cam 1 unit palanivendhan manufacturin systems

Computer Aided Manufacturing

M.PALANIVENDHAN

Department of Automobile Engineering

SRM University, kattankulathur campus

Computer Aided Manufacturing

• What is Manufacturing

• It is the process of converting the raw material into product.

• It encompasses

– Design of the product

– The selection of raw material

– The sequence of processes through which the product will be manufactured.

Difference between production and manufacturing

Need of

Manufacturing

• Globalization

• International outsourcing

• Local outsourcing

• Contract manufacturing

• Quality expectation

• Operational efficiency

Manufacturing

Process

Starting material

(Raw material)

Machinery

Tools

Power

Labor

Completed part

(Product)

Scrap

Changes in manufacturing

Manufacturing engineers are required to achieve the

following objectives to be competitive in a global context.

• ‘edu tio i i e to

• Lo e the ost of the p odu t • ‘edu e aste

• I p o e ualit

• I ease fle i ilit i a ufa tu i g to a hie e immediate and rapid response to: – Product changes

– Production changes

– Process change

– Equipment change

– Change of personnel

7

Manufacturing systems approaches

• Automation (Low labor high prod.)

• Material handling technologies(scm)

• Manufacturing systems (integration of automated or manual )

• Flexible manufacturing (low volume and high mix product)

• Quality programs (6sigma)

• CIM (CAD CAM)

• Lean production (more work fewer resources)

Manufacturing System – Definition

• A set of operations performed on materials

which bring them closer to the desired final

form.

Production systems

• A production system is a collection of people,

equipment and procedures.

– Facilities (factory and the equipment)

– Manufacturing support systems(manage production

and to solve the technical and logistics problems

encountered in ordering materials)

blue collar workers, white collar workers

The Facilities

• Factory, production machine,tooling,material

handling equipment,inspection equipment,

computer systems

• Manual work systems

– Without aid of powered tools, only of hand tool

• Worker –machine systems

– (human worker +machine tool)

• Automated systems

– without participation of a human worker

– 1.semi automated 2. Fully automated

Manufacturing Support Systems • To operate the production facilities efficiency to design the

processes and control the production and satisfy the product

quality

• Business Functions

– Comm to customer,sales,marketing

• Product Design

– Product development

• Manufacturing Planning

– Process planning, logistics issues, master

production schedule

• Manufacturing control

– Shop floor,inventory and quality control

Types of production

• Continuous process

• Mass production

• Batch production

Continuous Process

• In this type of industry, the

production process generally

follows a specific sequence.

• These industries can be easily

automated and computers are

widely used for process

monitoring, control and

optimization.

• Oil refineries, chemical plants,

food processing industries, etc

are examples of continuous

process industries.

Mass production

• Industries manufacturing

fasteners (nuts, bolts etc.),

integrated chips,

automobiles, entertainment

electronic products,

bicycles, bearings etc.

• which are all mass produced

can be classified as mass

production industries.

• Production lines are

specially designed and

optimized to ensure

automatic and cost effective

operation.

Batch Production

• The largest percentage of

manufacturing industries can

be classified as batch

production industries.

• The distinguishing features of

this type of manufacture are

the small to medium size of

the batch, and varieties of

such products to be taken up

in a single shop.

• Due to the variety of

components handled, work

centers should have broader

specifications.

• Another important fact is that

small batch size involves loss

of production time associated

with product changeover.

TYPES OF LAYOUT

• 1.FIXED POSITION LAYOUT

• 2.PROCESS LAYOUT

• 3.PRODUCT FLOW LAYOUT

• 4.GROUP TECHNOLOGY(CELLULAR) LAYOUT

1.Fixed position

part” stationary

workstations move

7/24/2014

• Fixed position layout – Product must remain stationary throughout production

sequence

– Machines are brought to the product

– Higher expense due to robustness and accuracy of

equipment

2.Process Layout

– organized by machine type

3.Product flow layout

-Assembly/flow/transfer line

• Product flow layout – Suited for high volume production

– Advantages: minimized material handling, easy to

automate material handling, less WIP, easier to

control

– Disadvantages: inefficient to alter the sequence of

operations, breakdown on one machine can stop

the entire line

What is Manufacturing

• It is the process of converting the raw material

into product.

