cadcamcim radhakrishnan subramanyan and raju

1.3 EVOLUTION OF COMPUTER INTEGRATED MANUFACTURING 41.5 NATURE AND ROLE OF THE ELEMENTS OF CIM SYSTEM 7 2.9 CHARACTERISTICS OF CONCURRENT ENGINEERING 25 2.10 KEY FACTORS INFLUENCING THE

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Manufacturing managers and engineers are ever concerned with improvement in quality,reduction in both manufacturing cost and delivery time The globalization of economyrequires introduction of new products with enhanced features at competitive costs.Another challenge is the reduction in product life span This necessitates considerabletime compression in product development cycle Yet another significant trend is masscustomization which calls for extreme flexibility in manufacturing The massiveoutsourcing in manufacturing is another important development in recent years.The new edition of CAD/CAM/CIM has been bought out to focus on the response

of CIM technology to address to these challenges Manufacturing in the new millennium

is moving towards more and more sophistication in exploiting the capabilities of computerhardware and software Robust design methodologies and integration of shape designand functional design are included in the present edition Optimized manufacturing is apossibility now with the extensive use of FEA Apart from design optimization, FEA isused to model and simulate complex manufacturing processes to evolve several iterations.This enables engineers to make right parts first time every time An additional chapter

on simulation softwares has been added in the present edition to introduce this powerfultool to the students

The authors would like to acknowledge the contribution of our erstwhile colleagues

in the PSG CAD/CAM Centre as well as Krishnaveni and Sasikala in word processingthe earlier editions and Govindaswamy for helping with some chapters in the presentedition Acknowledgements are due to K.J Reddy for providing some models forreproduction in this edition and to Pradeep for critical suggestions The excellent supportand encouragement extended by Padmini, Anitha and Hari during the revision of thisedition is gratefully acknowledged

P Radhakrishnan

S Subramanian

V Raju

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1.3 EVOLUTION OF COMPUTER INTEGRATED MANUFACTURING 4

1.5 NATURE AND ROLE OF THE ELEMENTS OF CIM SYSTEM 7

2.9 CHARACTERISTICS OF CONCURRENT ENGINEERING 25 2.10 KEY FACTORS INFLUENCING THE SUCCESS OF CE 26 2.11 EXAMPLE OF CONCURRENT ENGINEERING 26 2.12 TECHNIQUES TO IMPROVE MANUFACTURABILITY AND REDUCE LEAD TIME 27

2.14 TAGUCHI METHOD FOR ROBUST DESIGN 34

3 PRINCIPLES OF COMPUTER GRAPHICS 41

4.6 ARCHITECTURE OF A TYPICAL GRAPHICS WORKSTATION 90

5.3 COMPARISON OF COMMANDS IN POPULAR OPERATING SYSTEMS 106

6.21 REPRESENTATION OF CURVES AND SURFACES 154

6.30 BICUBIC POLYNOMIAL SURFACE PATCHES 164 6.31 BEZIER BICUBIC SURFACE PATCHES 165

6.33 SURFACE MODELING IN COMMERCIAL DRAFTING AND MODELING SOFTWARE 166

6.36 UNDERSTANDING CURVE AND SURFACE DESIGN 177 6.37 OTHER FEATURES USEFUL FOR CONCEPTUAL DESIGN 185 6.38 DATA TRANSFER TO OTHER SOFTWARES 185

7 FINITE ELEMENT MODELING AND ANALYSIS IN CIM 189

7.16 FINITE ELEMENT ANALYSIS APPLICATIONS TO METAL FORMING 244

8 CIM DATA BASE AND DATA BASE MANAGEMENT SYSTEMS 247

9.16 DECISION TABLES AND DECISION TREES 280

9.18 METHODS OF COMPUTER AIDED PROCESS PLANNING 282

10 PLANNING OF RESOURCES FOR MANUFACTURING THROUGH

10.10 COMMON ACRONYMS USED IN AN MRP-II ENVIRONMENT 314

10.13 ENTERPRISE RESOURCE PLANNING (ERP) 316

11.3 PROGRAMMABLE LOGIC CONTROLLERS 329

11.6 PROGRAMMING OF PLC 333 11.7 EXAMPLE OF APPLICATION OF PLC IN A CNC MACHINE 335

12.13 EXAMPLE OF PROGRAMMING A VERTICAL MACHINING CENTRE 423

13.12 APPLICATIONS OF INDUSTRIAL ROBOTS 496 13.13 THE INTEGRATION OF THE INDUSTRIAL ROBOT INTO A CIM SYSTEM 500 13.14 PRESENTATION OF WORK TO ROBOTS 501 13.15 PRODUCT DESIGN FOR AUTOMATIC MANUFACTURE BY ROBOTS 501

