Unit 2 manufacturing system design

Production planning
Definition
Production planning is defined as the determination, acquisition, and
arrangement of all facilities necessary for future production of products.
Objectives of production planning
• To determine from sales forecasts and engineering information, the kind of
materials ,machines, tools, buildings, methods and labour necessary in the
proper quantities and qualities, when and as required, to produce the
desired goods in the most economical manner.
• To make all preparation for manufacturing necessary to reach the
production goals established in the production budget and master schedule
and by the fluctuating demand of the customers.

Production planning
Levels of production planning
1.Factory planning
2.Process planning
3.Operation planning
 Factory planning
The sequence of work tasks is planned in terms of building, machines and equipment
required for manufacturing the desired goods and services.
 Process planning
The many operations involved in factory planning are located and the sequence of these
operations in production process is determined.
 Operation planning
The details of the methods required to preform each operation and the sequence of work
elements involved in each operation are planned.
Factors determining production planning
1.Volume of production
2.Nature of production processes and operations

Production control
Principle
Production control through control mechanism, tries to take
corrective action to match the planned and actual
production. the production control reviews the progress of
the work, and takes corrective steps in order to ensure that
programmed production takes place.
Objectives of production control
• To implement the production plans into effect by issuing
the necessary orders to the right persons through the
proper channels.
• To provide for optimum utilisation of all resources.
• To achieve the broad objectives of low cost of production
and reliable customer services.

Production control
Factors determining the production control
1.Nature of production
2.Complexity of operation
3.Magnitude of operation
Scope of production control
• Control of tooling
• Control of materials
• Control of manufacturing capacity
• Control of activities
• Control of quantity
• Control of material handling
• Control of due dates
• Control of information
• Control of quality
• control of planning

Production control
Phases of production planning and control
Pre-planning phase
Pre-planning is a macro-level planning, and deals with analysis of data is an outline of the
basis planning policy based on forecasted demand, market analysis, and product design
and development.
Pre-planning is concerned with decision making and data collection on the material,
methods, machines, and manpower.
Planning phase
The more detailed, realistic, and precise the planning, the greater conformity to schedules
achieved during production, and subsequently the greater the efficiency of the plant.
The planning has two types such as short term planning and long term planning are during
this phase.
Control phase
The final phase of ppc is the control phase .this stage involves dispatching, inspection,
expediting and evaluation.
The control phase provides the main sources of feedback information to ensure necessary
corrective actions.

Functions of ppc
Materials planning
This material planning function also covers fixation of materials
standard, batch quantities, delivery dates, standardisation and
reduction of varieties, procurement of parts and raw materials and
inspection of materials and finished parts.
Methods planning
This function also covers both the general study and selection of
production process which in turn requires a series of decision making
encompassing the theoretical feasibility of manufacturing the parts.
Facility planning
This function is mainly concerned with the detailed analysis of
available production facilities, equipment down time, maintenance
policy procedure and schedules.
Process planning
It is also known as routing, is the process of determining the sequence
of operations to be performed in the production process.

Function of ppc
Estimating
This function involves the extensive use of operation analysis in
conjunction with methods and routing as well as work measurement in
order to set up performance standards.
Scheduling
It involves fixing priorities for each job and determining the starting
time and finishing time for each operation, the starting dates and
finishing dates for each part, sub-assembly and final assembly.
Loading
It is also known as machine loading, is the process of assigning
specific jobs to machine, men or work centres based on relative
priorities and capacity utilisation.
Dispatching
It is the routine of setting production activities in motion through the
release of orders and instructions in accordance with the previously
planned time schedules and ratings.

