Automation in manufacturing five unit vtu, mechanical engineering notes pdf download

2016
Kiran Vijay Kumar
6/7/2016
AUTOMATION IN
MANUFACTURING

CONTENTS
Page
Unit 1: Introduction to automation
1. Introduction 1
2. Production System 1
3. Facilities 1
4. Manufacturing Support System 2
5. Automation in Manufacturing Systems 4
6. Reasons for Automating 5
7. Automation Principles 5
8. Automation Strategies 6
9. Automation Migration Strategy 7
10. Advantages of Automation Migration Strategy 8
Unit 2: Manufacturing Operation
11. Introduction 9
12. Manufacturing Operations 9
13. Manufacturing processes 9
14. Product/Production Relationships 11
15. Production concepts and Mathematical Models 12
16. Costs of Manufacturing Operations 15
17. Other Factory Operations 17
18. WIP Ratio 18
19. TIP Ratio 18
20. Worked Examples 19

Unit 6: Quality control systems
21. Introduction 23
22. Quality 23
23. Traditional Quality Control 23
24. Modern Quality Control 24
25. Quality Control Technologies 25
26. Taguchi Methods In Quality Engineering 25
27. Statistical Process Control 29
28. Control charts 29
29. Histograms 30
30. Pareto 31
31. Check Sheets 31
32. Defect Concentration Diagrams 32
33. Scatter Diagrams 32
34. Cause and Effect Diagrams 33
Unit 7: Inspection technologies
35. Introduction 34
36. Automated Inspection 34
37. Type I and Type II errors in automated system 35
38. Coordinate Measuring Machines (CMM) 36
39. CMM Construction 36
40. CMM Operation and Programming 40
41. Other CMM Software’s 41
42. CMM Applications and Benefits 42
43. Flexible Inspection Systems 42

44. Inspection Probes on Machine Tools 43
45. Machine Vision 43
46. Machine Vision Applications 45
47. Optical Inspection Methods 45
48. Non-contact Non-optical Inspection Techniques 47
Unit 8: Manufacturing support system
49. Process Planning 48
50. Computer-Aided Process Planning 50
51. Concurrent Engineering 52
52. Advanced Manufacturing Planning 53
53. Just-In-Time Production Systems 55
54. Lean Production 57
55. Agile Manufacturing 58
56. Market Forces and Agility 59
57. Reorganizing the Production System for Agility 59
58. Managing Relationships for Agility 59
59. Agility versus Mass Production 60
60. Comparison of Lean and Agile 60
REFERENCE

Automation in Manufacturing
Kiran Vijay Kumar
Syllabus:-
Introduction: Production System Facilities, Manufacturing Support systems, Automation in Production systems,
Automation principles & Strategies
Brief Introduction:-
• The word Manufacturing was derived from two Latin words,
that combination means made by hand
• The use of automated equipment in Manufacturing rather than manual worker is known as
Production systems:-
• The production system is the collection of people, equipment, and procedures organized to accomplish the
manufacturing operations of a company
• Production systems can be divided
1.
2.
1. Facilities :-
• The facilities of the production system consist of the factory, the equipment in the factory, and the way
the equipment is organized.
• Facilities also include the plant layout,
• The equipment is usually organized into
the workers who operate them as the
• There are three basic categories of manufacturing systems (a) manual work systems, (b) worker
systems and (c) automated systems.
a. Manual Work Systems:
• A manual work system consists of one or more worker performing one or
powered tools.
• Manual material handling tasks are common activities in manual work systems.
• Production tasks commonly require the use of
by the strength and skill of the human user.
• When using hand tools, a work holder
processing.
• Examples A machinist using a file to round the edges.
Unit – 1
Introduction to Automation
Production System Facilities, Manufacturing Support systems, Automation in Production systems,
The word Manufacturing was derived from two Latin words, Manus (Hand) and
made by hand.
The use of automated equipment in Manufacturing rather than manual worker is known as
Automation in Manufacturing.
is the collection of people, equipment, and procedures organized to accomplish the
company (or other organization).
Production systems can be divided into two categories or levels,
Facilities
Manufacturing support systems
The facilities of the production system consist of the factory, the equipment in the factory, and the way
plant layout, which is the way the equipment is physically arranged in the factory.
The equipment is usually organized into logical groupings, and we refer to these equipment arrangements and
them as the manufacturing systems in the factory.
There are three basic categories of manufacturing systems (a) manual work systems, (b) worker
systems and (c) automated systems.
Manual Work Systems:-
A manual work system consists of one or more worker performing one or more tasks without the aid of
Manual material handling tasks are common activities in manual work systems.
sks commonly require the use of hand tools. A hand tool is a small tool that is manually operated
kill of the human user.
work holder is often employed to hold the work part and position it securely during
Examples A machinist using a file to round the edges.
P a g e | 1
Production System Facilities, Manufacturing Support systems, Automation in Production systems,
(Hand) and Factus (Make), so
The use of automated equipment in Manufacturing rather than manual worker is known as
is the collection of people, equipment, and procedures organized to accomplish the
The facilities of the production system consist of the factory, the equipment in the factory, and the way
equipment is physically arranged in the factory.
logical groupings, and we refer to these equipment arrangements and
There are three basic categories of manufacturing systems (a) manual work systems, (b) worker-machine
more tasks without the aid of
. A hand tool is a small tool that is manually operated
the work part and position it securely during

Kiran Vijay Kumar
b. Worker-Machine Systems:
• In a worker-machine system, human workers operate power equipment such
production machine.
• This is one of the most widely used manufacturing systems.
• Worker – machine systems include combination of one or more workers and one or more pieces of equipment.
• Examples of worker – machine system
part for a custom-designed product.
c. Automated system :-
• An automated system is one in which a process is performed by a machine without the direct participation of a
human worker.
• Automation is implemented using a program of instructions combined with a control system that executes the
instructions.
• Power is required to drive the process and to operate the program and control system.
• There is not always a clear distinction between worker machine system and automated systems, because many
worker-machine systems operate with some degree of automation.
2. Manufacturing Support System
• This is the set of procedures used by the company to manage production and to solve the technical and
logical problems encountered in ordering materials, moving work through the factory and ensuring that
products meet quality standards
• Manufacturing support involves a cycle of information
• The information-processing cycle
(1) Business functions
(2) Product design
(3) Manufacturing planning
(4) Manufacturing control.
Machine Systems:-
m, human workers operate power equipment such
This is one of the most widely used manufacturing systems.
machine systems include combination of one or more workers and one or more pieces of equipment.
machine system are a machinist operating an engine lathe in a tool room to fabricate a
designed product.
An automated system is one in which a process is performed by a machine without the direct participation of a
Automation is implemented using a program of instructions combined with a control system that executes the
required to drive the process and to operate the program and control system.
There is not always a clear distinction between worker machine system and automated systems, because many
machine systems operate with some degree of automation.
turing Support System :-
is the set of procedures used by the company to manage production and to solve the technical and
standards.
Manufacturing support involves a cycle of information-processing activities,
processing cycle consist of four functions:
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as machine tool or other
machine systems include combination of one or more workers and one or more pieces of equipment.
a machinist operating an engine lathe in a tool room to fabricate a
An automated system is one in which a process is performed by a machine without the direct participation of a
Automation is implemented using a program of instructions combined with a control system that executes the
required to drive the process and to operate the program and control system.
There is not always a clear distinction between worker machine system and automated systems, because many
is the set of procedures used by the company to manage production and to solve the technical and

Kiran Vijay Kumar
1. Business Functions:-
• The business functions are the principal means of communicating
• They are, therefore, the beginning and the end of the information
• Included in this category are sales a
billing.
2. Product Design:-
• If the product is to be manufactured to customer
The manufacturer's product design department
• If the product is to be produced to customer
contracted to do the design work for the
• The departments of the firm
development, design engineering, drafting, and perhaps a prototype shop.
3. Manufacturing Planning:
• The information-processing activities in manufacturing planning include
requirements planning and capacity planning
• Process planning consists of determining the
needed to produce the part.
• The master production schedule
quantities.
• Raw materials must be purchased or requisitioned from storage. Purchased parts must be ordered from
suppliers, and all of these items must be planned so that they are available when needed. This
called capacity requirements planning.
• In addition, the master schedule must
producing each month with number of machines and manpower.
• A function called capacity planning
4. Manufacturing Control :
• Manufacturing control is concerned with managing and
implement the manufacturing plans
• The flow of information is from pla
• The manufacturing control functions are
• Shop floor control deals with the problem of monitoring the progress of the product
assembled, moved and inspected in the factory
The business functions are the principal means of communicating with the customer.
therefore, the beginning and the end of the information- processing cycle.
Included in this category are sales and marketing, sales forecasting, order entry, cost accounting, and customer
If the product is to be manufactured to customer design, the design will have been provided by the
The manufacturer's product design department will not be involved.
f the product is to be produced to customer specifications, the manufacturer's product des
do the design work for the product as well as to manufacture it.
that are organized to accomplish product design might include research
development, design engineering, drafting, and perhaps a prototype shop.
Manufacturing Planning:-
activities in manufacturing planning include process planning,
and capacity planning.
consists of determining the sequence of individual processing and assembly operations
master production schedule is a listing of the products to be made, when to be delivered
be purchased or requisitioned from storage. Purchased parts must be ordered from
these items must be planned so that they are available when needed. This
requirements planning.
In addition, the master schedule must not list more quantities of products than the factory is capable of
with number of machines and manpower.
y planning is planning the manpower and machine resources of the firm.
Manufacturing Control :-
Manufacturing control is concerned with managing and controlling the physical ope
implement the manufacturing plans.
The flow of information is from planning to control.
he manufacturing control functions are shop floor control, inventory control and quality control
deals with the problem of monitoring the progress of the product
ed in the factory
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rder entry, cost accounting, and customer
will have been provided by the customer.
manufacturer's product design department maybe
ct design might include research and
process planning, master scheduling,
sequence of individual processing and assembly operations
when to be delivered and in what
be purchased or requisitioned from storage. Purchased parts must be ordered from
these items must be planned so that they are available when needed. This entire task is
not list more quantities of products than the factory is capable of
the manpower and machine resources of the firm.
controlling the physical operations in the factory to
shop floor control, inventory control and quality control.
deals with the problem of monitoring the progress of the product as it is being processed,

Kiran Vijay Kumar
• Inventory control attempts to strike a proper balance between the danger of
cost of too much inventory.
• It deals with such issues as deciding the right quantities of materials to
when stock is low.
• The mission of quality control is to ensure that the quality of the product and its components
specified by the product designer.
• Final inspection and testing of the finished product is
product.
Automation in Manufacturing Systems
• Some elements of the firm's production system are likely to be automated, whereas others
manually or clerically.
• For our purposes here, automation
mechanical, electronic, and computer
• The automated elements of the production system can be separated into two categories:
(1) Automation of the manufacturing systems in the factory and
(2) Computerization of the manufacturing support systems.
• In modern production systems, the two categories
(1) Automation of the manufacturing systems :
• Automated manufacturing systems operate in the factory on the physical product.
• They perform operations such as processing, assembly, inspection, or material handling, in some
accomplishing more than one of these operations in the same system.
• They are called automated because they perform their operations with a reduced level of human participation
compared with the corresponding manual process.
• In some highly automated systems,
• Examples of automated manufacturing
1. Automated machine tools that process parts
2. Transfer lines that perform a series of machining operations
• Automated manufacturing systems can be classified into three basic types
(ii) Programmable automation and (iii) F
(i) Fixed Automation :
• Fixed automation is a system in which the sequence of processing
equipment configuration.
• Each of the operations in the sequence is usually simple, involving
an uncomplicated combination of the two
• Its Features are,
i. High initial investment
ii. High production rate.
iii. Low product variety
• E.g. machining transfer lines and automated assembly machines.
attempts to strike a proper balance between the danger of too little inventory and the carrying
It deals with such issues as deciding the right quantities of materials to order and when to re
is to ensure that the quality of the product and its components
specified by the product designer.
of the finished product is performed to ensure functional quality and appearance of
Automation in Manufacturing Systems:-
Some elements of the firm's production system are likely to be automated, whereas others
automation can be defined as a technology concerned with the application of
computer-based systems to operate and control production.
The automated elements of the production system can be separated into two categories:
Automation of the manufacturing systems in the factory and
of the manufacturing support systems.
In modern production systems, the two categories overlap to some extent.
Automation of the manufacturing systems :-
cturing systems operate in the factory on the physical product.
operations such as processing, assembly, inspection, or material handling, in some
accomplishing more than one of these operations in the same system.
mated because they perform their operations with a reduced level of human participation
compared with the corresponding manual process.
In some highly automated systems, there is virtually no human participation.
Examples of automated manufacturing systems include:
utomated machine tools that process parts.
ransfer lines that perform a series of machining operations.
Automated manufacturing systems can be classified into three basic types (i) Fixed automation,
Programmable automation and (iii) Flexible automation.
:-
is a system in which the sequence of processing (or assembly) operations is fixed by the
in the sequence is usually simple, involving perhaps a plain linear or rotational
an uncomplicated combination of the two.
igh initial investment.
High production rate.
product variety.
and automated assembly machines.
P a g e | 4
e inventory and the carrying
hen to reorder a given item
is to ensure that the quality of the product and its components meet the standards
nctional quality and appearance of
Some elements of the firm's production system are likely to be automated, whereas others will be operated
as a technology concerned with the application of
operate and control production.
The automated elements of the production system can be separated into two categories:
operations such as processing, assembly, inspection, or material handling, in some cases
mated because they perform their operations with a reduced level of human participation
(i) Fixed automation,
(or assembly) operations is fixed by the
perhaps a plain linear or rotational motion or

Kiran Vijay Kumar P a g e | 5
(ii) Programmable Automation :-
• In programmable automation, the production equipment is designed with the capability to change the sequence
of operations to accommodate different product configuration.
• The operation sequence is controlled by a program.
• New programs can be prepared and entered into the equipment to produce new products.
• Its features are,
i. High initial investment
ii. Lower production rate.
iii. High product variety.
iv. Suitable for batch production.
• E.g. Numerically Controlled (NC) machine tools, industrial robots, and programmable logic controllers.
(iii) Flexible Automation :-
• Flexible' automation is an extension of programmable automation.
• A flexible automated system is capable of producing a variety of parts with virtually no time lost for
changeovers from one part style to the next.
• There is no lost production time while reprogramming the system and altering the physical setup.
• Its features are,
i. High initial investment.
ii. Medium production variety.
iii. Medium production rate.
iv. Flexibility to deal with product design variations.
• E.g. the flexible manufacturing systems for performing machining operations.
(2) Computerization of the manufacturing support systems :-
• Automation of the manufacturing support systems is aimed at reducing the amount of manual and clerical effort
in product design, manufacturing planning and control, and the business functions of the firm.
• Nearly all modem manufacturing support systems are implemented using computer systems.
• Indeed, computer technology is used to implement automation of the manufacturing systems in the factory as well.
• The term computer integrated manufacturing (CIM) denotes the pervasive use of computer systems to design
the products, plan the production, control the operations, and perform the various business-functions needed in a
manufacturing firm.
• True CIM involves integrating all of these functions in one system that operates throughout the enterprise.
• For example, computer-aided design (CAD) denotes the use of computer systems to support the product design
function.
• Computer-aided manufacturing (CAM) denotes the use of computer systems to perform functions related to
manufacturing engineering, such as process planning and numerical control part programming.
• Some computer systems perform both CAD and CAM.
Reasons for Automating:-
1. To increase labor productivity.
2. To reduce labor cost.
3. To mitigate the effects of labor shortages.
4. To reduce or eliminate routine manual and clerical tasks.
5. To improve worker safety.
6. To improve product quality.
Automation (or USA) Principles:-
• The USA Principle is a good first step in any automation project.
• USA stands for,
1. Understand the existing process.
2. Simplify the process.
3. Automate the process.

1. Understand the existing process :-
• The obvious purpose of the first step in the USA approach is to comprehend the current process in all of its
details.
• What arc the inputs? What are the outputs? What exactly happens to the work unit between input and output?
What is the function of the process? How does it add value to the product? What are the upstream and
downstream operations in the production sequence, and can they be combined with the process under
consideration?
• Some of the basic charting tools used in methods Application of these tools to the existing process provide a
model of the process that can be analyzed and searched for weaknesses (and strengths).
• Mathematical models of the process may also be useful to indicate relationships between input parameters and
output variables.
2. Simplify the process :-
• Once the existing process is understood, then the search can begin for ways to simplify.
• This often involves a checklist of Questions about the existing process. What is the purpose of this step or this
transport? Is this step necessary? Can steps be combined? Can steps be performed simultaneously? Can steps be
integrated into a manually operated production line?
• Some of the ten strategies at automation and production systems are applicable to try to simplify the process.
3. Automate the process :-
• Once the process has been reduced to its simplest form, then automation can be considered.
• The possible forms of automation include the ten strategies.
• An automation migration strategy might be implemented for a new product that has not yet proven itself.
Automation Strategies:-
If automation seems a feasible solution to improving productivity, quality, or other measure of
performance, then the following ten strategies provide a road map to search for these improvements.
1. Specialization of operations:-
The first strategy involves the use of special-purpose equipment designed to perform one operation with the
greatest possible efficiency.
2. Combined operations:-
• Production occurs as a sequence of operations. Complex parts may require dozens, or even hundreds, of
processing steps.
• The strategy of combined operations involves reducing the number of distinct operation? Reduction machines
or workstations through which the part must be routed.
• This is accomplished by performing more than one operation at a given machine; thereby reducing the number
of separate machines needed which in turn reduces setup time.
3. Simultaneous operations:-
• A logical extension of the combined operations strategy is to simultaneously perform the operations that are
combined at one workstation.
• In effect, two or more processing (or assembly) operations are being performed simultaneously on the same
work part. Thus reducing total processing time.

4. Integration of operations:-
• Another strategy is to link several workstations together into a single integrated mechanism, using automated
work handling devices to transfer parts between stations.
• In effect, this reduces the number of separate machines through which the product must be scheduled with more
than one workstation.
• Several parts can be processed simultaneously, thereby increasing the overall output of the system.
5. Increased flexibility:-
• This strategy attempts to achieve maximum utilization of equipment for job shop and medium-volume
situations by using the same equipment for a variety of parts or products.
• It involves the use of the flexible automation concepts.
• Prime objectives are to reduce setup time and programming time for the production machine. This normally
translates into lower manufacturing lead time and less work-in-process.
6. Improved material handling and storage:-
• A great opportunity for reducing nonproductive time exists in the use of automated material handling and
storage systems.
• Typical benefits include reduced work-in-process and shorter manufacturing lead times.
7. On-line inspection:-
• Inspection for quality of work is traditionally performed after the process is completed which means that any
poor-quality product has already been produced by the time it is inspected.
• Incorporating inspection into the manufacturing process permits corrections to the process as the product is
being made.
• This reduces scrap and brings the overall quality of the product closer to the nominal specifications intended by
the designer.
8. Process control and optimization :-
• This includes a wide range of control schemes intended to operate the individual processes and associated
equipment more efficiently.
• By this strategy, the individual process times can be reduced and product quality improved.
9. Plant operations control:-
• This strategy is concerned with control at the plant level.
• It attempts to manage and coordinate the aggregate operations in the plant more efficiently.
• Its implementation usually involves a high level of computer networking within the factory.
10. Computer-integrated manufacturing (CIM) :-
• Taking the previous strategy one level higher, we have the integration of factory operations with engineering
design and the business functions of the firm.
• CIM involves extensive use of computer applications, computer data bases, and computer networking
throughout the enterprise.
Automation Migration Strategy:-
• If the product turns out to be successful and high future demand is anticipated, then it makes sense for the
company to automate production.
• The improvements are often carried out in phases.
• Many companies have an automation migration strategy: that is, a formalized plan for evolving the
manufacturing system, used to produce new products as demand grows.
• A typical automation migration strategy is as shown in fig.