14.5 STATISTICAL PROCESS CONTROL (SPC) 509

14.9 NON-CONTACT INSPECTION METHODS 512

14.11 COMPUTER AIDED INSPECTION USING ROBOTS 517 14.12 INTEGRATED COMPUTER AIDED INSPECTION SYSTEMS 518 14.13 FLEXIBLE INSPECTION SYSTEM (FIS) 520

15.5 COMPONENTS OF A SMALL LOCAL AREA NETWORK 528

15.8 NETWORKING STANDARDS AND THEIR DEVELOPMENT 533

15.11 ISSUES IN INTER-SYSTEM COMMUNICATION 538

15.14 MANAGING REMOTE SYSTEMS IN A NETWORK 541 15.15 DESIGN ACTIVITY IN A NETWORKED ENVIRONMENT 542

15.17 NETWORKING IN A MANUFACTURING COMPANY 542

15.19 INTERNET 548 15.20 HARDWARE ELEMENTS OF A NETWORK 551 15.21 ATM (ASYNCHRONOUS TRANSFER MODE) NETWORKS 554

15.23 DOCUMENT AND WORKFLOW MANAGEMENT SYSTEM 557 15.24 A CASE STUDY OF APPLICATION OF GLOBAL NETWORKING 562

17.1.4 PRODUCT DATA TECHNOLOGY SUPPORT FOR COMPUTER AIDED CONCURRENT

18.3 THE NIST - AMRF HIERARCHICAL MODEL 601

18.5 THE CIM MODEL OF DIGITAL EQUIPMENT CORPORATION 603

20.4 TYPES OF DATA COLLECTION SYSTEMS 646

20.6 AUTOMATIC DATA COLLECTION SYSTEM 648

20.9 MAGNETIC INK CHARACTER RECOGNITION 651

21.4 SIMULATION PROCESS FOR MANUFACTURING SYSTEMS ANALYSIS 656

21.7 PROCEDURE FOR SIMULATION USING SOFTWARE 659

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to manufacturing software without any loss of data CIM uses a common databasewherever feasible and communication technologies to integrate design, manufacturingand associated business functions that combine the automated segments of a factory or

a manufacturing facility CIM reduces the human component of manufacturing andthereby relieves the process of its slow, expensive and error-prone component CIM standsfor a holistic and methodological approach to the activities of the manufacturing enterprise

in order to achieve vast improvement in its performance

This methodological approach is applied to all activities from the design of the product

to customer support in an integrated way, using various methods, means and techniques

in order to achieve production improvement, cost reduction, fulfillment of scheduleddelivery dates, quality improvement and total flexibility in the manufacturing system.CIM requires all those associated with a company to involve totally in the process of productdevelopment and manufacture In such a holistic approach, economic, social and humanaspects have the same importance as technical aspects

CIM also encompasses the whole lot of enabling technologies including total qualitymanagement, business process reengineering, concurrent engineering, workflowautomation, enterprise resource planning and flexible manufacturing

A distinct feature of manufacturing today is mass customization This implies thatthough the products are manufactured in large quantities, products must incorporate

An overview of CIM is presented in this chapter A brief account of the evolution of CIM isincluded The major functions carried out in a manufacturing plant are surveyed and thedifferent levels of integration are identified

customer-specific changes to satisfy the diverse requirements of the customers Thisrequires extremely high flexibility in the manufacturing system.

The challenge before the manufacturing engineers is illustrated in Fig.1.1

COST

DELIVERY TIME QUALITY

Fig.1.1 Challenges in Manufacturing

Manufacturing industries strive to reduce the cost of the product continuously to remaincompetitive in the face of global competition In addition, there is the need to improve thequality and performance levels on a continuing basis Another important requirement is

on time delivery In the context of global outsourcing and long supply chains cutting acrossseveral international borders, the task of continuously reducing delivery times is really anarduous task CIM has several software tools to address the above needs

Manufacturing engineers are required to achieve the following objectives to becompetitive in a global context

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The advances in automation have enabled industries to develop islands of automation.Examples are flexible manufacturing cells, robotized work cells, flexible inspection cellsetc One of the objectives of CIM is to achieve the consolidation and integration of theseislands of automation This requires sharing of information among different applications

or sections of a factory, accessing incompatible and heterogeneous data and devices Theultimate objective is to meet the competition by improved customer satisfaction throughreduction in cost, improvement in quality and reduction in product development time