Function of ppc
Expediting
It is also known as follow-up or progressing, is a control function
that keeps track of the progress of work in accordance with
planned schedule.
Inspection and testing
Inspection and quantity control is another major function of
production planning and control, this ensures that the quality of
the product meets the specifications as ordered, or decided in
product development and design stage.
Evaluation
This function gathered can be used in preplanning, planning and
control stages in future manufacturing activities. variable
information regarding all the problems faced realizing the
product starting from preplanning to shipping stages is gathered
in this process

Forecasting
Principle
Many types of forecasting models that differ in
complexity and amount of data & way they
generate forecasts:
1. Forecasts are rarely perfect
2. Forecasts are more accurate for grouped data than
for individual items
3. Forecast are more accurate for shorter than longer
time periods
Types of methods
Qualitative methods – judgmental methods
• Forecasts generated subjectively by the forecaster
• Educated guesses
Quantitative methods – based on mathematical modeling:
• Forecasts generated through mathematical modeling

Forecasting methods
Qualitative Methods
Type Characteristics Strengths Weaknesses
Executive
opinion
A group of managers
meet & come up with
a forecast
Good for strategic or
new-product
forecasting
One person's opinion
can dominate the
forecast
Market
research
Uses surveys &
interviews to identify
customer preferences
Good determinant of
customer preferences
It can be difficult to
develop a good
questionnaire
Delphi
method
Seeks to develop a
consensus among a
group of experts
Excellent for
forecasting long-term
product demand,
technological
changes, and
Time consuming to
develop

Forecasting methods
Quantitative Methods
Time Series Models:
• Assumes information needed to generate a forecast is contained in a time
series of data
• Assumes the future will follow same patterns as the past
Causal Models or Associative Models
• Explores cause-and-effect relationships
• Uses leading indicators to predict the future
• Housing starts and appliance sales

Time series models
Forecaster looks for data patterns as
• Data = historic pattern + random variation
Historic pattern to be forecasted:
• Level (long-term average) – data fluctuates around a constant mean
• Trend – data exhibits an increasing or decreasing pattern
• Seasonality – any pattern that regularly repeats itself and is of a constant
length
• Cycle – patterns created by economic fluctuations
Random Variation cannot be predicted
Naive:
• The forecast is equal to the actual value observed during the last period – good
for level patterns
Simple Mean:
• The average of all available data - good for level patterns
Moving Average:
• The average value over a set time period
(e.g.: the last four weeks)
• Each new forecast drops the oldest data point & adds a new observation
• More responsive to a trend but still lags behind actual data

Time series model
Weighted Moving Average:
• All weights must add to 100% or 1.00
e.g. Ct .5, Ct-1 .3, Ct-2 .2 (weights add to 1.0)
• Allows emphasizing one period over others; above indicates more weight on recent data
(Ct=.5)
• Differs from the simple moving average that weighs all periods equally - more responsive to
trends
Exponential Smoothing:
Most frequently used time series method because of ease
of use and minimal amount of data needed
• Need just three pieces of data to start:
• Last period’s forecast (Ft)
• Last periods actual value (At)
• Select value of smoothing coefficient, ,between 0 and 1.0
• If no last period forecast is available, average the last few
periods or use naive method
• Higher values (e.g. .7 or .8) may place too much weight
on last period’s random variation

Other models
Linear Trend Line
A time series technique that computes a forecast with trend by drawing a straight line
through a set of data using this formula:
Y = a + bx where
Y = forecast for period X
X = the number of time periods from X = 0
A = value of y at X = 0 (Y intercept)
B = slope of the line
Forecasting Seasonality
Calculate the average demand per season
• E.g.: average quarterly demand
Calculate a seasonal index for each season of each year:
• Divide the actual demand of each season by the average demand per
season for that year
Average the indexes by season
• E.g.: take the average of all Spring indexes, then of all Summer indexes, ...

