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CHAPTER 1

JIT-An Introduction

JIT or JUST-IN-TIME Manufacturing is by now a'very widely discussed, researchedand'applied manufacturing philosophy, in a variety of industries across the globe.Its ultimate aim is to achieve 'perfection' in manufacturing through continuousimprovement and elimination of all waste. By making itself eminently suitable foradoption in any type of manufacture , Le., mass production, batch production,continuous. process production or custom oriented jo~ order pf$>duction,JIT holdsa true potential to become, what can be termed as a "Universal Manufactur ingPhilosophy" of the future. JIT is indeed a philosophy rather than a series oftechniques. By eliminating all waste and seeking continuous improvement, it aimsat creat ing a manufactur ing system that is responsive to the market needs. JIT.enables organizations to achieve simultaneously the goals of high quality, quickdelivery, low cost and a high degree of flexibi li ty for quick response. Being aphilosophy, JIT does notrestrict itselfto high technology manufacturing environmeritswhich make extensive use of modem technologies l~e Flexible ManufacturihgSystems (FMS) or Computer Integrated Manufacturing (CIM). JIT philosophy 'isvalid in any manufacturing environment, regardless of the level of advancementin the technological hardw.~e. Perhaps it is important to stress this point, so thatthere is no misconception about JIT being restricted to high technology systems.Similarly, the philosophy is not limited to any specific type of industry nor doesthe size of the organization matter. As will be seen in detail in subsequent chapters,organiza tions of different sizes , in a var iety of industries , have. successfullyimplemented the philosophy. Indeed, some recent applications show that JIT iseminently suited to non-manufacturing situations as well, such as in service andadministrative work situations. Many of such case illustrations will be describedin later chapters. Being of Japanese origin, there could be a tendency to believethat success of JIT is highly culture-specific. There is ample and conclusive evidenceto the contrary. Doubtless, cultural differences playa role in the adaptation of JITand in the determination of relative priorities for implementing specific componentsof JIT. But culture, per se, does not s tand in the way of i ts applicat ion.1.1 THE SPREADOFJIT MOVEMENTThe' basic idea of JIT was originally developed and brought to a high level ofsophistication by the Toyota Motor Company in Japan. The idea was formalizedinto a management system, when Toyota sought to meet the precise demands ofcustomers for different models and colours with minimum delay. Thus. ToyotaD..-A .,...: ('. . .. ..._ ~("\' .t y Y' " "r "l .

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4 Just In Time Manufacturing I lIT - An Introductioll

1. Company :annonC) :ameras. office equipment, etc.ement (PI) :Indexed) 100 to 250Waste elimination: $15 million in 1976$98 million in 1982:ccess

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(COn/d.)

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Table 1.2 Summary or Some Just InTime Applications Inthe United States-Buffa & Sarin [32]

lIT -An Introduction 7

Hewlett PackardComputers and Test Systems87 to39 standard hours30% to 45% reduct ion in manual set upPC Assembly : 8500 to 5750 sq f tHP Corporate mgt helped JIT; proud tobeamong fIrst to implement JITffQC.PC Assembly : 8500 to 5750 sqf tPC Assembly : 15 to 1.5 days

Harley DavidsonMotorcycles39% overall increaseMany operations combined. Overall set upreduction by 75%Turns up from 5 to 20. WlP & RMreduction by 60%46% decrease in scrap & rework35% decrease in w,arranty35% reduction in warehouse15% reduction in manufacturingAll suppl iers within 200 miles; weekly ordaily delivery

Presses : 38% to 80%Drills : 24% to 33%Shears : 45%Grinders : 44%Average : 45%Raw steel : 40%Purchased parts : 7%Crane Shafts : 30 to 3 daysImplemented process control charting in40% of operations.SignificantSignificant

: General Elect ric: Electncal appliancesDirect labour : 15%

Indirect labour : 25%Significant; from hours to minutesIn process by 40%Scrap and rework by 33%52000 sq. f t.From weeks to days. Mixed production.Daily vendor delivery.