• It encompasses

– Design of the product

– The selection of raw material

– The sequence of processes through which the

product will be manufactured.

Manufacturing can be defined as the

application of physical and chemical processes

to alter the geometry, properties, and/or

appearance of a given starting material to

make part or products

Manufacturing

Process

Starting material

(Raw material)

Machinery

Tools

Power

Labor

Completed part

(Product)

Scrap

Changes in manufacturing

Manufacturing engineers are required to achieve the

following objectives to be competitive in a global context.

• ‘edu tio i i e to

• Lo e the ost of the p odu t • ‘edu e aste

• I p o e ualit

• I ease fle i ilit i a ufa tu i g to a hie e immediate and rapid response to: – Product changes

– Production changes

– Process change

– Equipment change

– Change of personnel

TYPES OF MANUFACTURING

• Continuous process

• Mass production

• Batch production

Continuous Process

• In this type of industry, the production process

generally follows a specific sequence.

• These industries can be easily automated and

computers are widely used for process

monitoring, control and optimization.

• Oil refineries, chemical plants, food processing

industries, etc are examples of continuous

process industries.

Mass production

• Industries manufacturing fasteners (nuts, bolts

etc.), integrated chips, automobiles,

entertainment electronic products, bicycles,

bearings etc.

• which are all mass produced can be classified as

mass production industries.

• Production lines are specially designed and

optimized to ensure automatic and cost effective

operation.

• Automation can be either fixed type or flexible.

Batch Production

• The largest percentage of manufacturing industries can be classified as batch production industries.

• The distinguishing features of this type of manufacture are the small to medium size of the batch, and varieties of such products to be taken up in a single shop.

• Due to the variety of components handled, work centers should have broader specifications.

• Another important fact is that small batch size involves loss of production time associated with product changeover.

Volume

Manufacturing systems

• Agile manufacturing

• Flexible manufacturing

• Just-in-time manufacturing

• Lean manufacturing

• Mass production

• Ownership

• Prefabrication

• Rapid manufacturing

CIM WHEEL

Current trends in manufacturing • Group Technology

• Design for manufacturing

• Computer Aided Process Planning (CAPP)

• Total Quality Approach

• Concurrent engineering

• Rapid prototyping

• Computer Integrated manufacturing (CIM)

• Digital Manufacturing

• Green Manufacturing

• Lean Manufacturing

• Agile manufacturing

Automation in Manufacturing

• Automation are now perform operation

such as processing, assembly, inspection,

material handling, in some cases

accomplishing more than one of these

operations.

Classification of Automated

manufacturing system

• Fixed Automation

• Programmable Automation

• Flexible Automation

Fixed Automation

• Fixed automation is a system in

which sequence of processing

operation is fixed by the equipment

configuration.

Features of fixed automation

• High initial investments

• High production rates

• Relatively inflexible in accommodating

product variety

Examples of fixed automation

• Machining transfer lines

• Automation assembly machines.

Programmable Automation

• In Programmable Automation systems the

production equipments is designed with the

capability to change the sequence of

operation to accommodate different product

configuration.

Features of Programmable Automation

• High investment in general purpose

equipment

• Flower production rate than fixed automation

• Flexible to deal with variations and changes in

product configuration.

• More suitable for batch production

Examples of Programmable

Automation

• Numerical controlled machine tool

• Industrial robots

• Programmable logic controllers

Flexible Automation

• Flexible automation is capable of producing a

variety of parts with virtually no time lost for

changeover from one part style to the next.

• Continuous production of various mixtures of

products

• Medium production rate

• Flexibility to deal with product design

variations

Features of Flexible Automation

Fixed

Automation

Flexible

Automation

Programmable

Automation

Pro

duct va

rie

ty

Production quantity

100 10,000 1,000,000

Manual

Production

Factory

Operation

Design

Mfg.

Planning

Mfg.

Control

Business

Functions

GROUP TECHNOLOGY

GROUP TECHNOLOGY

• GT is a manufacturing philosophy in which similar parts are identified and grouped together to take advantage of their similarities in manufacturing and design.

• Similar parts are arranged into part families.

– eg. A factory manufacturing 10000 different parts may be categorized into 50 families.