Other models
Causal Models
• Often, leading indicators can help to predict changes
in future demand e.g. housing starts
• Causal models establish a cause-and-effect
relationship between independent and dependent
variables
• A common tool of causal modeling is linear
regression:
• Additional related variables may require multiple
regression modeling
Linear Regression

Other models
Multiple Regression
An extension of linear regression but:
• Multiple regression develops a relationship between a dependent variable and multiple
independent variables. The general formula is:
Measuring Forecast Error
• Forecasts are never perfect
• Need to know how much we should rely on our chosen
forecasting method
• Measuring forecast error
• Note that over-forecasts = negative errors and under-forecasts
= positive errors
Measuring Forecasting Accuracy
Mean Absolute Deviation (MAD)
• measures the total error in a forecast without regard to sign
Cumulative Forecast Error (CFE)
• Measures any bias in the forecast
Mean Square Error (MSE)
• Penalizes larger errors
Tracking Signal
• Measures if your model is working

Master production schedule
Principle
Master production schedule is a detailed plan that states how
many end items will be available for sale or distribution during
specific periods.
Purpose of master production schedule
• To set due dates for the availability of end items.
• To provide information regarding resources and materials
required to support the aggregate plan.
• As an input to MRP, which will set specific production
schedules for parts and components used in end items.
Inputs to MRP
1.Market requirement
2.Production plan from aggregate planning
3.Resource available
MRP output
The output of MRP is the list of end items available every period
that is fesible with respect to demand and capacity.

Material Requirements Planning (MRP)
Computer-based information system for ordering and scheduling of
dependent-demand inventories, i.e. what is needed, how much is
needed, and when is it needed
• Dependent demand – Demand for items that are sub-assemblies, parts or raw
materials to be used in the production of finished goods.
• Independent demand – finished products

MRP Inputs MRP Processing MRP Outputs
Master
schedule
Bill of
materials
Inventory
records
MRP computer
programs
Changes
Order releases
Planned-order
schedules
Exception reports
Planning reports
Performance-
control
reports
Inventory
transaction
Primary
reports
Secondary
reports

MRP Inputs
• Master Production Schedule (MPS) – States which end items are to be
produced, when they are needed, and in what quantities
• Bill of Materials (BOM) – a listing of all of the raw materials, parts,
and sub-assemblies needed to produce one unit of a product
• Inventory Records – includes information on the status of an item
during the planning horizon, eg. quantity, supplier, order lead time,
lot size

Master Schedule
Master schedule: One of three primary inputs in
MRP; states which end items are to be produced,
when these are needed, and in what quantities.
Cumulative lead time: The sum of the lead times that
sequential phases of a process require, from
ordering of parts or raw materials to completion of
final assembly.

Planning Horizon
1 2 3 4 5 6 7 8 9 10
Procurement
Fabrication
Subassembly
Assembly

Bill-of-Materials
Bill of materials: One of the three primary inputs
of MRP; a listing of all of the raw materials,
parts, subassemblies, and assemblies needed to
produce one unit of a product.
Product structure tree: Visual depiction of the
requirements in a bill of materials, where all
components are listed by levels.

Product Structure Tree
Chair
Seat
Legs (2)
Cross
bar
Side
Rails (2)
Cross
bar
Back
Supports (3)
Leg
Assembly
Back
Assembly
Level
0
1
2
3
Figure 15-5

Assembly Time Chart
1 2 3 4 5 6 7 8 9 10 11
Procurement of
raw material D
Procurement of
raw material F
Procurement of
part C
Procurement of
part H
Procurement of
raw material I
Fabrication
of part G
Fabrication
of part E
Subassembly A
Subassembly B
Final assembly
and inspection

MRP Processing
Processes the following for each time period:
• Gross requirements
• Schedule receipts
• Projected on hand
• Net requirements
• Planned-order receipts
• Planned-order releases

MRP Outputs
Primary Reports
• Planned Orders – schedule indicating the amount and timing of future
orders
• Order Releases – Authorization for the execution of planned orders
• Changes – revisions of due dates or order quantities, or cancellation
of orders

MRP Outputs
Secondary Reports
• Performance-control reports – Evaluation of system operation,
including deviations from plans and cost information
• Planning reports – Data useful for assessing future material
requirements
• Exception Reports – Data on major discrepancies encountered

Other Considerations
• Safety Stock
• Lot sizing
• Lot-for-lot ordering
• Economic order quantity
• Fixed-period ordering
• Part-period model