Space SavingsLead times

Set up time reduction

Space savingsLead times

Inventory, reduction

Inventory reduction

Space savingsLead times

Set up time reductionInventory reductionQuality improvementSpace savingsLead times

Quality improvement

Quality improvement

6. CompanyProduct CategoryProductivity improvementSet up 'time in).provementInventory reductionQuality improvement

5. CompanyProduct categoryProductivity improvementSet up time reduction

4. CompanyProduct CategoryProductivity improvement

Table 1.2 (Contd.)

19% to35%15% to 38%10% to 20%40%

Apple ComputersMicrocomputersi ) Inspect ion labour from 25 to 9i i) Assembly labour from 22 to4Estimate of 30% (lines mostly dedicated,stacted JIT)Est imate of 90% in WIP and raw materia lcompared to other factoriesScrap 'and rework reduced by 10%,incoming material quality up by 20%No need for warehouse; material delivered,'to point o fuseAll components less than 2 days. Dai lyscheduleBlack and DeckerElectrical productsAssembly operators: 24 to 6Support operators: 7 to5Punch press: I hour to I min.Drastic in many areasTurns increased from 16to 30Reduced complaints in packaging by 90%100% customer service levelSignificantProducts made in weekly lots: 50% to95%Deere and CompanyHeavy machinery, farm equipment, lawncare equipmentSubassemblyWeldingManufacturing cost :Material handling

in knowing more about ill grew. Names l ike Taiichi Ohno [146] and ShigeoShirigo [191], the original developers of the Toyota System. became the 'idols' tobe worshipped. Leading consultants (see Schonberger[180J), identified it as thekey to the Japanese manufacturing phenomenon. American industry, particularlythegiant automakers (]eneral Motors, Ford and Chrysler, ledthe American transitionto JIT. Giants in other, fields like General Eleclric, Hewlett Packard, Black andDecker, International Business Machines, were quick to respond to theJIT challenge.Table 1.2 gives data on some of the American JIT applications, other thah thoseby the big three automakers.

1. CompanyProduct Category",

Productivity improvement

Set up time reductionnventory reductionuality improvementpace savingsead times2. CompanyProduct Categoryroductivity improvementSet up time reductionnventory reduction

Quality improvementSpace savingsLead times

3. CompanyProduct Category

Productivity improvement

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. ~ ,. .."Ki "U,,"I"JUl,.IUI ""6lIT - An /1Ilroductio,Tablepember Companies or NPSRA [192]of what constitutes 'products ', 'processes', technology or organization are sure to Companyapital

ates. Employeesain Lineof (MillionsofMillionsof Business Yen)en) Oiresu4500,20065il-lessbearings Kibun69292,000,200ish-pasteproducts OgluaHoseki50,00010ndustrialjewels SeikicousticP,foductsystem Research Association" (or Shin Seisan Hoshiki in Japanese). This associationIkuyo1001,00050ubber,syntheticromises to usher in the second phase of Hi movement in Japan, i.e., its rapid resinproductsogaSeiko,000,20005elecommunication equipment609,00050ood products1,35739,000,500ndustrialinstromentsTHE NEW PRODUCTION SYSTEM RESEARCH ASSOCIATION HokushinElectrickylark,4252,805,211amily res'laurants. ShikawaGasket00,55070utomaticparts Nippon2100,00050lectrical acoustic Atsundenkiroducts, wireless equipmentokusei,0006,00025Lightrnetalcasting Aluminiumnd rolling IharaKoatsuTsugite00,00083ouplings, valves Nipponcoinco;0272,50020oin-opented mechnnisms4,800,60020inancialprinting -.rintingDesigriand building1606,00060 Kogyoof electrical ~nstallations Kawasaki400,10016lectricale.quipment Electricmainly sWltch- boards)okuseiNikkei000,00072luminiumhouse- Katei Yohinold goods OkamotoMachine3,0497,20020achine tools, ToolWorksrindingmachines,0006,20018orrugated sheets boardsWorld2020,700,163omen's,men's, and children's apparelNippon5,30079,800,874luminiumsmelting, LightMetalightpressed goods ShowaMaruto02,5006aper tubes for magnetic tapesisawaHomes,39726,200,158refabricatedhomes (Con/d.)