CIM makes full use of the capabilities of the digital computer to improvemanufacturing Two of them are:

i Variable and Programmable automation

ii Real time optimization

The computer has the capability to accomplish the above for hardware components ofmanufacturing (the manufacturing machinery and equipment) and software component

of manufacturing (the application software, the information flow, database and so on)

The capabilities of the computer are thus exploited not only for the various bits andpieces of manufacturing activity but also for the entire system of manufacturing Computershave the tremendous potential needed to integrate the entire manufacturing system andthereby evolve the computer integrated manufacturing system

1.2 TYPES OF MANUFACTURING

The term “manufacturing” covers a broad spectrum of activities Metal working industries,process industries like chemical plants, oil refineries, food processing industries, electronicindustries making microelectronic components, printed circuit boards, computers andentertainment electronic products etc are examples of manufacturing industries.Manufacturing involves fabrication, assembly and testing in a majority of situations However,

in process industries operations are of a different nature

Manufacturing industries can be grouped into four categories:

i

i Continuous Process IndustriesContinuous Process Industries

In this type of industry, the production process generally follows a specificsequence These industries can be easily automated and computers are widelyused for process monitoring, control and optimization Oil refineries, chemicalplants, food processing industries, etc are examples of continuous processindustries

ii

ii Mass Production IndustriesMass Production Industries

Industries manufacturing fasteners (nuts, bolts etc.), integrated chips, automobiles,entertainment electronic products, bicycles, bearings etc which are all massproduced can be classified as mass production industries Production lines arespecially designed and optimized to ensure automatic and cost effective operation.Automation can be either fixed type or flexible

iii Batch Production (Discrete Manufacturing)Batch Production (Discrete Manufacturing)

The largest percentage of manufacturing industries can be classified as batchproduction industries The distinguishing features of this type of manufacture arethe 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 centresshould have broader specifications Another important fact is that small batchsize involves loss of production time associated with product changeover

As mentioned earlier, integration of computer in process industries for productionautomation, process monitoring and control and optimization is relatively easy In thecase of mass production and batch production computer integration faces a number ofproblems as there are a large number of support activities which are to be tied together.These are discussed in detail later in this chapter

Automation of manufacture has been implemented using different techniques sincethe turn of the 20th Century Fixed automation is the first type to emerge Single spindleautomatic lathe, multi spindle automatic lathe and transfer lines are examples of fixedautomation Fixed automation using mechanical, electrical, pneumatic and hydraulicsystems is widely used in automobile manufacturing This type of automation has a severelimitation - these are designed for a particular product and any product change will requireextensive modifications to the automation system

The concept of programmable automation was introduced later These were electricallycontrolled systems and programs were stored in punched cards and punched tapes Typicalexamples of programmable automation are:

i Electrical programme controlled milling machines

ii Hydraulically operated Automatic lathes with programmable control drumiii Sequencing machines with punched card control /plug board control

Development of digital computers, microelectronics and microprocessors significantlyaltered the automation scenario during 1950-1990 Machine control systems are nowdesigned around microprocessors and microelectronics is part and parcel of industrialdrives and control The significant advances in miniaturization through integration of largenumber of components into small integrated chips and the consequent improvement inreliability and performance have increased the popularity of microelectronics This hasresulted in the availability of high performance desktop computing machines as well asfile servers which can be used for industrial control with the help of application softwarepackages

1.3 EVOLUTION OF COMPUTER INTEGRATED MANUFACTURING

Computer Integrated Manufacturing (CIM) is considered a natural evolution of thetechnology of CAD/CAM which by itself evolved by the integration of CAD and CAM.Massachusetts Institute of Technology (MIT, USA) is credited with pioneering the

Chapter 1Chapter 1Chapter 1Chapter 1Chapter 1

development in both CAD and CAM The need to meet the design and manufacturingrequirements of aerospace industries after the Second World War necessitated thedevelopment these technologies The manufacturing technology available during late 40’sand early 50’s could not meet the design and manufacturing challenges arising out of theneed to develop sophisticated aircraft and satellite launch vehicles This prompted the USAir Force to approach MIT to develop suitable control systems, drives and programmingtechniques for machine tools using electronic control

The first major innovation in machine control is the Numerical Control (NC),demonstrated at MIT in 1952 Early Numerical Control Systems were all basically hardwiredsystems, since these were built with discrete systems or with later first generation integratedchips Early NC machines used paper tape as an input medium Every NC machine wasfitted with a tape reader to read paper tape and transfer the program to the memory of themachine tool block by block Mainframe computers were used to control a group of NCmachines by mid 60’s This arrangement was then called Direct Numerical Control (DNC)

as the computer bypassed the tape reader to transfer the program data to the machinecontroller By late 60’s mini computers were being commonly used to control NC machines