• Each family will have some common characteristics feature or parameters.

PART FAMILY

• A part family is a collection of parts which are similar either because of geometric shape and size or because similar processing steps are required in their manufacture.

• Three methods of identifying part family:

1.Visual inspection

2.Part classification and coding schemes

3.Production flow analysis (PFA Chart)

Grouping according to geometric similarities

Grouping according to manufacturing similarities

Plant Layout

& Group

Technology

Process type

Layout

GT

(Cellular)

Layou

FUNCTIONAL LAYOUTS ARE INEFFICIENT

PROCESS-TYPE LAYOUT

Lathe Milling Drilling

Grinding

Assembly

Receiving and

Shipping

L

L L

L

L

L

L

L M

M M

M M

M

A A

A A

D

D D

D

G

G

G

G G

G

Process Layout Characteristics

• Advantages

– Deep knowledge of the process

– Common tooling and fixtures

– Most Flexible -- can produce many different part types

• Disadvantages

– Spaghetti flow -- everything gets all tangled up

– Lots of in-process materials

– Hard to control inter-department activities

– Can be difficult to automate

PRODUCT LAYOUT

Shipping

L L M D

L M D

G

L M G G

A A

Receiving

Part #1

Part #3

Part #2

Product Layout Characteristics

• Advantages

– Easy to control -- input control

– Minimum material handling -- frequently linked to the next process

– Minimal in-process materials

– Can be more easily automated

• Disadvantages

– Inflexible -- can only produce one or two parts

– Large setup

– Duplicate tooling is required for all cells

Cell #2

Cell #3

Cell #1

D D M I

D M L L I

D

M

L M

I

CELLULAR LAYOUT

Cellular Layout Characteristics

• Advantages

– Control is simplified

– Common tooling and fixtures

– Flexible -- can produce many different part types - a part

family

• Disadvantages

– More Setup time required

– Need to know about many different processes

TRANSFER

LINE

SPECIAL

SYSTEM FLEXIBLE

MANUFACTURING

SYSTEM

MANUFACTURING

Cells

STD. AND GEN.

MACHINERY

VO

LU

ME

HIGH

VARIETY

LOW HIGH

Advantages of Group Technology

• Standardization of part design and minimization of design duplication • New parts can be developed using previous similar designs. • Data reflecting the experience of the part designer and manufacturing process planner are stored in a database. • Process plans are also standardized and scheduled more

efficiently. • Setup times are reduced and parts are produced more efficiently. • Similar tools, clamps, jigs, fixtures and machinery are shared. • Needs to be implemented CIM, CAD/CAM and cellular manufacturing. Potential savings 5 to 75 %.

Classification and Coding of Parts

• Design Attributes: • External and internal shapes and dimensions • Aspect ratio • Tolerances specified • Surface finish specified • Part function

• Manufacturing Attributes: • Primary processes • Secondary and finishing processes • Tolerances and Surface finish • Sequence of operations • Tools, dies, fixtures and machinery • Production quantity and production rate

• Part Classification and Coding System

• • Classification means to sort similar parts into

predetermined groups based on appropriate

attributes (shape,manufacturing process, material,

etc.)

• • A code is a combination of letters and numbers

that are assigned to parts for information

processing

Coding Systems

• Types of Coding:

• Hierarchical coding (monocode)

• Polycoding (chain type)

• Decision-tree Coding (hybrid code)

• Major Industrial Coding Systems:

• Opitz System

• Multiclass System

• KK-3 system

Coding schemes

• Hierarchical

1

2 3

1 2

3 1 2

3

1 2

3

• Chain

1

2

3

.

.

1

2

3

.

.

Decision Tree Classification

OPITZ SYSTEM

• 12345 6789 ABCD

- Basic code consist of first 9 digits. This convey

both design and manufacturing data.

-Fi st digit alled fo ode

- Ne t digit alled supple e ta ode

- Ne t digit ABCD alled se o da ode

A Simple Rotaional Part

Given the part design shown define the "form

code" using the Opitz system

MULTI CLASS SYSTEM

• This developed by the organization for

industrial research.

• This is relatively flexible.

• This used for variety of diff types of mfg

product.

• It uses a hierarchical or decision tree coding

structure.