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JIT - An Introduction 11

Even though it is by now well r ecognized that JIT is not just an assortment oftechniques but really a philosophy, definitions of JIT advanced by different authorsin the pas t, have tended to view JIT in different ways, These are now evidentlyconverging to a common perception of JIT,In the past, there have been two contrasting views on JIT [2HI]. The first sees

i t as a narrow shop-floor-based technique concerned wi th making very smallbatches, just in time for the next production process, often accompanied by a pullsystem of production scheduling, using an information system called 'Kanban'cards. Terms like zero inventory production, stockless production, small batchproduction and synchronous manufacturing seem to fit this definition.An al te rnative view is that JIT is a highly integrated product ion, sales anddistribution system leading to continuous flow through the whole supply chain.S tudies in Japan strongly support the second view. In this sense, i t i s viewed as"Continuous Flow Manufacturing". No matter what the production processes are,what the composit ion of product i s or what the market needs are, lIT enables acontinuous flow of product, as it progresses through the process stages into themarket.A few other definitions of JIT advanced by some authors are considered below:Monden [138] descnbed JIT as "a product ion sys tem to produce the kind of

units needed, at the time needed and in quantit ies needed".Harper [196] describes it as "the hottest and most controversial subject facingmanufacturers and distributors". Hall [77] states that "JIT is not confined to a setof techniques for improving production defined in the narrowest way as materialconversion, It is a way to visualize the physical operations of the company fromraw material to customer delivery," Thus, there is no aspect of the company thatJIT does not touch. I t el iminates waste in al l areas of manufacturing inc ludingmarketing, planning and production, According to Hoeffer [196]. the JIT system"is a combination of purchasing, inventory control and production managementfunctions", Materials are purchased in small quantit ies with frequent deliveriesjust in time when they are needed, Under the JIT system, the parts needed for oneday's operations in manufacturing or assembly line are supplied by in-plant sourcesof suppliers for immediate use. Schonberger [173] describes JIT as a system "toproduce and deliver finished goods Just in Time tobe :;old,subassemblies Just inTime tobe assembled into finished goods and purchased materials just in Time tobe transfornled into fabricated parts,"Voss [210] views JIT as a "production methodology which a ims to improve

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Coinco (71 per cent), Okamoto Machine Tool Works (134per cent), Bando ChemicalInduslries (54 per cent) and Shigetsu Denki (76per cent). Indeed, profits increasedfor most NPS companies. Some other me~ber companies like Kawasaki Denki,Nozawa Hokuetsu Kogyo, Ihara Koatsu Tsugite recovered from deep financialtrouble.The NPSRA will doubtless provide a tremendous thrust to the further growth

of JIT in Japan, particularly amongst th~esmaller and medium size organizations.

1.3 SOME DEFINITIONS OF JIT

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A In Time Manufacturing(z,

Capitalalesmployeesa in Line o fMillions of Businessen) 3,7008,000.015elts and industrial goods502.60073Plywood"Sliizuki Denki t)I,817

