 13 Jan – 51.79 53.61 12-600 12-
  • 601. Exponential Smoothing (cont.) 70 – 60 – Actual α = 0.50 50 – 40 – Orders α = 0.30 30 – 20 – 10 – 0– | | | | | | | | | | | | | 1 2 3 4 5 6 7 8 9 10 11 12 13 Month 12-601 12-
  • 602. Adjusted Exponential Smoothing AFt +1 = Ft +1 + Tt +1 where T = an exponentially smoothed trend factor Tt +1 = β(Ft +1 - Ft) + (1 - β) Tt where Tt = the last period trend factor β = a smoothing constant for trend 12-602 12-
  • 603. Adjusted Exponential Smoothing (β=0.30) (β PERIOD MONTH DEMAND T3 = β(F3 - F2) + (1 - β) T2 = (0.30)(38.5 - 37.0) + (0.70)(0) 1 Jan 37 2 Feb 40 = 0.45 3 Mar 41 4 Apr 37 AF3 = F3 + T3 = 38.5 + 0.45 5 May 45 = 38.95 6 Jun 50 7 Jul 43 T13 = β(F13 - F12) + (1 - β) T12 8 Aug 47 = (0.30)(53.61 - 53.21) + (0.70)(1.77) 9 Sep 56 = 1.36 10 Oct 52 11 Nov 55 12 Dec 54 AF13 = F13 + T13 = 53.61 + 1.36 = 54.97 12-603 12-
  • 604. Adjusted Exponential Smoothing: Example FORECAST TREND ADJUSTED PERIOD MONTH DEMAND Ft +1 Tt +1 FORECAST AFt +1 1 Jan 37 37.00 – – 2 Feb 40 37.00 0.00 37.00 3 Mar 41 38.50 0.45 38.95 4 Apr 37 39.75 0.69 40.44 5 May 45 38.37 0.07 38.44 6 Jun 50 38.37 0.07 38.44 7 Jul 43 45.84 1.97 47.82 8 Aug 47 44.42 0.95 45.37 9 Sep 56 45.71 1.05 46.76 10 Oct 52 50.85 2.28 58.13 11 Nov 55 51.42 1.76 53.19 12 Dec 54 53.21 1.77 54.98 13 Jan – 53.61 1.36 54.96 12-604 12-
  • 605. Adjusted Exponential Smoothing Forecasts 70 – Adjusted forecast (β = 0.30) (β 60 – Actual 50 – Demand 40 – 30 – Forecast (α = 0.50) (α 20 – 10 – 0– | | | | | | | | | | | | | 1 2 3 4 5 6 7 8 9 10 11 12 13 Period 12-605 12-
  • 606. Linear Trend Line Σ xy - nxy y = a + bx b = Σx 2 - nx2 where a = y-bx a = intercept b = slope of the line where n = number of periods x = time period y = forecast for Σx demand for period x x = n = mean of the x values Σy y = n = mean of the y values 12-606 12-
  • 607. Least Squares Example x(PERIOD) y(DEMAND) xy x2 1 73 37 1 2 40 80 4 3 41 123 9 4 37 148 16 5 45 225 25 6 50 300 36 7 43 301 49 8 47 376 64 9 56 504 81 10 52 520 100 11 55 605 121 12 54 648 144 78 557 3867 650 12-607 12-
  • 608. Least Squares Example (cont.) 78 12 x = = 6.5 557 12 y = = 46.42 ∑xy - nxy 3867 - (12)(6.5)(46.42) b = 2 = =1.72 ∑x - nx2 650 - 12(6.5)2 a = y - bx = 46.42 - (1.72)(6.5) = 35.2 12-608 12-
  • 609. Linear trend line y = 35.2 + 1.72x Forecast for period 13 y = 35.2 + 1.72(13) = 57.56 units 70 – 60 – Actual 50 – Demand 40 – Linear trend line 30 – 20 – 10 – | | | | | | | | | | | | | 1 2 3 4 5 6 7 8 9 10 11 12 13 0– Period 12-609 12-
  • 610. Seasonal Adjustments Repetitive increase/ decrease in demand Use seasonal factor to adjust forecast Di Seasonal factor = Si = ∑D 12-610 12-
  • 611. Seasonal Adjustment (cont.) DEMAND (1000’S PER QUARTER) YEAR 1 2 3 4 Total 2002 12.6 8.6 6.3 17.5 45.0 2003 14.1 10.3 7.5 18.2 50.1 2004 15.3 10.6 8.1 19.6 53.6 Total 42.0 29.5 21.9 55.3 148.7 D1 42.0 D3 21.9 S1 = = = 0.28 S3 = = = 0.15 ∑D 148.7 ∑D 148.7 D2 29.5 D4 55.3 S2 = = = 0.20 S4 = = = 0.37 ∑D 148.7 ∑D 148.7 12-611 12-
  • 612. Seasonal Adjustment (cont.) For 2005 y = 40.97 + 4.30x = 40.97 + 4.30(4) = 58.17 4.30x SF1 = (S1) (F5) = (0.28)(58.17) = 16.28 (S (F SF2 = (S2) (F5) = (0.20)(58.17) = 11.63 (S (F SF3 = (S3) (F5) = (0.15)(58.17) = 8.73 (S (F SF4 = (S4) (F5) = (0.37)(58.17) = 21.53 (S (F 12-612 12-
  • 613. Forecast Accuracy Forecast error difference between forecast and actual demand MAD mean absolute deviation MAPD mean absolute percent deviation Cumulative error Average error or bias 12-613 12-
  • 614. Mean Absolute Deviation (MAD) Σ| Dt - Ft | MAD = n where t = period number Dt = demand in period t Ft = forecast for period t n = total number of periods   = absolute value 12-614 12-
  • 615. MAD Example PERIOD DEMAND, Dt Ft (α =0.3) (Dt - Ft) |Dt - Ft| 1 37 37.00 – – 2 40 37.00 3.00 3.00 3 41 Σ| D37.90 t | 3.10 t - F 3.10 4 5 MAD = 38.28 -6.72 37 45 38.83 n 1.83 1.83 6.72 6 50 40.29 9.69 9.69 7 43 53.39 = 43.20 -0.20 0.20 8 47 11 43.14 3.86 3.86 9 56 10 52 = 4.85 44.30 11.70 47.81 4.19 11.70 4.19 11 55 49.06 5.94 5.94 12 54 50.84 3.15 3.15 557 49.31 53.39 12-615 12-
  • 616. Other Accuracy Measures Mean absolute percent deviation (MAPD) ∑|Dt - Ft| MAPD = ∑Dt Cumulative error E = ∑et Average error ∑et E= n 12-616 12-
  • 617. Comparison of Forecasts FORECAST MAD MAPD E (E) Exponential smoothing (α = 0.30) 4.85 (α 9.6% 49.31 4.48 Exponential smoothing (α = 0.50) 4.04 (α 8.5% 33.21 3.02 Adjusted exponential smoothing 3.81 7.5% 21.14 1.92 (α = 0.50, β = 0.30) Linear trend line 2.29 4.9% – – 12-617 12-
  • 618. Forecast Control Tracking signal monitors the forecast to see if it is biased high or low ∑(Dt - Ft) E Tracking signal = = MAD MAD 1 MAD ≈ 0.8 б Control limits of 2 to 5 MADs are used most frequently 12-618 12-
  • 619. Tracking Signal Values DEMAND FORECAST, ERROR ∑E = TRACKING PERIOD Dt Ft Dt - Ft ∑(Dt - Ft) MAD SIGNAL 1 37 37.00 – – – – 2 40 37.00 3.00 3.00 3.00 1.00 3 41 37.90 3.10 6.10 3.05 2.00 4 37 38.83 -1.83 4.27 2.64 1.62 5 45 38.28 6.72 10.99 Tracking signal for period 3 3.66 3.00 6 50 40.29 9.69 20.68 4.87 4.25 7 43 43.20 -0.20 20.48 4.09 5.01 6.10 8 47 43.14 = TS3 3.86 = 2.00 24.34 4.06 6.00 9 56 44.30 3.05 11.70 36.04 5.01 7.19 10 52 47.81 4.19 40.23 4.92 8.18 11 55 49.06 5.94 46.17 5.02 9.20 12 54 50.84 3.15 49.32 4.85 10.17 12-619 12-
  • 620. Tracking Signal Plot 3σ – Tracking signal (MAD) 2σ – α Exponential smoothing (α = 0.30) 1σ – 0σ – -1σ – -2σ – Linear trend line -3σ – | | | | | | | | | | | | | 0 1 2 3 4 5 6 7 8 9 10 11 12 Period 12-620 12-
  • 621. Statistical Control Charts ∑(Dt - Ft)2 σ= n-1 Using σ we can calculate statistical control limits for the forecast error Control limits are typically set at ± 3σ 12-621 12-
  • 622. Statistical Control Charts 18.39 – σ UCL = +3σ 12.24 – 6.12 – Errors 0– -6.12 – -12.24 – σ LCL = -3σ -18.39 – | | | | | | | | | | | | | 0 1 2 3 4 5 6 7 8 9 10 11 12 Period 12-622 12-
  • 623. Time Series Forecasting using Excel Excel can be used to develop forecasts: Moving average Exponential smoothing Adjusted exponential smoothing Linear trend line 12-623 12-
  • 624. Exponentially Smoothed and Adjusted Exponentially Smoothed Forecasts 12-624 12-
  • 625. Demand and exponentially smoothed forecast 12-625 12-
  • 626. Data Analysis option 12-626 12-
  • 627. Computing a Forecast with Seasonal Adjustment 12-627 12-
  • 628. OM Tools 12-628 12-
  • 629. Regression Methods Linear regression a mathematical technique that relates a dependent variable to an independent variable in the form of a linear equation Correlation a measure of the strength of the relationship between independent and dependent variables 12-629 12-
  • 630. Linear Regression y = a + bx a = y-bx Σ xy - nxy Σx 2 - nx2 b = where a = intercept b = slope of the line Σx x =n = mean of the x data Σy y =n = mean of the y data 12-630 12-
  • 631. Linear Regression Example x y (WINS) (ATTENDANCE) xy x2 4 36.3 145.2 16 6 40.1 240.6 36 6 41.2 247.2 36 8 53.0 424.0 64 6 44.0 264.0 36 7 45.6 319.2 49 5 39.0 195.0 25 7 47.5 332.5 49 49 346.7 2167.7 311 12-631 12-
  • 632. Linear Regression Example (cont.) 49 8 x= = 6.125 346.9y = = 43.36 8 ∑xy - nxy2 b = ∑x2 - nx2 = (2,167.7) - (8)(6.125)(43.36) (311) - (8)(6.125)2 = 4.06 a = y - bx = 43.36 - (4.06)(6.125) = 18.46 12-632 12-
  • 633. Linear Regression Example (cont.) Regression equation Attendance forecast for 7 wins y = 18.46 + 4.06x y = 18.46 + 4.06(7) 60,000 – = 46.88, or 46,880 50,000 – 40,000 – Attendance, y 30,000 – Linear regression line, 20,000 – y = 18.46 + 4.06x 4.06x 10,000 – | | | | | | | | | | | 0 1 2 3 4 5 6 7 8 9 10 Wins, x 12-633 12-
  • 634. Correlation and Coefficient of Determination Correlation, r Measure of strength of relationship Varies between -1.00 and +1.00 Coefficient of determination, r2 Percentage of variation in dependent variable resulting from changes in the independent variable 12-634 12-
  • 635. Computing Correlation n∑ xy - ∑ x∑ y r= [n∑ x2 - (∑ x)2] [n∑ y2 - (∑ y)2] [n (8)(2,167.7) - (49)(346.9) r= [(8)(311) - (49)2] [(8)(15,224.7) - (346.9)2] r = 0.947 Coefficient of determination r2 = (0.947)2 = 0.897 12-635 12-
  • 636. Regression Analysis with Excel 12-636 12-
  • 637. Regression Analysis with Excel (cont.) 12-637 12-
  • 638. Regression Analysis with Excel (cont.) 12-638 12-
  • 639. Multiple Regression Study the relationship of demand to two or more independent variables y = β0 + β1x1 + β2x2 … + βkxk where β0 = the intercept β1, … , βk = parameters for the independent variables x1, … , xk = independent variables 12-639 12-
  • 640. Multiple Regression with Excel 12-640 12-
  • 641. Chapter 13 Inventory Management Operations Management - 6th Edition Roberta Russell & Bernard W. Taylor, III Beni Asllani University of Tennessee at Chattanooga
  • 642. Lecture Outline Elements of Inventory Management Inventory Control Systems Economic Order Quantity Models Quantity Discounts Reorder Point Order Quantity for a Periodic Inventory System 13-642 13-
  • 643. What Is Inventory? Stock of items kept to meet future demand Purpose of inventory management how many units to order when to order 13-643 13-
