9789810683849_PPT_MFG_Chapter39_final[1]

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Manufacturing Engineering Technology in SI Units, 6th EditionChapter 39:

Computer-Integrated Manufacturing Systems

Copyright 2010 Pearson Education South Asia Pte Ltd


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Chapter Outline

1. Introduction

2. Cellular Manufacturing

3. Flexible Manufacturing Systems

4. Holonic Manufacturing

5. Just-in-time Production

6. Lean Manufacturing

7. Communications Networks in Manufacturing

8. Artificial Intelligence

9. Economic Considerations



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Introduction

Integration means that manufacturing processes,

operations and management are treated as a

system

Flexible manufacturing is capable of respondingto product changes, fluctuating demands and

ensuring on-time delivery of products to the

customer Holonic manufacturingis a new concept on how

manufacturing units can be organized to achieve

higher efficiency in operations



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Cellular Manufacturing

A manufacturing cell is a small unit consisting of one or

more workstations.

A workstation contains one machine (single-machine cell)

or several machines (group-machine cell) Capabilities of cellular manufacturing:

1. Loading and unloading raw materials

2. Changing tools at workstations

3. Transferring workpieces and tooling between

workstations

4. Scheduling and controlling the total operation in the cell



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Flexible Manufacturing Cells (FMCs)

Manufacturing cells can be made flexible by

1. CNC machines

2. Machining centers

3. Industrial robots

4. Mechanized systems for

handling materials and parts FMCs can be unattendedorunmanned

Cost of FMCs is very high, have increasedproductivity, flexibility and controllability



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Cell Design

Design and placement require efficient layout and

organization of the plant and the consideration of

product flow lines

Cost of flexible cells is high, but outweighed by

increased productivity, flexibility and

controllability



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EXAMPLE 39.1

Manufacturing Cells in a Small Machine Shop

In a small shop, the machines in the cells are

arranged to allow an operator to machine a part in

the most efficient and precise manner

Each cell allows the operator to monitor the

performance of the machines in the cell



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Flexible Manufacturing Systems

Aflexible manufacturing system (FMS) integrates

all of the major elements of production into a

highly automated system



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The system can handle a variety of part

configurations and produce them in any order



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FMS have the following major benefits:

1. Parts can be produced in any order

2. Direct labor and inventories are reduced or

eliminated

3. Lead times required for product changes are

shorter

4. System is self-correcting, production is morereliable and product quality is uniform



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Elements of FMS

Basic elements are:

1. Workstations and cells

2. Automated handling and transport of materials

and parts

3. Control systems

May incorporate furnaces, various machines,

trimming presses, heat-treating facilities, and

cleaning equipment



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Scheduling

Machines must not stand idle and proper

scheduling and process planning are crucial

Scheduling for FMS is dynamic, no setup time is

wasted in switching between manufacturing

operations



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Economic Justification of FMS

FMS installations are capital intensive

Thorough costbenefit analysis must be

conducted before any final decision is made

Analysis include the costs of capital, energy,

materials and labour



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EXAMPLE 39.2

Flexible Manufacturing Systems in Large and Small Companies

Large FMS requires the extensive training of

personnel

An FMS leads to a manufacturing enterprise that

is less lean



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Holonic Manufacturing

Holonic manufacturingis a new concept

describing a unique organization of

manufacturing units

Each component is an independent entity and asubservientpartof a hierarchical organization

3 fundamental observations:

1. Complex systems will evolve2. Holons are simultaneously self-contained

3. A holarchy consists of (a) autonomous wholes

and (b) dependent parts Copyright 2010 Pearson Education South Asia Pte Ltd


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Holonic Manufacturing

A manufacturing holon is an autonomous and

cooperative building block of a manufacturing

system

Maximum flexibility can be achieved byproviding intelligence to:

1. Support all production and control functions

2. Manage the underlying equipment and systems



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Just-in-time Production

Thejust-in-time (JIT)production has the

following goals:

1. Receive supplies just in time to be used

2. Produce parts just in time to be made into

subassemblies

3. Produce subassemblies just in time to be

assembled into finished products4. Produce and deliver finished products just in time

to be sold



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JIT is also calledzero inventory, stockless

production, and demand scheduling

This approach emphasizes

1. Pride and dedication

2. Elimination of idle resources

3. Teamwork



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Advantages of JIT

Advantages of just-in-time:

1. Low inventory carrying costs

2. Fast detection of defects

3. Reduced inspection and reworking of parts

4. High-quality products made at low cost



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Kanban

Kanbanmeans visible record

Record consisted of two types of cards:

1. Production card

2. Conveyance cardormove card



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Lean Manufacturing

Lean manufacturing involves:

1. Identify value

2. Identify value streams

3. Make the value stream flow

4. Establish pull



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Communications Networks in Manufacturing

Local area network(LAN) is a hardware-and-

software system where logically related groups of

machines and equipment communicate with each

other Wide area networks (WANs) is used for longer

distances

Different types of networks can be linked withfiletransfer protocols (FTPs)



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Wireless local area networks (WLANs) allow

equipment data-collection devices to maintain a

network connection

Wireless networks are slower than hardwired;their flexibility makes them desirable



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Communications Standards

Each cells computers have their own

specifications and proprietary standards

Manufacturing automation protocol (MAP)

was standardised

The International Organization

for Standardization (ISO)/OpenSystem Interconnect (OSI)

reference model is accepted

worldwide



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Artificial Intelligence

Artificial intelligence (AI) is that part of computer

science which is concerned with systems that

exhibit some characteristics

The goal of AI is tosimulate such humanbehaviours on the computer

AI has a major effect on the design, automation,

and overall economics of the manufacturingoperation



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Expert Systems

An expert system (ES) is defined as an intelligent

computer program that solve difficult real-life

problems by the use ofknowledge-based andinferentialprocedures



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Expert Systems

The field of knowledge required to perform the

task is called the domain of the expert system

To construct expert systems one needs:

1. A great deal of knowledge

2. A mechanism for manipulating that knowledge to

create solutions



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Natural-language Processing

Natural-language interfaces allow a user to obtain

information commands or typed questions

Computer software will have speech synthesis

and recognition (voice recognition) capabilities



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Machine Vision

Computers and software can be combined with

cameras and other optical sensors

Can perform inspecting, identifying, sorting parts

and guiding robots



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Artificial Neural Networks

Humans are much better at pattern-based tasks

Artificial neural networks (ANN) gain

capabilities through computer imitation

Artificial neural networks are used in noise

reduction, speech recognition and process control



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Fuzzy Logic

Fuzzy logic is an element in control systems and

pattern recognition

Fuzzy models are mathematical means of

representing vagueness and imprecise information

These models have the ability to recognize,

represent, manipulate, interpret, and utilize dataand information that are vague or lack precision



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Economic Considerations

FMS which need thorough costbenefit analysis

consist of:

1. The cost of capital, energy, materials, and labor

2. Expected markets for the products to be produced

3. Anticipated fluctuations in market demand and in

the type of product

4. The time and effort required for installing anddebugging the system

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