2,10020ilm capacitors. Hoketsu Kogyo

1,0013,00060ir Compressors51,10020teel cabinets andother storage systemS

5,4600,500,585as furnaces, hotwater equipment 1,6351,000,929athroom cabinets.. kitchen cabinets2,6188,90093oundry plant30,00040Secondary concrete products,3122,00076Paper drapers,sanitary products 3,00043,500.157luminium sash

become a stockholder. The companies are allowed to buy shares whenever theychoose and are not pressured. As of 1985, MIP had a capi ta l of $505,000. Anyprofit made by NPSRA is shared among its members. 'The NPSRAhad a team of 11ins tructors in 1985, most of whom were former. ' 'employeesof Toyota Motor Company or its affil iates. They learnt nT either from.Ohno himself or from Kikuo Suzumara, Chairman of NPSRA's ImplementationCoi'(lIni~ and formerly a chief inspector under Ohno atToyota. There isa groupof another 100 individuals drawn from various member companies, who serve ~L'lStructors.The 11instructorsare referred to as Implementation Committee Members.Although the membership fee is modest, there is great selectivity in admission

of new members. The assOCiat iongoes to great lengths in determining the topmanagement's commitment to NPS,before admission. Although in the earlieryears,there wasa total veil of secrecy on its activities, limited disclosure concerningNPS has now been permi tted s ince the spring of 1985, so as to avoid unfoundedcri tici sm, public suspicion and also to let member companies provide validexplanations to the public and fmancial institutions for their improved performance.Many member companies have dramatically improved their business in a shortperiod of time. Companies once considered moribund have returned to life andvigour with renewed prospects of a bright future. For example, Yo1cogawaHokushinElectric, a member of NPSRA, reported an ordinary profit improvement of43 per'cent over'the previous year in March 1985, despite the burden of its merger withHokushin Denki. Skylark, a restaurant chain, improved its profit by 16 per centfor the period ending December 1984, compared to the previous year. The othernotable examples of profit improvement (compared to previous years) are Nippon

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r,C"'JustJriIime Miinufa;iurin~12 JustIn Time Manufacturingoverall productivity through the elimination of waste and which leads to improvedquality." In the manufacturing assembly process, JlT provides for the cost effectiveproduction and delivery of only the necessary parts , in the r ight quanti ty, a t theright time and place, while using a minimum of facilities, equipment, materialsand human resources. JIT is dependent on the balance between stabil ity of theusers' scheduled requirements and the suppliers' manufacturing flexibility. It isaccomplished through the application of specific techniques which require totalemployee involvement and "teamwork" ..It should be obvious that most of the above definitions allude to JIT as acomprehensive framework which enables one to conceive, design, implement andoperate a manufacturing and supporting system, as an integrative whole, based onthe cardinal principles of "continuous improvement" and "elimination of all waste".Thus JIT is a philosophy that aims at simultaneous attainment of goals of perfectquality, quick delivery, low cost and high degree of flexibility. By enablingsimultaneous achievement of. these, often viewed in the past as conflicting goals,JIT allows development of manufactur ing systems that are a radical departuryfrom the systems of ' the past-systems that were good at accomplishing one orsome of theabove goals simultaneously, but defmitely not allof them. Organizationsadopting JIT philosophy will, therefore, derive their competitive advantage not onthe basis of cost alone or quality alone or delivery alone or flexibility alone. Thecompeti tive advantage will be a powerful advantage drawn from the combinedeffects of cost, quality, delivery and flexibility. Such is the power of JIT.1.4 CORE JAPANESE PRACTICES OF JITIn the form in which JIT evolved in Japan, the core practices can best be describedwith reference to Toyota Production System. This .system is described in detail inChapter 2. In a broad sense, the TPS made use of two key concepts: JIT andAulonomation. Autollomation implied autonomous defect control or what is knownas 'Jidoka' in Japanese. JIT meant production and conveyance of necessary unitsin necessary quantities at necessary time. The JIT ideal was achieved through fourprerequisites: (i) design of processes, (ii) standardization of jobs, (iii) smoothingof production and (iv) an information system called the Kanban system. A keyfeature of the design of processes was the use of 'multi process holding' a:ld'multifunction worker' (shojinka). Another key concept was 'creative thinking orinventive ideas' (soikufu) lo facilitate capitalization on worker suggestions.To realize the above, the Toyota system established the following core

practices [138):(i) Kanban System(ii) Production smoothing to adapt to demand changes