Capacity Planning
• Capacity requirements planning – the process of determining short-
range capacity requirements
• Load reports – Department or work centre reports that compare
known or expected future capacity requirements with projected
capacity availability
• Time fences – series of time intervals during which order changes are
allowed or restricted

MRP Planning
Develop a tentative
master production
schedule
Use MRP to
simulate material
requirements
Convert material
requirements to
resource requirements
Firm up a portion
of the MPS
Is shop
capacity
adequate?
Can
capacity be
changed to meet
requirements
Revise tentative
master production
schedule
Change
capacity
Yes
No
Yes
No

Benefits of MRP
• Low levels of inventories and reduction in manufacturing lead time
• Ability to track material requirements hence reducing shortages
• Ability to evaluate capacity requirements
• Means of allocating production time

Manufacturing Resources Planning (MRP II)
• Involves the whole production process, starting with aggregate
planning, then MPS and finally MRP.
• Emphasizes integration with:
• Financial planning
• Marketing
• Engineering
• Purchasing
• Manufacturing
• Personnel

Market
Demand
Production
plan
Problems?
Rough-cut
capacity planning
Yes No YesNo
Finance
Marketing
Manufacturing
Adjust
production plan
Master
production schedule
MRP
Capacity
planning
Problems?
Requirements
schedules
Adjustmasterschedule
MRP II

Enterprise Resource Planning (ERP)
• Integration of financial, manufacturing and human resources on a
single computer system.
• Represents expanded effort to integrate standardized record keeping
using one database that will permit information sharing among
different areas of an organization to manage the system more
effectively.

Material
Requirements Planning
• Material requirements planning (MRP): A computerized
information system developed specifically to help manufacturers
manage dependent demand inventory and schedule replenishment
orders.
• MRP explosion: A process that converts the requirements of
various final products into a material requirements plan that
specifies the replenishment schedules of all the subassemblies,
components, and raw materials needed to produce final products.
• Bill of materials (BOM): A record of all the components of an
item, the parent–component relationships, and the usage quantities
derived from engineering and process designs.

MRP Inputs
Inventory
transactions
Inventory
records
Other
sources
of demand
Authorized
master production
schedule
Bills of
materials
Engineering
and process
designs
Material
requirements
plan
MRP
explosion

Bill of Materials Terms
• Usage quantity: The number of units of a component
that are needed to make one unit of its immediate
parent.
• Inventory items:
• End item: The final product sold to a customer.
• Intermediate item: An item that has at least one parent and at
least one component.
• Subassembly: An intermediate item that is assembled (as
opposed to being transformed by other means) from more than
one component.
• Purchased item: An item that has one or more parents but no
components because it comes from a supplier.
• Part commonality: The degree to which a component has
more than one immediate parent.

Bill of Materials
Seat cushion
Seat-frame
boards
Front
legs A
Ladder-back
chair
Back
legs
Leg supports
Back slats

J (4)
Seat-frame boards
I (1)
Seat cushion
H (1)
Seat frame
G (4)
Back slats
F (2)
Back legs
C (1)
Seat
subassembly
D (2)
Front
legs
B (1)
Ladder-back
subassembly
E (4)
Leg
supports
A Ladder-back
chair
Bill of Materials

Master
Production Schedule
• Master production schedule (MPS): A part of the material
requirements plan that details how many end items will be produced
within specified periods of time.
Ladder-back chair
Kitchen chair
Desk chair
1 2
April May
3 4 5 6 7 8
Aggregate
production plan
for chair family
200
670
200
150
120
200
150
200
120
670
MPS for a Family of chairs

Master Production Scheduling
Process
Operations must first create a prospective MPS to test
whether it meets the schedule with the resources.