Kiran Vijay Kumar
Phase 1: Manual production using single
introduction of the new product for reasons already
Phase 2: Automated production using single
product grows, and it becomes clear that
labor and increase production rate. Work units are
Phase 3: Automated integrated production
automated transfer of work units between stations.
mass quantities and for several years, then integration of the single
reduce labor and increase production
Advantages of Automation Migration Strategy
1. It allows introduction of the new product in the shortest possible
workstations are the easiest to design and implement
2. It allows automation to be introduced gradually (in planned phases), as demand for
engineering changes in the product are made, and time i
manufacturing system.
3. It avoids the commitment to a high lev
for the product will not justify it
using single-station manned cells operating independently.
introduction of the new product for reasons already mentioned: quick and low-cost tooling to get started
using single-station automated cells operating independently.
product grows, and it becomes clear that automation can be justified, then the single stations are automated to reduce
production rate. Work units are still moved between workstations manua
Automated integrated production using a multi-station automated system
automated transfer of work units between stations. When the company is certain that the product will be produced in
for several years, then integration of the single-station automated cells is warranted to further
reduce labor and increase production rate.
Migration Strategy:-
It allows introduction of the new product in the shortest possible time, since production
workstations are the easiest to design and implement.
It allows automation to be introduced gradually (in planned phases), as demand for
engineering changes in the product are made, and time is allowed to do a thorough design job on the automated
a high level of automation from the start, since there is
for the product will not justify it.
P a g e | 8
operating independently. This is used for
cost tooling to get started.
operating independently. As demand for the
automation can be justified, then the single stations are automated to reduce
workstations manually.
with serial operations and
When the company is certain that the product will be produced in
automated cells is warranted to further
time, since production cells based on manual
It allows automation to be introduced gradually (in planned phases), as demand for the product grows,
to do a thorough design job on the automated
always a risk that demands

Kiran Vijay Kumar
Syllabus:-
Manufacturing Operations, Product/Production Relationship, Production concepts and Mathematical Models &
Costs of Manufacturing Operations.
Introduction:-
• Manufacturing can be defined as is application of physical
geometry, properties, and/or appearance of a given starting material to make parts
• Manufacturing also includes the joining of multiple parts to make assembled products.
• The processes that accomplish manufacturing involve a combination of machinery,
manual labor.
Manufacturing Operations:-
• There are certain basic activities that must be carried out in a factory to convert raw materials into
finished products.
• Limiting our scope to a plant engaged in making discrete products, the factory activities are:
(1) Processing and assembly operations, (2) Material handling, (3) Inspection and test, and
(4) Coordination and control.
• Our viewpoint is that value i
the product.
• Unnecessary operations, whether they are processing, assembly, material handling or inspection.
Must be eliminated from the sequence of steps performed to complete a given
Manufacturing processes:-
Manufacturing
Process
Unit – 2
Manufacturing Operation
Costs of Manufacturing Operations.
can be defined as is application of physical and chemical processes to alter the
geometry, properties, and/or appearance of a given starting material to make parts
Manufacturing also includes the joining of multiple parts to make assembled products.
The processes that accomplish manufacturing involve a combination of machinery,
-
There are certain basic activities that must be carried out in a factory to convert raw materials into
Limiting our scope to a plant engaged in making discrete products, the factory activities are:
(4) Coordination and control.
Our viewpoint is that value is added through the totality of manufacturing operations performed on
Unnecessary operations, whether they are processing, assembly, material handling or inspection.
Must be eliminated from the sequence of steps performed to complete a given
Processing
Operation
Shaping
Operation
Solidification
Process
Particulate
Processing
Deformation
Process
Meterial
Removal
Process
Property -
Enhancing
Operation
Heat
Treatment
Surface
Processing
Operation
Cleaning
Surface
Teatment
Coating &
thin fim
depositionAssemmbly
Operation
Permanent
Joint
Temporary
Joint
P a g e | 9
and chemical processes to alter the
geometry, properties, and/or appearance of a given starting material to make partsor products;
Manufacturing also includes the joining of multiple parts to make assembled products.
The processes that accomplish manufacturing involve a combination of machinery, tools, power, and
There are certain basic activities that must be carried out in a factory to convert raw materials into
Limiting our scope to a plant engaged in making discrete products, the factory activities are:
s added through the totality of manufacturing operations performed on
Unnecessary operations, whether they are processing, assembly, material handling or inspection.
Must be eliminated from the sequence of steps performed to complete a given product.
Solidification
Process
Particulate
Processing
Deformation
Process
Meterial
Removal
Process
Treatment
Cleaning
Surface
Teatment
Coating &
thin fim
deposition

Processing Operations:-
• A processing operation transforms a work material from one state of completion to a more advanced
state that is closer to the final desired part or product.
• It adds value by changing the geometry, properties or appearance of the starting material.
• Material is fed into the process. Energy is applied by the machinery and tooling to transform the
material and the completed work part exits the process.
• Most production operations produce waste or scrap, either as a natural byproduct at the process.
• More than one processing operation is usually required to transform the starting material into final
form.
• An important objective in manufacturing is to reduce waste in either of these forms.
• In general, processing operations are performed on discrete work parts, but some processing
operations are also applicable to assembled items.
• For example painting a welded sheet metal car body.
• Three categories of processing operations are distinguished: (1) shaping operations, (2) property-
enhancing operations and (3) surface processing operations.
1. Shaping Operations:-
Shaping operations apply mechanical force or heat or other forms and combinations of energy to
effect a change in geometry of the work material.
• The classification have Four categories:
1. Solidification processes:
The important processes in this category arc casting and molding, in which the starting material is a
heated liquid or semi fluid, in which state it can be poured or otherwise forced to flow into a mold cavity
where it cools and solidifies, taking a solid shape that is the same as the cavity.
2. Particulate processing:
The starting material is a powder. The common technique involves pressing the powders in a die cavity
under high pressure to cause the powders to take the shape of the cavity. Then it is sintered heated to a
temperature below the melting point, which causes the individual particles to bond together.
3. Deformation processes:-
In most cases, the starting material is a ductile metal that is shaped by applying stresses that exceed the
metal's yield strength.Deformation processes include forging, extrusion and rolling. Also included in this
category are sheet metal processes such as drawing, forming; and bending.
4. Material removal processes:-
The starting material is solid, from which excess material is removed from the starting work piece so
that the resulting part has the desired geometry. Most important in this category are machining operations
such as milling, drilling and turning. Other material removal processes are known as nontraditional
processes because they do not use traditional cutting and grinding tools. Instead, they are based on lasers,
electron beams, chemical erosion, electric discharge, or electrochemical energy.
2. Property enhancing operations:-
• These are Operations designed to improve mechanical or physical properties of the work material.
• The most important property-enhancing operations involve heat treatments, which include various
temperature-induced strengthening and/or toughening processes for metals and glasses.
• Property-enhancing operations do not alter part shape, except unintentionally in some cases, for
example, warping of a metal part during heat treatment or shrinkage of a ceramic part during
sintering.

3. Surface processing operations:-
• It include: (1) cleaning, (2) surface treatments and (3) coating and thin film deposition processes.
• Cleaning includes both chemical and mechanical processes to remove dirt, oil, and other
contaminants from the surface.
• Surface treatments include mechanical working, such as shot peening and sand blasting, and physical
processes, like diffusion and ion implantation.
• Coating and thin film deposition processes apply a coating of material to the exterior surface of the
work part. Common coating processes include electro plating of aluminum, and organic coating.
Assembly Operation:-
• The second basic type of manufacturing operation is assembly, in which two or more separate parts
are joined to form a new entity.
• Components of the new entity are connected together either permanently or temporarily.
• Permanent joining processes include welding, brazing, soldering and adhesive bonding. They
combine parts by forming a joint that cannot be easily disconnected.
• A temporary joining process is method available to fasten two (or more) parts together in a joint that
can be conveniently disassembled.
• The uses of threaded fasteners (e.g. screws, bolts, nuts) are important traditional methods in this
category.
Product/Production Relationships:-
• Companies organize their manufacturing operations and production systems as a function of the
particular products they make.
• It is instructive to recognize that there are certain product parameters that are influential in
determining how the products are manufactured
• Let us consider four key parameters: (1) production quantity, (2) product variety, (3) complexity of
assembled products, and (4) complexity of individual parts.
Production Quantity and Product Variety:-
Let Q = production quantity and P = product variety. Thus we can discuss product variety and
production quantity relationships as PQ relationships. Q refers to the number of units of a given part or
product that are produced annually by a plant. Let us identify each part or product style by using the
subscript j. so that Qj = annual quantity of style j. Then let Qf = total quantity of all parts or products made
in the factory. Qj and Qf are related as follows:
Qf = ∑
P refers to the different product designs or types that are produced in a plant. Let us divide the
parameter P into two levels P1 & P2. P1 refers to the number of distinct product lines produced by the
factory (i.e. hard product variety) and P2 refers to the number of models in a product line (i.e. soft product
variety). Product variety P is given by,
P = ∑
Product and Part Complexity:-
For a Fabricated component, a possible measure of part complexity is the number of processing
steps required to produce it. For an assembled product, one possible indicator of product complexity is its
number of components - more the parts, more complex the product is. Let np = the number of parts per
product and we have processing complexity of each part as the number of operations required to make it;
let no = the number of operations or processing steps to make a part.

Let us develop some simple relationships among the parameters P, Q, np and n0 that indicate the
level of activity in a manufacturing plant. We will ignore the differences between Pl and P2 here.
Assuming that the products are all assembled and that all component parts used in these products are
made in the plant, then the total number of parts manufactured by the plant per year is given by:
npf = ∑
Where, npf = total number of parts made in the factory (pc/yr), Qj = annual quantity of product style j
(products/yr), and npj = number of parts in product j (pc/product).
Finally, if all parts are manufactured in the plant, then the total number of processing operations
performed by the plant is given by:
nof = ∑ ∑
Where, nof = total number of operation cycles performed in the factory (ops/yr), and nojk = number of
processing operations for each part k.
For Problem Purpose:-
We might try to simplify this to better conceptualize the situation by assuming that the number of product
designs P are produced in equal quantities Q, all products have the same number of components np, and
all components require an equal number of processing steps no. In this case, the total number of product
units produced by the factory is given by:
Qf = PQ
The total number of parts produced by the factory is given by:
npf = PQnp
And the total number of manufacturing operation cycles performed by the factory is given by,
nof = PQnpn0
Production concepts and Mathematical Models:-
1. Ideal Cycle Time, Tc:-
It is the time that one work unit spends being processed or assembled.
• Expressed as,
Tc= To + Th + Tt (in min/piece)
Or
Tc = Tr + [ To]max
Where,
Tr is time to transfer work units between stations each cycle (min/piece),
To is actual processing or assembly operation time(in min/piece)
Th is handling time (in min/piece)
Tt is tool handling time (in min/piece)
[To]max is operation time at the bottleneck station
• In above equation we use the max To because the longest service time establishes the pace of the
production line.
• The remaining stations with smaller service times will have to wait for the slowest station. The other
stations will be idle.

2. Actual average production time, Tp :-
It is the total time required to produce or assemble a work unit.
• Expressed as,
Tp = (in min/piece)
Where,
Tsu is setup time (in min/piece)
Q is batch quantity
Tc is Operation cycle time (in min/piece)
• For job shop production when quantity, Q = 1 ═> Tp = Tsu + Tc
• For quantity type mass production, Q becomes very large, (Tsu/Q) → 0 ═> Tp = Tc .
3. Ideal or mass production rate, Rc :-
It is the reciprocal of the Ideal Cycle Time.
• Expressed as,
Rc = (in piece/min)
Where,
Tc is Ideal Cycle Time (in min/piece)
4. Actual average production rate, Rp:-
It is the reciprocal of the actual average production time.
• Expressed as,
Rp = (in piece/min)
Where,
Tp is actual average production time (in min/piece)
5. Production Capacity, PC:-
Production capacity is defined as the maximum rate of output that a production facility
is able to produce under a given set of assumed operating conditions.
• The production facility usually refers to a plant or factory, and so the term plant capacity is often used
for this measure.
• The number of hours of plant operation pet week is a critical issue in defining plant capacity.
• Expressed as,
PC = nSwHshRp
Where,
PC = production capacity of the facility (output units/wk),
n= = number of work centers producing in the facility.
Sw = number of shifts per period (shift/wk),
Hsh = hr/5hift (hr), and
Rp = hourly production rate of each work center (output units/hr).

6. Utilization, U:-
Utilization refers to the amount of output of a production facility relative to its capacity.
• Utilization can be assessed for an entire plant, a single machine in the plant, or any other productive
resource (i.e., labor).
• Utilization is usually expressed as a percentage.
• Expressing this as an equation,
U =
Where,
U = utilization of the facility,
Q = actual quantity produced by the facility during a given time period (i.e. pc/wk),and
PC = production capacity for the same period (piece/wk.).
7. Availability, A:-
Availability is a common measure of reliability for equipment.
• It is especially appropriate for automated production equipment.
• Availability is defined using two other reliability terms, mean time between failure (MTBF) and mean
time to repair (MTTR).
• The MTBF indicates the average length of time the piece of equipment runs between breakdowns.
• The MTTR indicates the average time required to service the equipment and put it back into operation
when a breakdown occurs.
• Expressed as,
A =
8. Manufacturing Lead Time, MLT:-
We define manufacturing lead time as the total time required to process a given part or
product through the plant.
• Production usually consists of a series of individual processing and assembly operations.
• Between the operations are material handling, storage, inspections, and other nonproductive activities.
• Let us therefore divide the activities of production into two main categories, operations and
nonoperation elements.
• An operation is performed on a work unit when it is in the production machine.
• The nonoperation elements include handling, temporary storage, inspections, and other sources of
delay when the work unit is not in the machine.
• Expressed as,
MLT = no (Tsu + QTc +Tno) (in min)
Where,
MLT is average manufacturing lead time for a part or product (min).
n0 is the number of separate operations (machines).
9. Work-in-Process, WIP:-
Work in process (WIP) is the quantity of parts or products currently located in the
factory that are either being processed or are between processing operations.
• WIP is inventory that is in the state of being transformed from raw material to finished product.
• Work-in-process represents an investment by the firm, but one that cannot be turned into revenue
until all processing has been completed.
• Many manufacturing companies sustain major costs because work remains in-process in the factory
too long.

• An approximate measure of work-in-process can be obtained from the following,
WIP = !"# $
Where
WIP = work-in-process in the facility (pc),
A = availability,
U = utilization,
PC = production capacity of the facility (pc/wk),
MLT = manufacturing lead time, (wk),
Sw = number of shifts per week (shift/wk), and
Hsh = hours per shift (hr/shift).
Costs of Manufacturing Operations:-
Manufacturing cost can be classified as,
1. Fixed and Variable Costs
2. Direct Labor, Material, and Overhead cost
3. Cost of Equipment Usage
1. Fixed and Variable Costs:-
• A Fixed Cost (FC) is one that remains constant for any level of production output.
• Examples include the cost of the factory building and production equipment, insurance, and property taxes.
• All of the fixed costs can be expressed as annual amounts.
• Expenses such as insurance and property taxes occur naturally as annual costs.
• Capital investments such as building and equipment can be converted to their equivalent uniform
annual costs using interest rate factors.
• A Variable Cost (VR) is one that varies in proportion to the level of production output. As output
increases, variable cost increases.
• Examples include direct labor, raw materials, and electric power to operate the production equipment.
• The ideal concept of variable cost is that it is directly proportional to output level. When fixed cost
and variable cost are added,
• we have the following total cost equation:
TC = FC + VC (Q)
Where,
TC = total annual cost ($/yr),
FC = fixed annual cost ($/yr),
VC = variable cost ($/pc), and
Q = annual quantity produced (pc/yr)

Kiran Vijay Kumar
When comparing automated and manual production methods
the automated method is high relative to the manual
relative to the manual method, as pictured in Figure.
quantity range, while automation has an advantage for high quantities.
2. Direct Labor, Material, and
• The direct labor cost is the sum of the wages and benefits paid to the workers who operate the
production equipment and perform the processing and assembly tasks.
• The material cost is the cost of all raw materials used to make the product. In the case of a stamping
plant, the raw material consists of the steel sheet stock used to make stampings.
• For the rolling mill that made the sheet stock, the raw material is the iron ore or scra
which the sheet is rolled.
• In the case of an assembled product, materials include component parts manufactured by supplier
firms. Thus, the definition of "raw material" depends on the company.
• The final product of one company can be the raw
• Overhead costs are all of the other expenses associated with running the manufacturing firm.
• Overhead divides into two categories: (
(a) Factory overhead:
It consists of the costs of operating the factory other than direct labor and materials. Factory overhead
is treated as fixed cost, although some of the items in our list could be correlated with the output level of
the plant.
(b) Corporate overhead:
It is the cost of running the company other than its manufacturing activities.
Many companies operate more than one factory, and this is one of the reasons for dividing
overhead into factory and corporate categories. Overhead costs can be allocated according to a number of
different bases, including direct labor
When comparing automated and manual production methods, it is typical
the automated method is high relative to the manual method, and the variable cost of automation is low
relative to the manual method, as pictured in Figure. The manual method has a cost advantage in the low
automation has an advantage for high quantities.
Direct Labor, Material, and Overhead cost:-
is the sum of the wages and benefits paid to the workers who operate the
production equipment and perform the processing and assembly tasks.
is the cost of all raw materials used to make the product. In the case of a stamping
For the rolling mill that made the sheet stock, the raw material is the iron ore or scra
In the case of an assembled product, materials include component parts manufactured by supplier
Thus, the definition of "raw material" depends on the company.
The final product of one company can be the raw material for another company.
are all of the other expenses associated with running the manufacturing firm.
Overhead divides into two categories: (a) factory overhead and (b) corporate overhead.
consists of the costs of operating the factory other than direct labor and materials. Factory overhead
cost of running the company other than its manufacturing activities.
labor cost, material cost, direct labor hours, and space.
P a g e | 16
it is typical that the fixed cost of
iable cost of automation is low
he manual method has a cost advantage in the low
is the sum of the wages and benefits paid to the workers who operate the
is the cost of all raw materials used to make the product. In the case of a stamping
For the rolling mill that made the sheet stock, the raw material is the iron ore or scrap iron out of
In the case of an assembled product, materials include component parts manufactured by supplier
material for another company.
are all of the other expenses associated with running the manufacturing firm.
) corporate overhead.
consists of the costs of operating the factory other than direct labor and materials. Factory overhead
direct labor hours, and space.