IiJIT - An Introduc.,,-

(vii) Visual Control System to achieve the autonomation concept.(viii) Functional Management System to promote companywide quality control,etc.In Chapter 2, these practices are analysed in detail. Toyota and the other Japaneseapplications reveal that the core nT practices they adopted belonged to fourcategories:(i) people related(ii) process related(iii) planning related and(iv) quality related.Another way to look at these is todist inguish them on the basis of two types as

follows:(i) practices that help develop continuous flow manufacture( ii) pract ices that are of 'enabling ' type, i .e ., they enable JIT to occur .

'" . '"Let us consider this further.1.4.1 Creating Continuous Flow ManufactureOne of the aims of JIT is to create continuous flow manufacture. JIT systemsought to achieve this through core practices related to design of process, materialhandling, cellular manufacture, product focus, use of multiple small machinesrather than large ones and process balancing. Flow was supported by flexibility,which was more often gained by the use of very small batches, flexibi lity in theworkforce, use of spare pl1ysical capacity and flexible automation. At the supplierend, methods adopted consisted of getting suppliers to deliver at the point of use,frequent delivery by suppliers in small lots at precise times and giving excellentdata to the suppliers to al low them to do this. At the customer end this included"making today what is needed tomorro~". Great at tent ion was paid to developgood forecasts and-production plans. A 'Master Production Schedule' drove JITmanufacturing. Such schedules were often prepared in blocks of ten days in whichproduction was stable . 'The stra tegic context was clear. JIT was developed tomaintain a continuous stream of products into the market, ena}lling the Japanesecompanies to seek new markets, gain higher market shares and improve theircompetitive position worldwide.1.4.2 Enabling JIT to OccurMany practices, some of which were traditionally present in Japanese Operations

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1fT -An Introduction IS1.5 BASIC ELEMENTS OFJITThe definitions provided by Voss [211] for the basic 111'elements are adoptedhere. As mentioned earlier, the elements defined here are by no means.exhaustive.A much more detailed list is considered by Gilbert [63] in his 1IT implementationsurvey. The interested reader may refer to Chapter 5 for this detailed list.Flow/Layout: The physical layout of production facilities is arranged so that theprocess flow is as streamlined as possible, i.e., for each component, the proportionof value added t ime is maximized. The proport ion of queuing and non-value'adding t ime are minimized. The flow is analysed in these terms and the layoutconfigured accordingly resulting in the reduction and/or elimination of stores andconveyors. Use of dedicated lines, U-shaped or parallei lines, use of small machineswith multiple copies, small plants with multiple copies may be possible. Flexibilityof equipment is essential to adjust quickly to changes in market demand, producttype, etc..Smoothed Build-up Rate: This should be consistent with the build-up rate, i .e.,as smooth as possible. JlT systems often t ry to smooth the bui ld-up rate over amonthly cycle. To achieve this, JIT systems often resort to undercapacity scheduling,so that they could respond to demand changes by essentially smoothing production,and by holding down to minimum any deviations from the schedule.Mixed Model Scheduling: JIT objective is to match the production rale to orderdemand as closely as possible. One method ofdoing this is to increase the flexibilityof production lines to allow concurrent assembly of different models on the sameline. This enables the JlT system to achieve synchronized scheduling and regularityin end product scheduling.Small Lots and Minimum Set Up Times: The object of minimizing set up lim.esis to reduce the batch sizes tothe minimum possible, thus reducing themanufacturingcycle time and the manufactUring inventory. This also results in release of Goorspace and minimizing material handling. Use of 'SMED'- Single Minute Exchangeof Dies System-is common to set-up reduction projects.Buffer Stock Removal: Constant elimination of buffer stocks is emphasized tohighlight production problems previously shielded by high inventory levels. Thesehave to be resolved without delay in order to maintain product ion. Removal ofbuffers also releases space.Kanban System: It is a pull'system of managing material movement comprisinga 'Kanban Card' based information sys tem. It helps trigger the movement ofmaterial from one operation to the next. Merely by alter ing the f requency of thecirculating Kanban, the production sys tem can be made to adjust to demandfluctuations within limits. The number of cards in the system detemlines the lotalinventory. Hence, the objective is to minimize the total number of Kanban.Quality: The achievement of high quality levels is a prerequisite of successfulJIT. Commonly used quality programmes in support of HT include zero defects,statistical process control, process data collection, worker centred quality control,use of Baka-yoke stop devices, autonomous inspection and counting.Product and Process Simplification: This can be achieved by two measures: therational ization of the product range and the simpli fication of the methods or