  • 644. Inventory and Supply Chain Management Bullwhip effect demand information is distorted as it moves away from the end-use customer end- higher safety stock inventories to are stored to compensate Seasonal or cyclical demand Inventory provides independence from vendors Take advantage of price discounts Inventory provides independence between stages and avoids work stoppages 13-644 13-
  • 645. Inventory and Quality Management in the Supply Chain Customers usually perceive quality service as availability of goods they want when they want them Inventory must be sufficient to provide high-quality customer service in QM 13-645 13-
  • 646. Types of Inventory Raw materials Purchased parts and supplies Work-in-process (partially completed) products (WIP) Items being transported Tools and equipment 13-646 13-
  • 647. Two Forms of Demand Dependent Demand for items used to produce final products Tires stored at a Goodyear plant are an example of a dependent demand item Independent Demand for items used by external customers Cars, appliances, computers, and houses are examples of independent demand inventory 13-647 13-
  • 648. Inventory Costs Carrying cost cost of holding an item in inventory Ordering cost cost of replenishing inventory Shortage cost temporary or permanent loss of sales when demand cannot be met 13-648 13-
  • 649. Inventory Control Systems Continuous system (fixed-order- (fixed-order- quantity) constant amount ordered when inventory declines to predetermined level Periodic system (fixed-time- (fixed-time- period) order placed for variable amount after fixed passage of time 13-649 13-
  • 650. ABC Classification Class A 5 – 15 % of units 70 – 80 % of value Class B 30 % of units 15 % of value Class C 50 – 60 % of units 5 – 10 % of value 13-650 13-
  • 651. ABC Classification: Example PART UNIT COST ANNUAL USAGE 1 $ 60 90 2 350 40 3 30 130 4 80 60 5 30 100 6 20 180 7 10 170 8 320 50 9 510 60 10 20 120 13-651 13-
  • 652. ABC Classification: Example (cont.) TOTAL PART PART VALUE UNIT COSTQUANTITY OF% CUMMULATIVE VALUE % OF TOTAL % TOTAL ANNUAL USAGE 9 $30,6001 35.9 $ 60 6.0 90 6.0 8 16,0002 18.7 350 5.0 40 11.0 2 14,000 16.4 4.0 A 1 5,400 3 6.3 30 9.0 130 15.0 24.0 4 4,8004 5.6 80 6.0 60 30.0 B 100 40.0 3 3,9005 4.6 30 10.0 6 3,6006 20 4.2 % OF TOTAL 18.0 %180TOTAL OF 58.0 5 3,000 CLASS 7 ITEMS3.5 10VALUE 13.0 170 71.0 QUANTITY 10 2,400 2.8 12.0 83.0 7 A 8 1,700 9, 8, 2 2.0 320 71.017.0 C 50 100.0 15.0 B 9 1, 4, 3 510 16.5 $85,400 60 25.0 C 10 6, 5, 10, 720 12.5 120 60.0 Example 10.1 13-652 13-
  • 653. Economic Order Quantity (EOQ) Models EOQ optimal order quantity that will minimize total inventory costs Basic EOQ model Production quantity model 13-653 13-
  • 654. Assumptions of Basic EOQ Model Demand is known with certainty and is constant over time No shortages are allowed Lead time for the receipt of orders is constant Order quantity is received all at once 13-654 13-
  • 655. Inventory Order Cycle Order quantity, Q Demand Average rate inventory Inventory Level Q 2 Reorder point, R 0 Lead Lead Time time time Order Order Order Order placed receipt placed receipt 13-655 13-
  • 656. EOQ Cost Model Co - cost of placing order D - annual demand Cc - annual per-unit carrying cost per- Q - order quantity CoD Annual ordering cost = Q CcQ Annual carrying cost = 2 CoD CcQ Total cost = + Q 2 13-656 13-
  • 657. EOQ Cost Model Deriving Qopt Proving equality of costs at optimal point CoD CcQ TC = + Q 2 CoD CcQ = ∂TC CoD Cc Q 2 =– 2 + ∂Q Q 2 2CoD C0D Q2 = Cc Cc 0=– 2 + Q 2 2CoD 2CoD Qopt = Qopt = Cc Cc 13-657 13-
  • 658. EOQ Cost Model (cont.) Annual cost ($) Total Cost Slope = 0 CcQ Minimum Carrying Cost = 2 total cost CoD Ordering Cost = Q Optimal order Order Quantity, Q Qopt 13-658 13-
  • 659. EOQ Example Cc = $0.75 per gallon Co = $150 D = 10,000 gallons 2CoD CoD CcQ Qopt = TCmin = + Cc Q 2 2(150)(10,000) (150)(10,000) (0.75)(2,000) Qopt = TCmin = + (0.75) 2,000 2 Qopt = 2,000 gallons TCmin = $750 + $750 = $1,500 Orders per year = D/Qopt Order cycle time = 311 days/(D/Qopt) days/(D = 10,000/2,000 = 311/5 = 5 orders/year = 62.2 store days 13-659 13-
  • 660. Production Quantity Model An inventory system in which an order is received gradually, as inventory is simultaneously being depleted AKA non-instantaneous receipt model assumption that Q is received all at once is relaxed p - daily rate at which an order is received over time, a.k.a. production rate d - daily rate at which inventory is demanded 13-660 13-
  • 661. Production Quantity Model (cont.) Inventory level Maximum Q(1-d/p) (1-d/p) inventory level Average Q inventory (1-d/p) (1-d/p) 2 level 0 Begin End Time order order Order receipt receipt receipt period 13-661 13-
  • 662. Production Quantity Model (cont.) p = production rate d = demand rate Q Maximum inventory level = Q - p d d = Q 1 -p 2CoD Qopt = Q d Cc 1 - d Average inventory level = 1- p 2 p CoD CcQ d TC = Q + 2 1 - p 13-662 13-
  • 663. Production Quantity Model: Example Cc = $0.75 per gallon Co = $150 D = 10,000 gallons d = 10,000/311 = 32.2 gallons per day p = 150 gallons per day 2C o D 2(150)(10,000) Qopt = = = 2,256.8 gallons Cc 1 - d 0.75 1 - 32.2 p 150 CoD CcQ d TC = Q + 2 1 - p = $1,329 Q 2,256.8 Production run = p = = 15.05 days per order 150 13-663 13-
  • 664. Production Quantity Model: Example (cont.) D 10,000 Number of production runs = Q = 2,256.8 = 4.43 runs/year d 32.2 Maximum inventory level = Q 1 - p = 2,256.8 1 - 150 = 1,772 gallons 13-664 13-
  • 665. Solution of EOQ Models with Excel 13-665 13-
  • 666. Solution of EOQ Models with Excel (Con’t) 13-666 13-
  • 667. Solution of EOQ Models with OM Tools 13-667 13-
  • 668. Quantity Discounts Price per unit decreases as order quantity increases CoD CcQ TC = + + PD Q 2 where P = per unit price of the item D = annual demand 13-668 13-
  • 669. Quantity Discount Model (cont.) ORDER SIZE PRICE 0 - 99 $10 TC = ($10 ) 100 – 199 8 (d1) 200+ 6 (d2) TC (d1 = $8 ) TC (d2 = $6 ) Inventory cost ($) Carrying cost Ordering cost Q(d1 ) = 100 Qopt Q(d2 ) = 200 13-669 13-
  • 670. Quantity Discount: Example QUANTITY PRICE Co = $2,500 1 - 49 $1,400 Cc = $190 per TV 50 - 89 1,100 D = 200 TVs per year 90+ 900 2C o D 2(2500)(200) Qopt = = = 72.5 TVs Cc 190 For Q = 72.5 CoD CcQopt TC = + + PD = $233,784 Qopt 2 For Q = 90 CoD CcQ TC = + + PD = $194,105 Q 2 13-670 13-
  • 672. Reorder Point Level of inventory at which a new order is placed R = dL where d = demand rate per period L = lead time 13-672 13-
  • 673. Reorder Point: Example Demand = 10,000 gallons/year Store open 311 days/year Daily demand = 10,000 / 311 = 32.154 gallons/day Lead time = L = 10 days R = dL = (32.154)(10) = 321.54 gallons 13-673 13-
  • 674. Safety Stocks Safety stock buffer added to on hand inventory during lead time Stockout an inventory shortage Service level probability that the inventory available during lead time will meet demand 13-674 13-
  • 675. Variable Demand with a Reorder Point Q Inventory level Reorder point, R 0 LT LT Time 13-675 13-
  • 676. Reorder Point with a Safety Stock Inventory level Q Reorder point, R Safety Stock 0 LT LT Time 13-676 13-
  • 677. Reorder Point With Variable Demand R = dL + zσd L where d = average daily demand L = lead time σd = the standard deviation of daily demand z = number of standard deviations corresponding to the service level probability zσd L = safety stock 13-677 13-
  • 678. Reorder Point for a Service Level Probability of meeting demand during lead time = service level Probability of a stockout Safety stock σ zσd L dL R Demand 13-678 13-
  • 679. Reorder Point for Variable Demand The paint store wants a reorder point with a 95% service level and a 5% stockout probability d = 30 gallons per day L = 10 days σd = 5 gallons per day For a 95% service level, z = 1.65 R = dL + z σd L Safety stock = z σd L = 30(10) + (1.65)(5)( 10) = (1.65)(5)( 10) = 326.1 gallons = 26.1 gallons 13-679 13-
  • 680. Determining Reorder Point with Excel 13-680 13-
  • 681. Order Quantity for a Periodic Inventory System Q = d(tb + L) + zσd tb + L - I where d = average demand rate tb = the fixed time between orders L = lead time σd = standard deviation of demand zσd tb + L = safety stock I = inventory level 13-681 13-
  • 683. Fixed- Fixed-Period Model with Variable Demand d = 6 packages per day σd = 1.2 packages tb = 60 days L = 5 days I = 8 packages z = 1.65 (for a 95% service level) Q = d(tb + L) + zσd tb + L - I = (6)(60 + 5) + (1.65)(1.2) 60 + 5 - 8 = 397.96 packages 13-683 13-
  • 684. Fixed- Fixed-Period Model with Excel 13-684 13-
  • 685. Chapter 13 Supplement Simulation Operations Management Roberta Russell & Bernard W. Taylor, III
  • 686. Lecture Outline Monte Carlo Simulation Computer Simulation with Excel Areas of Simulation Application Supplement 13-686 13-
  • 687. Simulation Mathematical and computer modeling technique for replicating real-world problem situations Modeling approach primarily used to analyze probabilistic problems It does not normally provide a solution; instead it provides information that is used to make a decision Physical simulation Space flights, wind tunnels, treadmills for tires Mathematical-computerized simulation Computer-based replicated models Supplement 13-687 13-