Kiran Vijay Kumar
3. Cost of Equipment Usage
• The trouble with overhead rates as we have developed them here is that they are based on labor cost
alone.
• A machine operator who runs an old, small engine lathe whose book value is zero will be
the same overhead rate as an operator running a new CNC turning center.
• If differences in rates of different production machines are not recognized, manufacturing costs will
not be accurately measured by the overhead rate structure.
• To deal with this difficulty, it is appropriate to divide the cost of a worker running a machine into two
components: (1) direct labor and (2) machine
• These costs apply not to the entire factory operations, but to individual work centers.
• A work center is a production cell consisting of (1) One worker and one machine. (2) One worker and
several machines. (3) Several workers operating one machine or (4) several workers and machines.
• In any of these cases, it is advantageous to separate the labor expe
estimating total production costs.
Other Factory Operations:-
(1) Material handling (2) inspection and test and (3) coordination a
1. Material handling and storage:
• A means of moving and storing materials between processing and/or assembly operations is
common task in industries.
• In most manufacturing plants, materials spend more time being moved and stored than being
processed.
• In some cases, the majority of the
storing materials.
• It is important that this function be carried out as efficiently as possible.
Eugene Merchant, an advocate and spokesman for the machine tool industry for
materials in a typical metal machining batch factory or job shop
in processing.
The observations made by him are,
• About 95% of a part's time is spent either moving or waiting (temporary storage).
• Only 5% of its time is spent on the machine tool.
• Out of this 5%, less than 30% of the
taking place & the remaining 70% is required for loading and unloading,
positioning, tool position
Cost of Equipment Usage:-
The trouble with overhead rates as we have developed them here is that they are based on labor cost
A machine operator who runs an old, small engine lathe whose book value is zero will be
the same overhead rate as an operator running a new CNC turning center.
If differences in rates of different production machines are not recognized, manufacturing costs will
not be accurately measured by the overhead rate structure.
h this difficulty, it is appropriate to divide the cost of a worker running a machine into two
(1) direct labor and (2) machine.
These costs apply not to the entire factory operations, but to individual work centers.
tion cell consisting of (1) One worker and one machine. (2) One worker and
In any of these cases, it is advantageous to separate the labor expense from the ma
estimating total production costs.
handling (2) inspection and test and (3) coordination and control.
Material handling and storage:
A means of moving and storing materials between processing and/or assembly operations is
In most manufacturing plants, materials spend more time being moved and stored than being
cases, the majority of the labor cost in the factory is consumed in handling, moving, and
It is important that this function be carried out as efficiently as possible.
Eugene Merchant, an advocate and spokesman for the machine tool industry for
materials in a typical metal machining batch factory or job shopspend more time waiting or being moved than
The observations made by him are,
About 95% of a part's time is spent either moving or waiting (temporary storage).
5% of its time is spent on the machine tool.
f this 5%, less than 30% of the time on the machine is time during which actual cutting
he remaining 70% is required for loading and unloading,
oning, gaging, and other elements of nonprocessing time.
P a g e | 17
The trouble with overhead rates as we have developed them here is that they are based on labor cost
A machine operator who runs an old, small engine lathe whose book value is zero will be casted at
If differences in rates of different production machines are not recognized, manufacturing costs will
h this difficulty, it is appropriate to divide the cost of a worker running a machine into two
These costs apply not to the entire factory operations, but to individual work centers.
tion cell consisting of (1) One worker and one machine. (2) One worker and
nse from the machine expense in
nd control.
A means of moving and storing materials between processing and/or assembly operations is a
In most manufacturing plants, materials spend more time being moved and stored than being
labor cost in the factory is consumed in handling, moving, and
Eugene Merchant, an advocate and spokesman for the machine tool industry for many years, observed that
spend more time waiting or being moved than
About 95% of a part's time is spent either moving or waiting (temporary storage).
time on the machine is time during which actual cutting is
he remaining 70% is required for loading and unloading, part handling and
ng time.

2. Inspection and test:
• Inspection and test are quality control activities.
• The purpose of inspection is to determine whether the manufactured product meets the established
design standards and specifications.
• For example, inspection examines whether the actual dimensions of a mechanical part are within the
tolerances indicated on the engineering drawing for the part.
• Testing is generally concerned with the functional specifications of the final product rather than with
the Individual parts that go into the product.
• For example, final testing of the product ensures that it functions and operates in the manner specified
by the product designer.
3. Coordination and Control:
• Coordination and control in manufacturing includes both the regulation of individual processing and
assembly operations as well as the management of plant level activities.
• Control at the process level involves the achievement of certain performance objectives by properly
manipulating the inputs and other parameters of the process.
• Control at the plant level includes effective use of labor, maintenance of the equipment, moving
materials in the factory, controlling inventory, shipping products of good quality on schedule, and
keeping plant operating costs at a minimum possible level.
• The manufacturing control function at the plant level represents the major point of intersection
between the physical operations in the factory and the information processing activities that occur in
production.
WIP Ratio:-
It is the ratio of the Work In Process to the Total No. of Machines.
• Expressed as,
WIP ratio =
%&
'
=
(
!"# $
)
( * +)
Where,
no = no. of machines processing or assembly.
nm = total no. of machines in the factory.
TIP Ratio:-
It refers to Time In Process ratio. It gives the measure of total time the product lies in the
plant relative to the time it actually undergoes processing.
• Expressed as,
TIP Ratio =
,

WORKED EXAMPLES
E.g. 1 Suppose a company has designed a new product line and is planning to build a new plant to
manufacture this product line. The new line consists of 100 different product types, and for each product
type the company wants to produce 10,000 units annually. The products average 1000 components each,
and the average number of processing steps required for each component is 10. All parts will be made in
the factory. Each processing step takes an average of 1 min. Determine: (a) How many products. (b) How
many parts, and (c) How many production operations will be required each year, and (d) How many
workers will be needed for the plant, if it operates one shift for 250 day/yr?
Solution:
(a) The total number of units to be produced by the factory is given by,
Q = PQ = 100 X 10,000 = 1,000,000 products annually.
(b) The total number of parts produced is:
npf = PQnp= 1,000,000 X 1000 = 1,000,000,000 parts annually.
(c) The number of distinct production operations is:
nof = PQnpn0 = 1,000,000,000 X 10 = 10,000,000,000operations.
(d) To find the number of workers required. First consider the total time to perform these operations. If
each operation takes 1 min (1/60 hr),
Total time = 10,000,000.000 X 1/60 = 166,666,667 hr
If each worker works 2000 hr/yr (40 hr/wk x 50 wk/yr), then the total number of workers required is:
w =
-..,...,..0
1222
= 83,333 workers.
E. g. 2 An average of 20 new orders is started through a certain factory each month. On average, an order
consists of 50 parts to be processed through 10 machines in the factory. The operation time per machine
for each part = 15 min. The nonoperation time per order at each machine averages 8 hr, and the required
setup time per order = 4 hr. There are 25 machines in the factory, 80% of which are operational at any
time (the other 20%are in repair or maintenance). The plant operates 160 hr/month. (a) What is the
manufacturing lead time for an average order? (b) Production Rate (c) What is the plant capacity (on
monthly basis) (d) What is the utilization of the plant according to the definition given in the text? (e)
Determine the average level of work-in-process (number of parts- in-process) in the plant (f) WIP Ratio
(g) TIP Ratio.
Solution:
(a) Manufacturing Lead Time:
MLT = no (Tsu + QTc +Tno) = 10[4 + (50 ×
-4
.2
) + 8] = 245hrs
(b) Production Rate:
Rp =
-
56
=
-
7
89:;<8=
<
>
=
-
7
?; @ × .B@
@
>
= 3.03parts/hour
(c) Plant Capacity:
PC =
CD
C
(SwHsh) Rp =
14
-2
(160) 3.03 = 1212parts/month
(d) Plant utilization:
U=
E
FG
=
12×42
-1-1
= 0.825 or 82.5%
(e) Work In Process:
WIP =
!"# $
=
2.H ×2.H14 -1-1 1I4
-.2
= 1224.87parts
(f) WIP Ratio:
[WIP]ratio =
JKF
=
-11I.H0
14
= 48.99 : 1

(g) TIP Ratio:
[TIP]ratio =
LM5
5=
=
1I4
-2×2.14
= 98 : 1
E. g. 3 A certain part is routed through six machines in a batch production plant. The setup and operation
time' for each machine are given in the table below. The batch size is 100 and the average nonoperation
time per machine is 12 hr. Determine: (a) manufacturing lead time and (b ) production rate for operation .
Machine Setup time (hrs) Operation time (min)
1. 4 5
2. 2 3.5
3. 8 10
4. 3 1.9
5. 3 4.1
6. 4 2.5
Solution:
(a) Manufacturing Lead Time:
MLT = nm (Tsu + QTc +Tno)
1. For first machine:
[MLT]1 = 1[4 +{100×
4
.2
} + 12] = 24.33hrs
2. For second machine:
[MLT]2 = 1[2 +{100×
O.4
.2
} + 12] = 19.83hrs
3. For third machine:
[MLT]3 = 1[8+{100×
-2
.2
} + 12] = 36.66hrs
4. For fourth machine:
[MLT]4 = 1[3 +{100×
-.P
.2
} + 12] = 18.16hrs
5. For fifth machine:
[MLT]5 = 1[3 +{100×
I.-
.2
} + 12] = 21.83hrs
6. For sixth machine:
[MLT]6 = 1[4 +{100×
1.4
.2
} + 12] = 20.16hrs
(b) Production Rate:
Rp =
-
56
=
-
7
89:;<8=
<
>
=
E
Q59: E5=R
1. For first machine:
[Rp]1 =
-22
7I -22S
@
T
U>
= 8.10part/hrs
2. For second machine:
[Rp]2 =
-22
71 -22S
V.@
T
U>
= 12.76part/hrs
3. For third machine:
[Rp]3 =
-22
7H -22S
W
T
U>
= 4.05part/hrs

4. For fourth machine:
[Rp]4 =
-22
7O -22S
W.X
T
U>
= 16.21part/hrs
5. For fifth machine:
[Rp]5 =
-22
7O -22S
?.W
T
U>
= 10.16part/hrs
6. For sixth machine:
[Rp]6 =
-22
7I -22S
B.@
T
U>
= 12.24part/hrs
E.g. 4 The following data are given: direct labor rate $10.00/hr; applicable factoryoverhead rate on labor
= 60%; capital investment in machine = $100,000; service life of the machine = 8 yr; rate of return =
20%; salvage value in 8 yr = 0; and applicable factory overhead rate on machine = 50%. The work center
will be operated one 8-hr shift, 250 day/yr. determine the appropriate hourly rate for the work center.
Solution:
Labor cost per hour = CL (1+ FOHRL) = $10.00(1 + 0.60) = $16.00/hr
Now the uniform annual cost can be determined:
UAC = IC S
Y - Y Z
- Y Z -
U = 100,000 S
2.1 - 2.1 [
- 2.1 [ -
U = $26,060.00/yr =
1.2.2.22
H×142
= $13.03/hr
The factory overhead rate = Cm (1 + FOHRm) = $13.03(1 + 0.50) = $19.55/hr
Total cost rate is, Co = Labor cost per hour + Factory overhead rate
Co = 16.00 + 19.55 = $35.55/hr.
E. g. 5 Suppose that all costs have been compiled for a certain manufacturing firm for last year. The
summary is shown in the table below. The company operates two different manufacturing plants plus a
corporate headquarters. Determine: (a) the factory overhead rate for each plant and (b) the corporate
overhead rate. These rates will be used by the firm in the following year.
Solution:
(a) A separate factory overhead rate must be determined for each plant.
FOHR =
#
]
For plant l,
FOHR1 =
1,222,222
H22,222
= 2.5 or 250%
For plant 2,
FOHR2 =
-,-22,222
I22,222
= 2.75 or 275%

(b) The corporate overhead rate is based on the total labor cost at both plants
COHR =
#
]
COHR =
0,122,222
-,122,222
= 6.0 or 600%
E.g. 6 A customer orders of 50 parts are to be processed through plant 1 of the previous example. Raw
materials and tooling are supplied by the customer. The total time for processing the parts (including
setup and other direct labor) is 100 hr. Direct labor cost is $l0.00/hr. The factory overhead rate is 250%
and the corporate overhead rate is 600%. Compute the cost of the job.
Solution:
(a) The direct labor cost for the job is = (100 hr) ($l0.00/hr) = $1000.
(b) The allocated factory overhead charge, at 250% of direct labor is,
FOHR =
#
]
2.5000 =
^_`G
-222
FOHC = ($1000) (2.50) = $2500.
(c) The allocated corporate overhead charge, at 600% of direct labor, is
COHR =
#
]
6.0000 =
^_`G
-222
COHC = ($1000) (6.00) = $6000.

UNIT - 6
Quality Control Systems
Sylabus:-
Traditional and Modern Quality Control Methods, Taguchi Methods in Quality Engineering, Introduction
to SQC Tools.
Introduction:-
In the 1980s. The issue of quality control (QC) became a national concern in the United States.
The Japanese automobile industry had demonstrated that high-quality cars could he produced at relatively
low cost. This combination of high quality and low cost was a contradiction of conventional wisdom in
the United States, where it was always believed that superior quality is achieved only at a premium price.
Cars were perhaps the most visible product area where the Japanese excelled.In the United States, quality
control has traditionally been concerned with detecting poor quality in manufactured products and taking
corrective action to eliminate it. The term quality assurance suggests this broader scope of activities that
are implemented in an organization to ensure that a product (or service) will satisfy (or even surpass) the
requirements of the customer.
Quality:-
The dictionary" defines quality as "the degree of excellence which a thing possesses," or "the
feature that makes something what it is"-its characteristic elements and attributes.
Definitions,
Conformance to requirements, fitness for use and is customer satisfaction.
- By Crosby & Juran
The totality of features and characteristics of a product or service that bear on its ability to satisfy given
need.
- By American Society for Quality Control
(ASQC)
Traditional Quality Control:-
Traditional QC focused on inspection. In many factories, the only department responsible for QC was
the inspection department. Much attention was given to sampling and statistical methods. The term
statistical quality control (SQC) was used to describe these methods.
• In SQC, inferences (or inspection) are made about the quality of a population of manufactured items
(e.g. components, subassemblies, products] based on a sample taken from the population.
• The sample consists of one or more of the items drawn at random from the population & each item in
the sample are inspected for certain quality characteristics of interest.
• Two statistical sampling methods dominate the field of SQC: (1) control charts and (2) acceptance
sampling.
(1) Control charts:-
• A control chart is a graphical technique in which statistics on one or more process parameters of
interest are plotted over time to determine if the process is behaving normally or abnormally.
• The chart has a central line that indicates the value of the process mean under normal operation.
• Abnormal process behavior is identified when the process parameter strays significantly from the
process mean. Control charts are widely used in statistical process control.

(2) Acceptance sampling:-
• Acceptance sampling is a statistical technique in which a sample drawn from a batch of parts is
inspected, and a decision is made whether to accept or reject the batch on the basis of the quality of
the sample.
• Acceptance sampling is traditionally used for various purposes: (1) receiving inspection of raw
materials from a vendor, (2) deciding whether or not to ship a batch of parts or products to a
customer, and (3) inspection of parts between steps in the manufacturing sequence.
• In statistical sampling, which includes both control charts and acceptance sampling, there are risks
that defects will slip through the inspection process, resulting in defective products being delivered to
the customer.
• With the growing demand for 100% good quality, the use of sampling procedures has declined over
the past several decades in favor of 100% automated inspection.
The management principles and characteristics of traditional QC included the following,
• Customers are external to the organization: - The sales and marketing department is responsible
for relations with customers.
• The company is organized by functional departments: - There is little appreciation of the
interdependence of the departments in the larger enterprise, the loyalty and viewpoint of each
department tends to be centered on itself rather than on the corporation. There tend, to exist an
adversarial relationship between management and labor.
• Quality is the responsibility of the inspection department: - The quality function in the
organization emphasizes inspection and conformance to specifications, its objective is simple:
elimination of defects.
• Inspection follows production: - The objectives of production (to ship product) often clash with the
objective, of QC (to ship only good product).
• Knowledge of SQC techniques resides only in the minds of the QC experts in the organization,
Workers' responsibilities are limited, Managers and technical staff do all the planning. Workers
follow instructions.
• There is an emphasis on maintaining the status quo.
Modern Quality Control:-
High quality is achieved by a combination of good management and good technology. The two
factors must be integrated to achieve an effective quality system in an organization. The management
factor is captured in the frequently used term-total quality management: The technology factor includes
traditional statistical tools combined with modern measurement and inspection technologies.
• Total quality management (TOM) denotes a management approach that pursues three main
objectives: (1) achieving customer satisfaction, (2) continuous improvement, and (3) encouraging
involvement of the entire work force.
• These objectives contrast sharply with the practices of traditional management regarding the QC
function.

Factors which reflect the modern view of quality management with the traditional approach to quality
management:
• Quality is focused on customer satisfaction. Products are designed and manufactured with this quality
focus. Juran's definition, "quality is customer satisfaction," defines the requirement for any product.
The technical specifications, the product features must be established to achieve customer satisfaction.
The product must be manufactured free of deficiencies.
• The quality goals of an organization are driven by top management, which determines the overall
attitude toward quality in a company. The quality goals of a company are not established in
manufacturing; they are defined at the highest levels of the organization.
Does the company want to simply meet specifications set by the customer, or does it want to make products that
go beyond the technical specification? Does it want to be known us the lowest price supplier of the highest
quality producer in its industry?
Answers to these kinds of questions define the quality goals of the company. These must be set
by top management. Through the goals they define, the actions they take, and the examples they set,
top management determines the overall attitude toward quality in the company.
• Quality control is pervasive in the organization, not just the job of the inspection department. It
extends from the top of the organization through all levels. There is recognition of the important
influence that product design has on product quality. Decisions made in product design directly impact
the quality that can be achieved in manufacturing.
• In manufacturing, the viewpoint is that inspecting the product after it is made is not good enough.
Quality must be built into the product. Production workers must inspect their own work and not rely
on the inspection department to find their mistakes.
• Quality is the job of everyone in the organization. It even extends outside the immediate organization
to the suppliers. One of the tenets of a modem QC system is to develop close relationships with
suppliers.
• High product quality is a process of continuous improvement. It is a never-ending chase to design
better products and then to manufacture them better.
Quality Control Technologies:-
Good technology also plays an important role in achieving high quality.
Modern technologies in QC include:
(1) Quality engineering
(2) Quality function deployment.
Other technologies in modern QC include,
(3) Statistical process control,
(4) 100% automated inspection,
(5) On-line inspection,
(6) Coordinate measurement machines for dimensional measurement and
(7) Non-contact sensors such as machine vision for inspection.
Taguchi Methods In Quality Engineering:-
• The areas of quality engineering and Total Quality Management overlap to a significant degree, since
implementation of good quality engineering is strongly dependent on management support and
direction.
• The field of quality engineering owes much to G. Taguchi, who has had an important influence on its
development, especially in the design area-both product design and process design.
• In this section, we review some of the Taguchi methods: (1) off-line and on-line quality control, (2)
robust design, and (3) loss function.