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solutions to the problems. Often, problem solving was forced through deliberateremoval ofbuffers. Quality circles or similar type of small group activity were themain instrument used for this purpose.Waste Redl4ction: A typical practice used was the 3M practice-muri (unreasonableness), mura (unevenness), and muda (waste). The emphasis was on removalof all sorts of waste such as inventory, excess movement, defects, unnecessaryactivities like inspection, etc.Visibility: Practices were used to make production visible; EXli1:nplesare: use of!Andon ' l ight boards signall ing t rouble spots , use of standard containers wi thspecial inserts to enable quick counting of quantities and display of daily operatingachievement on TV screens.Total Preventive Maintenance: Routine mairitenance was moved to the operatorarid the rol,e of maintenance function, was that of planning, maintenance, majorrepairs, debugging new machines and training operators.Statistical Process Control: The Japanese companies 'have emphasized qualityfor a long time. Quality management was key to niaking JITpossible. Statisticalprocess control was an important p~ctice of quality management. Autonomationhelped in automatic defect control. Poor quali ty in production or in par ts maderealization of JIT difficult.People Involvement: This was a JIT prerequisite. I l.was achieved through teamwork, education (Particularly of supervisors and operators), f lexibility in workpractices andskills, simple payment schemes, appropriate skill training, appointmentto management positions people who understood production.

"Design: Design for manufacture reduced uncertainty in manufacture. Modulardesign enabled large variety of finished items to be produced, while maintainingsimplicity of manufacture.Process and Equipment: This was not always bui lt on autonomation, but wasflexible enough.Management Control: Management targets were set, directly related to the objectives of JIT and long term control against these targets. Typical control measuresincluded number of machine breakdowns per month, stock levels and quali tychievement.Others: The Japanese management emphasized great attent ion to detail , a t a llstages. Continuous simplification and improvement was sought to achieve "flow".High level of technical support and excel lent product ion engineering were thehallmark of the Japanese Operations ~nagemcnt System.Even though Toyota pioneered the Kanban System, extensive use of Kanban

was confined to a few Japanese companies. Similarly, 'single source purchasing'was not widely practised, and dual sourcing (ex: 50: 50 or 70 : 30 spl it of orders)was quite prevalent. Single SOurcepurchasing was more limited to items requiringmajor tooling or where joint development effort was needed.The above review of typical Japanese JIT practices is useful to define the basic

elements of JIT. Any JIT system will have to be broadly configured around theseelements. An exhaustive list of these elements is quite unnecessary, since continuousinnovations are sure to Causechanges in ll,ese and also because at least some of thesewill be culture specific. A few of the important elements of JIT are defined below.