  • 688. Monte Carlo Simulation Select numbers randomly from a probability distribution Use these values to observe how a model performs over time Random numbers each have an equal likelihood of being selected at random Supplement 13-688 13-
  • 689. Distribution of Demand LAPTOPS DEMANDED FREQUENCY OF PROBABILITY OF PER WEEK, x DEMAND DEMAND, P(x) 0 20 0.20 1 40 0.40 2 20 0.20 3 10 0.10 4 10 0.10 100 1.00 Supplement 13-689 13-
  • 690. Roulette Wheel of Demand 0 90 x=4 x=0 80 x=3 20 x=2 x=1 60 Supplement 13-690 13-
  • 691. Generating Demand from Random Numbers DEMAND, RANGES OF RANDOM NUMBERS, x r 0 0-19 1 20-59 20- r = 39 2 60-79 60- 3 80-89 80- 4 90-99 90- Supplement 13-691 13-
  • 692. Random Number Table Supplement 13-692 13-
  • 693. 15 Weeks of Demand WEEK r DEMAND (x) (x REVENUE (S) 1 39 1 4,300 2 73 2 8,600 3 72 2 8,600 4 75 2 8,600 5 37 1 4,300 6 02 0 0 7 87 3 12,900 8 98 4 17,200 9 10 0 0 10 47 1 4,300 11 93 4 17,200 Average demand 12 21 1 4,300 = 31/15 13 95 4 17,200 = 2.07 laptops/week 14 97 4 17,200 15 69 2 8,600 Σ = 31 $133,300 Supplement 13-693 13-
  • 694. Computing Expected Demand E(x) = (0.20)(0) + (0.40)(1) + (0.20)(2) + (0.10)(3) + (0.10)(4) = 1.5 laptops per week •Difference between 1.5 and 2.07 is due to small number of periods analyzed (only 15 weeks) •Steady-state result Steady- •an average result that remains constant after enough trials Supplement 13-694 13-
  • 695. Random Numbers in Excel Supplement 13-695 13-
  • 696. Simulation in Excel Supplement 13-696 13-
  • 697. Simulation in Excel (cont.) Supplement 13-697 13-
  • 698. Decision Making with Simulation Supplement 13-698 13-
  • 699. Decision Making with Simulation (cont.) Supplement 13-699 13-
  • 700. Areas of Simulation Application Waiting Lines/Service Complex systems for which it is difficult to develop analytical formulas Determine how many registers and servers are needed to meet customer demand Inventory Management Traditional models make the assumption that customer demand is certain Simulation is widely used to analyze JIT without having to implement it physically Supplement 13-700 13-
  • 701. Areas of Simulation Application (cont.) Production and Manufacturing Systems Examples: production scheduling, production sequencing, assembly line balancing, plant layout, and plant location analysis Machine breakdowns typically occur according to some probability distributions Capital Investment and Budgeting Capital budgeting problems require estimates of cash flows, often resulting from many random variables Simulation has been used to generate values of cash flows, market size, selling price, growth rate, and market share Supplement 13-701 13-
  • 702. Areas of Simulation Application (cont.) Logistics Typically include numerous random variables, such as distance, different modes of transport, shipping rates, and schedules to analyze different distribution channels Service Operations Examples: police departments, fire departments, post offices, hospitals, court systems, airports Complex operations that no technique except simulation can be employed Environmental and Resource Analysis Examples: impact of manufacturing plants, waste-disposal facilities, nuclear power plants, waste and population conditions, feasibility of alternative energy sources Supplement 13-702 13-
  • 703. Chapter 14 Sales and Operations Planning Operations Management Roberta Russell & Bernard W. Taylor, III
  • 704. Lecture Outline The Sales and Operations Planning Process Strategies for Adjusting Capacity Strategies for Managing Demand Quantitative Techniques for Aggregate Planning Hierarchical Nature of Planning Aggregate Planning for Services 14-704 14-
  • 705. Sales and Operations Planning Determines the resource capacity needed to meet demand over an intermediate time horizon Aggregate refers to sales and operations planning for product lines or families Sales and Operations planning (S&OP) matches supply and demand Objectives Establish a company wide game plan for allocating resources Develop an economic strategy for meeting demand 14-705 14-
  • 706. Sales and Operations Planning Process 14-706 14-
  • 707. The Monthly S&OP Planning Process 14-707 14-
  • 708. Meeting Demand Strategies Adjusting capacity Resources necessary to meet demand are acquired and maintained over the time horizon of the plan Minor variations in demand are handled with overtime or under-time under- Managing demand Proactive demand management 14-708 14-
  • 709. Strategies for Adjusting Capacity Level production Overtime and under-time under- Producing at a constant rate Increasing or decreasing and using inventory to working hours absorb fluctuations in Subcontracting demand Let outside companies Chase demand complete the work Hiring and firing workers to Part- Part-time workers match demand Hiring part time workers to Peak demand complete the work Maintaining resources for Backordering high- high-demand levels Providing the service or product at a later time period 14-709 14-
  • 710. Level Production Demand Production Units Time 14-710 14-
  • 711. Chase Demand Demand Production Units Time 14-711 14-
  • 712. Strategies for Managing Demand Shifting demand into other time periods Incentives Sales promotions Advertising campaigns Offering products or services with counter- cyclical demand patterns Partnering with suppliers to reduce information distortion along the supply chain 14-712 14-
  • 713. Quantitative Techniques For AP Pure Strategies Mixed Strategies Linear Programming Transportation Method Other Quantitative Techniques 14-713 14-
  • 714. Pure Strategies Example: QUARTER SALES FORECAST (LB) Spring 80,000 Summer 50,000 Fall 120,000 Winter 150,000 Hiring cost = $100 per worker Firing cost = $500 per worker Inventory carrying cost = $0.50 pound per quarter Regular production cost per pound = $2.00 Production per employee = 1,000 pounds per quarter Beginning work force = 100 workers 14-714 14-
  • 715. Level Production Strategy Level production (50,000 + 120,000 + 150,000 + 80,000) = 100,000 pounds 4 SALES PRODUCTION QUARTER FORECAST PLAN INVENTORY Spring 80,000 100,000 20,000 Summer 50,000 100,000 70,000 Fall 120,000 100,000 50,000 Winter 150,000 100,000 0 400,000 140,000 Cost of Level Production Strategy (400,000 X $2.00) + (140,00 X $.50) = $870,000 14-715 14-
  • 716. Chase Demand Strategy SALES PRODUCTION WORKERS WORKERS WORKERS QUARTER FORECAST PLAN NEEDED HIRED FIRED Spring 80,000 80,000 80 0 20 Summer 50,000 50,000 50 0 30 Fall 120,000 120,000 120 70 0 Winter 150,000 150,000 150 30 0 100 50 Cost of Chase Demand Strategy (400,000 X $2.00) + (100 x $100) + (50 x $500) = $835,000 14-716 14-
  • 717. Level Production with Excel 14-717 14-
  • 718. Chase Demand with Excel 14-718 14-
  • 719. Mixed Strategy Combination of Level Production and Chase Demand strategies Examples of management policies no more than x% of the workforce can be laid off in one quarter inventory levels cannot exceed x dollars Many industries may simply shut down manufacturing during the low demand season and schedule employee vacations during that time 14-719 14-
  • 720. Mixed Strategies with Excel 14-720 14-
  • 721. Mixed Strategies with Excel (cont.) 14-721 14-
  • 722. General Linear Programming (LP) Model LP gives an optimal solution, but demand and costs must be linear Let Wt = workforce size for period t Pt =units produced in period t It =units in inventory at the end of period t Ft =number of workers fired for period t Ht = number of workers hired for period t 14-722 14-
  • 723. LP MODEL Minimize Z = $100 (H1 + H2 + H3 + H4) + $500 (F1 + F2 + F3 + F4) + $0.50 (I1 + I2 + I3 + I4) + $2 (P1 + P2 + P3 + P4) Subject to P1 - I1 = 80,000 (1) Demand I1 + P2 - I2 = 50,000 (2) constraints I2 + P3 - I3 = 120,000 (3) I3 + P4 - I4 = 150,000 (4) Production 1000 W1 = P1 (5) constraints 1000 W2 = P2 (6) 1000 W3 = P3 (7) 1000 W4 = P4 (8) 100 + H1 - F1 = W1 (9) Work force W1 + H2 - F2 = W2 (10) constraints W2 + H3 - F3 = W3 (11) W3 + H4 - F4 = W4 (12) 14-723 14-
  • 724. Setting up the Spreadsheet 14-724 14-
  • 725. The LP Solution 14-725 14-
  • 726. Transportation Method EXPECTED REGULAR OVERTIME SUBCONTRACT QUARTER DEMAND CAPACITY CAPACITY CAPACITY 1 900 1000 100 500 2 1500 1200 150 500 3 1600 1300 200 500 4 3000 1300 200 500 Regular production cost per unit $20 Overtime production cost per unit $25 Subcontracting cost per unit $28 Inventory holding cost per unit per period $3 Beginning inventory 300 units 14-726 14-
  • 727. Transportation Tableau PERIOD OF USE Unused PERIOD OF PRODUCTION 1 2 3 4 Capacity Capacity Beginning 0 3 6 9 Inventory 300 — — — 300 1 Regular 600 20 300 23 100 26 — 29 1000 Overtime 25 28 31 100 34 100 Subcontract 28 31 34 37 500 2 Regular 1200 20 — 23 — 26 1200 Overtime 25 28 150 31 150 28 31 34 Subcontract 250 250 500 3 20 23 Regular 1300 — 1300 25 28 Overtime 200 — 200 28 31 Subcontract 500 500 4 20 Regular 1300 1300 25 Overtime 200 200 28 Subcontract 500 500 Demand 900 1500 1600 3000 250 14-727 14-