At this stage NC became truly soft wired with the facilities of mass program storage, line editing and software logic control and processing This development is called ComputerNumerical Control (CNC)

off-Since 70’s, numerical controllers are being designed around microprocessors, resulting

in compact CNC systems A further development to this technology is the distributednumerical control (also called DNC) in which processing of NC program is carried out indifferent computers operating at different hierarchical levels - typically from mainframehost computers to plant computers to the machine controller Today the CNC systems arebuilt around powerful 32 bit and 64 bit microprocessors PC based systems are alsobecoming increasingly popular

Manufacturing engineers also started using computers for such tasks like inventorycontrol, demand forecasting, production planning and control etc CNC technology wasadapted in the development of co-ordinate measuring machine’s (CMMs) which automatedinspection Robots were introduced to automate several tasks like machine loading,materials handling, welding, painting and assembly All these developments led to theevolution of flexible manufacturing cells and flexible manufacturing systems in late 70’s.Evolution of Computer Aided Design (CAD), on the other hand was to cater to thegeometric modeling needs of automobile and aeronautical industries The developments

in computers, design workstations, graphic cards, display devices and graphic inputand output devices during the last ten years have been phenomenal This coupled withthe development of operating system with graphic user interfaces and powerful interactive(user friendly) software packages for modeling, drafting, analysis and optimizationprovides the necessary tools to automate the design process

CAD in fact owes its development to the APT language project at MIT in early 50’s.Several clones of APT were introduced in 80’s to automatically develop NC codes from

the geometric model of the component Now, one can model, draft, analyze, simulate,modify, optimize and create the NC code to manufacture a component and simulate themachining operation sitting at a computer workstation.

If we review the manufacturing scenario during 80’s we will find that themanufacturing is characterized by a few islands of automation In the case of design,the task is well automated In the case of manufacture, CNC machines, DNC systems,FMC, FMS etc provide tightly controlled automation systems Similarly computer controlhas been implemented in several areas like manufacturing resource planning, accounting,sales, marketing and purchase Yet the full potential of computerization could not beobtained unless all the segments of manufacturing are integrated, permitting the transfer

of data across various functional modules This realization led to the concept of computerintegrated manufacturing Thus the implementation of CIM required the development

of whole lot of computer technologies related to hardware and software

1.4 CIM HARDWARE AND CIM SOFTWARE

CIM Hardware comprises the following:

i Manufacturing equipment such as CNC machines or computerized work centres,robotic work cells, DNC/FMS systems, work handling and tool handling devices,storage devices, sensors, shop floor data collection devices, inspection machinesetc

ii Computers, controllers, CAD/CAM systems, workstations / terminals, data entryterminals, bar code readers, RFID tags, printers, plotters and other peripheraldevices, modems, cables, connectors etc.,

CIM software comprises computer programmes to carry out the following functions:Management Information System

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Manufacturing Facilities Planning

Work Flow Automation

Business Process Engineering

Network Management

Quality Management

1.5 NATURE AND ROLE OF THE ELEMENTS OF CIM SYSTEM

Nine major elements of a CIM system are in Fig 1.2 They are:

i Marketing: Marketing: The need for a product is identified by the marketing division Thespecifications of the product, the projection of manufacturing quantities and thestrategy for marketing the product are also decided by the marketing department.Marketing also works out the manufacturing costs to assess the economic viability

of the product

ii Product Design: Product Design: The design department of the company establishes the initialdatabase for production of a proposed product In a CIM system this isaccomplished through activities such as geometric modeling and computer aideddesign while considering the product requirements and concepts generated bythe creativity of the design engineer Configuration management is an importantactivity in many designs Complex designs are usually carried out by severalteams working simultaneously, located often in different parts of the world Thedesign process is constrained by the costs that will be incurred in actual productionand by the capabilities of the available production equipment and processes Thedesign process creates the database required to manufacture the part

iii Planning:Planning: The planning department takes the database established by thedesign department and enriches it with production data and information toproduce a plan for the production of the product Planning involves severalsubsystems dealing with materials, facility, process, tools, manpower, capacity,scheduling, outsourcing, assembly, inspection, logistics etc In a CIM system,this planning process should be constrained by the production costs and bythe production equipment and process capability, in order to generate anoptimized plan