• Coding structure up to 30 digits.

MULTI CLASS SYSTEM

Digit Function

0 – code system prefix

1 – main shape category

2,3 – external and internal configuration

4 - machined secondary elements

5,6 –Functional description

7-12 – Dimensional data (length,diameter)

13-Tolerances

14,15 – Material chemistry

16 – Raw material shape

17- production quantity

18- machined element orientation

PRODUCTION FLOW ANALYSIS(PFA)

• It does not use part classification and coding system.

• It does not use part drawing

• It used to analyze the operation sequence and machine routing.

• PFA uses manufacturing data rather than design data.

• Dis adv: It provides no mechanism for rationalizing the manufacturing routings.

PFA PROCEDURE

• 1.DATA COLLECTION

• 2. SORTING OF PROCESS ROUTINGS.

• 3.PFA CHART

• 4. ANALYSIS

• Part Family & Manufacturing Cell

Formation: General Procedure • 1. Define the scope of the study including system boundaries

• 2. Identify the similarity attributes of interest

• 3. Simplify:

• Group obviously similar parts into representative part-type

• G oup pie es of e uip e t that ust sta togethe i to

representative machine-type

• 4. Find process plans using part-types and machine types

found in the previous step

• 5. Determine the Part-Machine Incidence Matrix

based on the process plans found in the previous step

• 6. Find the best Product Families and Machine Cells using

clustering methods.

EXAMPLE:

Consider a problem of 4 machines and 6 parts. Try

to group them.

Machines 1 2 3 4 5 6

M1 1 1 1

M2 1 1 1

M3 1 1 1

M4 1 1 1

93

Components

Machines 2 4 6 1 3 5

M1 1 1 1

M2 1 1 1

M3 1 1 1

M4 1 1 1

94

Components

Rank Order Clustering Algorithm:

Rank Order Clustering Algorithm is a simple

algorithm used to form machine-part groups.

95

Step 1: Assign binary weight and calculate a

decimal weight for each row and column using the

following formulas:

96

Decimal we

Decimal we bpjn p

ight for row i = b

ight for column j =

ipm-p

p=1

m

p=1

n

2

2

Step 2: Rank the rows in order of decreasing

decimal weight values.

Step 3: Repeat steps 1 and 2 for each column.

Step 4: Continue preceding steps until there is

no change in the position of each element in

the row and the column.

97

EXAMPLE:

Consider a problem of 5 machines and 10 parts. Try to group

them by using Rank Order Clustering Algorithm.

Machines 1 2 3 4 5 6 7 8 9 10

M1 1 1 1 1 1 1 1 1 1

M2 1 1 1 1 1

M3 1 1 1 1

M4 1 1 1 1 1 1

M5 1 1 1 1 1 1 1 1

98

Components

Table 1

Machines 1 2 3 4 5 6 7 8 9 10 Decimal

equivalent

M1 1 1 1 1 1 1 1 1 1 1007

M2 1 1 1 1 1 451

M3 1 1 1 1 568

M4 1 1 1 1 1 1 455

M5 1 1 1 1 1 1 1 1 1020

29 28 27 26 25 24 23 22 21 20

99

Binary weight

Components

Table 2

Binary

weight Machines 1 2 3 4 5 6 7 8 9 10

24 M5 1 1 1 1 1 1 1 1

23 M1 1 1 1 1 1 1 1 1 1

22 M3 1 1 1 1

21 M4 1 1 1 1 1 1

20 M2 1 1 1 1 1 Decimal

equivalent 28 27 27 27 28 20 28 26 11 11

29 28 27 26 25 24 23 22 21 20

100

Binary weight

Components

Table 3

Binary

weight

Machines 1 5 7 2 3 4 8 6 9 10 Decimal

equivalent

24 M5 1 1 1 1 1 1 1 1 1020

23 M1 1 1 1 1 1 1 1 1 1 1019

22 M3 1 1 1 1 900

21 M4 1 1 1 1 1 1 123

20 M2 1 1 1 1 1 115 Decimal

equivalent 28 28 28 27 27 27 26 20 11 11

29 28 27 26 25 24 23 22 21 20

101

Binary weight

Components

Table 4

Manufacturing Cell Layout

• Once machine clusters are identified, one needs to

decide the best machine layout to

implement.