  • 728. Burruss’ Production Plan REGULAR SUB- SUB- ENDING PERIOD DEMAND PRODUCTION OVERTIME CONTRACT INVENTORY 1 900 1000 100 0 500 2 1500 1200 150 250 600 3 1600 1300 200 500 1000 4 3000 1300 200 500 0 Total 7000 4800 650 1250 2100 14-728 14-
  • 729. Using Excel for the Transportation Method of Aggregate Planning 14-729 14-
  • 730. Other Quantitative Techniques Linear decision rule (LDR) Search decision rule (SDR) Management coefficients model 14-730 14-
  • 731. Hierarchical Nature of Planning Production Capacity Resource Items Planning Planning Level Product lines Sales and Resource Operations requirements Plants or families Plan plan Master Rough-cut Critical Individual production capacity work products schedule plan centers Material Capacity All Components requirements requirements work plan plan centers Shop Input/ Manufacturing Individual floor output operations machines schedule control Disaggregation: process of breaking an aggregate plan into more detailed plans 14-731 14-
  • 732. Collaborative Planning Sharing information and synchronizing production across supply chain Part of CPFR (collaborative planning, forecasting, and replenishment) involves selecting products to be jointly managed, creating a single forecast of customer demand, and synchronizing production across supply chain 14-732 14-
  • 733. Available-to-Promise (ATP) Quantity of items that can be promised to customer Difference between planned production and customer orders already received AT in period 1 = (On-hand quantity + MPS in period 1) – (CO until the next period of planned production) ATP in period n = (MPS in period n) – (CO until the next period of planned production) Capable-to-promise quantity of items that can be produced and mad available at a later date 14-733 14-
  • 734. ATP: Example 14-734 14-
  • 735. ATP: Example (cont.) 14-735 14-
  • 736. ATP: Example (cont.) Take excess units from April ATP in April = (10+100) – 70 = 40 = 30 ATP in May = 100 – 110 = -10 =0 ATP in June = 100 – 50 = 50 14-736 14-
  • 737. Rule Based ATP Product Request Yes Is the product Is an alternative Yes product available Available- available at to-promise this location? at an alternate location? No No Allocate inventory Capable-to- Yes Is an alternative promise date Available- to-promise product available at this location? No Yes Allocate Is the customer Revise master inventory willing to wait for schedule the product? Yes Is this product available at a different location? No Trigger production Lose sale No 14-737 14-
  • 738. Aggregate Planning for Services 1. Most services cannot be inventoried 2. Demand for services is difficult to predict 3. Capacity is also difficult to predict 4. Service capacity must be provided at the appropriate place and time 5. Labor is usually the most constraining resource for services 14-738 14-
  • 739. Yield Management 14-739 14-
  • 741. Yield Management: Example NO-SHOWS NO- PROBABILITY P(N < X) 0 .15 .00 1 .25 .15 2 .30 .40 .517 3 .30 .70 Optimal probability of no-shows no- P(n < x) ≤ P(n Cu = 75 = .517 Cu + Co 75 + 70 Hotel should be overbooked by two rooms 14-741 14-
  • 742. Chapter 14 Supplement Linear Programming Operations Management Roberta Russell & Bernard W. Taylor, III
  • 743. Lecture Outline Model Formulation Graphical Solution Method Linear Programming Model Solution Solving Linear Programming Problems with Excel Sensitivity Analysis Supplement 14-743 14-
  • 744. Linear Programming (LP) A model consisting of linear relationships representing a firm’s objective and resource constraints LP is a mathematical modeling technique used to determine a level of operational activity in order to achieve an objective, subject to restrictions called constraints Supplement 14-744 14-
  • 745. Types of LP Supplement 14-745 14-
  • 746. Types of LP (cont.) Supplement 14-746 14-
  • 747. Types of LP (cont.) Supplement 14-747 14-
  • 748. LP Model Formulation Decision variables mathematical symbols representing levels of activity of an operation Objective function a linear relationship reflecting the objective of an operation most frequent objective of business firms is to maximize profit most frequent objective of individual operational units (such as a production or packaging department) is to minimize cost Constraint a linear relationship representing a restriction on decision making Supplement 14-748 14-
  • 749. LP Model Formulation (cont.) Max/min z = c1x1 + c2x2 + ... + cnxn subject to: a11x1 + a12x2 + ... + a1nxn (≤, =, ≥) b1 a21x1 + a22x2 + ... + a2nxn (≤, =, ≥) b2 : an1x1 + an2x2 + ... + annxn (≤, =, ≥) bn xj = decision variables bi = constraint levels cj = objective function coefficients aij = constraint coefficients Supplement 14-749 14-
  • 750. LP Model: Example RESOURCE REQUIREMENTS Labor Clay Revenue PRODUCT (hr/unit) (lb/unit) ($/unit) Bowl 1 4 40 Mug 2 3 50 There are 40 hours of labor and 120 pounds of clay available each day Decision variables x1 = number of bowls to produce x2 = number of mugs to produce Supplement 14-750 14-
  • 751. LP Formulation: Example Maximize Z = $40 x1 + 50 x2 Subject to x1 + 2x2 ≤ 40 hr (labor constraint) 4x1 + 3x2 ≤ 120 lb (clay constraint) x1 , x2 ≥ 0 Solution is x1 = 24 bowls x2 = 8 mugs Revenue = $1,360 Supplement 14-751 14-
  • 752. Graphical Solution Method 1. Plot model constraint on a set of coordinates in a plane 2. Identify the feasible solution space on the graph where all constraints are satisfied simultaneously 3. Plot objective function to find the point on boundary of this space that maximizes (or minimizes) value of objective function Supplement 14-752 14-
  • 753. Graphical Solution: Example x2 50 – 40 – 4 x1 + 3 x2 ≤ 120 lb 30 – Area common to 20 – both constraints 10 – x1 + 2 x2 ≤ 40 hr | | | | | | 0– 10 20 30 40 50 60 x1 Supplement 14-753 14-
  • 754. Computing Optimal Values x1 + 2x 2 = 40 x2 4x1 + 3x 2 = 120 40 – 4 x1 + 3 x2 = 120 lb 4x1 + 8x 2 = 160 -4x1 - 3x 2 = -120 30 – 5x 2 = 40 x2 = 8 20 – x1 + 2 x2 = 40 hr x1 + 2(8) = 40 x1 = 24 10 – 8 | | 24 | | x1 0– 10 20 30 40 Z = $40(24) + $50(8) = $1,360 Supplement 14-754 14-
  • 755. Extreme Corner Points x1 = 0 bowls x2 x2 = 20 mugs Z = $1,000 x1 = 224 bowls x2 = 8 mugs 40 – Z = $1,360 x1 = 30 bowls 30 – x2 = 0 mugs Z = $1,200 A 20 – 10 – B | | | C| 0– 10 20 30 40 x1 Supplement 14-755 14-
  • 756. Objective Function x2 40 – 4x1 + 3x2 = 120 lb 3x Z = 70x1 + 20x2 70x 20x 30 – Optimal point: x1 = 30 bowls A x2 = 0 mugs 20 – Z = $2,100 B 10 – x1 + 2x2 = 40 hr 2x | | | C | 0– 10 20 30 40 x1 Supplement 14-756 14-
  • 757. Minimization Problem CHEMICAL CONTRIBUTION Brand Nitrogen (lb/bag) Phosphate (lb/bag) Gro- Gro-plus 2 4 Crop- Crop-fast 4 3 Minimize Z = $6x1 + $3x2 subject to 2x1 + 4x2 ≥ 16 lb of nitrogen 4x1 + 3x2 ≥ 24 lb of phosphate x 1, x 2 ≥ 0 Supplement 14-757 14-
  • 758. Graphical Solution x2 14 – x1 = 0 bags of Gro-plus Gro- 12 – x2 = 8 bags of Crop-fast Crop- Z = $24 10 – A 8– Z = 6x1 + 3x2 6x 3x 6– 4– B 2– C | | | | | | | 2 4 6 8 10 12 14 x1 0– Supplement 14-758 14-
  • 759. Simplex Method A mathematical procedure for solving linear programming problems according to a set of steps Slack variables added to ≤ constraints to represent unused resources x1 + 2x2 + s1 =40 hours of labor 40 4x1 + 3x2 + s2 =120 lb of clay 120 Surplus variables subtracted from ≥ constraints to represent excess above resource requirement. For example, 2x1 + 4x2 ≥ 16 is transformed into 4x 16 2x1 + 4x2 - s1 = 16 4x 16 Slack/surplus variables have a 0 coefficient in the objective function Z = $40x1 + $50x2 + 0s1 + 0s2 Supplement 14-759 14-
  • 760. Solution Points with Slack Variables Supplement 14-760 14-
  • 761. Solution Points with Surplus Variables Supplement 14-761 14-
  • 762. Solving LP Problems with Excel Supplement 14-762 14-
  • 763. Solving LP Problems with Excel (cont.) Supplement 14-763 14-
  • 764. Solving LP Problems with Excel (cont.) Supplement 14-764 14-
  • 765. Sensitivity Range for Labor Hours Supplement 14-765 14-
  • 766. Sensitivity Range for Bowls Supplement 14-766 14-
  • 767. Chapter 15 Resource Planning Operations Management Roberta Russell & Bernard W. Taylor, III
  • 768. Lecture Outline Material Requirements Planning (MRP) Capacity Requirements Planning (CRP) Enterprise Resource Planning (ERP) Customer Relationship Management (CRM) Supply Chain Management (SCM) Product Lifecycle Management (PLM) 15-768 15-
  • 770. Material Requirements Planning (MRP) Computerized inventory control and production planning system When to use MRP? Dependent demand items Discrete demand items Complex products Job shop production Assemble-to-order environments 15-770 15-
  • 771. Demand Characteristics Independent demand Dependent demand 100 x 1 = 100 tabletops 100 tables 100 x 4 = 400 table legs Continuous demand Discrete demand 400 – 400 – 300 – No. of tables 300 – No. of tables 200 – 200 – 100 – 100 – 1 2 3 4 5 Week M T W Th F M T W Th F 15-771 15-
  • 772. Material Master production Requirements schedule Planning Product Material Item structure requirements master file planning file Planned order releases Work Purchase Rescheduling orders orders notices 15-772 15-