iv Purchase:Purchase: The purchase departments is responsible for placing the purchaseorders and follow up, ensure quality in the production process of the vendor,receive the items, arrange for inspection and supply the items to the stores orarrange timely delivery depending on the production schedule for eventual supply

to manufacture and assembly

v Manufacturing Engineering: Manufacturing Engineering: Manufacturing Engineering is the activity of carryingout the production of the product, involving further enrichment of the databasewith performance data and information about the production equipment andprocesses In CIM, this requires activities like CNC programming, simulation andcomputer aided scheduling of the production activity This should include on-line dynamic scheduling and control based on the real time performance of theequipment and processes to assure continuous production activity Often, theneed to meet fluctuating market demand requires the manufacturing systemflexible and agile

vi Factory Automation Hardware:Factory Automation Hardware: Factory automation equipment further enrichesthe database with equipment and process data, resident either in the operator orthe equipment to carry out the production process In CIM system this consists

of computer controlled process machinery such as CNC machine tools, flexible

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manufacturing systems (FMS), Computer controlled robots, material handlingsystems, computer controlled assembly systems, flexibly automated inspectionsystems and so on

vii Warehousing: Warehousing: Warehousing is the function involving storage and retrieval ofraw materials, components, finished goods as well as shipment of items Intoday’s complex outsourcing scenario and the need for just-in-time supply ofcomponents and subsystems, logistics and supply chain management assumegreat importance

viii Finance:Finance: Finance deals with the resources pertaining to money Planning

of investment, working capital, and cash flow control, realization ofreceipts, accounting and allocation of funds are the major tasks of thefinance departments

Fig.1.3 Various Activities in CIM

FEM - Finite Element Modeling MeM - Mechanism Modeling ERP - EnterpriseResource Planning

ix Information Management: Information Management: Information Management is perhaps one of the crucialtasks in CIM This involves master production scheduling, database management,communication, manufacturing systems integration and management informationsystems

It can be seen from Fig 1.3 that CIM technology ties together all the manufacturing andrelated functions in a company Implementation of CIM technology thus involves basicallyintegration of all the activities of the enterprise

1.6 DEVELOPMENT OF CIM

CIM is an integration process leading to the integration of the manufacturing enterprise.Fig 1.4 indicates different levels of this integration that can be seen within an industry.Dictated by the needs of the individual enterprise this process usually starts with theneed to interchange information between the some of the so called islands of automation.Flexible manufacturing cells, automatic storage and retrieval systems, CAD/CAM baseddesign etc are the examples of islands of automation i.e a sort of computer basedautomation achieved completely in a limited sphere of activity of an enterprise Thisinvolves data exchange among computers, NC machines, robots, gantry systems etc.Therefore the integration process has started bottom up The interconnection of physicalsystems was the first requirement to be recognized and fulfilled

Fig 1.4 Levels of Integration Against Evolution of CIM

The next level of integration, application integration in Fig 1.4 is concerned with theintegration of applications, the term applications being used in the data processing sense.The applications are those which are discussed in section 1.4 under the heading CIMhardware and software Application integration involves supply and retrieval ofinformation, communication between application users and with the system itself Thusthe application integration level imposes constraints on the physical integration level.There has to be control of the applications themselves also

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The highest level of integration, business integration in Fig.1.4 is concerned with themanagement and operational processes of an enterprise The management processprovides supervisory control of the operational process which in turn co-ordinates theday-to-day execution of the activities at the application level The business integrationlevel therefore places constraints on the application level This level offers considerablechallenge to the integration activity

QUESTIONS

1 Describe the need for CIM and the issues addressed by CIM

2 What are the different types of manufacturing? Make an assessment of the extent

of computer control in specific cases of each types of manufacturing

3 What are the various activities of a manufacturing plant which can be carried outthrough computer control?

4 Discuss the main elements of CIM systems

5 Differentiate among physical integration, application integration and businessintegration Give specific examples of each

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2.2 PRODUCT DEVELOPMENT CYCLE

Industries have to continuously upgrade their products as well as introduce new products

in the market in order to retain as well as to increase their market share The productdevelopment is the responsibility of the research and development (R&D) department of

a manufacturing company When a product is initially introduced the sales volume will below If the product is good and satisfies the customers, the sales will pick up Sometimes,

if there are any problems in the product the company will have to make changes orimprovements in the product which is a very expensive proposition If the defect is seriousenough the company may have to recall an entire batch of products at enormous cost andloss of goodwill The sales and service department usually takes care of attending to thecustomers’ problems That is why manufacturers of automobiles, entertainment electronicgoods, fast moving consumer goods like washing machines and refrigerators etc haveelaborate sales and service network

The sales volume will pick up gradually and peak after some time The product willcontinue to sell for some time The sales will then start gradually declining owing toavailability of better products in the market It is time for the company to introduce a newand improved product in the market as well as to retire the old product The companieswill usually advice the customers that the old product will be further supported by thesales and service department only for a limited period of time

The cycle through which a product goes through from development to retirement iscalled the product life cycle The variation of the sales volume during the life cycle of aproduct is graphically shown in Fig.2.1.