Kiran Vijay Kumar
(1) Off-line and on-line quality control
Taguchi believes that the quality system must be distributed throughout the organization,
divided quality system into two basic functions: off
Off line quality control:-
This function is concerned with design issues, both product and process design. It is applicable
prior to production and shipment of
precedes on-line control.
• Off-line quality control consists of two stages:
• The product design stage is concerned with the development of a new pr
existing product. The goals in product design are to properly identify customer needs and to design a
product that meets those needs but can also be manufactured consistently and economically.
• The process design stage is concern
standards, documenting procedures, and developing dear and workable specifications for
manufacturing. It is a manufacturing engineering function.
A three-step approach applicable to both of thes
parameter design, and (c) tolerance design
(a) System design:-
• System design involves the application of engineering knowledge and analysis to develop a prototype
design that will meet customer needs.
• In the product design stage, system design refers to the final product configuration and features,
including starting materials, components and subassemblies. For example, in the design of a new car,
system design includes the size of the car, its styling,
target it for a certain market segment.
• In process design, system design means selecting the most appropriate manufacturing methods. For
example, it means selecting a forging operation rather than casting to
Obviously, the product and process design stages overlap because product design determines the
manufacturing process to a great degree. Also, the quality of the product is impacted significantly by
decisions made during product design.
(b) Parameter design:-
• Parameter design is concerned with determining optimal parameter settings for the product and
process.
• In parameter design, the nominal values for the product or process parameters are specified.
• Examples of parameters in product design include the dimensions of components in an assembly or
the resistance of an electronic component.
line quality control: -
Taguchi believes that the quality system must be distributed throughout the organization,
divided quality system into two basic functions: off-line and on-line quality control.
prior to production and shipment of the product. In the sequence of the two functions off
line quality control consists of two stages: (1) product design and (2) process design
stage is concerned with the development of a new product or a new model of an
stage is concerned with specifying the processes and equipment, setting work
manufacturing. It is a manufacturing engineering function.
step approach applicable to both of these design stages is outlined:
parameter design, and (c) tolerance design.
involves the application of engineering knowledge and analysis to develop a prototype
design that will meet customer needs.
In the product design stage, system design refers to the final product configuration and features,
system design includes the size of the car, its styling, engine size and power, and other features that
target it for a certain market segment.
In process design, system design means selecting the most appropriate manufacturing methods. For
example, it means selecting a forging operation rather than casting to produce a certain component.
uct design.
is concerned with determining optimal parameter settings for the product and
In parameter design, the nominal values for the product or process parameters are specified.
Examples of parameters in product design include the dimensions of components in an assembly or
the resistance of an electronic component.
P a g e | 26
Taguchi believes that the quality system must be distributed throughout the organization, so he
line quality control.
the product. In the sequence of the two functions off-line control
(1) product design and (2) process design.
oduct or a new model of an
ed with specifying the processes and equipment, setting work
e design stages is outlined: (a) system design, (b)
involves the application of engineering knowledge and analysis to develop a prototype
In the product design stage, system design refers to the final product configuration and features,
engine size and power, and other features that
In process design, system design means selecting the most appropriate manufacturing methods. For
produce a certain component.
is concerned with determining optimal parameter settings for the product and
In parameter design, the nominal values for the product or process parameters are specified.
Examples of parameters in product design include the dimensions of components in an assembly or

• Examples of parameters in process design include the speed and feed in a machining operation or the
furnace temperature in a sintering process.
• The nominal value is the ideal or target value that the product or process designer would like the
parameter to be set at for optimum performance.
• It is in the parameter design stage that a robust design is achieved.
(c) Tolerance design:-
• In tolerance design, the objective is to specify appropriate tolerances about the nominal values
established in parameter design.
• A reality that must be addressed in manufacturing is that the nominal value of the product or process
parameter cannot be achieved without some inherent variation.
• A tolerance is the allowable variation that is permitted about the nominal value.
• The tolerance design phase attempts to achieve a balance between setting wide tolerances to facilitate
manufacture and minimizing tolerances to optimize product performance.
• Tolerance design is strongly influenced by the Taguchi loss function.
On-line quality control:-
This function of quality assurance is concerned with production operations and customer
relations. In production, Taguchi classifies three approaches to quality control:
1. Process diagnosis and adjustment. In this approach, the process is measured periodically and
adjustments are made to move parameter of interest toward nominal values.
2. Process prediction and correction. This refers to the measurement of process parameter, at periodic
intervals so that trends can be projected. If projections indicate deviations from target values,
corrective process adjustments are made.
3. Process measurement and action. This involves inspection of all units (100%) to detect deficiencies
that will be reworked or scrapped. Since this approach occurs after the unit is already made. It is less
desirable than the other two forms of control.
The Taguchi on-line approach includes customer relations, which consists of two elements.
• First, there is the traditional customer service that deals with repairs, replacements, and complaints.
• And second, there is a feedback system in which information on failures, complaints. and related data
are communicated back to the relevant departments in the organization for correction.
For example, customer complaints of frequent failures of a certain component are communicated
back to the product design department so that the components design can be improved.
(2) Robust design:-
• The objective of parameter design in Taguchi's off-line/on-line quality control is to set specifications
on product and process parameters to create a design that resists failure or reduced performance in the
face of variations.
• Taguchi call, the variations noise factors. A noise factor is a source of variation that is impossible or
difficult to control and that affects the functional characteristics of the product.
Three types of noise factors can be distinguished:
1. Unit-to-unit noise factors: - These are inherent random variations in the process and product caused
by variability in raw materials, machinery, and human participation. They are associated with a
production process that is in statistical control.
2. Internal noise factors: - These sources of variation are internal to the product or process. They
include: (1) time-dependent factors, such as wear of mechanical components, spoilage of raw
materials, and fatigue of metal parts; and (2) operational errors such as improper settings on the
product or machine tool.
3. External noise factors: - An external noise factor is a source of variation that is external to the
product or process, such as outside temperature, humidity, raw material supply, and input voltage.

Kiran Vijay Kumar
• A robust design is one in which the function and performance of the product or process are relatively
insensitive to variations in any of these noise factors
• In product design, robustness means that the product can maintain consistent performance with
minimal disturbance due to variations in uncontrollable factors in its operating environment.
• In process design, robustness means that the process continues t
effect from uncontrollable variations in its operating environment.
(3) Taguchi loss function:-
• The Taguchi loss function is a useful concept in tolerance design. Taguchi defines quality as "the loss
a product costs society from the time the product is released for shipment".
• Loss includes costs to operate, failure to function, maintenance and repair costs, customer
dissatisfaction, injuries caused by poor design, and similar costs.
• Some of these losses are difficult to qu
• Defective products (or their components) those are detected, repaired, reworked, or scrapped before
shipments are not considered part of this loss.
• Instead, any expense to the company resulting fro
manufacturing cost rather than a quality Joss.
Loss occurs when a product's functional characteristic differ from
When the dimension of a component deviates from its nominal value,
adversely affected. No matter how small the deviation, there is some loss in function. The loss increases
at an accelerating rate as the deviation grows, according to Taguchi. If we let
x = the quality characteristic of interest and
N = its nominal value,
Then the loss function will be a U
curve:
Where, L( x) = loss function;
is one in which the function and performance of the product or process are relatively
insensitive to variations in any of these noise factors.
In product design, robustness means that the product can maintain consistent performance with
process design, robustness means that the process continues to produce good product with minimal
effect from uncontrollable variations in its operating environment.
The Taguchi loss function is a useful concept in tolerance design. Taguchi defines quality as "the loss
y from the time the product is released for shipment".
Loss includes costs to operate, failure to function, maintenance and repair costs, customer
dissatisfaction, injuries caused by poor design, and similar costs.
Some of these losses are difficult to quantify in monetary terms but they are nevertheless real.
Defective products (or their components) those are detected, repaired, reworked, or scrapped before
shipments are not considered part of this loss.
Instead, any expense to the company resulting from scrap or rework of defective product is a
manufacturing cost rather than a quality Joss.
Loss occurs when a product's functional characteristic differ from its nominal or target value.
When the dimension of a component deviates from its nominal value, the component's function is
at an accelerating rate as the deviation grows, according to Taguchi. If we let
= the quality characteristic of interest and
Then the loss function will be a U-shaped curve as in. Taguchi uses a quadratic equation to describe this
L(x) = k(x - N)2
= loss function; k = constant of proportionality
P a g e | 28
is one in which the function and performance of the product or process are relatively
In product design, robustness means that the product can maintain consistent performance with
o produce good product with minimal
The Taguchi loss function is a useful concept in tolerance design. Taguchi defines quality as "the loss
Loss includes costs to operate, failure to function, maintenance and repair costs, customer
antify in monetary terms but they are nevertheless real.
Defective products (or their components) those are detected, repaired, reworked, or scrapped before
m scrap or rework of defective product is a
its nominal or target value.
the component's function is
shaped curve as in. Taguchi uses a quadratic equation to describe this

Kiran Vijay Kumar
Statistical Process Control (SPC)
Statistical process control
process. SPC methods are applicable in both manufacturing and nonmanufacturing situations, but most of
the applications are in manufacturing. The overall objectives of SPC are to (1) improv
process output, (2) reduce process variability and achieve process stability, and (3) solve processing
problems.
There are seven principal methods or tools used in SPC; these tools are sometimes referred to as
the "magnificent seven".
1. Control charts
2. Histograms
3. Pareto charts
4. Check sheet
5. Defect concentration diagrams
6. Scatter diagrams
7. Cause and effect diagrams
1. Control charts:-
Control charts are the most widely used method in SPC. The underlying principle of contro
charts is that the variations in any process divide into two types, as previously described: (1) random
variations, which are the only variations present if the process is in statistical control; and (2) assignable
variations, which indicate a departure
The purpose of a control chart is to identify when the process has gone out of statistical
control, thus signaling the need for some corrective action to be taken.
• A control chart is a graphical technique in which statistics computed from measured values of a
certain process characteristic are plotted over time to determine if the process remains in statistical
control.
• The general form of the control chart is illustrated in Figure
• The chart consists of three horizontal lines that remain constant over time: a center, a lower control
limit (L CL), and an upper control limit (VCL).
• The center is usually set at the nominal design value & the VCL and LCL are generally set at ±3
standard deviations of the sample means.
• It is highly unlikely that a sample drawn from the process lies outside the VCL or LCL while the
process is in statistical control.
• Therefore, if it happens that a sample value does
the process is out of control.
• An investigation is undertaken to determine the reason for the out
appropriate corrective action is taken to eliminate the condition.
(SPC):-
Statistical process control (SPC) involves the use of various methods to measure and analyze a
the applications are in manufacturing. The overall objectives of SPC are to (1) improv
5. Defect concentration diagrams
7. Cause and effect diagrams
Control charts are the most widely used method in SPC. The underlying principle of contro
variations, which indicate a departure from statistical control.
control, thus signaling the need for some corrective action to be taken.
is a graphical technique in which statistics computed from measured values of a
The general form of the control chart is illustrated in Figure.
The chart consists of three horizontal lines that remain constant over time: a center, a lower control
limit (L CL), and an upper control limit (VCL).
The center is usually set at the nominal design value & the VCL and LCL are generally set at ±3
ard deviations of the sample means.
It is highly unlikely that a sample drawn from the process lies outside the VCL or LCL while the
process is in statistical control.
Therefore, if it happens that a sample value doesfall outside these limits, it is inte
the process is out of control.
An investigation is undertaken to determine the reason for the out-of
appropriate corrective action is taken to eliminate the condition.
P a g e | 29
(SPC) involves the use of various methods to measure and analyze a
the applications are in manufacturing. The overall objectives of SPC are to (1) improve the quality of the
Control charts are the most widely used method in SPC. The underlying principle of control
is a graphical technique in which statistics computed from measured values of a
The chart consists of three horizontal lines that remain constant over time: a center, a lower control
The center is usually set at the nominal design value & the VCL and LCL are generally set at ±3
It is highly unlikely that a sample drawn from the process lies outside the VCL or LCL while the
fall outside these limits, it is interpreted to mean that
of-control condition and

Kiran Vijay Kumar
There are two basic types of control charts:
attributes.
(a) Control charts for variables:
• Control charts for variables require a measurement of the quality characteristic of interest.
• A process that is out of statistical control manifests thi
(1) process mean and/or (2) process variability.
• Corresponding to these possibilities, there are two principal types of control charts for variables:
chart and (2) R chart.
• The a̅ chart (call it "x bar chart") is used to plot the average measured value of a certain quality
characteristic for each of a series of samples taken from the production process. It indicates how the
process means changes over time.
• The R chart plots the range of each
whether if changes over time.
(b) Control charts for attributes:
• Control charts for attributes monitor the number of defects present in the sample or the fraction defect
rate as the planed statistic.
• Examples of these kinds of attributes include number of defects per automobile, fraction of
nonconforming parts in a sample, existence or absence of flash in a plastic molding, and number of flaws
in a roll of sheet steel.
• Inspection procedures that involve GO/NO
whether a part is good or bad.
• The two principal types of control charts for attributes are:
defect rate in successive samples; and (2) the
nonconformities per sample.
2. Histograms:-
• The histogram is a basic graphical tool in statistics.
• After the control chart, it is probably the most important member of the SPC tool kit.
• A histogram is a statistical graph consisting of bars representing different values or ranges of values,
in which the length of each bar is proportional to the frequency or relative frequency of the value or
range as shown in Figure.
• It is a graphical display of the
There are two basic types of control charts: (a) control charts for variables and (b) control charts for
Control charts for variables:-
Control charts for variables require a measurement of the quality characteristic of interest.
A process that is out of statistical control manifests this condition in the form of significant changes in:
(2) process variability.
Corresponding to these possibilities, there are two principal types of control charts for variables:
bar chart") is used to plot the average measured value of a certain quality
process means changes over time.
plots the range of each sample, thus monitoring the variability of the process and indicating
Control charts for attributes:-
Control charts for attributes monitor the number of defects present in the sample or the fraction defect
Examples of these kinds of attributes include number of defects per automobile, fraction of
ple, existence or absence of flash in a plastic molding, and number of flaws
Inspection procedures that involve GO/NO-GO gaging are included in this group since they determine
s of control charts for attributes are: (1) the p chart,
defect rate in successive samples; and (2) the c chart, which plots the number of defects, flaws or other
The histogram is a basic graphical tool in statistics.
After the control chart, it is probably the most important member of the SPC tool kit.
is a statistical graph consisting of bars representing different values or ranges of values,
the length of each bar is proportional to the frequency or relative frequency of the value or
It is a graphical display of the frequency distribution of the numerical data.
P a g e | 30
(a) control charts for variables and (b) control charts for
Control charts for variables require a measurement of the quality characteristic of interest.
s condition in the form of significant changes in:
Corresponding to these possibilities, there are two principal types of control charts for variables: (1) cd
bar chart") is used to plot the average measured value of a certain quality
sample, thus monitoring the variability of the process and indicating
Control charts for attributes monitor the number of defects present in the sample or the fraction defect
Examples of these kinds of attributes include number of defects per automobile, fraction of
ple, existence or absence of flash in a plastic molding, and number of flaws
are included in this group since they determine
, which plots the fraction
which plots the number of defects, flaws or other
After the control chart, it is probably the most important member of the SPC tool kit.
is a statistical graph consisting of bars representing different values or ranges of values,
the length of each bar is proportional to the frequency or relative frequency of the value or

Kiran Vijay Kumar
• What makes the histogram such a useful statistical tool
visualize the features of a complete set of data.
• These features include:
i. The shape of the distribution,
ii. Any central tendency exhibited by the distribution,
iii. Approximations of the mean and mode of the distribution, and
iv. The amount of scatter or spread in the data.
3. Pareto:-
• A Pareto chart is a special form of histogram as shown in Figure. in which attribute data are arranged
according to some criterion suc
• When appropriately used, it provides a graphical display of the tendency for a small proportion of a
given population to be more valuable than the much larger majority. This tendency is sometimes
referred to as Pareto's Law.
• Pareto's Law stated as: "the vital few and the trivial many
Pareto (1848-1923), an Italian economist and sociologist who studied the distribution of wealth in
Italy and found that most of it was held by a small percentage of
• Pareto's Law applies not only to the distribution of wealth but to many other distributions as well. The
law is often identified as the 80%
its people
• Similarly in industries 80%of inventory value is accounted for by
of a factory's production output is concentrated in only 20% of its product models.
4. Check Sheets:-
• The check sheet is a data gathering tool generally used in the preliminary stages of the study of a quality
problem.
• The operator running the process (e.g., the machine operator) is often given the responsibility for
recording the data on the check sheet, and the data ar
marks.
• Check sheets can take many different forms, depending on the problem situation and the ingenuity of
the analyst.
• The form should be designed to allow some interpretation of results directly from the raw
although subsequent data analysis may be necessary to recognize trends, diagnose the problem, or
identify areas of further study.
What makes the histogram such a useful statistical tool is that it enables the analyst to quickly
visualize the features of a complete set of data.
The shape of the distribution,
Any central tendency exhibited by the distribution,
Approximations of the mean and mode of the distribution, and
The amount of scatter or spread in the data.
is a special form of histogram as shown in Figure. in which attribute data are arranged
according to some criterion such as cost or value.
When appropriately used, it provides a graphical display of the tendency for a small proportion of a
the vital few and the trivial many". This "law" was identified by Vilfredo
1923), an Italian economist and sociologist who studied the distribution of wealth in
Italy and found that most of it was held by a small percentage of the population.
Pareto's Law applies not only to the distribution of wealth but to many other distributions as well. The
law is often identified as the 80%-20% rule: 80% of the wealth of a nation is in the hands of20% of
80%of inventory value is accounted for by 20% of the items in inventory 80%
is a data gathering tool generally used in the preliminary stages of the study of a quality
The operator running the process (e.g., the machine operator) is often given the responsibility for
recording the data on the check sheet, and the data are often recorded in the form of simple check
Check sheets can take many different forms, depending on the problem situation and the ingenuity of
The form should be designed to allow some interpretation of results directly from the raw
identify areas of further study.
P a g e | 31
is that it enables the analyst to quickly
Approximations of the mean and mode of the distribution, and
is a special form of histogram as shown in Figure. in which attribute data are arranged
When appropriately used, it provides a graphical display of the tendency for a small proportion of a
". This "law" was identified by Vilfredo
1923), an Italian economist and sociologist who studied the distribution of wealth in
the population.
Pareto's Law applies not only to the distribution of wealth but to many other distributions as well. The
of the wealth of a nation is in the hands of20% of
of the items in inventory 80%
is a data gathering tool generally used in the preliminary stages of the study of a quality
The operator running the process (e.g., the machine operator) is often given the responsibility for
e often recorded in the form of simple check
Check sheets can take many different forms, depending on the problem situation and the ingenuity of
The form should be designed to allow some interpretation of results directly from the raw data,

Kiran Vijay Kumar
The following are types of check sheets:
1. Process distribution check sheet:
2. Defective item check sheet:
occurring, together with their frequency of occurrence.
3. Defect location check sheet:
purpose is the same as the defect concentration diagram.
4. Defect factor check sheet: - This check sheet is used to monitor the input parameters in a process that
might affect the incidence of defects. The input parameters might include equipment,
process cycle time, operating
5. Defect Concentration Diagrams
• This is a graphical method that has been found to be useful in analyzing the causes of product or part
defects.
• The defect concentration diagram
which have been sketched the various defect types at the locations where they each occurred.
• By analyzing the defect types and corresponding locations, the u
possibly be identified.
• The above Montgomery describes a case study involving the final assembly of refrigerators that were
plagued by surface defects.
• A defect concentration diagram (Figure 21.7) was utilized to analyze the problem. The defects were
clearly shown to be concentrated around the middle section of the refrigerator.
• On investigation, it was learned that a belt was wrapped around each unit fo
purposes. It became evident that the defects were caused by the belt, and corrective action was taken
to improve the handling method.
6. Scatter Diagrams:-
• In many industrial problems involving manufacturing operations, it is desirable to
relationship that exists between two process variables. The scatter diagram is useful in this regard.
• A scatter diagram is simply an .x
in Figure.
• The data are plotted as pairs; for each x
• The shape of the data points considered in aggregate often reveals a pattern or relationship between
the two variables.
The following are types of check sheets:
Process distribution check sheet: - This is designed to collect data on process variability.
Defective item check sheet: - This check sheet is intended to enumerate the variety of defects
with their frequency of occurrence.
Defect location check sheet: - This is intended to identify where defects occur on the pro
as the defect concentration diagram.
This check sheet is used to monitor the input parameters in a process that
might affect the incidence of defects. The input parameters might include equipment,
process cycle time, operating temperature-whatever is relevant to the process being studied.
Defect Concentration Diagrams:-
This is a graphical method that has been found to be useful in analyzing the causes of product or part
defect concentration diagram is a drawing of the product with all relevant views displayed, onto
By analyzing the defect types and corresponding locations, the underlying causes of the defects can
The above Montgomery describes a case study involving the final assembly of refrigerators that were
A defect concentration diagram (Figure 21.7) was utilized to analyze the problem. The defects were
On investigation, it was learned that a belt was wrapped around each unit fo
to improve the handling method.
In many industrial problems involving manufacturing operations, it is desirable to
is simply an .x-y plot of the data taken of the two variables in question, as shown
ed as pairs; for each xvalue, there is a corresponding y, value.
The shape of the data points considered in aggregate often reveals a pattern or relationship between
P a g e | 32
s variability.
This check sheet is intended to enumerate the variety of defects
This is intended to identify where defects occur on the product. Its
This check sheet is used to monitor the input parameters in a process that
might affect the incidence of defects. The input parameters might include equipment, operator,
whatever is relevant to the process being studied.
This is a graphical method that has been found to be useful in analyzing the causes of product or part
is a drawing of the product with all relevant views displayed, onto
nderlying causes of the defects can
The above Montgomery describes a case study involving the final assembly of refrigerators that were
A defect concentration diagram (Figure 21.7) was utilized to analyze the problem. The defects were
On investigation, it was learned that a belt was wrapped around each unit for material handling
In many industrial problems involving manufacturing operations, it is desirable to identify a possible
y plot of the data taken of the two variables in question, as shown
value.
The shape of the data points considered in aggregate often reveals a pattern or relationship between