  • 773. MRP Inputs and Outputs Inputs Outputs Master production Planned order schedule releases Product structure file Work orders Purchase orders Item master file Rescheduling notices 15-773 15-
  • 774. Master Production Schedule Drives MRP process with a schedule of finished products Quantities represent production not demand Quantities may consist of a combination of customer orders and demand forecasts Quantities represent what needs to be produced, not what can be produced Quantities represent end items that may or may not be finished products 15-774 15-
  • 775. Master Production Schedule (cont.) PERIOD MPS ITEM 1 2 3 4 5 Pencil Case 125 125 125 125 125 Clipboard 85 95 120 100 100 Lapboard 75 120 47 20 17 Lapdesk 0 50 0 50 0 15-775 15-
  • 776. Product Structure File 15-776 15-
  • 777. Product Structure Clipboard Top clip (1) Bottom clip (1) Pivot (1) Spring (1) Rivets (2) Finished clipboard Pressboard (1) 15-777 15-
  • 778. Product Structure Tree Clipboard Level 0 Pressboard Clip Ass’y Rivets Level 1 (1) (1) (2) Top Clip Bottom Clip Pivot Spring Level 2 (1) (1) (1) (1) 15-778 15-
  • 779. Multilevel Indented BOM LEVEL ITEM UNIT OF MEASURE QUANTITY 0---- Clipboard ea 1 -1--- Clip Assembly ea 1 --2-- Top Clip ea 1 --2-- Bottom Clip ea 1 --2-- Pivot ea 1 --2-- Spring ea 1 -1--- Rivet ea 2 -1--- Press Board ea 1 15-779 15-
  • 780. Specialized BOMs Phantom bills Transient subassemblies Never stocked Immediately consumed in next stage K-bills Group small, loose parts under pseudo-item pseudo- number Reduces paperwork, processing time, and file space 15-780 15-
  • 781. Specialized BOMs (cont.) Modular bills Product assembled from major subassemblies and customer options Modular bill kept for each major subassembly Simplifies forecasting and planning X10 automobile example 3 x 8 x 3 x 8 x 4 = 2,304 configurations 3 + 8 + 3 + 8 + 4 = 26 modular bills 15-781 15-
  • 782. Modular BOMs X10 Automobile Engines Exterior color Interior Interior color Body (1 of 3) (1 of 8) (1 of 3) (1 of 8) (1 of 4) 4-Cylinder (.40) Bright red (.10) Leather (.20) Grey (.10) Sports coupe (.20) 6-Cylinder (.50) White linen (.10) Tweed (.40) Light blue (.10) Two-door (.20) Two- 8-Cylinder (.10) Sulphur yellow (.10) Plush (.40) Rose (.10) Four-door (.30) Four- Neon orange (.10) Off-white (.20) Off- Station wagon (.30) Metallic blue (.10) Cool green (.10) Emerald green (.10) Black (.20) Jet black (.20) Brown (.10) Champagne (.20) B/W checked (.10) 15-782 15-
  • 783. Time-phased Bills an assembly chart shown against a time scale Forward scheduling: start at today‘s date and schedule forward to determine the earliest date the job can be finished. If each item takes one period to complete, the clipboards can be finished in three periods Backward scheduling: start at the due date and schedule backwards to determine when to begin work. If an order for clipboards is due by period three, we should start production now 15-783 15-
  • 784. Item Master File DESCRIPTION INVENTORY POLICY Item Pressboard Lead time 1 Item no. 7341 Annual demand 5000 Item type Purch Holding cost 1 Product/sales class Comp Ordering/setup cost 50 Value class B Safety stock 0 Buyer/planner RSR Reorder point 39 Vendor/drawing 07142 EOQ 316 Phantom code N Minimum order qty 100 Unit price/cost 1.25 Maximum order qty 500 Pegging Y Multiple order qty 1 LLC 1 Policy code 3 15-784 15-
  • 785. Item Master File (cont.) PHYSICAL INVENTORY USAGE/SALES On hand 150 YTD usage/sales 1100 Location W142 MTD usage/sales 75 On order 100 YTD receipts 1200 Allocated 75 MTD receipts 0 Cycle 3 Last receipt 8/25 Last count 9/5 Last issue 10/5 Difference -2 CODES Cost acct. 00754 Routing 00326 Engr 07142 15-785 15-
  • 786. MRP Processes Exploding the bill Netting of material process of subtracting on- on- Netting out inventory hand quantities and scheduled receipts from Lot sizing gross requirements to Time- Time-phasing produce net requirements requirements Lot sizing determining the quantities in which items are usually made or purchased 15-786 15-
  • 787. MRP Matrix 15-787 15-
  • 788. MRP: Example Master Production Schedule 1 2 3 4 5 Clipboard 85 95 120 100 100 Lapdesk 0 60 0 60 0 Item Master File CLIPBOARD LAPDESK PRESSBOARD On hand 25 20 150 On order 175 (Period 1) 0 0 (sch receipt) LLC 0 0 1 Lot size L4L Mult 50 Min 100 Lead time 1 1 1 15-788 15-
  • 789. MRP: Example (cont.) Product Structure Record Clipboard Level 0 Pressboard Clip Ass’y Rivets Level 1 (1) (1) (2) Lapdesk Level 0 Pressboard Trim Beanbag Glue Level 1 (2) (3’) (1) (4 oz) 15-789 15-
  • 790. MRP: Example (cont.) ITEM: CLIPBOARD LLC: 0 PERIOD LOT SIZE: L4L LT: 1 1 2 3 4 5 Gross Requirements 85 95 120 100 100 Scheduled Receipts 175 Projected on Hand 25 Net Requirements Planned Order Receipts Planned Order Releases 15-790 15-
  • 791. MRP: Example (cont.) ITEM: CLIPBOARD LLC: 0 PERIOD LOT SIZE: L4L LT: 1 1 2 3 4 5 Gross Requirements 85 95 120 100 100 Scheduled Receipts 175 Projected on Hand 25 115 Net Requirements 0 Planned Order Receipts Planned Order Releases (25 + 175) = 200 units available (200 - 85) = 115 on hand at the end of Period 1 15-791 15-
  • 792. MRP: Example (cont.) ITEM: CLIPBOARD LLC: 0 PERIOD LOT SIZE: L4L LT: 1 1 2 3 4 5 Gross Requirements 85 95 120 100 100 Scheduled Receipts 175 Projected on Hand 25 115 20 Net Requirements 0 0 Planned Order Receipts Planned Order Releases 115 units available (115 - 85) = 20 on hand at the end of Period 2 15-792 15-
  • 793. MRP: Example (cont.) ITEM: CLIPBOARD LLC: 0 PERIOD LOT SIZE: L4L LT: 1 1 2 3 4 5 Gross Requirements 85 95 120 100 100 Scheduled Receipts 175 Projected on Hand 25 115 20 0 Net Requirements 0 0 100 Planned Order Receipts 100 Planned Order Releases 100 20 units available (20 - 120) = -100 — 100 additional Clipboards are required Order must be placed in Period 2 to be received in Period 3 15-793 15-
  • 794. MRP: Example (cont.) ITEM: CLIPBOARD LLC: 0 PERIOD LOT SIZE: L4L LT: 1 1 2 3 4 5 Gross Requirements 85 95 120 100 100 Scheduled Receipts 175 Projected on Hand 25 115 20 0 0 0 Net Requirements 0 0 100 100 100 Planned Order Receipts 100 100 100 Planned Order Releases 100 100 100 Following the same logic Gross Requirements in Periods 4 and 5 develop Net Requirements, Planned Order Receipts, and Planned Order Releases 15-794 15-
  • 795. MRP: Example (cont.) ITEM: LAPDESK LLC: 0 PERIOD LOT SIZE: MULT 50 LT: 1 1 2 3 4 5 Gross Requirements 0 60 0 60 0 Scheduled Receipts Projected on Hand 20 Net Requirements Planned Order Receipts Planned Order Releases 15-795 15-
  • 796. MRP: Example (cont.) ITEM: LAPDESK LLC: 0 PERIOD LOT SIZE: MULT 50 LT: 1 1 2 3 4 5 Gross Requirements 0 60 0 60 0 Scheduled Receipts Projected on Hand 20 20 10 10 0 0 Net Requirements 0 40 50 Planned Order Receipts 50 50 Planned Order Releases 50 50 Following the same logic, the Lapdesk MRP matrix is completed as shown 15-796 15-
  • 797. MRP: Example (cont.) ITEM: CLIPBOARD LLC: 0 PERIOD LOT SIZE: L4L LT: 1 1 2 3 4 5 Planned Order Releases 100 100 100 ITEM: LAPDESK LLC: 0 PERIOD LOT SIZE: MULT 50 LT: 1 1 2 3 4 5 Planned Order Releases 50 50 ITEM: PRESSBOARD LLC: 0 PERIOD LOT SIZE: MIN 100 LT: 1 1 2 3 4 5 Gross Requirements Scheduled Receipts Projected on Hand 150 Net Requirements Planned Order Receipts Planned Order Releases 15-797 15-
  • 798. MRP: Example (cont.) ITEM: CLIPBOARD LLC: 0 PERIOD LOT SIZE: L4L LT: 1 1 2 3 4 5 Planned Order Releases 100 100 100 ITEM: LAPDESK LLC: 0 x1 x1 PERIOD x1 LOT SIZE: MULT 50 LT: 1 1 2 3 4 5 Planned Order Releases 50 50 x2 ITEM: PRESSBOARD LLC: 0 x2 PERIOD LOT SIZE: MIN 100 LT: 1 1 2 3 4 5 Gross Requirements 100 100 200 100 0 Scheduled Receipts Projected on Hand 150 Net Requirements Planned Order Receipts Planned Order Releases 15-798 15-
  • 799. MRP: Example (cont.) ITEM: CLIPBOARD LLC: 0 PERIOD LOT SIZE: L4L LT: 1 1 2 3 4 5 Planned Order Releases 100 100 100 ITEM: LAPDESK LLC: 0 PERIOD LOT SIZE: MULT 50 LT: 1 1 2 3 4 5 Planned Order Releases 50 50 ITEM: PRESSBOARD LLC: 0 PERIOD LOT SIZE: MIN 100 LT: 1 1 2 3 4 5 Gross Requirements 100 100 200 100 0 Scheduled Receipts Projected on Hand 150 50 50 0 0 0 Net Requirements 50 150 100 Planned Order Receipts 100 150 100 Planned Order Releases 100 150 100 15-799 15-
  • 800. MRP: Example (cont.) Planned Order Report PERIOD ITEM 1 2 3 4 5 Clipboard 100 100 100 Lapdesk 50 50 Pressboard 100 150 100 15-800 15-
  • 801. Lot Sizing in MRP Systems Lot-for-lot ordering policy Fixed-size lot ordering policy Minimum order quantities Maximum order quantities Multiple order quantities Economic order quantity Periodic order quantity 15-801 15-
  • 802. Using Excel for MRP Calculations 15-802 15-
  • 803. Advanced Lot Sizing Rules: L4L Total cost of L4L = (4 X $60) + (0 X $1) = $240 15-803 15-
  • 804. Advanced Lot Sizing Rules: EOQ 2(30)(60 EO Q = = 60 minimum order quantity 1 Total cost of EOQ = (2 X $60) + [(10 + 50 + 40) X $1)] = $220 15-804 15-
  • 805. Advanced Lot Sizing Rules: POQ POQ = Q / d = 60 / 30 = 2 periods worth of requirements Total cost of POQ = (2 X $60) + [(20 + 40) X $1] = $180 15-805 15-