Fig 2.1 Variation of the Sales Volume Vs Life of a Product

The product development cycle starts with developing the product concept, evolvingthe design, engineering the product, manufacturing the part, marketing and servicing This

is shown in Fig 2.2 The idea of a product may come from a patent, suggestion of thecustomers, feedback of the sales and service department, market research carried out bythe marketing department or from the R&D department itself The next stage is theconceptualization of the product The cost at which the product could be sold in the market

is decided and the overall design in terms of shape, functional specifications, ergonomics,aesthetics etc are considered in detail and finalized at this stage The work of productdevelopment is then taken to the next stage by the design department who carefully designseach assembly and each component of the assembly Detailed design analysis andoptimization is carried out at this stage A design may have several variants For example,

a passenger car may have what is called a stripped down version with the bare minimumoptions and luxury versions with several add on functionalities Between these two extremeversions, there will be a number of models or variants to meet the needs of customers withdifferent paying capacities In a similar way, a satellite launch vehicle may be designed fordifferent payloads A fighter aircraft may have different versions A refrigerator will have

to be marketed with different capacities The design department creates these designsthrough a top down approach or a bottom up approach In top down approach, theentire assembly is designed first and individual designs are done latter In bottom upapproach, the component design is done first and the product is realized by assemblingthe components suitably The design also will involve preparation of detail drawings

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Engineering the product consists of process planning, tool design, facility design, capacityplanning, quality assurance activities, procurement, assembly planning, etc Marketingdepartment will have the responsibility of carrying out appropriate product launch activities

as well as planning the sales and service network, advertising and training of sales andservice personnel

Concept

Design

Planning

Manufacture Marketing

Service

Fig 2.2 Product Development Cycle

In actual practice product development activities form a spiral as shown in Fig 2.3.The product goes through a series of continuous refinement and improvements, additionsetc A typical example is a software package improved versions of which are released asnew versions at periodic intervals The feedback from the marketing and services leads

to improvements in design and/or evolution of new designs As an example, the reader

is advised to make a study of the evolution of the various models of aircraft or passengercars over the last five decades

This is how most of the present products have been evolved over the period One canevidently realize it by comparing a 1928 model T Ford car with the current jelly beanshaped cars However, the design evolution however does not stop at any stage and is acontinuous process

Similarly one can observe the vast improvements that have taken place in the design ofentertainment electronic goods, computers, aircrafts and even domestic appliances likerefrigerators Often an altogether new concept may make a design obsolete Songs wererecorded at different times on discs, tapes, cassettes and CD-ROMS Correspondingly, thedesign of the music player has also undergone radical changes from the old gramophonerecord player to the present MP3 player It is interesting to note the rate of obsolescence oftechnology in music players

in a typical sequential product development process finalizes the design withoutconsulting the manufacturing, quality or purchase departments Planning might feel itnecessary to request design changes based on a number of reasons like the procurement

or facility limitations Changes in design may be called for when the manufacturingdepartment is unable to meet design specifications or there are problems in assembly.These changes are however to be incorporated in design The design documents aretherefore sent back to the design department for incorporating the changes The design/redesign path is shown in Fig 2.4 The design documents are passed on back and forth

to incorporate design changes as illustrated This will lead to inevitable conflicts, eachdepartment sticking to their own decisions and may often require intervention of seniormanagement to resolve conflicts or differences in opinion Design changes will involveboth material and time wastages In such a situation, time taken to product development

is usually more than what is anticipated and correspondingly the response to the marketrequirements will be slow compared to a competing company which can create an errorfree design at the first instance In an age of reduced product life cycles as we witness

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today the time delay between market demand and introduction of product in the markethas to be as short as possible Sequential product development process, therefore, maynot suit the present global scenario

Fig 2.4 Design and Redesign Path

Even after the prototype development stage is over, the need for design change mayarise during service Such changes are usually few in number, but are very costly

Thus in the traditional manufacturing, the design documents move sequentially throughthe various departments of the organization The R & D group completes the design taskand passes the data to planning, which in turn passes the information to manufacturingand so on If any downstream department wants to introduce any change, the process has

to backtrack and this often involves additional expenditure as well as inevitable delay inrealizing the product

Fig 2.5 Across the Wall Approach in Sequential Engineering

Sequential Engineering is often called “across the wall” method Figure 2.5 illustratesthe insulated way each department may function in sequential approach Each segment

of the product development team (Design, Planning, Manufacturing etc.) completes its

task in isolation and passes over the documents to the next segment There is no interactionamong the groups before the design is finalized If a serious mistake in the product isdetected during testing, the revision process has to start from design, resulting in materialswastage and loss of time In the context of extensive outsourcing, there is also need forintensive consultation between vendors and manufacturers.