Developing a Master
Production Schedule
Forecast is less than
booked orders in week 1;
projected on-hand inventory
balance = 55 + 0 – 38 = 17.
Forecast exceeds booked
orders in week 2; projected on-
hand inventory balance
= 17 + 0 – 30 = –13. The
shortage signals a need to
schedule an MPS quantity for
completion in week 2.
MPS for
Weeks 1 & 2

Inventory Record
• Inventory record: A record that shows an item’s lot-size policy, lead
time, and various time-phased data.
• Gross requirements: The total demand derived from all parent
production plans.
• Scheduled Receipts (open orders) are orders that have been placed
but not yet completed.
• Projected on-hand inventory: An estimate of the amount of inventory
available each week after gross requirements have been satisfied.
• Planned receipts: Orders that are not yet released to the shop or
supplier.
• Planned order release: An indication of when an order for a specified
quantity of an item is to be issued.

Inventory Record
8-Period Worksheet

Planning Factors
• Planning lead time: An estimate of the time
between placing an order for an item and
receiving the item in inventory.
• Setup time
• Processing time
• Materials handling time between operations
• Waiting time
• Lot-sizing rules: A rule that determines the
timing and size of order quantities.

51
What is Shop Floor Control?
• Definition: Shop Floor Control (SFC) is the process by which
decisions directly affecting the flow of material through the factory are
made.
• Functions:
WIP
Tracking
Throughput
Tracking
Status
Monitoring
Work
Forecasting
Capacity
Feedback
Quality
Control
Material Flow
Control

52
Planning for SFC
• Gross Capacity Control: Match line to demand via:
• Varying staffing (no. shifts or no. workers/shift)
• Varying length of work week (or work day)
• Using outside vendors to augment capacity
• Bottleneck Planning:
• Bottlenecks can be designed
• Cost of capacity is key
• Stable bottlenecks are easier to manage
• Span of Control:
• Physically or logically decompose system
• Span of labor management (10 subordinates)
• Span of process management (related technology?)

Business Scenario
• Engineering informed you that they updated the BOM for the redesigned pump.
• You are a material planner. You want to verify the changes and you want to view
other master data (work center, routing) used in ME.
• Before scheduling production you realize that you need to rerun MRP due to the
change in the BOM
• MRP will generate a planned order. You will convert one of them to a production
order.
• You will process the steps of issuing material to production order, confirming
activities, receiving the finished pump into inventory, …

Organizational Level in ME
• Client
• Company code
• Plant
• Storage location

Master Data Used
• Material Master
• Bill Of Material (BOM)
• Routing
• Work center/Resources
• Task lists
• PRTs (Production resource tools)

Work Center (Resource) Data
• Basic data:
• Task list usage: specify the task list types (routing, rate routing, master recipe,
equipment task list, or inspection plans).
• Standard value: is a planned value used to carry out an operation, such as the
execution time. They are used in costing, scheduling, and capacity
requirements planning in order to calculate costs, execution times, and
capacity requirements.

Production Order processing-Glossary
• WIP: Work in Process
• PDC : Plan Data Collector
• Material withdrawal: Get the components for the
assembly
• Material Staging : Transferring the material from your
main store to production location.

Production Order: Goods issue Posting
• The goods issue posting (GI) is executed for a consumption of a material
component for production order
• The following functions are executed:
• Storage location update
• Reservation
• Determination of actual costs: evaluation and update order
• Creation of:
• Material document: goods movement (MM stock point of view)
• Accounting document: : goods movement (financial accounting point of view)
• Cost accounting documents: serve various analysis purposes (financial controlling point of view)

Production Order: Goods issue Posting

Production Order: Goods receipt Posting
• The goods receipt posting (GR) realizes the stock receipt of a produced product.
• The following functions are executed:
• Storage location update
• Reservation
• Determination of actual costs: evaluation and update order
• Creation of:
• Material document: goods movement (MM stock point of view)
• Accounting document: : goods movement (financial accounting point of view)
• Cost accounting documents: serve various analysis purposes (financial controlling point of view)

Period-End Closing: Settlement
• Initial or first contribution margin for the period: Compare the standard cost of
goods manufactured for the product with the revenues
• Second contribution margin for the period: the variances between the actual
costs and the standard cost of goods manufactured.