/ Just In Time Manufacturing

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X ~j-'_I ': .. ,.16 Just In Time Manufacturingmanufacture. Simplification is also brought about through component i temstandardization and component routing standardization.Standard Containers: JITemphasizes use of small standardized containers. Thisway it is possible to greatly simplify the material movement and the use ofmaterial handling equipment.Preventive Maintenance: Effective JIT requires removal of causes of uncertaintyand waste. A major cause of uncertainty is breakdown. Rigorous preventivemaintenance attempts to remove this uncertainty.Flexible Workforce: Perhaps this is the most critical requirement of JIT systems.Cross-t raining of both shop floor and office staf f and engineers is an effectiveway ofdoing this. This also requires expanded job descriptions and a job hierarchycomprising few grades and levels. Compensation systems have to be designedaccordingly. Flexible workforce is necessary to match production rate and producttype as closely as possible to the market demand.Organization in Modules or Cells: Many lff factories are organized in smallautonomous modules or cel ls , each cell being totally responsiole for i ts ownproduction'and supply of the adjacent module. The cells are designed so that ihematerial flow between cells is minimized. For this purpose it is common tocreate'families' of parts which are then processed by a dedicated 'group' of machines ina cell. Within the cell, the workforce is trained to work as a group and often manyfunctions normally considered as staff functions such as scheduling and maintenanceare brought into the cell or module.Continuous Improvement: l IT is not a one-t ime effort . It embodies the ethics ofcontinuous improvemem, which needs !o)Je supported by all levels of staff in theproduction team. JIT seeks plant-wige involvement in work improvement projects.Suggestion schemes are therefore strongly encouraged and supported.JITPurchasing:Materials and components are purchased in compliance withwell defined requirements in terms of quantity, quality and delivery. JIT purchasingemphasizes small lot purchasing, vendor development, long tenn buyer-sellerrelationships, vendor involvement in product design, high quality of purchasedmaterial, frequcm part delivery, cooperative transportation systems, etc. A fullfledged JlT is virtually impossible without supplier JIT.1.6 BENEFITS OFJITPerhaps the most significant benefit of JIT is to improve the [t'-sponsiveness of thefi rm to the changes in the market place-thereby affording it an overwhelmingadvantage in competition. Specific benefits will depend upon scope of application,nature of industry, resources committed, type and size of the market, technologyof processes, cte.Therefore they vary from organization to organization. The typeand quantum of benefi ts derived are discussed in detail in the chapters on casestudies and application surveys. Tables 1.1 and 1.2 illustrate the benefilS typicallyderived.Conceptually, the JlT benefits could be grouped into the following categories.(i) Product cost-is greatly reduced due to reduction of manufa':tming cycle

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If[ - AnIntroduct ion 17time, reduction of scrap, inventories, space requirement, material handlingand elimination of non-value adding operations.

(ii) Quality-is greatly improved due to fast detection and correction of defects,use of automatic stop devices, higher quality 'Of purchased parts, workercentred quality control aod statistical process control. Total preventivemaintenance, and lower inventory levels also help quality improvement

(iii) Design-Due to fast response to engineering change, alternative designscan be quickly brought on the shop floor.

(iv) Productivity-Order of magnitude productivity improvements are obtaineddue to the use of flexible workforce, reduced rework, reduced inspection,reduced part delay and reduced throughput time. Workers acquire multipleskills and become highly productive.

(v) Flexibility-System's flexibility, i .e., response to change improves. Thechange may involve variations in quantity of demand, type of products,routing pattern, alternate materials, workforce availability, etc.

(vi) Administrative efficiency-There are fewer suppliers",minimal expeditingand release of papers, simple communication and receiving. Many timesincoming inspection is eliminated altogether. Figure 1.1 gives'the blockdiagram developed by Schonberger [180] to understand the effects of JIT.

In most appl icat ions, the benefi ts reported have been dramat ic . However, apoint commonly made by most implement ing organizations is that there are somany intangible and non-quantifiable benefits of JIT, that it is grossly erroneousto assess lIT's impact purely fiom quantified benefits. As such, traditional methodsnormally adopted to evaluate investment proposals, with their heavy bias on financialevaluation, do not apply in JIT situations. A long term view of the benefits, ratherthan immediate short term benefits is also very much stressed. Finally, most ftnnsemphasize development of new measures of performance in many areas, to evaluateaccurately the effectS of JIT. As stated earlier, the question of JIT benefits willbe addressed in the discussion on case studies and appl ication surveys in laterchapters.