2.4 CONCURRENT ENGINEERING

Concurrent engineering or Simultaneous Engineering is a methodology of restructuringthe product development activity in a manufacturing organization using a crossfunctional team approach and is a technique adopted to improve the efficiency ofproduct design and reduce the product development cycle time This is also sometimesreferred to as Parallel Engineering Concurrent Engineering brings together a widespectrum of people from several functional areas in the design and manufacture of aproduct Representatives from R & D, engineering, manufacturing, materialsmanagement, quality assurance, marketing etc develop the product as a team Everyoneinteracts with each other from the start, and they perform their tasks in parallel Theteam reviews the design from the point of view of marketing, process, tool design andprocurement, operation, facility and capacity planning, design for manufacturability,assembly, testing and maintenance, standardization, procurement of components andsub-assemblies, quality assurance etc as the design is evolved Even the vendordevelopment department is associated with the prototype development Any possiblebottleneck in the development process is thoroughly studied and rectified All thedepartments get a chance to review the design and identify delays and difficulties.The departments can start their own processes simultaneously For example, the tooldesign, procurement of material and machinery and recruitment and training ofmanpower which contributes to considerable delay can be taken up simultaneously asthe design development is in progress Issues are debated thoroughly and conflicts areresolved amicably

Concurrent Engineering (CE) gives marketing and other groups the opportunity toreview the design during the modeling, prototyping and soft tooling phases ofdevelopment CAD systems especially 3D modelers can play an important role in earlyproduct development phases In fact, they can become the core of the CE They offer avisual check when design changes cost the least

Intensive teamwork between product development, production planning andmanufacturing is essential for satisfactory implementation of concurrent engineering.The teamwork also brings additional advantages ; the co-operation between variousspecialists and systematic application of special methods such as QFD (Quality FunctionDeployment), DFMA (Design for Manufacture and Assembly) and FMEA (Failure Modeand Effect Analysis) ensures quick optimization of design and early detection of possiblefaults in product and production planning This additionally leads to reduction in leadtime which reduces cost of production and guarantees better quality

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2.5 COMPARISON OF CONCURRENT ENGINEERING AND SEQUENTIAL

ENGINEERING

A comparison of concurrent and sequential engineering based on cost is attempted inthis section The distribution of the product development cost during the productdevelopment cycle is shown in Fig 2.6 This figure shows that though only about 15%

of the budget is spent at the time of design completion, whereas the remaining 85% isalready committed The decisions taken during the design stage have an importantbearing on the cost of the development of the product Therefore the development costand product cost can be reduced by proper and careful design CE facilitates this Thesignificantly large number of nonconformities detected in the later stages of productdevelopment cycle in sequential engineering results in large time and cost overrun

PRODUCT LIFE CYCLE

Fig 2.7 Distribution of Design Changes Across the Life Cycle of a Product

2.5.2 COST OF CHANGES IN DESIGN

The cost of introducing a design change in a product progressively increases as thedevelopment proceeds through design and manufacturing This can be elaborated with asimple example If a change in the conceptual 3D CAD model costs Rs.50, 000 The samechange during the planning stage would cost Rs.1, 50,000 By the time the product moves

to prototyping and testing, the change may cost Rs.2, 50,000 The cost goes up to Rs.25,00,000

if the product is in the manufacturing stage and Rs.50,00,000 or more after the companyreleases the product to sales and marketing Figure 2.8 illustrates this While these numbersdiffer greatly from company to company and from product to product, they give a feel ofthe importance of feedback early in the design cycle

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 X1000

Design Planning Prototyping Manufacture Marketing

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2.5.3 HOLISTIC APPROACH TO PRODUCT DEVELOPMENT

Concurrent engineering approach introduces a new philosophy in product development

No longer is product development considered the exclusive activity of the designdepartment Participation of planning, manufacturing, quality, service, vendordevelopment and marketing personnel in the development process enables the crossfunctional team to view the development as a total responsibility and this results inbetter communication among the various departments