Kiran Vijay Kumar
For example, the scatter diagram in Figure indicates that a negative correlation exists between
cobalt content and wear resistance of a cemented carbide cutting tool. As cobalt content increases, wear
resistance decreases. One must be circumspect in using
that might be indicated by the data.
7. Cause and Effect Diagrams
• The cause and effect diagram
of a given problem.
• It is not really a statistical tool in the sense of the preceding tools as shown in Figure.
• The diagram consists of a central stem leading to the effect (the problem), with multiple branches
coming off the stem listing the various groups of possible c
• Because of its characteristic appearance, the cause and effect diagram is also known as a
diagram.
• In application, the cause and effect diagram is developed by a quality team.
• The team then attempts to determine which caus
action against them.
resistance decreases. One must be circumspect in using scatter diagrams and in extrapolating the trends
that might be indicated by the data.
Cause and Effect Diagrams:-
cause and effect diagram is a graphical-tabular chart used to list and analyze the potential causes
It is not really a statistical tool in the sense of the preceding tools as shown in Figure.
The diagram consists of a central stem leading to the effect (the problem), with multiple branches
coming off the stem listing the various groups of possible causes of the problem.
Because of its characteristic appearance, the cause and effect diagram is also known as a
In application, the cause and effect diagram is developed by a quality team.
The team then attempts to determine which causes are most consequential and how to take corrective
P a g e | 33
scatter diagrams and in extrapolating the trends
tabular chart used to list and analyze the potential causes
It is not really a statistical tool in the sense of the preceding tools as shown in Figure.
The diagram consists of a central stem leading to the effect (the problem), with multiple branches
auses of the problem.
Because of its characteristic appearance, the cause and effect diagram is also known as a fishbone
es are most consequential and how to take corrective

UNIT - 7
Inspection Technologies
Syllabus:-
Inspection Technologies: Automated Inspection, Coordinate Measuring Machines: Construction,
operation & Programming, Software, Application & Benefits, Flexible Inspection System, Inspection Probes on
Machine Tools, Machine Vision, Optical Inspection Techniques & Non-contact Non-optical Inspection
Technologies.
Introduction:-
In quality control, inspection is the means by which poor quality is detected and good quality is assured.
Inspection is traditionally accomplished using labor-intensive methods that are time-consuming and costly.
Consequently, manufacturing lead time and product cost are increased without adding any real value. In addition,
manual inspection is performed after the process, often after a significant time delay. Therefore, if a bad product has
been made, it is too late to correct the defect(s) during regular processing. Parts already manufactured that do not
meet specified quality standards must either be scrapped or reworked at additional cost.
The term inspection refers to the activity of examining the product, its components, subassemblies, or
materials out of which it is made, to determine whether they conform to design specifications. The design
specifications are defined by the product designer.
Automated Inspection:-
An alternative to manual inspection is automated inspection. Automation of the inspection procedure will
almost always reduce the inspection time per piece and automated machines are not given to the fatigue and human
inspectors, Economic system of an automated inspection system depends on whether the savings in labor cost and
improvement in accuracy will more than offset the investment and/or development costs of the system.
Automated inspection can be defined as the automation of one or more of the steps involved in the
inspection procedure.
There are a number of alternative ways in which automated or semi automated inspection can be implemented:
1. Automated presentation of parts by an automatic handling system with a human operator still performing the
examination and decision steps.
2. Automated examination and decision by an automatic inspection machine, with manual loading (presentation)
of parts into the machine.
3. Completely automated inspection system in which parts presentation, examination and decision are all
performed automatically.
In the first Case, the inspection procedure is performed by a human worker with all of the possible errors in this
form of inspection. In cases (2) and (3), the actual inspection operation is accomplished by an automated system.
• As in manual inspection, automated inspection can be performed using statistical sampling or 100%. When
statistical sampling is used, sampling errors are possible.
• With either sampling or 100% inspection, automated systems can commit inspection errors, just as human
inspectors can make such errors.
• For simple inspection tasks, such as automatic gaging of a single dimension. on a part, automated systems
operate with high accuracy (low error rate ).
• As the inspection operation becomes more complex and difficult, the error rate tends to increase.
For example, detecting defects in integrated circuit chips or printed circuit boards.lt should be mentioned
that these inspection tasks are also complex and difficult for human workers and this is one of the reasons for
developing automated inspection systems that can do the job.

Kiran Vijay Kumar
Type I and Type II errors in automated system
A Type I error occurs when the automated system indicates a defect when no defect is really present, and a
Type II error occurs when the system misses a real defect.
• Some automated inspection systems can be adjusted in terms of their sensitivity for detecting the defect they are
designed to find. This is accomplished by means of a "gain" adjustment or similar control.
• When the sensitivity adjustment is low, the probability of a Type I error is low but the probability of Type II
error is high.
• When the sensitivity adjustment is increased, the probab
of a Type II error decreases.
• This relationship is portrayed in above Figure. Because of these errors, 100% automated inspection cannot
guarantee 100% good quality product.
The full potential of automated inspection is best achieved when it is integrated into the manuf
process. When 100% inspection is used, and when the results of the procedure lead to some positive action.
Positive actions resulting from automated inspection:
two or more quality levels.
(a) Feedback process control
In this case, data are fed back to the preceding manufacturing process responsible for the quality
characteristics being evaluated or gaged in the inspection operation. The purpose of feedback is to allow
compensating adjustments to be made in the process to reduce variability and improve quality.
(b) Parts sortation:-
Type I and Type II errors in automated system:-
Type II error occurs when the system misses a real defect.
Some automated inspection systems can be adjusted in terms of their sensitivity for detecting the defect they are
When the sensitivity adjustment is low, the probability of a Type I error is low but the probability of Type II
When the sensitivity adjustment is increased, the probability of Type I error increases,
This relationship is portrayed in above Figure. Because of these errors, 100% automated inspection cannot
guarantee 100% good quality product.
The full potential of automated inspection is best achieved when it is integrated into the manuf
Positive actions resulting from automated inspection:(a) feedback process control and (b) sortation of parts into
Feedback process control:-
this case, data are fed back to the preceding manufacturing process responsible for the quality
adjustments to be made in the process to reduce variability and improve quality.
P a g e | 35
Some automated inspection systems can be adjusted in terms of their sensitivity for detecting the defect they are
When the sensitivity adjustment is low, the probability of a Type I error is low but the probability of Type II
ility of Type I error increases, whereas the probability
This relationship is portrayed in above Figure. Because of these errors, 100% automated inspection cannot
The full potential of automated inspection is best achieved when it is integrated into the manufacturing
(a) feedback process control and (b) sortation of parts into
this case, data are fed back to the preceding manufacturing process responsible for the quality
adjustments to be made in the process to reduce variability and improve quality.

Kiran Vijay Kumar
In this case, the parts are sorted according to quality level, acceptable versus unacceptable quality. There
may be more than two levels of quality approp
Sortation and inspection may be accomplished in several ways.
Coordinate Measuring Machines (CMM)
Coordinate metrology is concerned with the measurement of the actual shape and
and comparing these with the desired shape and dimensions, as might be specified on a part drawing.
measuring machine (CMM) is an electromechanical system designed to perform
To accomplish measurements in 3-D, a basic CMM is composed of the following components:
• Probe head and probe to contact the workpart surfaces.
• Mechanical structure that provides motion of the probe in three Cartesian axes and displacement transducers to
measure the coordinate values of each axis
In addition, many CMMs have the following components:
• Drive system and control unit to move each of the three axis.
• Digital computer system with application software.
CMM Construction:-
In the construction of a CMM, the probe is fastened to a mechanical structure that allows movement of the
probe relative to the part. The part is usually located on a worktable that is connected to the structure.
The two basic components of the CMM:
(1) Probe:
The contact probe is a key component of a CMM and it indicates when contact has been made with the part
surface during measurement. The tip of the probe is usually a ruby ball. Ruby is a form of corundum
oxide), whose desirable properties in this application include high hardness for wear resistance and low density for
minimum inertia. Probes can have either a single tip, as in Figure 23.4(a), or multiple tips as in Figure23.4 (b).
Most probes today are touch-trigger
Commercially available touch-trigger probes utilize any of various triggering mechanisms, including the following:
1. The trigger is based on a highly sensitive
is deflected from its neutral position.
2. The trigger actuates when electrical contact is established between the probe and the (metallic) part surface.
3. The trigger uses a piezoelectric
probe.
this case, the parts are sorted according to quality level, acceptable versus unacceptable quality. There
may be more than two levels of quality appropriate for the process (e.g., acceptable, reworkable, and scrap).
Sortation and inspection may be accomplished in several ways.
Coordinate Measuring Machines (CMM):-
is concerned with the measurement of the actual shape and
and comparing these with the desired shape and dimensions, as might be specified on a part drawing.
is an electromechanical system designed to performcoordinate metrology.
D, a basic CMM is composed of the following components:
Probe head and probe to contact the workpart surfaces.
Mechanical structure that provides motion of the probe in three Cartesian axes and displacement transducers to
e values of each axis
In addition, many CMMs have the following components:
Drive system and control unit to move each of the three axis.
Digital computer system with application software.
The two basic components of the CMM: (1) its probe and (2) its mechanical structure,
surface during measurement. The tip of the probe is usually a ruby ball. Ruby is a form of corundum
trigger probes, which actuate when the probe makes contact with the part surface.
trigger probes utilize any of various triggering mechanisms, including the following:
The trigger is based on a highly sensitive electrical contact switch that emits a signal when the tip of the probe
is deflected from its neutral position.
The trigger actuates when electrical contact is established between the probe and the (metallic) part surface.
The trigger uses a piezoelectric sensor that generates a signal based on tension or compression loading of the
P a g e | 36
this case, the parts are sorted according to quality level, acceptable versus unacceptable quality. There
riate for the process (e.g., acceptable, reworkable, and scrap).
is concerned with the measurement of the actual shape and dimensions of an object
and comparing these with the desired shape and dimensions, as might be specified on a part drawing.Acoordinate
coordinate metrology.
D, a basic CMM is composed of the following components:
Mechanical structure that provides motion of the probe in three Cartesian axes and displacement transducers to
surface during measurement. The tip of the probe is usually a ruby ball. Ruby is a form of corundum (aluminum
which actuate when the probe makes contact with the part surface.
trigger probes utilize any of various triggering mechanisms, including the following:
electrical contact switch that emits a signal when the tip of the probe
The trigger actuates when electrical contact is established between the probe and the (metallic) part surface.
sensor that generates a signal based on tension or compression loading of the

Kiran Vijay Kumar
• Immediately after contact is made between the probe and the surface of the object, the coordinate positions of
the probe are accurately measured by displacement
recorded by the CMM controller.
• Common displacement transducers used on CMMs include optical scales, rotary encoders, and magnetic scales.
• After the probe has been separated from the contact su
(2) Mechanical structure:
There are various physical configurations for achieving the motion of the probe, each with its relative
advantages and disadvantages. Nearly all CMMs have a mechanical configuration that
six types.
(a) Cantilever, (b) Moving Bridge, (c) Fixed bridge, (d) Horizontal arm (moving ram type), (e) Gantry, and
(f) Column.
(a) Cantilever:
• In the cantilever configuration, illustrated in Figure, the probe is attached to a vertical quill that moves in the z
axis direction relative to a horizontal arm that overhangs a fixed worktable.
• The quill can also be moved along the length of the arm to
relative to the worktable to achieve x
• The advantages of this construction are: (1) convenient access to the worktable, (2) high throughput
which parts can be mounted and measured on
CMM,) and (4) relatvely small floor space requirements. Its disadvantage is lower rigidity than most other
CMM constructions.
Immediately after contact is made between the probe and the surface of the object, the coordinate positions of
the probe are accurately measured by displacement transducers associated with each of the three linear axes and
recorded by the CMM controller.
Common displacement transducers used on CMMs include optical scales, rotary encoders, and magnetic scales.
After the probe has been separated from the contact surface, it returns to its neutral position.
advantages and disadvantages. Nearly all CMMs have a mechanical configuration that fits into one of the following
Cantilever, (b) Moving Bridge, (c) Fixed bridge, (d) Horizontal arm (moving ram type), (e) Gantry, and
In the cantilever configuration, illustrated in Figure, the probe is attached to a vertical quill that moves in the z
axis direction relative to a horizontal arm that overhangs a fixed worktable.
The quill can also be moved along the length of the arm to achieve y-axis motion, and the arm can be moved
relative to the worktable to achieve x-axis motion.
The advantages of this construction are: (1) convenient access to the worktable, (2) high throughput
which parts can be mounted and measured on the CMM, (3) capacity to measure large workparts (on large
P a g e | 37
Immediately after contact is made between the probe and the surface of the object, the coordinate positions of
transducers associated with each of the three linear axes and
Common displacement transducers used on CMMs include optical scales, rotary encoders, and magnetic scales.
rface, it returns to its neutral position.
fits into one of the following
Cantilever, (b) Moving Bridge, (c) Fixed bridge, (d) Horizontal arm (moving ram type), (e) Gantry, and
In the cantilever configuration, illustrated in Figure, the probe is attached to a vertical quill that moves in the z-
axis motion, and the arm can be moved
The advantages of this construction are: (1) convenient access to the worktable, (2) high throughput-the rate at
the CMM, (3) capacity to measure large workparts (on large

Kiran Vijay Kumar
(b) Moving bridge:
• In the moving bridge design, illustrated in Figure,
relative to a stationary table on which is positioned the part to be measured.
• This provides a more rigid structure than the cantilever design and its advocates claim that this makes the
moving bridge CMM more accurate.
• However, one of the problems encountered with the moving bridge design is
in which the two legs of the bridge move at slightly different speeds, resulting in twisting of the bridge.
• This phenomenon degrades the accuracy of the measurements. Yawing is reduced on moving bridge CMMs
when dual drives and position feedback controls are installed for both legs.
• The moving bridge design is the most widely used in industry & it is well suited to the size rang
commonly encountered in production machine shops.
(c) Fixed bridge:
• In this configuration, illustrated in Figure, the bridge is attached to the CMM bed and the worktable is moved in
the x-direction beneath the bridge. This construction
rigidity and accuracy.
• However, throughput is adversely affected because of the additional mass involved to move the heavy
worktable with part mounted on it.
(d) Horizontal arm:
Moving bridge:
In the moving bridge design, illustrated in Figure, the probe is mounted on a bridge structure that is moved
relative to a stationary table on which is positioned the part to be measured.
This provides a more rigid structure than the cantilever design and its advocates claim that this makes the
dge CMM more accurate.
However, one of the problems encountered with the moving bridge design is yawing
grades the accuracy of the measurements. Yawing is reduced on moving bridge CMMs
when dual drives and position feedback controls are installed for both legs.
The moving bridge design is the most widely used in industry & it is well suited to the size rang
commonly encountered in production machine shops.
Fixed bridge:
In this configuration, illustrated in Figure, the bridge is attached to the CMM bed and the worktable is moved in
direction beneath the bridge. This construction eliminates the possibility of yawing, hence increasing
However, throughput is adversely affected because of the additional mass involved to move the heavy
worktable with part mounted on it.
Horizontal arm:
P a g e | 38
the probe is mounted on a bridge structure that is moved
This provides a more rigid structure than the cantilever design and its advocates claim that this makes the
yawing {also known as walking),
grades the accuracy of the measurements. Yawing is reduced on moving bridge CMMs
The moving bridge design is the most widely used in industry & it is well suited to the size range of parts
In this configuration, illustrated in Figure, the bridge is attached to the CMM bed and the worktable is moved in
eliminates the possibility of yawing, hence increasing
However, throughput is adversely affected because of the additional mass involved to move the heavy

Kiran Vijay Kumar
• The horizontal arm configuration consists of a cantilevered horizontal arm mounted to a vertical column. The
arm moves vertically and in and out to achieve y
• To achieve x-axis motion, either the column is moved horizontally past the worktable (called the
design), or the worktable is moved past the column (called the
• The moving ram design is illustrated in Figure. The cantilever design of the horizontal arm configuration makes
it less rigid and therefore less accurate than
• On the positive side, it allows good accessibility to the work area. Large horizontal arm machines are suited to
the measurement of automobile bodies.
(e) Gantry:
• This construction, illustrated in Figure, is generally intended for
• The probe quill (z-axis) moves relative to the horizontal arm extending between the two rails of the gantry.
• The workspace in a large gantry type CMM can be as great as 25 m (82 ft) in the x
the y-direction by 6 m (20 ft) in the z
(f) Column:
• This configuration, illustrated in Figure, is similar to the construction of a machine tool.
• The x- and y-axis movements are achieved by moving the worktable, while the probe quill is moved vertica
along a rigid column to achieve z
In all of these constructions, special design features are used to build high accuracy and precision into the
frame. These features include precision rolling
to isolate the CMM and reduce vibrations in the Factory from being transmitted through the floor, and various
schemes to counterbalance the overhanging arm in the case of the cantilever construction.
guration consists of a cantilevered horizontal arm mounted to a vertical column. The
arm moves vertically and in and out to achieve y-axis and a-axis motions.
axis motion, either the column is moved horizontally past the worktable (called the
design), or the worktable is moved past the column (called the moving table design).
The moving ram design is illustrated in Figure. The cantilever design of the horizontal arm configuration makes
it less rigid and therefore less accurate than other CMM structures.
On the positive side, it allows good accessibility to the work area. Large horizontal arm machines are suited to
the measurement of automobile bodies.
This construction, illustrated in Figure, is generally intended for inspecting large objects.
axis) moves relative to the horizontal arm extending between the two rails of the gantry.
The workspace in a large gantry type CMM can be as great as 25 m (82 ft) in the x-
direction by 6 m (20 ft) in the z-direction
This configuration, illustrated in Figure, is similar to the construction of a machine tool.
axis movements are achieved by moving the worktable, while the probe quill is moved vertica
along a rigid column to achieve z-axis motion.
frame. These features include precision rolling-contact bearings and hydrostatic air-bearings,
P a g e | 39
guration consists of a cantilevered horizontal arm mounted to a vertical column. The
axis motion, either the column is moved horizontally past the worktable (called the moving ram
design).
The moving ram design is illustrated in Figure. The cantilever design of the horizontal arm configuration makes
On the positive side, it allows good accessibility to the work area. Large horizontal arm machines are suited to
inspecting large objects.
axis) moves relative to the horizontal arm extending between the two rails of the gantry.
-direction by 11m (26 ft) in
This configuration, illustrated in Figure, is similar to the construction of a machine tool.
axis movements are achieved by moving the worktable, while the probe quill is moved vertically
bearings, installation mountings

CMM Operation and Programming:-
Positioning the probe relative to the part can be accomplished in several ways, ranging from manual
operation to Direct Computer Control (DCC). This includes: (1) types of CMM controls and (2) programming of
computer-controlled CMMs.
CMM Controls: The methods of operating and controlling a CMM can be classified into four main
categories: (1) manual drive, (2) manual drive with computer-assisted data processing, (3) motor drive with
computer-assisted data processing, and (4) DCC with computer-assisted data processing.
(1) Manual drive CMM:
• The human operator physically moves the probe along the machine's axis to make contact with the part and
record the measurements.
• The three orthogonal slides are designed to be nearly frictionless to permit the probe to be free floating in the x-,
y-, and z-directions.
• The measurements are provided by a digital readout, which the operator can record either manually or with
paper printout. Any calculations on the data (e.g., calculating the center and diameter of a hole) must be made
by the operator.
(2) CMM with manual drive and computer-assisted data processing:
• It provides some data processing and computational capability for performing the calculations required to
evaluate a given part feature.
• The types of data processing and computations range from simple conversions between U.S. customary units
and metric to more complicated geometry calculations, such as determining the angle between two planes.
• The probe is still free floating to permit the operator to bring it into contact with the desired part surfaces.
(3) Motor-driven CMM with computer-assisted data processing:
• This uses electric motors to drive the probe along the machine axis under operator control, a joystick or similar
device is used as the means of controlling the motion.
• Features are low-power stepping motors and friction clutches are utilized to reduce the effects of collisions
between the probe and the part.
• The motor drive can be disengaged to permit the operator to physically move the probe as in the manual control
method.
• Motor-driven CMMs are generally equipped with data processing to accomplish the geometric computations
required in feature assessment.
(4) CMM with direct computer control (DCC):
• It operates like a CNC machine tool, it is motorized and the movements of the coordinate axes are controlled by
a dedicated computer under program control.
• The computer also performs the various data processing and calculation functions and compiles a record of the
measurements made during inspection. As with a CNC machine tool, the DCC CMM requires part
programming.
DCC Programming: There are two principle methods of programming a DCC measuring machine: (1)
manual lead through and (2) off-line programming
.
(1) Manual lead through method:
• In this method the operator leads the CMM probe through the various motions required in the inspection
sequence, indicating the points and surfaces that are to be measured and recorded into the control memory.
• It is similar to the robot programming technique.
• During regular operation, the CMM controller plays back the program to execute the inspection procedure.