  • 806. Planned Order Report Item #2740 Date 9 - 25 - 05 On hand 100 Lead time 2 weeks On order 200 Lot size 200 Allocated 50 Safety stock 50 SCHEDULED PROJECTED DATE ORDER NO. GROSS REQS. RECEIPTS ON HAND ACTION 50 9-26 AL 4416 25 25 9-30 AL 4174 25 0 10-01 10- GR 6470 50 - 50 10-08 10- SR 7542 200 150 Expedite SR 10-01 10- 10-10 10- CO 4471 75 75 10-15 10- GR 6471 50 25 10-23 10- GR 6471 25 0 10-27 10- GR 6473 50 - 50 Release PO 10-13 10- Key: AL = allocated WO = work order CO = customer order SR = scheduled receipt PO = purchase order GR = gross requirement 15-806 15-
  • 807. MRP Action Report Current date 9-25-08 9-25- ITEM DATE ORDER NO. QTY. ACTION #2740 10-08 10- 7542 200 Expedite SR 10-01 10- #3616 10-09 10- Move forward PO 10-07 10- #2412 10-10 10- Move forward PO 10-05 10- #3427 10-15 10- Move backward PO 10-25 10- #2516 10-20 10- 7648 100 De-expedite De- SR 10-30 10- #2740 10-27 10- 200 Release PO 10-13 10- #3666 10-31 10- 50 Release WO 10-24 10- 15-807 15-
  • 808. Capacity Requirements Planning (CRP) Creates a load profile Identifies under-loads and over-loads Inputs Planned order releases Routing file Open orders file 15-808 15-
  • 809. CRP MRP planned order releases Capacity Open Routing requirements orders file planning file Load profile for each process 15-809 15-
  • 810. Calculating Capacity Maximum capability to produce Rated Capacity Theoretical output that could be attained if a process were operating at full speed without interruption, exceptions, or downtime Effective Capacity Takes into account the efficiency with which a particular product or customer can be processed and the utilization of the scheduled hours or work Effective Daily Capacity = (no. of machines or workers) x (hours per shift) x (no. of shifts) x (utilization) x ( efficiency) 15-810 15-
  • 811. Calculating Capacity (cont.) Utilization Percent of available time spent working Efficiency How well a machine or worker performs compared to a standard output level Load Standard hours of work assigned to a facility Load Percent Ratio of load to capacity load Load Percent = x 100% capacity 15-811 15-
  • 812. Load Profiles graphical comparison of load versus capacity Leveling underloaded conditions: Acquire more work Pull work ahead that is scheduled for later time periods Reduce normal capacity 15-812 15-
  • 813. Reducing Over-load Conditions Over- 1. Eliminating unnecessary requirements 2. Rerouting jobs to alternative machines, workers, or work centers 3. Splitting lots between two or more machines 4. Increasing normal capacity 5. Subcontracting 6. Increasing efficiency of the operation 7. Pushing work back to later time periods 8. Revising master schedule 15-813 15-
  • 814. Initial Load Profile 120 – 110 – 100 – Hours of capacity 90 – 80 – 70 – 60 – 50 – 40 – Normal capacity 30 – 20 – 10 – 0– 1 2 3 4 5 6 Time (weeks) 15-814 15-
  • 815. Adjusted Load Profile 120 – 110 – 100 – Hours of capacity 90 – 80 – 70 – Work an 60 – extra Push back Pull ahead 50 – shift Overtime Push back Normal 40 – capacity 30 – 20 – 10 – 0– 1 2 3 4 5 6 Time (weeks) Load leveling process of balancing underloads and overloads 15-815 15-
  • 816. Relaxing MRP Assumptions Material is not always the most constraining resource Lead times can vary Not every transaction needs to be recorded Shop floor may require a more sophisticated scheduling system Scheduling in advance may not be appropriate for on-demand production. 15-816 15-
  • 817. Enterprise Resource Planning (ERP) Software that organizes and manages a company’s business processes by sharing information across functional areas integrating business processes facilitating customer interaction providing benefit to global companies 15-817 15-
  • 818. Organizational Data Flows Source: Adapted from Joseph Brady, Ellen Monk, and Bret Wagner, Concepts in Enterprise Resource Planning (Boston: Course Technology, 2001), pp. 7–12 15-818 15-
  • 821. ERP Implementation Analyze business processes Choose modules to implement Which processes have the biggest impact on customer relations? Which process would benefit the most from integration? Which processes should be standardized? Align level of sophistication Finalize delivery and access Link with external partners 15-821 15-
  • 822. Customer Relationship Management (CRM) Software that Plans and executes business processes Involves customer interaction Changes focus from managing products to managing customers Analyzes point-of-sale data for patterns point-of- used to predict future behavior 15-822 15-
  • 823. Supply Chain Management Software that plans and executes business processes related to supply chains Includes Supply chain planning Supply chain execution Supplier relationship management Distinctions between ERP and SCM are becoming increasingly blurred 15-823 15-
  • 824. Product Lifecycle Management (PLM) Software that Incorporates new product design and development and product life cycle management Integrates customers and suppliers in the design process though the entire product life cycle 15-824 15-
  • 825. ERP and Software Systems 15-825 15-
  • 826. Connectivity Application programming interfaces (APIs) give other programs well-defined ways of speaking to well- them Enterprise Application Integration (EAI) solutions EDI is being replaced by XML, business language of Internet Service- Service-oriented architecture (SOA) collection of “services” that communicate with each other within software or between software 15-826 15-
  • 827. Chapter 16 Lean Systems Operations Management Roberta Russell & Bernard W. Taylor, III
  • 828. Lecture Outline Basic Elements of Lean Production Benefits of Lean Production Implementing Lean Production Lean Services Leaning the Supply Chain Lean Six Sigma Lean and the Environment Lean Consumption 16-828 16-
  • 829. Lean Production Doing more with less inventory, fewer workers, less space Just-in-time (JIT) smoothing the flow of material to arrive just as it is needed “JIT” and “Lean Production” are used interchangeably Muda waste, anything other than that which adds value to product or service 16-829 16-
  • 830. Waste in Operations 16-830 16-
  • 831. Waste in Operations (cont.) 16-831 16-
  • 832. Waste in Operations (cont.) 16-832 16-
  • 833. Basic Elements 1. Flexible resources 2. Cellular layouts 3. Pull system 4. Kanbans 5. Small lots 6. Quick setups 7. Uniform production levels 8. Quality at the source 9. Total productive maintenance 10. Supplier networks 16-833 16-
  • 834. Flexible Resources Multifunctional workers perform more than one job general-purpose machines perform several basic functions Cycle time time required for the worker to complete one pass through the operations assigned Takt time paces production to customer demand 16-834 16-
  • 835. Standard Operating Routine for a Worker 16-835 16-
  • 836. Cellular Layouts Manufacturing cells comprised of dissimilar machines brought together to manufacture a family of parts Cycle time is adjusted to match takt time by changing worker paths 16-836 16-
  • 837. Cells with Worker Routes 16-837 16-
  • 838. Worker Routes Lengthen as Volume Decreases 16-838 16-
  • 839. Pull System Material is pulled through the system when needed Reversal of traditional push system where material is pushed according to a schedule Forces cooperation Prevent over and underproduction While push systems rely on a predetermined schedule, pull systems rely on customer requests 16-839 16-
  • 840. Kanbans Card which indicates standard quantity of production Derived from two-bin inventory system two- Maintain discipline of pull production Authorize production and movement of goods 16-840 16-
  • 841. Sample Kanban 16-841 16-
  • 842. Origin of Kanban a) Two-bin inventory system Two- b) Kanban inventory system Bin 1 Kanban Bin 2 Reorder card Q-R R R Q = order quantity R = reorder point - demand during lead time 16-842 16-
  • 843. Types of Kanban Production kanban Signal kanban authorizes production of a triangular kanban goods used to signal Withdrawal kanban production at the previous workstation authorizes movement of goods Material kanban Kanban square used to order material in a marked area designated advance of a process to hold items Supplier kanban rotates between the factory and suppliers 16-843 16-
  • 847. Determining Number of Kanbans average demand during lead time + safety stock No. of Kanbans = container size dL + S N = C where N = number of kanbans or containers d = average demand over some time period L = lead time to replenish an order S = safety stock C = container size 16-847 16-
  • 848. Determining Number of Kanbans: Example d = 150 bottles per hour L = 30 minutes = 0.5 hours S = 0.10(150 x 0.5) = 7.5 C = 25 bottles dL + S (150 x 0.5) + 7.5 N= = C 25 = 75 + 7.5 = 3.3 kanbans or containers 25 Round up to 4 (to allow some slack) or down to 3 (to force improvement) 16-848 16-
  • 849. Small Lots Require less space and capital investment Move processes closer together Make quality problems easier to detect Make processes more dependent on each other 16-849 16-
  • 851. Less Inventory Exposes Problems 16-851 16-