• For a good cell layout one must consider:

• -Technological considerations

• -Streamlined material flow

• Hollier methods specifies the machine layout that

maximizes the proportion of in-sequence

moves within the cell.

Hollier Method • 1. Develop the From-To Chart

• 2. Determine the From/To ratio for each a hi e di idi g the F o -su the To-

su fo ea h a hi e

• 3. Arrange the machines in order of decreasing From/To ratios

• • Ma hi es ith high atios a e pla ed at the beginning of the flow.

• • I the ase of ties, pla e a hi es ith highe F o alues fi st.

Solve the problem using Hollier

Method 1:

2 3 1 4 From

2 - - 62 145 207

3 167 167

1 12 12

4 140 140

167 0 202 157

Step 1

17

Solve the problem using Hollier

Method :

2 3 1 4 From

2 - - 62 145 207

3 167 167

1 12 12

4 140 140

167 0 202 157

Step 1 Step 2

17

2 3 1 4 From

2 - - 62 145 207

3 167 167

1 12 12

4 140 140

167 0 202 157

Machine 3

first

Solve the problem using Hollier

Method :

2 1 4 From

2 - 62 145 207

1 12 12

4 140 140

To 0 202 157

Step 1 Step 2

17

2 1 4 From

2 - 62 145 207

1 12 12

4 140 140

To 0 202 157

Machine 2

next

Solve the problem using Hollier

Method1 :

1 4 From

1 12 12

4 140 140

To 140 12

Step 1 Step 2

17

1 4 From

1 12 12

4 140 140

To 140 12

3 2 4 1

The flow diagram

40

167 145 140

12

17

62

190

Machine 4 next

Solve the problem using Hollier

Method 2:

2 3 1 4 From

2 - - 62 145 207

3 167 167

1 12 12

4 140 140

167 0 202 157

From to From

to ratio

order

2 207 167 124 2

3 167 0 infinity 1

1 12 202 0.06 4

4 140 157 0.89 3

Step 1 Step 2

3 2 4 1

The flow diagram

167

40

167 145 140

12

17

62

190

Flexible Manufacturing System

• A highly automated GT machine cell,

consisting of a group of processing stations

(usually CNC machine tools), interconnected

by an automated material handling and

storage system, and controlled by an

integrated computer system

Five Types of FMS Layouts

• 1.In-line

• 2.Loop

• 3.Ladder

• 4.Open field

• 5.Robot-centered cell

In-line FMS Layouts

Loop FMS Layouts

Ladder FMS Layouts

Open field FMS Layouts

Robot-centered cell FMS Layouts

FMS Components • Hardware components

– Workstations - CNC machines in a machining type system

– Material handling system - means by which parts are moved between stations

– Central control computer - to coordinate the activities of the components so as to achieve a

– smooth overall operation of the system

• Software and control functions

• Human labor

Computer Functions in a FMS

• NC part programming - development of NC

programs for new parts introduced into the

system

• Production control - product mix, machine

scheduling, and other planning functions

• NC program download - part program commands

must be downloaded to individual stations

• Machine control - individual workstations require

controls, usually CNC

Computer Functions in a FMS • Work part control - monitor status of each work part in

the system, status of pallet fixtures, orders on loading/unloading pallet fixtures

• Tool management - tool inventory control, tool status relative to expected tool life, tool changing and resharpening, and transport to and from tool grinding

• Transport control - scheduling and control of work handling system

• System management - compiles management reports on performance (utilization, piece counts, production rates, etc.)

Duties Performed by Human Labor

• Loading and unloading parts from the system

• Changing and setting cutting tools

• Maintenance and repair of equipment

• NC part programming

• Programming and operating the computer

system

• Overall management of the system

FMS Applications

• Machining –most

common application of

FMS technology

• Assembly

• Inspection

• Sheet metal processing

(punching, shearing,

bending, and forming)

• Forging

FMS Benefits

• Higher machine utilization than a

conventional machine shop due to better

work handling, off-line setups, and improved

scheduling

• Reduced work-in-process due to continuous

production rather than batch production

• Lower manufacturing lead times

• Greater flexibility in production scheduling