(2) Off-line programming:
• Off line programming is accomplished in the manner of computer-assisted NC part programming. The program
is prepared off-line based on the pan drawing (in computer) and then downloaded to the CMM controller for
execution.
• The programming statements for a computer- controlled CMM include motion commands, measurement
commands, and report formatting commands.
• The motion commands are used to direct the probe to a desired inspection location.
• The measurement statements are used to control the measuring and inspection function of the machine, calling
the various data processing and calculation routines into play.
• Finally, the formatting statements permit the specification of the output reports to document the inspection.
An enhancement of off-line programming is CAD programming. Off-line programming on a CAD system
is facilitated by the Dimensional Measuring Interface Standard (DMlS). DMTS is a protocol that permits two-way
communication between CAD systems and CMMs.
Other CMM Software’s:-
CMM software is the set of programs and procedures (with supporting documentation) used to operate the
CMM and its associated equipment.
In addition to Part programming software discussed in above context some additional software used are,
(1) Core software,
(2) Post-inspection software, and
(3) Reverse engineering and application-specific software.
(1) Core software:
Core software consists of the minimum basic programs required for the CMM to function, excluding part
programming software which applies only to DCC machines. This software is generally applied either before or
during the inspection procedure.
Core programs normally include the following:
• Probe calibration: This function is required to define the parameters of the probe (such as tip radius, tip
positions for a multi-tip probe) so that coordinate measurements can be automatically compensated for the
probe dimensions when the tip contacts the part surface, avoiding the necessity to perform probe tip
calculations. Calibration is usually accomplished by causing the probe to contact a cube or sphere of known
dimensions.
• Part coordinate system definition: This software permits measurements of the part to be made without
requiring a time-consuming part alignment procedure on the CMM worktable. Instead of physically aligning the
part to the CMM axes, the measurement axis are mathematically aligned relative to the part.
• Geometric feature construction: This software addresses the problems associated with geometric features
whose evaluation requires more than one point measurement. The software integrates the multiple
measurements so that a given geometric feature such as flatness, squareness, determining the center of a hole or
the axis of a cylinder, and so on can be evaluated.
• Tolerance analysis: This software allows measurements taken on the part to be compared to the dimensions and
tolerances specified on the engineering drawing.
(2) Post-Inspection Software:
Post-inspection software is composed of the set of programs that are applied after the inspection procedure.
Such software often adds significant utility and value to the inspection function.
The programs included in this group are the following:
• Statistical analysis: This software is used to carry out any of various statistical analyses on the data collected by
the CMM. For example part dimension data can be used to assess process capability of the associated
manufacturing process or for statistical process control.
Two alternative approaches have been adopted by CMM makers in this area. The first approach is to
provide software that creates a database of the measurements taken and facilitates exporting of the database to
other software packages. The data collected in this approach by a CMM are already coded in digital form &
permits the user to select among many statistical analysis packages that are commercially available. The second
approach is to include a statistical analysis program among the software supplied by the CMM builder. This
approach is generally quicker and easier, but the range of analyses available is not as great.

• Graphical data representation: The purpose of this software is to display the data collected during the CMM
procedure in a graphical or pictorial way, thus permitting easier visualization of form errors and other data by
the user.
(3) Reverse Engineering and Application-Specific Software:
Reverse engineering software is designed to take an existing physical part and construct a computer model
of the part geometry based on a large number of measurements of its surface by a CMM. This is currently a
developing area in CMM and CAD software.
The simplest approach is to use the CMM in the manual mode of operation in which the operator moves the
probe by hand and scans the physical part to create a digitized three-dimensional (3-D) surface model.
Application-specific software refers to programs written for certain types of part and/or products and
whose applications are generally limited to specific industries. Some Important examples are,
• Gear checking: These programs are used on a CMM to measure the geometric features of a gear, such as tooth
profile, tooth thickness, pitch, and helix angle.
• Thread checking: These are used for inspection of cylindrical and conical threads.
• Cam checking: This specialized software is used to evaluate the accuracy of physical cams relative to design
specifications.
• Automobile body checking: This software is designed for CMMs used to measure sheet metal panels,
subassemblies, and complete car bodies in the automotive industry.
• Operate accessory equipment associated with the CMM such as probe changers, rotary worktables used on
the CMM, and automatic part loading and unloading devices.
CMM Applications and Benefits:-
There are many of applications of CMMs some of them are,
1. 100% inspection or sampling inspection, the CMM measurements are frequently used for statistical process
control.
Other CMM applications includes,
2. Audit inspection and calibration of gages and fixtures.
Audit inspection refers to the inspection of incoming parts from a vendor to ensure that the vendor's quality
control systems are reliable. This is usually done on a sampling basis. In effect, this application is the same as post-
process inspection.
Gage and fixture calibration involves the measurement of various gages, fixtures, and other inspection and
production tooling to validate their continued use.
The advantages or benefits of using CMMs over manual inspection methods are,
• Reduced inspection cycle time: Because of the automated techniques included in the operation of a CMM,
inspection procedures are speeded and labor productivity is improved.
• Flexibility: A CMM is a general-purpose machine that can be used to inspect a variety of different part
configurations with minimal changeover time. In the case of the DCC machine, where programming is
performed off-line, changeover time on the CMM involves only the physical setup.
• Reduced operator errors: Automating the inspection procedure has the obvious effect of reducing human errors
in measurements and setups.
• Greater inherent accuracy and precision: A CMM is inherently more accurate and precise than the manual
surface plate methods that are traditionally used for inspection.
• Avoidance of multiple setups: Traditional inspection techniques often require multiple setups to measure
multiple part features and dimensions. In general, all measurements can be made in a single setup on a CMM,
thereby increasing throughout and measurement accuracy.
Flexible Inspection Systems:-
A flexible inspection system (FIS) takes the versatility of the CMM one step further. In concept, the FIS is
related to a CMM in the way a flexible manufacturing system (FMS) is related to a machining center. A flexible
inspection system is defined as a highly automated inspection workcell consisting of one or more CMMs and other
types of inspection equipment plus the parts handling systems needed to move parts into, within, and out of the cell.
Robots might be used to accomplish some of the parts-handling tasks in the system. All the components of the FIS
are computer controlled.

Kiran Vijay Kumar
An example of an FIS at Boeing Aerospace Company is reported in Schaffer is illustrated in the layout in
Figure bellow,
• The system consists of two DCC
storage-and-retrieval cart that interconnects the various components of the cell.
• A staging area for loading and unloading pallets into and out of the cell is located immedi
• The CMMs in the cell perform dimensional inspection based on programs prepared off
• The robotic station is equipped with an ultrasonic inspection probe to check skin thickness of hollow wing
sections for Boeing's aerospace
Inspection Probes on Machine Tools
A machine-mounted inspection probe is
the inspection. The argument against this is that certain errors inherent in the cutting operation will als
manifested in the measuring operation.
For example, if there is misalignment between the machine tool axis, thus producing out
this condition will not be identified by the machine mounted probe because the movement of the probe is af
the same axis misalignment.
To generalize, errors that are common to both the production process and the measurement procedure will
go undetected by a machine-mounted inspection probe. These errors include: machine tool geometry errors (such as
the axis misalignment problem identified above), thermal distortions in the machine tool axes, and errors in any
thermal correction procedures applied to the machine tool.
Errors that are not common to both systems should be detectable by the measurement p
measurable errors include tool and/or tool holder deflection, workpart deflection, tool offset errors, and effects of
tool wear on the workpart.
In practice, the use of machine
and saving time as an alternative to expensive off
Machine Vision:-
Machine vision can be defined as the acquisition of image data, followed by the processing and
interpretation of these data by computer for some useful application. Machine vision (also called
since a digital computer is required to process the image dat
applications in industrial inspection.
DCC CMMs, a robotic inspection station, an automated storage system, and a
retrieval cart that interconnects the various components of the cell.
A staging area for loading and unloading pallets into and out of the cell is located immedi
The CMMs in the cell perform dimensional inspection based on programs prepared off
The robotic station is equipped with an ultrasonic inspection probe to check skin thickness of hollow wing
sections for Boeing's aerospace products.
Inspection Probes on Machine Tools:-
mounted inspection probe is that the same machine tool making the part is also performing
the inspection. The argument against this is that certain errors inherent in the cutting operation will als
manifested in the measuring operation.
For example, if there is misalignment between the machine tool axis, thus producing out
this condition will not be identified by the machine mounted probe because the movement of the probe is af
mounted inspection probe. These errors include: machine tool geometry errors (such as
he axis misalignment problem identified above), thermal distortions in the machine tool axes, and errors in any
thermal correction procedures applied to the machine tool.
Errors that are not common to both systems should be detectable by the measurement p
In practice, the use of machine-mounted inspection probes has proved to be effective in improving
and saving time as an alternative to expensive off-line inspection operations.
can be defined as the acquisition of image data, followed by the processing and
interpretation of these data by computer for some useful application. Machine vision (also called
since a digital computer is required to process the image data) is a rapidly growing technology, with its principal
applications in industrial inspection.
P a g e | 43
CMMs, a robotic inspection station, an automated storage system, and a
A staging area for loading and unloading pallets into and out of the cell is located immediately outside the FIS.
The CMMs in the cell perform dimensional inspection based on programs prepared off-line.
The robotic station is equipped with an ultrasonic inspection probe to check skin thickness of hollow wing
that the same machine tool making the part is also performing
the inspection. The argument against this is that certain errors inherent in the cutting operation will also be
For example, if there is misalignment between the machine tool axis, thus producing out-of-square parts,
this condition will not be identified by the machine mounted probe because the movement of the probe is affected by
mounted inspection probe. These errors include: machine tool geometry errors (such as
he axis misalignment problem identified above), thermal distortions in the machine tool axes, and errors in any
Errors that are not common to both systems should be detectable by the measurement probe. These
mounted inspection probes has proved to be effective in improving quality
can be defined as the acquisition of image data, followed by the processing and
interpretation of these data by computer for some useful application. Machine vision (also called computer vision,
a) is a rapidly growing technology, with its principal

Kiran Vijay Kumar
The operation of a machine vision system can be divided into the following three functions:
(1) Image acquisition and digitization. (2) Image processing and analys
(1) Image Acquisition and Digitization
• Image acquisition and digitization is accomplished using a video camera and a digitizing system to store the
image data tor subsequent analysis.
• The camera is focused on the subject of inter
matrix of discrete picture elements (called pixels). In which each element has a value that is proportional to the
light intensity of that portion of the scene.
• The intensity value for each pixel is converted into its equivalent digital value by an ADC, this is digitization of
the image.
(2) Image Processing and Analysis
• The second function in the operation of a machine vision system is image processing and analysis, the amount
of data that must be processed is significant.
• The data for each frame must be analyzed within the time required to complete one scan (1/30 sec). A number
of techniques have been developed for analyzing the image data in a machine vision system.
• One category of techniques in image processing and analysis is called segmentation.
are intended to define and separate regions of interest within the image.
• Two of the common segmentation techniques are
• Thresholding involves the conversion of each pixel intensity level into a binary value, representing either white
or black.
• Edge detection is concerned with determining the location of boundaries between an object and its surroundings
in an image.
• Another set of techniques in image processing and analysis that normally follows segmentation
extraction.
• Feature extraction methods are designed to determine features such as object's area, length, width, diameter,
perimeter, center of gravity, and aspect ratio based
(3) Interpretation:-
• For any given application, the image must be interpreted based on the extracted features. The interpretation
function is usually concerned with recognizing the object, a task termed
recognition.
• The objective in these tasks is to identify the object in the image by comparing it with predefined models or
standard values.
• Two commonly used interpretation techniques are
• Template matching is the name given to various methods that attempt to compare one or more features of an
image with the corresponding features of a model or template stored in computer memory.
• Feature weighting is a technique in which several features (e.g., area,
a single measure by assigning a weight to each feature according to its relative importance in identifying the
object.
Image acquisition and digitization. (2) Image processing and analysis, and (3) Interpretation.
Image Acquisition and Digitization:
Image acquisition and digitization is accomplished using a video camera and a digitizing system to store the
image data tor subsequent analysis.
The camera is focused on the subject of interest and an Image is obtained by dividing the viewing area into a
light intensity of that portion of the scene.
ixel is converted into its equivalent digital value by an ADC, this is digitization of
Image Processing and Analysis:-
The second function in the operation of a machine vision system is image processing and analysis, the amount
must be processed is significant.
The data for each frame must be analyzed within the time required to complete one scan (1/30 sec). A number
ques in image processing and analysis is called segmentation.
intended to define and separate regions of interest within the image.
Two of the common segmentation techniques are thresholding and edge detection.
olves the conversion of each pixel intensity level into a binary value, representing either white
is concerned with determining the location of boundaries between an object and its surroundings
s in image processing and analysis that normally follows segmentation
Feature extraction methods are designed to determine features such as object's area, length, width, diameter,
perimeter, center of gravity, and aspect ratio based on the area and boundaries of the object.
For any given application, the image must be interpreted based on the extracted features. The interpretation
function is usually concerned with recognizing the object, a task termed object recogni
The objective in these tasks is to identify the object in the image by comparing it with predefined models or
Two commonly used interpretation techniques are template matching and feature weighting
is the name given to various methods that attempt to compare one or more features of an
is a technique in which several features (e.g., area, length, and perimeter) are combined into
P a g e | 44
is, and (3) Interpretation.
Image acquisition and digitization is accomplished using a video camera and a digitizing system to store the
est and an Image is obtained by dividing the viewing area into a
ixel is converted into its equivalent digital value by an ADC, this is digitization of
The second function in the operation of a machine vision system is image processing and analysis, the amount
The data for each frame must be analyzed within the time required to complete one scan (1/30 sec). A number
ques in image processing and analysis is called segmentation.Segmentation techniques
olves the conversion of each pixel intensity level into a binary value, representing either white
is concerned with determining the location of boundaries between an object and its surroundings
s in image processing and analysis that normally follows segmentation is feature
Feature extraction methods are designed to determine features such as object's area, length, width, diameter,
on the area and boundaries of the object.
For any given application, the image must be interpreted based on the extracted features. The interpretation
object recognition or pattern
The objective in these tasks is to identify the object in the image by comparing it with predefined models or
template matching and feature weighting.
is the name given to various methods that attempt to compare one or more features of an
length, and perimeter) are combined into

Kiran Vijay Kumar
Machine Vision Applications:-
Machine vision applications in manufacturing divide into three
and (3) visual guidance and control.
Inspection: By far, quality control
constitutes about 80% of machine vision applications.
automated inspection tasks, most of which are either on
almost always in mass production where the time required to program and set up the vision s
over many thousands of units.
Part identification: applications are those in which the vision system is used to recognize and perhaps
distinguish parts or other objects so that some action can be taken. The applications include part sorting, counting
different types of parts flowing past along a conveyor,
accomplished by 2-D vision systems.
Visual guidance and control:
similar machine to control the movement of the machine.
continuous arc welding, part positioning and/or reorientation, bin picking, collision avoidance, machining
operations, and assembly tasks. Most of these applications require 3
Optical Inspection Methods:
Machine vision tends to imitate the capabilities of the human optical sensory system, which includes not
only the eyes but also the complex interpretive powers of the brain but in optical inspection techniques it has a much
simpler mode of operation.
Scanning Laser Systems:-
The unique feature of a laser
that it uses a coherent beam of light that can be projected with minimum diffusion. Because of this feature
have been used in a number of industrial processing and measuring applications. High
for welding and cutting of materials, and low
• The scanning laser uses a laser beam that is deflected by a rotating mirror to produce a beam of light that can be
focused to sweep past an object.
• A photodetector on the far side of the object senses the light beam except for the time period during the sweep
when it is interrupted by the object.
• This time period can be measured with great accuracy and related to the size of the object in the path of the laser
beam.
• The scanning laser beam device can complete its measurement in a very short time cycle.
• A microprocessor counts the time interruption of the scanning laser beam as it sweeps past the object, makes the
conversion from time to a linear dimension, and signals other equipment to make adjustments in the
manufacturing process and/or activate a sort
The applications of the scanning laser technique include rolling mill operations, wire extrusion, and
machining and grinding processes.
Machine vision applications in manufacturing divide into three categories: (1) inspection, (2) identification,
and (3) visual guidance and control.
By far, quality control inspection is the biggest category. Estimates are that inspection
constitutes about 80% of machine vision applications. Machine vision installations in industry perform a variety of
automated inspection tasks, most of which are either on-line-in-process or on-line/post-process. The applications are
almost always in mass production where the time required to program and set up the vision s
applications are those in which the vision system is used to recognize and perhaps
different types of parts flowing past along a conveyor, and inventory monitoring. Part identification can usually be
D vision systems.
Visual guidance and control: involves applications in which a vision system is teamed with a robot or
similar machine to control the movement of the machine. Examples of these applications include seam tracking in
operations, and assembly tasks. Most of these applications require 3-D vision.
:-
-
The unique feature of a laser (laser stands for light amplification by stimulated emission of radiation) is
that it uses a coherent beam of light that can be projected with minimum diffusion. Because of this feature
have been used in a number of industrial processing and measuring applications. High-energy laser beams
for welding and cutting of materials, and low-energy lasers are utilized in various measuring and gaging situations.
r uses a laser beam that is deflected by a rotating mirror to produce a beam of light that can be
focused to sweep past an object.
A photodetector on the far side of the object senses the light beam except for the time period during the sweep
nterrupted by the object.
This time period can be measured with great accuracy and related to the size of the object in the path of the laser
The scanning laser beam device can complete its measurement in a very short time cycle.
A microprocessor counts the time interruption of the scanning laser beam as it sweeps past the object, makes the
manufacturing process and/or activate a sortation device on the production line.
P a g e | 45
categories: (1) inspection, (2) identification,
is the biggest category. Estimates are that inspection
installations in industry perform a variety of
process. The applications are
almost always in mass production where the time required to program and set up the vision system can be spread
applications are those in which the vision system is used to recognize and perhaps
and inventory monitoring. Part identification can usually be
involves applications in which a vision system is teamed with a robot or
Examples of these applications include seam tracking in
stands for light amplification by stimulated emission of radiation) is
that it uses a coherent beam of light that can be projected with minimum diffusion. Because of this feature lasers
energy laser beams are used
energy lasers are utilized in various measuring and gaging situations.
r uses a laser beam that is deflected by a rotating mirror to produce a beam of light that can be
A photodetector on the far side of the object senses the light beam except for the time period during the sweep
This time period can be measured with great accuracy and related to the size of the object in the path of the laser
The scanning laser beam device can complete its measurement in a very short time cycle.
A microprocessor counts the time interruption of the scanning laser beam as it sweeps past the object, makes the