INTRODUCTION
• Manufacturing is the process of converting raw material into
finished or semi finished part.
• Production is the use of man, material and machine to produce
finished products.
• Production system can be defined as a transformation system in
which a saleable product or service is created by working upon a
set of inputs.

PRODUCTION SYSTEM
Production system can be broadly classified as-
• JOB SHOP PRODUCTION- products are made to satisfy a specific order.
• BATCH PRODUCTION- number of identical articles are manufactured either to
meet a continuous demand or present demand.
• MASS PRODUCTION- same type of products is manufactured to meet the
continuous demand of the product

CELLULAR MANUFACTURING
• Organizing the production equipment into machine cells,
where each cell specialize in the production of a part family
is called cellular manufacturing.
• It is an application of group technology in manufacturing.
• Cellular manufacturing can be implemented by
manual or automated methods.
• When automated, the term flexible manufacturing is
applied.

Unit 2 manufacturing system design

CELLULAR MANUFACTURING
• This approach facilitates continuous flow of production.
• It provides flexibility to produce variety of low demand products.
• This layout is suitable for medium variety and medium volume environment.
• Cellular layout is also known as product- process layout.

GROUP TECHNOLOGY
• A manufacturing philosophy in which similar parts are
identified & grouped together to take advantage of their
similarities in design and production.
• It contributes to the integration of CAD (Computer Aided Design) and CAM
(Computer Aided Manufacturing).
• The group of similar parts is known as part family and the group of machineries
used to process an individual part family is known as machine cell.

METHODS TO IDENTIFY PART FAMILIES
• VISUAL INSPECTION- using best judgment to group
parts into part families.
• PART CLASSIFICATION & CODING- identifying the
similarities among parts & relating them with
numerical coding system.
• PRODUCTION FLOW ANALYSIS- Using operation and route sheets to
classify parts into part families.

ADVANTAGES
• Reduced work-in-process inventory
• Less floor space required
• Shorter flow time of the product, no wait in batches
due to less distance between machines
• Reduced raw material and finished goods inventory
• Reduced set up time
• Heightened sense of employee participation
• Increased use of equipment and machinery

LIMITATIONS
• When new products manufacturing are required, if they do not fit into the
existing cell then whole manufacturing set up needs to be restructured.
• To implement cellular layout cost required is high.

INTRODUCTION
• JIT philosophy means getting the right quantity of goods at the right place and
the right time.
• JIT exceeds the concept of inventory reduction; it is an all-encompassing
philosophy geared to eliminate waste, anything that does not add value.
• Just in time (JIT) is a production strategy that strives to improve a business' return
on investment by reducing in-process inventory and associated carrying costs.

HISTORY OF JIT
• Just in time is a type of operations management approach which originated in
Japan in the 1950s.
• JIT is a Japanese management philosophy which has been applied in practice
since the early 1970s in many Japanese manufacturing organizations.
• It was first developed and perfected within the Toyota manufacturing plants by
Taiichi Ohno as a means of meeting consumer demands with minimum delays .

OBJECTIVES OF JIT
• To reduce all non-value added activities.
• Elimination of in-plant inventory.
• Elimination of in-transit inventory.
• Quality and reliability improvement.

ELEMENTS OF JIT IN MANUFACTURING
CONTINUOUS IMPROVEMENT
• Attacking fundamental problems - anything that does not add value to the
product.
• Devising systems to identify problems.
• Striving for simplicity - simpler systems may be easier to understand, easier to
manage and less likely to go wrong.
• A product oriented layout - produces less time spent moving of materials and
parts.

CONTD.
• Quality control at source - each worker is responsible for the
quality of their own output.
• Poka-yoke - `foolproof' tools, methods, jigs etc. prevent
mistakes.
• Preventative maintenance, Total productive maintenance –
ensuring machinery and equipment functions perfectly when it
is required, and continually improving it

CONTD.
Eliminating waste. There are seven types of waste:
• waste from overproduction.
• waste of waiting time.
• transportation waste.
• processing waste.
• inventory waste.
• waste of motion.
• waste from product defects.