2.5.4 ROBUST PRODUCTS

Concurrent approach to product design results in products with fewer errors andtherefore avoids the loss of goodwill of the customers due to poorly engineered products.The entire product development team looks at each and every aspect of products – cost,specifications, aesthetics, ergonomics, performance and maintainability The resultingproduct will naturally satisfy the customer

2.5.5 REDUCTION IN LEAD TIME FOR PRODUCT DEVELOPMENT

Time compression in product development is an important issue today Concurrentengineering reduces the product development time significantly as the preparatory work

in all downstream functions can take place concurrently with design Elimination of theerrors in design appreciably reduces the possibility of time overrun, enabling thedevelopment schedule to be maintained

2.6 IMPLEMENTATION OF CONCURRENT ENGINEERING

The cycle of engineering design and manufacturing planning involves interrelatedactivities in different engineering disciplines simultaneously, than sequentially as shown

in Fig 2.9 (A) In addition, the activities necessary to complete a particular task within

a specific engineering discipline have to emerge wherever possible from their sequentialflow into a concurrent workflow with a high degree of parallelism as illustrated in Fig.2.9 (B) Concurrency implies that members of the multidisciplinary project team work inparallel This also means that there is no strict demarcation of jobs among variousdepartments The multi-disciplinary approach has the advantage of several inputs whichcan be focused effectively early in the design process Presently engineering departmentsare practicing this approach but still with a high degree of manual involvement andredundancy Planning scenarios experience a similar approach One of the most criticallinks in the entire product life cycle, i.e the close interaction between design andmanufacturing has been made possible in concurrent engineering Thus the productdevelopment process has been freed from the large number of constraints arising fromthe limitations of the sequential engineering This has changed the way manufacturersbring the products to market For example, many manufacturers no longer view productdevelopment as a relay race in which marketing passes the baton to R &D, which inturn passes it to manufacturing Representatives drawn from marketing, planning, design,

purchase, vendors, manufacturing, quality control and other department participate inproduct development right from the beginning Concurrent engineering is thus a cross-functional approach to product design Total quality management which is beingpracticed by many companies is closely related to concurrent engineering.

Marketing Design Planning Purchase Outsourcing Manufacturing Quality Finance Sales & Service

Chapter 2Chapter 2Chapter 2Chapter 2Chapter 2

2.7 CONCURRENT ENGINEERING AND INFORMATION TECHNOLOGY

The challenge to engineering information systems today is to have the ability to handlevery large amount of data and information which the engineering organizations have tocope with Design changes, status reviews, releases and their effects on cost, delivery andquality have to be managed It has to be made sure that the workplace of each engineer,planner and manager is not overloaded so as to make the work ineffective

Concurrent or simultaneous engineering is an orthogonal concept that defines howconcurrent and simultaneous work flows are organized and the information flow, storage,retrieval and decision making can be supported and controlled In particular the principlesand methods of concurrent or simultaneous engineering integrate these activities throughthe information technology (IT) Hence IT is the backbone of this approach Software toolsare available today to perform all the manufacturing related activities These tools todaypermit almost seamless transfer of data from one application to another The possibilities

of extensive reuse of data are another welcome feature Naturally IT assures productivityincrease and shorter overall cycle times with improved quality

The product design is currently carried out using a wide range of related and reasonablywell integrated design support tools A number of tools exist in the market which addressesthe specific requirements of certain design activities The manufacturing engineers have awide choice today to manage product development through product life cycle management(PLM) software However, there exists no coherent view yet as to how the design activityshould be structured to provide rapid throughput of satisfactorily validated designs Theapproach therefore will be to identify the necessary tools required for the design of productsand include all of them in some kind of integrated platform Concurrent engineeringtogether with CIM aims to achieve this objective Thus concurrent engineering helps tocreate an environment in which teams of product engineers can develop products frominitial concept to prototype and to final product with the integration of manufacturingengineering and design of production facilities

The pressure to be the first in the market with a new product requires the design to beright from the beginning Therefore in every phase of the product development, fromconcept to final design, sufficient information has to be provided to the productdevelopment team based on which the members of the team take the right decisions withrespect to production, production planning and product support Special attention has to

be given to the adoption of new production technologies and to take make or buy decisionsincluding the early integration of the suppliers into the development process

As a result of these requirements, information systems have to be developed whichintegrate the different engineering disciplines and their support tools, promoting andpushing a conversion of the currently practiced sequential work flow into a moreconcurrent work flow with a higher degree of parallelism to shorten the productdevelopment lead-time