Kiran Vijay Kumar
Linear Array Devices:-
The operation of a linear array for automated inspection i
except that the pixels are arranged in only one dimension rather than two.
• A schematic diagram showing one possible arrangement of a linear array device is presented in above Figure.
• The device consists of a light source that emits a planar sheet of light directed at an object. On the opposite side
of the object is a linear array of closely spaced photo diodes. Typical numbers of diodes in the array are 256,
1024, and 2048.
• The sheet of light is blocked by the
indicate the object's dimension of interest.
Advantages: simplicity, accuracy, and speed. It has no moving parts and is claimed to possess a resolution
as small as 50millions of an inch. It can complete a measurement in a much smaller time cycle than either machine
vision or the scanning laser beam technique.
Optical Triangulation Techniques
Triangulation techniques are based on the trigonometric relationships of a right triangle. Triangulation is
used for range-finding. That is, determining the distance or range of an object from two known points.
• Use of the principle in an optical measuring system is explained with reference to Figure.
• A light source (typically a laser) is used to focus a narrow beam at an object to form a spot of light on the
object.
• A linear array of photo diodes or other position
spot.
The angle A of the beam directed at the object is fixed and known and so is the distance
source and the photosensitive detector. Accordingly, the range
source and the photosensitive detector in Figure can be determined as a function of the angle from trigonometric
relationships as follows:
The operation of a linear array for automated inspection is similar in some respects to machine vision,
except that the pixels are arranged in only one dimension rather than two.
A schematic diagram showing one possible arrangement of a linear array device is presented in above Figure.
light source that emits a planar sheet of light directed at an object. On the opposite side
The sheet of light is blocked by the object, and this blocked light is measured by the photo diode array to
indicate the object's dimension of interest.
simplicity, accuracy, and speed. It has no moving parts and is claimed to possess a resolution
vision or the scanning laser beam technique.
Optical Triangulation Techniques:-
finding. That is, determining the distance or range of an object from two known points.
the principle in an optical measuring system is explained with reference to Figure.
A light source (typically a laser) is used to focus a narrow beam at an object to form a spot of light on the
A linear array of photo diodes or other position-sensitive optical detector is used to determine the location of the
of the beam directed at the object is fixed and known and so is the distance
source and the photosensitive detector. Accordingly, the range R of the object from the base line defined by the light
R=L cot A
P a g e | 46
s similar in some respects to machine vision,
A schematic diagram showing one possible arrangement of a linear array device is presented in above Figure.
light source that emits a planar sheet of light directed at an object. On the opposite side
object, and this blocked light is measured by the photo diode array to
simplicity, accuracy, and speed. It has no moving parts and is claimed to possess a resolution
finding. That is, determining the distance or range of an object from two known points.
the principle in an optical measuring system is explained with reference to Figure.
A light source (typically a laser) is used to focus a narrow beam at an object to form a spot of light on the
sitive optical detector is used to determine the location of the
of the beam directed at the object is fixed and known and so is the distance L between the light
ject from the base line defined by the light

Non-contact Non-optical Inspection Techniques:-
In addition to noncontact optical inspection methods, there are also a variety of non optical techniques used
for inspection tasks in manufacturing. Examples include sensor techniques based on electrical fields, radiation,
and ultrasonic’s.
Electrical Field Techniques:
Under certain conditions, an electrical field can be created by an electrically active probe. The field is
affected by an object in the vicinity of the probe. Examples of electrical fields include reluctance, capacitance and
inductance.
• In the typical application, the object (workpart) is positioned in a defined relation with respect to the probe.
• By measuring the effect of the object on the electrical field, an indirect measurement or gaging of certain part
characteristics can be made, such as dimensional features, thickness of sheet material and in some cases, flaws
(cracks and voids below the surface) in the material.
Radiation Techniques:
Radiation techniques utilize X-ray radiation to accomplish noncontact inspection procedures on metals and
weld-fabricated products.
• In the typical application, the amount of radiation absorbed by the metal object can be used to indicate thickness
and presence of flaws ill the metal part or welded section.
An example is the use of X-ray inspection techniques to measure thickness of sheet metal made in a rolling mill.
Ultrasonic Inspection Methods:
Ultrasonic techniques make use of very high frequency sound (> 20,000 Hz] for various inspection tasks.
Some of the techniques are performed manually, whereas others are automated.
• In one of the automated method, involves the analysis of ultrasonic waves that are emitted by a probe and
reflected off the object to be inspected.
• In the setup of the inspection procedure, an ideal test part is placed in front of the probe to obtain a reflected
sound pattern. This sound pattern becomes the standard against which production parts are later compared.
• If the reflected pattern from a given production part matches the standard, the part is considered acceptable;
otherwise, it is rejected.
One technical problem with this technique involves the presentation of production parts in front of the probe. To
avoid extraneous variations in the reflected sound patterns, the parts must always be placed in the same position and
orientation relative to the probe.

UNIT - 8
Manufacturing Support System
Sylabus:-
Manufacturing Support System: Process Planning, Computer Aided Process Planning, Concurrent
Engineering & Design for Manufacturing, Advanced Manufacturing Planning, Just-in Time Production System,
Basic concepts of lean and Agile manufacturing.
Process Planning:-
Process planning involves determining the most appropriate manufacturing and assembly
processes and the sequence in which they should be accomplished to produce a given part or product
according to specifications set for the product design documentation. The scope and variety of processes
that can be planned are generally limited by the available processing equipment and technological
capabilities of the company or plant.
Process planning is usually accomplished by manufacturing engineers. Following is a list of the
many decisions and details usually included within the scope of process planning.
• Interpretation of design drawings: The part or product design must be analyzed at the start of the
process planning procedure.
• Processes and sequence: The process planner must select which processes are required and their
sequence. A brief description of all processing steps must be prepared.
• Equipment selection: In general, process planners must develop plans that utilize existing equipment
in the plant. Otherwise, the component must be purchased, or an investment must be made in new
equipment.
• Tools, dies, molds, fixtures and gages: The process planner must decide what tooling is required for
each processing step.
• Methods analysis: Workplace layout, small tools, hoists for lifting heavy parts, even in some cases
hand and body motions must be specified for manual operations.
• Work standards: Work measurement techniques are used to set time standards for each operation.
• Cutting tools and cutting conditions: These must be specified for machining operations, often with
reference to standard handbook recommendations.
Process Planning for Parts:-
For individual parts, the processing sequence is documented on a form called a route sheet or
operation sheet.
Route sheets are used to specify the process plan. They are counterparts, one for product design, the other
for manufacturing.
A typical route sheet includes the following information:
(1) All operations to be performed on the workpart, listed in the order in which they should be
performed;
(2) A brief description of each operation indicating the processing to be accomplished, with references to
dimensions and tolerances on the part drawing;
(3) The specific machine, on which the work is to be done; and
(4) Any special tooling, such as dies, molds, cutting tools, jigs or fixtures, and gages.
Some companies also include setup times, cycle time standards, and other data. It is called a route
sheet because the processing sequence defines the route that the part must follow in the factory.

Kiran Vijay Kumar
A typical processing sequence to fabricate an individual part consists of: (1) a basic process, (2)
secondary processes, (3) operations to enhance physical properties, and (4) finishing operation.
• A basic process determines the starting geometry of the work part
and rolling of sheet metal arc examples of basic processes.
• The starting geometry must often be refined by
starting geometry into the final geometry.
• Operations to enhance properties do
properties. Heat-treating operations on metal parts are the most common example.
• Finally, finishing operations
Examples include electroplating, thin film deposition techniques, and painting.
Process Planning for Assemblies
The type of assembly method used for a given product depends on factors such as: (1) The anticipated
production quantities; (2) Complexity
Process planning for assembly involves development of assembly instructions similar to the list of
work elements but in more detail.
• For low production quantities, the entire assembly is completed at a single station.
• For high production on an assembly line, process planning consists of allocating work elements to the
individual stations of the line, a procedure called
• The assembly line routes the work units to individual stations in the proper order as determined by the
line balancing solution.
• As in process planning for individual components, any tools and fixtures required to accomplish an
assembly task must be determined, designed, and built; and the workstation arrangement must be laid out.
Make or Buy Decision:-
An important question that arises in process planning is whether a given part should be produced in
the company's own factory or purchased from an outs
known as the make or buy decision.
If the company does not possess the technological equipment or expertise in the particular
manufacturing processes required making the part, then the answer is obvious: The
purchased because there is no internal alternative.
However, in many cases, the part could either be made internally using existing equipment, or it could
be purchased externally from vendors that possess similar manufacturing capability.
cal processing sequence to fabricate an individual part consists of: (1) a basic process, (2)
determines the starting geometry of the work part. Metal casting, plastic molding,
and rolling of sheet metal arc examples of basic processes.
The starting geometry must often be refined by secondary processes, operations that transform the
starting geometry into the final geometry.
properties do not alter the geometry of the part; instead, they alter physical
treating operations on metal parts are the most common example.
Finally, finishing operations usually provide a coating on the work part (or assembly) surface.
Process Planning for Assemblies:-
production quantities; (2) Complexity of the assembled product,and (3) Assembly processes used.
work elements but in more detail.
For low production quantities, the entire assembly is completed at a single station.
For high production on an assembly line, process planning consists of allocating work elements to the
individual stations of the line, a procedure called line balancing.
The assembly line routes the work units to individual stations in the proper order as determined by the
As in process planning for individual components, any tools and fixtures required to accomplish an
rmined, designed, and built; and the workstation arrangement must be laid out.
the company's own factory or purchased from an outside vendor, and the answers to this question is
decision.
manufacturing processes required making the part, then the answer is obvious: The
purchased because there is no internal alternative.
P a g e | 49
cal processing sequence to fabricate an individual part consists of: (1) a basic process, (2)
. Metal casting, plastic molding,
operations that transform the
not alter the geometry of the part; instead, they alter physical
treating operations on metal parts are the most common example.
usually provide a coating on the work part (or assembly) surface.
and (3) Assembly processes used.
For low production quantities, the entire assembly is completed at a single station.
For high production on an assembly line, process planning consists of allocating work elements to the
The assembly line routes the work units to individual stations in the proper order as determined by the
As in process planning for individual components, any tools and fixtures required to accomplish an
rmined, designed, and built; and the workstation arrangement must be laid out.
ide vendor, and the answers to this question is
manufacturing processes required making the part, then the answer is obvious: The part must be

Kiran Vijay Kumar
Computer-Aided Process Planning
There is much interest by manufacturing firms in automating the task of process planning using
computer-aided process planning (CAPP) systems. The shop
details of machining and other processes are gradually retiring, and these people will be unavailable in the
future to do process planning. An alternative way of accomplishing this function is needed, and CAPP
systems are providing this alternative. CAPP is usually considered to be par
manufacturing (CAM). In fact, a synergy results when CAM is combined with computer
create a CAD/CAM system. In such a system, CAPP becomes the direct connection between design and
manufacturing.
The benefits of computer
• Process rationalization and standardization:
consistent process plans than when process planning is done completely manually. Standard plans
tend to result in lower manufacturing costs and higher product quality.
• Increased productivity of process planners:
process plans in the data files permit more work to be accomplished by the process planners.
• Reduced lead time for process planning:
route sheets in a shorter lead time compared to manual preparation.
• Improved legibility: Computer
prepared route sheets.
• Incorporation of other application programs:
application programs, such as cost estimating and work standards.
Computer-aided process planning systems are designed around two approaches. These
approaches are called: (1) retrieval CAPP systems and (2) generative CAPP systems. Some CAPP
systems combine the two approaches in what is known as semi
(1) Retrieval CAPP systems:
lanning:-
aided process planning (CAPP) systems. The shop-trained people who are familiar with the
processes are gradually retiring, and these people will be unavailable in the
systems are providing this alternative. CAPP is usually considered to be par
In fact, a synergy results when CAM is combined with computer
The benefits of computer-automated process planning includes,
Process rationalization and standardization: Automated process planning leads to more logical and
manufacturing costs and higher product quality.
Increased productivity of process planners: The systematic approach and the
ime for process planning: Process planners working with a CAPP system can provide
route sheets in a shorter lead time compared to manual preparation.
Computer-prepared route sheets are neater and easier to read than manually
Incorporation of other application programs: The CAPP program can be interfaced with other
application programs, such as cost estimating and work standards.
aided process planning systems are designed around two approaches. These
roaches are called: (1) retrieval CAPP systems and (2) generative CAPP systems. Some CAPP
systems combine the two approaches in what is known as semi-generative CAPP.
Retrieval CAPP systems:-
P a g e | 50
trained people who are familiar with the
processes are gradually retiring, and these people will be unavailable in the
systems are providing this alternative. CAPP is usually considered to be part of computer-aided
In fact, a synergy results when CAM is combined with computer-aided design to
Automated process planning leads to more logical and
The systematic approach and the availability of standard
Process planners working with a CAPP system can provide
prepared route sheets are neater and easier to read than manually
The CAPP program can be interfaced with other
aided process planning systems are designed around two approaches. These
roaches are called: (1) retrieval CAPP systems and (2) generative CAPP systems. Some CAPP
generative CAPP.

Kiran Vijay Kumar
• A retrieval CAPP system, also called a
technology (GT) and parts classification and coding.
• Before the system can be used for process planning, a significant amount of information must be
compiled and entered into the CAPP data files. This is referred to as t
• It consists of the following steps: (1) Selecting an appropriate classification and coding scheme for
the company, (2) forming part families for the parts produced by the company; and (3) preparing
standard process plans for the part families.
• After the preparatory phase has been completed, the system is ready for use;
the GT code number for the part.
• If the file contains a process plan for the part it is retrieved and displayed for the user. The
process plan is examined to determine whether any modifications are necessary.
• If the file does not contain a standard process plan for the given code number, the user may search the
computer file for a similar or related code number for which a
• This route sheet becomes the standard process plan for the new part code number.
• The process planning session concludes with the process plan formatter, which prints out the route
sheet in the proper format.
• One of the commercially available retrieval CAPP systems is MultiCapp system.
(2) Generative CAPP Systems:
A generative system creates the process plan based on logical procedures similar to the
procedures a human planner would use. In a fully generative CAPP system,
planned without human assistance and without a set of predefined standard plans.
In first step the technical knowledge of manufacturing and the logic used by successful process
planners must be captured and coded into a computer pr
planning, the knowledge and logic of the human process planners is incorporated into a so
"knowledge base". The generative CAPP system then uses that knowledge base to solve process planning
problems.
The second step in generative process planning is a computer
to be produced. This description contains all of the pertinent data and information needed to plan the
process sequence. Two possible ways of providing this descr
that is developed on a CAD system during product design and (2) a GT code number of the part that
defines the part features in significant detail.
The third step in a generative CAPP system is the capability
planning logic contained in the knowledge base to a given part description. This problem
procedure is referred to as the “
knowledge base and inference engine, the CAPP system synthesizes a new process plan from scratch for
each new part it is presented.
system, also called a variant CAPP system, is based on the principles of group
technology (GT) and parts classification and coding.
Before the system can be used for process planning, a significant amount of information must be
compiled and entered into the CAPP data files. This is referred to as the “preparatory phase”.
It consists of the following steps: (1) Selecting an appropriate classification and coding scheme for
the part families.
After the preparatory phase has been completed, the system is ready for use;the first step is to derive
the GT code number for the part.
If the file contains a process plan for the part it is retrieved and displayed for the user. The
If the file does not contain a standard process plan for the given code number, the user may search the
computer file for a similar or related code number for which a standard route sheet does exist.
This route sheet becomes the standard process plan for the new part code number.
The process planning session concludes with the process plan formatter, which prints out the route
ommercially available retrieval CAPP systems is MultiCapp system.
Generative CAPP Systems:-
procedures a human planner would use. In a fully generative CAPP system,
planners must be captured and coded into a computer program. In an expert system applied to process
planning, the knowledge and logic of the human process planners is incorporated into a so
". The generative CAPP system then uses that knowledge base to solve process planning
e second step in generative process planning is a computer-compatible description of the part
process sequence. Two possible ways of providing this description are: (l) the geometric model of the part
defines the part features in significant detail.
The third step in a generative CAPP system is the capability to apply the process knowledge and
planning logic contained in the knowledge base to a given part description. This problem
procedure is referred to as the “inference engine” in terminology of expert systems. By using its
ce engine, the CAPP system synthesizes a new process plan from scratch for
P a g e | 51
is based on the principles of group
Before the system can be used for process planning, a significant amount of information must be
he “preparatory phase”.
It consists of the following steps: (1) Selecting an appropriate classification and coding scheme for
the first step is to derive
If the file contains a process plan for the part it is retrieved and displayed for the user. The standard
If the file does not contain a standard process plan for the given code number, the user may search the
standard route sheet does exist.
This route sheet becomes the standard process plan for the new part code number.
The process planning session concludes with the process plan formatter, which prints out the route
ommercially available retrieval CAPP systems is MultiCapp system.
procedures a human planner would use. In a fully generative CAPP system, the process sequence is
ogram. In an expert system applied to process
planning, the knowledge and logic of the human process planners is incorporated into a so-called
". The generative CAPP system then uses that knowledge base to solve process planning
compatible description of the part
iption are: (l) the geometric model of the part
to apply the process knowledge and
planning logic contained in the knowledge base to a given part description. This problem-solving
” in terminology of expert systems. By using its
ce engine, the CAPP system synthesizes a new process plan from scratch for