FUNCTIONING OF JIT.
• Involves keeping stock levels to a minimum.
• Stock arrives just in time to be used in production.
• Works best where there is close relationship between manufacturer and
supplier.
• Goods not produced unless firm has an order from a customer.
• Aims to get highest volume of output at lowest unit cost.

ADVANTAGES OF JIT
• Reduction in inventories.
• Improved quality.
• Reduced space requirements.
• Shorter lead times.
• Lower production costs.
• Increased productivity.
• Increased machine utilization.
• Greater flexibility.

DISADVANTAGES OF JIT
• Danger of disrupted production due to non arrival of supplies.
• Danger of lost sales.
• High dependence on suppliers.
• Less time for quality control on arrival of materials.
• Increased ordering and admin costs.
• May lose bulk-buying discounts.

MRP
• MRP stands for Material requirement planning.
Basic definition:
• It is a planning technique which production schedule of end products into
detailed schedule for raw materials and parts used in those end products.
• MRP is a means for determining the number of parts, components, and materials
needed to produce a product

OBJECTIVES OF MRP
• INVENTORY REDUCTION:
Determines how many components are needed and when in order to
meet MASTER PRODUCTION SCHEDULE.
• REDUCTION IN PRODUCTION AND DELIVERY LEAD TIMES:
It helps to meet delivery deadlines by coordinating inventories, procurement
and production decision
• REALISTIC COMMITMENTS:
Improves customer satisfaction

FUNDAMENTAL CONCEPTS OF MRP
INDEPENDENT DEMAND:
• Demand for the product is not directly related to demand for other items Is the
demand for finished product.
• It needs to be forecasted.
DEPENDENT DEMANDS:
• Demand for the product is directly related to demand for some other product.
• Is the demand derived from finished product.
• Components required for finished product.

MRP II
• Manufacturing resource planning (MRPII) is defined as a method for the effective
planning of all resources of a manufacturing company.
• MRP II serves as an extension of MRP(closed loop manufacturing resource
planning, also abbreviated as CLMRP).

ADVANTAGES
• More efficient use of resources
Reduced inventories
Less idle time
Fewer bottlenecks
• Better priority planning
Quicker production starts
Schedule flexibility
• Improved customer service
Meet delivery dates
Improved quality
Lower price possibility
• Improved employee moral

DISADVANTAGES
• High costs and technical complexities in implementation.
• The time required for planning and implementing an MRP
system is generally very long.
• Data entry and file maintenance requires considerable
inputs in the form of training and education of the personnel.
• Dependence on forecast values and estimated lead-time can
sometimes be misleading

COMPUTER- GENERATED TIME
STANDARDS

INTRODUCTION
• Work measurement can be defined as the development of a time
standard to indicate the value of a work task.
• According to a survey conducted by industrial engineering magazine
and patton consultants, inc., 95% of the manufacturing firms
responding to the survey use work measurement.

There are various purposes for which work measurement is used. Among these are:
• Wage incentives
• Estimating and job costing
• Production scheduling and capacity planning
• Measurement of worker performance

The techniques used to determine time standards in manufacturing include the
following:
• Direct time study
• The use of standard data
• Predetermined time standard systems
• Estimates based on previous experience
• Work sampling

ADVANTAGES OF COMPUTERIZED TIME
STANDARD SYSTEMS:
• Reduction in time required by the time study analyst to set the
standard.
• Greater accuracy and uniformity in the time standards.
• Ease of maintaining the methods and standards file when
engineering and methods changes occur.
• Elimination of the controversial performance rating step.
• Time standards can often be set before the job gets into production.
• Improved manufacturing data base for PP, Scheduling, Forecasting
labor requirements, tool control, and so on.

Unit 2 manufacturing system design

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Unit 2 manufacturing system design