  • 852. Components of Lead Time Processing time Reduce number of items or improve efficiency Move time Reduce distances, simplify movements, standardize routings Waiting time Better scheduling, sufficient capacity Setup time Generally the biggest bottleneck 16-852 16-
  • 853. Quick Setups Internal setup SMED Principles Separate internal setup from Can be performed external setup only when a process is stopped Convert internal setup to external setup External setup Streamline all aspects of setup Can be performed Perform setup activities in in advance parallel or eliminate them entirely 16-853 16-
  • 854. Common Techniques for Reducing Setup Time 16-854 16-
  • 855. Common Techniques for Reducing Setup Time (cont.) 16-855 16-
  • 856. Common Techniques for Reducing Setup Time (cont.) 16-856 16-
  • 857. Uniform Production Levels Result from smoothing production requirements on final assembly line Kanban systems can handle +/- 10% +/- demand changes Reduce variability with more accurate forecasts Smooth demand across planning horizon Mixed- Mixed-model assembly steadies component production 16-857 16-
  • 859. Quality at the Source Visual control Jidoka makes problems visible authority to stop the production line Poka-yokes Andons call lights that signal prevent defects from quality problems occurring Kaizen Under-capacity a system of continuous scheduling improvement; “change for leaves time for planning, the good of all” problem solving, and maintenance 16-859 16-
  • 861. Examples of Visual Control (cont.) 16-861 16-
  • 862. Examples of Visual Control (cont.) 16-862 16-
  • 863. 5 Whys One of the keys to an effective Kaizen is finding the root cause of a problem and eliminating it A practice of asking “why?” repeatedly until the underlying cause is identified (usually requiring five questions) Simple, yet powerful technique for finding the root cause of a problem 16-863 16-
  • 864. Total Productive Maintenance (TPM) Breakdown maintenance Repairs to make failed machine operational Preventive maintenance System of periodic inspection and maintenance to keep machines operating TPM combines preventive maintenance and total quality concepts 16-864 16-
  • 865. TPM Requirements Design products that can be easily produced on existing machines Design machines for easier operation, changeover, maintenance Train and retrain workers to operate machines Purchase machines that maximize productive potential Design preventive maintenance plan spanning life of machine 16-865 16-
  • 866. 5S Scan Goal Eliminate or Correct Seiri(sort) Keep only what you Unneeded equipment, tools, furniture; need unneeded items on walls, bulletins; items blocking aisles or stacked in corners; unneeded inventory, supplies, parts; safety hazards A place for Items not in their correct places; correct places Seiton(set in order) everything and not obvious; aisles, workstations, & equipment everything in its locations not indicated; items not put away place immediately after use Seisou (shine) Cleaning, and looking Floors, walls, stairs, equipment, & surfaces not for ways to keep clean; cleaning materials not easily clean and organized accessible; lines, labels, signs broken or unclean; other cleaning problems Seiketsu Maintaining and Necessary information not visible; standards monitoring the first not known; checklists missing; quantities and (standardize) three categories limits not easily recognizable; items can’t be Sticking to the rules located within 30 seconds Number of workers without 5S training; number Shisuke (sustain) of daily 5S inspections not performed; number of personal items not stored; number of times job aids not available or up-to-date 16-866 16-
  • 867. Supplier Networks Long-term supplier contracts Synchronized production Supplier certification Mixed loads and frequent deliveries Precise delivery schedules Standardized, sequenced delivery Locating in close proximity to the customer 16-867 16-
  • 868. Benefits of Lean Production Reduced inventory Improved quality Lower costs Reduced space requirements Shorter lead time Increased productivity 16-868 16-
  • 869. Benefits of Lean Production (cont.) Greater flexibility Better relations with suppliers Simplified scheduling and control activities Increased capacity Better use of human resources More product variety 16-869 16-
  • 870. Implementing Lean Production Use lean production to finely tune an operating system Somewhat different in USA than Japan Lean production is still evolving Lean production is not for everyone 16-870 16-
  • 871. Lean Services Basic elements of lean production apply equally to services Most prevalent applications lean retailing lean banking lean health care 16-871 16-
  • 872. Leaning the Supply Chain “pulling” a smooth flow of material through a series of suppliers to support frequent replenishment orders and changes in customer demand Firms need to share information and coordinate demand forecasts, production planning, and inventory replenishment with suppliers and supplier’s suppliers throughout supply chain 16-872 16-
  • 873. Leaning the Supply Chain (cont.) Steps in Leaning the Supply Chain: Build a highly collaborative business environment Adopt the technology to support your system 16-873 16-
  • 874. Lean Six Sigma Lean and Six Sigma are natural partners for process improvement Lean Eliminates waste and creates flow More continuous improvement Six Sigma Reduces variability and enhances process capabilities Requires breakthrough improvements 16-874 16-
  • 875. Lean and the Environment Lean’s mandate to eliminate waste and operate only with those resources that are absolutely necessary aligns well with environmental initiatives Environmental waste is often an indicator of poor process design and inefficient production 16-875 16-
  • 876. EPA Recommendations Commit to eliminate environmental waste through lean implementation Recognize new improvement opportunities by incorporating environmental, heath and safety (EHS) icons and data into value stream maps Involve staff with EHS expertise in planning Find and drive out environmental wastes in specific process by using lean process-improvement tools process- Empower and enable workers to eliminate environmental wastes in their work areas 16-876 16-
  • 877. Lean Consumption Consumptions process involves locating, buying, installing, using, maintaining, repairing, and recycling. Lean Consumption seeks to: Provide customers what they want, where and when they want it Resolve customer problems quickly and completely Reduce the number of problems customers need to solve 16-877 16-
  • 878. Chapter 17 Scheduling Operations Management Roberta Russell & Bernard W. Taylor, III
  • 879. Lecture Outline Objectives in Scheduling Loading Sequencing Monitoring Advanced Planning and Scheduling Systems Theory of Constraints Employee Scheduling 17-879 17-
  • 880. What is Scheduling? Last stage of planning before production occurs Specifies when labor, equipment, and facilities are needed to produce a product or provide a service 17-880 17-
  • 881. Scheduled Operations Process Industry Batch Production Linear programming Aggregate planning EOQ with non-instantaneous non- replenishment Master scheduling Mass Production Material requirements Assembly line balancing planning (MRP) Project Capacity requirements Project -scheduling planning (CRP) techniques (PERT, CPM) 17-881 17-
  • 882. Objectives in Scheduling Meet customer due Minimize overtime dates Maximize machine or Minimize job lateness labor utilization Minimize response time Minimize idle time Minimize completion Minimize work-in- work-in- time process inventory Minimize time in the system 17-882 17-
  • 883. Shop Floor Control (SFC) scheduling and monitoring of day-to-day production day-to- in a job shop also called production control and production activity control (PAC) usually performed by production control department Loading Check availability of material, machines, and labor Sequencing Release work orders to shop and issue dispatch lists for individual machines Monitoring Maintain progress reports on each job until it is complete 17-883 17-
  • 884. Loading Process of assigning work to limited resources Perform work with most efficient resources Use assignment method of linear programming to determine allocation 17-884 17-
  • 885. Assignment Method 1. Perform row reductions 4. If number of lines equals number subtract minimum value in each of rows in matrix, then optimum row from all other row values solution has been found. Make 2. Perform column reductions assignments where zeros appear subtract minimum value in each Else modify matrix column from all other column subtract minimum uncrossed value values from all uncrossed values add it to all cells where two lines 3. Cross out all zeros in matrix intersect use minimum number of other values in matrix remain horizontal and vertical lines unchanged 5. Repeat steps 3 and 4 until optimum solution is reached 17-885 17-
  • 886. Assignment Method: Example Initial PROJECT Matrix 1 2 3 4 Bryan 10 5 6 10 Kari 6 2 4 6 Noah 7 6 5 6 Chris 9 5 4 10 Row reduction Column reduction Cover all zeros 5 0 1 5 3 0 1 4 3 0 1 4 4 0 2 4 2 0 2 3 2 0 2 3 2 1 0 1 0 1 0 0 0 1 0 0 5 1 0 6 3 1 0 5 3 1 0 5 Number lines ≠ number of rows so modify matrix 17-886 17-