Kiran Vijay Kumar
Concurrent Engineering (Simultaneous
Concurrent engineering
functions of design engineering, manufacturing engineering, and other functions are integrated to reduce
the elapsed time required to bring a new product to market.
In a company that practices concurrent engineering, the manufacturing engineering department
becomes involved in the product development cycle early on, providing advice on how the product and its
components can be designed to facilitate manufacture and assembly. It also provides with the early stages
of manufacturing planning for the product. This concur
Figure.
In addition to manufacturing engineering, other functions are also involved which contributes
during product development to improve not only the new product's function and performance, but also its
produce ability, inspect ability, testability, serviceability, and maintainability. Through early involvement,
as opposed to reviewing the final product design after it is too late to conveniently make any changes in
the design, the duration of the product
Concurrent engineering involves several elements: (1) Design for mfg. & assembly, (2) Design
for quality (3) Design for cost & (4) Design for life cycle.
(1) Design for Manufacturing and Assembly:
It is important for the manufacturing engineer to be given the opportunity to advise the design
engineer as the product design is evolving, to favorably influence the manufacturability of the product.
Terms used to describe such attempts to favorably influ
Design for Manufacturing (DFM) and
inextricably linked, so let us use the term
manufacturing and assembly involves the systematic consideration of manufacturability and
assemblability in the development of a new product design.
This includes: (a) organizational changes and (b) design principles and guideline.
(a) Organizational Changes in DFM/A:
in a company's organizational structure, either formally or informally, so that closer interaction and
better communication occurs between design and manufacturing personnel.
(b) Design Principles and Guidelines:
for how to design a given product to maximize manufacturability and assemblability. Some of these
are universal design guidelines that can be applied to near
guideline sometimes conflict with one another.
]
imultaneous Engineering):-
Concurrent engineering refers to an approach used in product development in which the
design engineering, manufacturing engineering, and other functions are integrated to reduce
the elapsed time required to bring a new product to market.
involved in the product development cycle early on, providing advice on how the product and its
of manufacturing planning for the product. This concurrent engineering approach is pictured as shown in
the design, the duration of the product development cycle is substantially reduced.
for quality (3) Design for cost & (4) Design for life cycle.
Design for Manufacturing and Assembly:-
Terms used to describe such attempts to favorably influence the manufacturability of a new product are
(DFM) and Design for Assembly (DFA). Of course, DFM and DFA are
inextricably linked, so let us use the term design for manufacturing and assembly
assembly involves the systematic consideration of manufacturability and
assemblability in the development of a new product design.
Organizational Changes in DFM/A: Effective implementation of DFM/A, involves making changes
better communication occurs between design and manufacturing personnel.
Design Principles and Guidelines: DFM/A also relies on the use of design principles and guidelines
are universal design guidelines that can be applied to nearly any product design situation.
guideline sometimes conflict with one another.
P a g e | 52
refers to an approach used in product development in which the
design engineering, manufacturing engineering, and other functions are integrated to reduce
involved in the product development cycle early on, providing advice on how the product and its
rent engineering approach is pictured as shown in
development cycle is substantially reduced.
ence the manufacturability of a new product are
(DFA). Of course, DFM and DFA are
and assembly (DFM/A). Design for
assembly involves the systematic consideration of manufacturability and
ve implementation of DFM/A, involves making changes
also relies on the use of design principles and guidelines
ly any product design situation. These

(2) Design for Quality:-
• DFM/A is the most important component of concurrent engineering because it has the potential for the
greatest impact on product cost and development time.
• However the importance of quality in international competition cannot be minimized.
• Quality does not just happen. It must be planned during product design and during production.
• Design for quality (DFQ) is the term that refers to the principles and procedures employed to ensure
that the highest possible quality is designed into the product.
The general objectives of DFQ are,
(1) To design the product to meet or exceed customer requirements;
(2) To design the product to be "robust," in the sense of Taguchi; and
(3) To continuously improve the performance, functionality, reliability, safety and other quality aspects of
the product
to provide superior value to the customer.
(3) Design for cost:-
• The cost of a product is a major factor in determining its commercial success.
• Cost affects the price charged for the product and the profit made by the company producing it.
• Design for product cost (DFC) refers to the efforts of a company to specifically identify how design
decisions affect product costs and to develop ways to reduce cost through design.
• Although the objectives of DFC and DFM/A overlap to some degree, since improved
manufacturability usually results in lower cost.
(4) Design for life cycle:-
• To the customer, the price paid for the product may be a small portion of its total cost when life cycle
costs are considered.
• Design for life cycle refers to the product after it has been manufactured and includes factors ranging
from product delivery to product disposal.
• The producer of the product is often obligated to offer service contracts that limit customer liability
for out-of-control maintenance and service costs.
• In these cases, accurate estimates of these life cycle costs must be included in the total product cost.
Advanced Manufacturing Planning:-
Advanced manufacturing planning emphasizes planning for the future. It is a corporate level
activity that is distinct from process planning because it is concerned with products being contemplated in
the company's long-term- plans (2-10-year future), rather than products currently being designed and
released.
Advanced manufacturing planning involves working with sates, marketing, and design
engineering to forecast the new products that will be introduced and to determine what production
resources will be needed to make those future products.

Kiran Vijay Kumar
The general advanced planning cycle is as shown in fig.
Activities in advanced manufacturing planning include: (1) new technology evaluation, (2) investment
project management, (3) facilities planning, and (4)
(1) New Technology Evaluation:
• Certainly one of the reasons why a company may consider installing new technologies is because
future product lines require processing methods not currently used by the company.
• To introduce the new products, the company must either implement new processing technologies or
purchase the components made by the new technologies from vendors.
The reasons why a company may need to introduce new technologies:
(1) Quality improvement. (2) Productivity improve
(5) modernization and replacement of worn
(2) Investment project management:
Investments in new technologies or new equipment are generally made one
duration of each project may be several months to several years.
For each project, the following sequence of steps must usually be accomplished:
(1) Proposal to justify the investment is prepared.
(2) Management approvals are grant
(3) Vendor quotations are solicited.
(4) Order is placed to the winning vendor.
(5) Vendor progress in building the equipment is monitored.
(6) Any special tooting and supplies are ordered.
(7) The equipment is installed and debugged.
(8) Training of operators.
(9) Responsibility for running the equipment is turned over to the operating department.
The general advanced planning cycle is as shown in fig.
project management, (3) facilities planning, and (4) manufacturing research.
New Technology Evaluation: -
Certainly one of the reasons why a company may consider installing new technologies is because
oducts, the company must either implement new processing technologies or
purchase the components made by the new technologies from vendors.
The reasons why a company may need to introduce new technologies:
(1) Quality improvement. (2) Productivity improvement, (3) cost reduction, (4) lead time reduction, and
(5) modernization and replacement of worn-out facilities with new equipment.
Investment project management:-
Investments in new technologies or new equipment are generally made one
duration of each project may be several months to several years.
For each project, the following sequence of steps must usually be accomplished:
(1) Proposal to justify the investment is prepared.
(2) Management approvals are granted for the investment.
(3) Vendor quotations are solicited.
(4) Order is placed to the winning vendor.
(5) Vendor progress in building the equipment is monitored.
(6) Any special tooting and supplies are ordered.
(7) The equipment is installed and debugged.
P a g e | 54
Certainly one of the reasons why a company may consider installing new technologies is because
oducts, the company must either implement new processing technologies or
ment, (3) cost reduction, (4) lead time reduction, and
Investments in new technologies or new equipment are generally made one project at a time. The

(3) Facilities planning:-
• When new equipment is installed in an existing plant, an alteration of the facility is required.
• The planning work required to renovate an existing facility or design a new one is carried out by the
plant engineering department and is called facilities planning.
• In the design or redesign of a production facility manufacturing engineering and plant engineering
must work closely to achieve a successful installation.
Facility planning is concerned with (1) facilities location and (2) facilities design.
Facilities location deals with the problem of determining the optimum geographical location for a
new facility. Factors that must be considered in selecting the best location include: location relative to
customers and suppliers, labor availability, skills of labor pool, transportation, & cost of living.
Facilities design consists of the design of the plant, which includes plant layout, material
handling, building, and related issues. The plant layout is the physical arrangement of equipment and
space in the building.Material handling is concerned with the efficient movement of work in the factory.
Building design deals with the architectural and structural design of the plant.
(4) Manufacturing Research and Development:-
To develop the required manufacturing technologies, the company may find it necessary to undertake
a program of manufacturing research and development (R&D). Manufacturing research can take various
forms including:
• Development of new processing technologies- This R&D activity involves the development of new
processes that have never been used before.
• Adaptation of existing processing technologies-This R&D activity involves use of already existing
processes.
• Process fine tuning- This involves research on processes used by the company.
• Software systems development-These are projects to develop manufacturing-related software for the
company.
• Automation systems development- These projects deal with development of hardware or
hardware/software combinations.
• Operations research and simulation- Operations research involves the development of mathematical
models to analyze operational problems.
Just-In-Time Production Systems:-
• Just-in-time (JIT) production systems were developed in Japan to minimize inventories, especially
WlP.
• WIP and other types of inventory are seen by the Japanese as waste that should be minimized or
eliminated.
• The ideal just-in-time production system produces and delivers exactly the required number of each
component to the downstream operation in the manufacturing sequence just in time when that
component is needed.
• The JIT discipline can be applied not only to production operations but to supplier delivery operations
as well.
• The principal objective of JIT is to reduce inventories.
• However, inventory reduction cannot happen simply. Certain requisites must be in place for a JIT
production system to operate successfully.

They are: (1) a pull system of production control, (2) small batch sizes and reduced setup times,
and (3) stable and reliable production operations.
(1) Pull System of Production Control:-
• JIT is based on a pull system of production control, in which the order to make and deliver parts at
each workstation in the production sequence comes from the downstream station that uses those parts.
• When the supply of parts at a given workstation is about to be exhausted, that station orders the
upstream station to replenish the supply.
• When this procedure is repeated at each workstation throughout the plant, it has the effect of pulling
parts through the production system.
• One way to implement a pull system is to use kanbans, the word kanban means "card" in Japanese.
• The Kanban system of production control, developed and made famous by Toyota, the Japanese
automobile company, is based on the use of cards that authorize (1) parts production and (2) parts
delivery in the plant.
• Thus, there are two types of kanbans: (1) production kanbans and (2) transport kanbans.
A production kanban (P-kanban) authorizes the upstream station to produce a batch of parts as they are
produced.
A transport kanban (T-kanban) authorizes transport of the container of parts to the downstream station.
(2) Small Batch Sizes and Reduced Setup Times:-
To minimize WIP inventories in manufacturing, batch size and setup time must be minimized. The
relationship between batch size and setup time is given by the Economic Order Quality or EOQ formula,
Q = EOQ = e
]f
$
Where,
Ch = holding (carrying) cost ($/pc/yr),
Csu = setup cost ($/setup or $/order),
Da = annual demand (pc/yr)
Average inventory level is equal to one half the batch sizes. To reduce average inventory level,
batch size must be reduced. And to reduce batch size, setup cost must be reduced. This means reducing
setup times. Reduced setup times permit smaller batches and lower WIP levels.
(3) Stable and reliable production operations:-
Other requirements for a successful JIT production system include: (1) stable production schedules, (2)
on-time delivery, (3) defect-free components and materials, (4) reliable production equipment. (5) a
workforce that is capable, committed, and cooperative, and (6) a dependable supplier base.
Stable Schedule: Production must flow as smoothly as possible, which means minimum
fluctuation from the fixed schedule. Perturbations or fluctuation in downstream operations tend to be
magnified in upstream operations.
On- Time Delivery, Zero Defects, and Reliable Equipment: Just-in-time production requires
near perfection in on-time delivery, parts quality, and equipment reliability, because of the small lot sizes
used in JIT. Parts must be delivered before stock-outs occur at downstream stations. Otherwise, these
stations are starved for work and production must be stopped.
Workforce and Supplier Base: Workers in a JIT production system must be cooperative,
committed, and cross-trained. Small batch sizes means that workers must be willing and able to perform a
variety of tasks and to produce a variety of pan styles at their workstations. As indicated above, they must
be inspectors as well as production workers to ensure the quality of their own output. They must be able
to deal with minor technical problem that may be experienced with the production equipment so that
major breakdowns are avoided.

The suppliers of raw materials and components to the company must be held to the same
standards of on-time delivery, zero defects, and other JIT requirements as the company itself.
Lean Production and Agile Manufacturing:-
Lean Production
Agile Manufacturing
Comparison of Lean and Agile
Lean Production:-
Definitions of lean production,
"gore and more with less and less-less human effort, less equipment, less time, and less space-while
coming closer and closer to providing customers with exactly what they want".
- ByWomack and Jones
“hn adaptation of mass production in which workers and work cells are made more flexible and efficient
by adopting methods that reduce waste in all forms”.
- By another author of The Machine that
Changed the World
Lean production is based on four principles,
1. Minimize waste
2. Perfect first-time quality
3. Flexible production lines
4. Continuous improvement
1. Minimize waste:-
• All four principles of lean production are derived from the first principle: minimize waste.
• Taiichi Ohno's list of waste forms can be listed as follows:
(1) Production of defective parts, (2) Production of more than the number of items needed, (3)
Unnecessary inventories, (4) Unnecessary processing steps, (5) Unnecessary movement of people, (6)
unnecessary transport of materials, and (7) workers waiting.
• The various procedures used in the Toyota plants were developed to minimize these forms of waste.
For example, lean principle 2 (perfect first-time quality), discussed next, is directed at eliminating
production of defective parts. The just-in-time production system was intended to produce no more than
the minimum number of parts needed at the next workstation. This reduced unnecessary inventories.
2. Perfect first-time quality:-
• In the area of quality, the comparison between mass production and lean production provides better
understanding.
• In mass production, quality control is defined in terms of an acceptable quality level or AQT which
means that a certain level of fraction defects is sufficient, even satisfactory.
• But in lean production, perfect quality is required & the just-in-time delivery discipline used in lean
production necessitates a zero defects level in parts quality, because if the part delivered to the
downstream workstation is defective, production stops.
• There is minimum inventory in a lean system to act as a buffer but in mass production, inventory
buffers are used just in case these quality problems occur.
• The defective work parts are simply taken off the line and replaced with acceptable units; however, the
problem is that such a policy tends to perpetuate the cause of the poor quality.
• Therefore, defective parts continue to be produced but in lean production a single defect draws
attention to the quality problem, forcing corrective action and a permanent solution.

3. Flexible production lines:-
• Mass production is predicated largely on the principles of Frederick W. Taylor, one of the leaders of
the scientific management movement in the early 1901.
• According to Frederick W. Taylor, workers had to be told every detail of their work methods and
were incapable of planning their own tasks.
• By comparison, Lean production makes use of worker teams to organize the tasks to be accomplished
and worker involvement to solve technical problems.
• In mass production, the goal is to maximize efficiency which can be achieved using long production
runs of identical parts.
• In lean production, procedures are designed to speed the changeover & reduced setup times allow for
smaller batch sizes, thus providing the production system with greater flexibility.
• Flexible production systems were needed in Toyota's comeback period because of the much smaller
car market in Japan and the need to be as efficient as possible.
4. Continuous improvement:-
• In mass production, there is a tendency to set up the operation, and if it is working, leave it alone.
• Mass production lives by the motto “If it ain't broke, don't fix it."
• Lean production supports the policy of continuous improvement, called kaizen by the Japanese.
• Continuous improvement means constantly searching for and implementing ways to reduce cost,
improve quality, and increase productivity.
• The scope of continuous improvement goes beyond factory operations and involves design
improvements as well.
• Continuous improvement is carried out one project at a time.
The projects may be concerned with any of the following problem areas: cost reduction, quality
improvement, productivity improvement, setup time reduction, cycle time reduction, manufacturing lead
time and work-in-process inventory reduction, and improvement of product design to increase
performance and customer appeal.
Agile Manufacturing:-
Definitions of Agile Manufacturing,
(1) “An enterprise level manufacturing strategy of introducing new products into rapidly changing
markets.” and
(2) “An organizational ability to thrive in a competitive environment characterized by continuous and
sometimes unforeseen change.”
Agile Manufacturing is based on four principles,
1. Organize to Master Change.
2. Leverage the Impact of People and Information.
3. Cooperate to Enhance Competitiveness.
4. Enrich the Customer.
1. Organize to Master Change- "An agile company is organized in a way that allows it to thrive on
change and uncertainty". In a company that is agile, the human and physical resources can be rapidly
reconfigured to adapt to changing environment and market opportunities.
2. Leverage the Impact of People and Information- In an agile company, knowledge is valued,
innovation is rewarded, and authority is distributed to the appropriate level of the organization.
Management provides the resources that personnel need. The organization is entrepreneurial in spirit.
There is a "climate of mutual responsibility for joint success".

3. Cooperate to Enhance Competitiveness- "Cooperation internally and with other companies-is an
agile competitor's operational strategy of first choice."? The objective is to bring products to market
as rapidly as possible.
4. Enrich the Customer- "An agile company is perceived by its customers as enriching them in a
significant way, not only itself." The products of an agile company are perceived as solutions to
customer’s problems. Pricing of the product can be based on the value of the solution to the customer
rather than on manufacturing cost.
Market Forces and Agility:-
A number of market forces can be identified that are driving the evolution of agility and agile
manufacturing in business. These forces include:
• Intensifying competition- Signs of intensifying competition include (1) global competition, (2)
decreasing cost of information, (3) growth in communication technologies.(4) pressure to reduce
time-to-market, (5) shorter product lives, and (6) increasing pressures on costs and profits.
• Fragmentation of mass markets-Mass production was justified by the existence of very large
markets for mass-produced products. The signs of the trend toward fragmented markets include: (1)
emergence of niche markets, (2) high rate of model changes; (3) declining barriers to market entry
from global competition; and (4) shrinking windows of market opportunity. Producers must develop
new product styles in shorter development periods.
• Cooperative business relationships-There is more cooperation occurring among corporations in the
United States. The cooperation takes many forms. Including: (1) increasing inter-enterprise
cooperation, (2) increased outsourcing, (3) global sourcing, (4) improved labor management
relationships, and (5) the formation of virtual enterprises among companies. One might view the
increased rate of corporate mergers that are occurring at time of writing as an extension of these
cooperative relationships.
• Changing customer expectations-Market demands are changing. Customers are becoming more
sophisticated and individualistic in their purchases. Rapid delivery of the product, support throughout
the product life. and high quality are attributes expel:
• Increasing societal pressures-Modern companies are expected to be responsive to social issues,
including workforce training and education, legal pressures, environmental impact issues, gender
issues, and civil rights issues.
Reorganizing the Production System for Agility:-
• Companies seeking to be agile must organize their production operations differently than the
traditional organization.
• By changing the organization in three basic areas:
(1) Product design,
(2) Marketing, and
(3) Production operations.
• Thus by changing all or any one of the above characteristics the organization could perform agile
manufacturing.
Managing Relationships for Agility:-
Cooperation should be the business strategy of first choice (third principle of agility). The general policies
and practices that promote cooperation in relationships and, in general, promote agility in an organization
include the following:
• Management philosophy that promotes motivation and support among employees
• Trust-based relationships
• Empowered workforce
• Shared responsibility for success or failure
• Pervasive entrepreneurial spirit

There are two different types of relationships that should be distinguished in the context of agility
(1) Internal relationships and (2) relationships between the company and other organization.
Agility versus Mass Production:-
In mass production, companies produce large quantities of standardized products. The purest
form of mass production provides huge volumes of identical products. Over the years, the technology of
mass production has been refined to allow for minor variations in the product.
In agile manufacturing, the products are customized. The term used to denote this form of
production is mass customization, which means large quantities of products having unique individual
features that have been specified by and/or customized for their respective customers.
In mass production, Production quantity Q is very large, Production verity P is very small, and in
mass customization. P is very large, Q is very small,
Along with the trend toward more customized products, today's products have shorter expected
market lives. Mass production was justified by the existence of very large markets for its mass-produced
goods. Mass markets have become fragmented, resulting in a greater level of customization for each
market.
In mass production, products are produced based on sales forecasts. If the forecast is wrong, this
can sometimes result in large inventories of finished goods that are slow in selling. Agile companies
produce to order: customized products for individual customers. Inventories of finished products are
minimized.
Comparison of Lean and Agile:-
Sl.
No.
Lean Production Agile Manufacturing
1. Minimize waste Enrich the customer
2. Perfect first-time quality Cooperate to enhance competitiveness
3. Flexible production lines Organize to master change
4. Continuous improvement Leverage the impact of people and information
5. Enhancement of mass production Break with mass production; emphasis on mass
customization.
6. Flexible production for product variety Greater flexibility for customized products
7. Focus on factory operations Scope is enterprise wide
8. Emphasis on supplier management Formation of virtual enterprises
9. Emphasis on efficient use of resources Emphasis on thriving in environment marked by
continuous unpredictable change
10. Relies on smooth production schedule Acknowledges and attempts to be responsive to
change.

REFERENCE
1. Automation, Production system and CIM by MP Grover (2001).

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