  • 887. Assignment Method: Example (cont.) Modify matrix Cover all zeros 1 0 1 2 1 0 1 2 0 0 2 1 0 0 2 1 0 3 2 0 0 3 2 0 1 1 0 3 1 1 0 3 Number of lines = number of rows so at optimal solution PROJECT PROJECT 1 2 3 4 1 2 3 4 Bryan 1 0 1 2 Bryan 10 5 6 10 Kari 0 0 2 1 Kari 6 2 4 6 Noah 0 3 2 0 Noah 7 6 5 6 Chris 1 1 0 3 Chris 9 5 4 10 Project Cost = (5 + 6 + 4 + 6) X $100 = $2,100 17-887 17-
  • 888. Sequencing Prioritize jobs assigned to a resource If no order specified use first-come first-served (FCFS) Other Sequencing Rules FCFS - first-come, first-served LCFS - last come, first served DDATE - earliest due date CUSTPR - highest customer priority SETUP - similar required setups SLACK - smallest slack CR - smallest critical ratio SPT - shortest processing time LPT - longest processing time 17-888 17-
  • 889. Minimum Slack and Smallest Critical Ratio SLACK considers both work and time remaining SLACK = (due date – today’s date) – (processing time) CR recalculates sequence as processing continues and arranges information in ratio form time remaining due date - today’s date CR = remaining work = remaining processing time If CR > 1, job ahead of schedule If CR < 1, job behind schedule If CR = 1, job on schedule 17-889 17-
  • 890. Sequencing Jobs through One Process Flow time (completion time) Time for a job to flow through system Makespan Time for a group of jobs to be completed Tardiness Difference between a late job’s due date and its completion time 17-890 17-
  • 891. Simple Sequencing Rules PROCESSING DUE JOB TIME DATE A 5 10 B 10 15 C 2 5 D 8 12 E 6 8 17-891 17-
  • 892. Simple Sequencing Rules: FCFS FCFS START PROCESSING COMPLETION DUE SEQUENCE TIME TIME TIME DATE TARDINESS A 0 5 5 10 0 B 5 10 15 15 0 C 15 2 17 5 12 D 17 8 25 12 13 E 25 6 31 8 23 Total 93 48 Average 93/5 = 18.60 48/5 = 9.6 17-892 17-
  • 893. Simple Sequencing Rules: DDATE DDATE START PROCESSING COMPLETION DUE SEQUENCE TIME TIME TIME DATE TARDINESS C 0 2 2 5 0 E 2 6 8 8 0 A 8 5 13 10 3 D 13 8 21 12 9 B 21 10 31 15 16 Total 75 28 Average 75/5 = 15.00 28/5 = 5.6 17-893 17-
  • 894. Simple Sequencing A(10-0) – 5 = 5 B(15-0) – 10 = 5 Rules: SLACK C(5-0) – 2 = 3 D(12-0) – 8 = 4 E(8-0) – 6 = 2 SLACK START PROCESSING COMPLETION DUE SEQUENCE TIME TIME TIME DATE TARDINESS E 0 6 6 8 0 C 6 2 8 5 3 D 8 8 16 12 4 A 16 5 21 10 11 B 21 10 31 15 16 Total 82 34 Average 82/5 = 16.40 34/5 = 6.8 17-894 17-
  • 895. Simple Sequencing Rules: SPT SPT START PROCESSING COMPLETION DUE SEQUENCE TIME TIME TIME DATE TARDINESS C 0 2 2 5 0 A 2 5 7 10 0 E 7 6 13 8 5 D 13 8 21 12 9 B 21 10 31 15 16 Total 74 30 Average 74/5 = 14.80 30/5 = 6 17-895 17-
  • 896. Simple Sequencing Rules: Summary AVERAGE AVERAGE NO. OF MAXIMUM RULE COMPLETION TIME TARDINESS JOBS TARDY TARDINESS FCFS 18.60 9.6 3 23 DDATE 15.00 5.6 3 16 SLACK 16.40 6.8 4 16 SPT 14.80 6.0 3 16 17-896 17-
  • 897. Sequencing Jobs Through Two Serial Process Johnson’s Rule 1. List time required to process each job at each machine. Set up a one-dimensional matrix to represent desired one- sequence with # of slots equal to # of jobs. 2. Select smallest processing time at either machine. If that time is on machine 1, put the job as near to beginning of sequence as possible. 3. If smallest time occurs on machine 2, put the job as near to the end of the sequence as possible. 4. Remove job from list. 5. Repeat steps 2-4 until all slots in matrix are filled and all 2- jobs are sequenced. 17-897 17-
  • 898. Johnson’s Rule JOB PROCESS 1 PROCESS 2 A 6 8 B 11 6 C 7 3 D 9 7 E 5 10 E A D B C 17-898 17-
  • 899. Johnson’s Rule (cont.) E A D B C E A D B C Process 1 (sanding) 5 11 20 31 38 Idle time E A D B C Process 2 (painting) 5 15 23 30 37 41 Completion time = 41 Idle time = 5+1+1+3=10 17-899 17-
  • 900. Guidelines for Selecting a Sequencing Rule 1. SPT most useful when shop is highly congested 2. Use SLACK for periods of normal activity 3. Use DDATE when only small tardiness values can be tolerated 4. Use LPT if subcontracting is anticipated 5. Use FCFS when operating at low-capacity levels low- 6. Do not use SPT to sequence jobs that have to be assembled with other jobs at a later date 17-900 17-
  • 901. Monitoring Work package Shop paperwork that travels with a job Gantt Chart Shows both planned and completed activities against a time scale Input/Output Control Monitors the input and output from each work center 17-901 17-
  • 902. Gantt Chart Job 32B 3 Behind schedule Job 23C Facility 2 Ahead of schedule Job 11C Job 12A 1 On schedule 1 2 3 4 5 6 8 9 10 11 12 Days Today’s Date Key: Planned activity Completed activity 17-902 17-
  • 903. Input/Output Control Input/Output Report PERIOD 1 2 3 4 TOTAL Planned input 65 65 70 70 270 Actual input 0 Deviation 0 Planned output 75 75 75 75 300 Actual output 0 Deviation 0 Backlog 30 20 10 5 0 17-903 17-
  • 904. Input/Output Control (cont.) Input/Output Report PERIOD 1 2 3 4 TOTAL Planned input 65 65 70 70 270 Actual input 60 60 65 65 250 Deviation -5 -5 -5 -5 -20 Planned output 75 75 75 75 300 Actual output 75 75 65 65 280 Deviation -0 -0 -10 -10 -20 Backlog 30 15 0 0 0 17-904 17-
  • 905. Advanced Planning and Scheduling Systems Infinite - assumes infinite capacity Loads without regard to capacity Then levels the load and sequences jobs Finite - assumes finite (limited) capacity Sequences jobs as part of the loading decision Resources are never loaded beyond capacity 17-905 17-
  • 906. Advanced Planning and Scheduling Systems (cont.) Advanced planning and scheduling (APS) Add-ins to ERP systems Add- Constraint- Constraint-based programming (CBP) identifies a solution space and evaluates alternatives Genetic algorithms based on natural selection properties of genetics Manufacturing execution system (MES) monitors status, usage, availability, quality 17-906 17-
  • 907. Theory of Constraints Not all resources are used evenly Concentrate on the” bottleneck” resource Synchronize flow through the bottleneck Use process and transfer batch sizes to move product through facility 17-907 17-
  • 908. Drum-Buffer-Rope Drum Bottleneck, beating to set the pace of production for the rest of the system Buffer Inventory placed in front of the bottleneck to ensure it is always kept busy Determines output or throughput of the system Rope Communication signal; tells processes upstream when they should begin production 17-908 17-
  • 909. TOC Scheduling Procedure Identify bottleneck Schedule job first whose lead time to bottleneck is less than or equal to bottleneck processing time Forward schedule bottleneck machine Backward schedule other machines to sustain bottleneck schedule Transfer in batch sizes smaller than process batch size 17-909 17-
  • 910. A B C D B3 1 7 C3 2 15 D3 3 5 B2 2 3 C2 1 10 D2 2 8 B1 1 5 C1 3 2 D1 3 10 Key: i Item i Synchronous ij k l Operation j of item i performed at machine center k takes l minutes Manufacturing to process 17-910 17-
  • 911. Synchronous Manufacturing (cont.) Demand = 100 A’s Machine setup time = 60 minutes MACHINE 1 MACHINE 2 MACHINE 3 B1 5 B2 3 C1 2 B3 7 C3 15 D3 5 C2 10 D2 8 D1 10 Sum 22 26* 17 * Bottleneck 17-911 17-
  • 912. Synchronous Manufacturing (cont.) Machine 1 Setup Setup C2 B1 B3 2 1002 1562 2322 Idle Machine 2 Setup Setup C3 B2 D2 12 1512 1872 2732 Machine 3 Setup Setup C1 D1 Idle D3 0 200 1260 1940 Completion 2737 time 17-912 17-
  • 913. Employee Scheduling Labor is very flexible resource Scheduling workforce is complicated, repetitive task Assignment method can be used Heuristics are commonly used 17-913 17-
  • 914. Employee Scheduling Heuristic 1. Let N = no. of workers available Di = demand for workers on day i X = day working O = day off 2. Assign the first N - D1 workers day 1 off. Assign the next N - D2 workers day 2 off. Continue in a similar manner until all days are have been scheduled 3. If number of workdays for full time employee < 5, assign remaining workdays so consecutive days off are possible 4. Assign any remaining work to part-time employees part- 5. If consecutive days off are desired, consider switching schedules among days with the same demand requirements 17-914 17-
  • 915. Employee Scheduling DAY OF WEEK M T W TH F SA SU MIN NO. OF WORKERS REQUIRED 3 3 4 3 4 5 3 Taylor Smith Simpson Allen Dickerson 17-915 17-
  • 916. Employee Scheduling (cont.) DAY OF WEEK M T W TH F SA SU MIN NO. OF WORKERS REQUIRED 3 3 4 3 4 5 3 Taylor O X X O X X X Smith O X X O X X X Simpson X O X X O X X Allen X O X X X X O Dickerson X X O X X X O Completed schedule satisfies requirements but has no consecutive days off 17-916 17-
  • 917. Employee Scheduling (cont.) DAY OF WEEK M T W TH F SA SU MIN NO. OF WORKERS REQUIRED 3 3 4 3 4 5 3 Taylor O O X X X X X Smith O O X X X X X Simpson X X O O X X X Allen X X X O X X O Dickerson X X X X O X O Revised schedule satisfies requirements with consecutive days off for most employees 17-917 17-
  • 918. Automated Scheduling Systems Staff Scheduling Schedule Bidding Schedule Optimization 17-918 17-
  • 919. Thank You www.bookfiesta4u.com 2-919