The Toyota Production SystemHigh Quality and Low CostReadings;James Womack, Daniel T. Jones and Daniel Roos, The Machine that Changed the World, 1990, Ch 3 and 4Kenneth N. McKay, “The Evolution of Manufacturing Control-What Has Been, What Will Be” Working Paper 03 –2001Michael McCoby, “Is There a Best Way to Build a Car?”HBR Nov-Dec 1997COST VSDEFECTSConsumer ReportsGains of importsThe Toyota Production SystemHistorical ViewPerformance measuresElements of TPSDifficulties with ImplementationSix Eras of Manufacturing PracticeThree Major Mfg Systems from 1800 to 20001800 1900 2000Machine tools, specialized machine tools, Taylorism, SPC, CNC, CAD/CAMInterchangeableParts at U.S.ArmoriesMassProductionat FordToyotaProductionSystemKey Elements for New Mfg SystemsJapaneseBanksTaiichiOhnoCNC,Integrationof LaborJobs,SecurityPost WarToyotaProductionSystemEarningsHenryFordMovingAssemblyLine,etc$5/dayImmigrantTrans-portationMassProductionU.S.GovtRoswellLee/JohnHallMachineTools,Division ofLabor“YankeeIngenuity”MilitaryInterchange-able PartsResourcesLeaderEnablingTechnologyWorkForceMotivationNeed ofSocietyElement/SystemQ. By what method did thesenew systems come about?A. Trial and ErrorHistory of the Development of the ToyotaProduction System ref; Taiichi Ohno19451975The Toyota Production SystemHistorical ViewPerformance measuresElements of TPSDifficulties with ImplementationSix Eras of Manufacturing PracticeJapanese Japanese in American in All Europein Japan North America North AmericaPerformance:Producvitity (hours/Veh.) 16.8 21.2 25.1 36.2Quality (assemblydefects/100 vehicles) 60 65 82.3 97Layout:Space (sq.ft./vehicle/yr) 5.7 9.1 7.8 7.8Size of Repair Area (as %of assembly space) 4.1 4.9 12.9 14.4Inventories(days for 8sample parts) 0.2 1.6 2.9 2Work Force:% of Work Force in Teams 69.3 71.3 17.3 0.6Job Rotation (0 = none,4 = frequent) 3 2.7 0.9 1.9Suggestions/Employee 61.6 1.4 0.4 0.4Number of Job Classes 11.9 8.7 67.1 14.8Training of New ProductionWorkers (hours) 380.3 370 46.4 173.3Absenteeism 5 4.8 11.7 12.1Automation:Welding (% of direct steps) 86.2 85 76.2 76.6Painting(% of direct steps) 54.6 40.7 33.6 38.2Assembly(% of direct steps) 1.7 1.1 1.2 3.1Source: IMVP World Assembly Plant Survey, 1989, and J. D. Power Initial Quality Survery, 1989Summary of Assembly Plant Characteristics, Volume Producers,1989(Average for Plants in Each Region)Cost Vs Defects Ref. “Machine that Changed the World” Womack, Jones and RoosCost Vs AutomationRef. “Machine that Changed the World” Womack, Jones and RoosThe Toyota Production SystemHistorical ViewPerformance measuresElements of TPSDifficulties with ImplementationSix Eras of Manufacturing PracticeHow do you get this kind ofperformance?Womack, Jones and RoosJ T. Black’s 10 StepsDemand Flow Technology’s 9 PointsWomack Jones and Roos• New Technology?– No silver bullet• Automation?– Yes, but integrated with system• Standardized Production?– Not in the usual “don’t stop the line” sense• Lean Characteristics?– Integration of Tasks (opposite of deskilling)– Identification and removal of defects (stop the line!)– kaizen – institutionalizing changeJ T. Black’s 10 StepsRef; JT. Black “Factory with a Future” 19911. Form cells2. Reduce setup3. Integrate quality control4. Integrate preventive maintenance5. Level and balance6. Link cells – KANBAN7. Reduce WIP8. Build vendor programs9. Automate10. ComputerizeDemand Flow Technology’s9 Points1. Product Synchronization2. Mixed Model Process Maps3. Sequence of Events4. Demand at Capacity5. Operational Cycle Time6. Total Product Cycle Time7. Line Balancing8. Kanbans9. Operational Method SheetsCurrent Value Stream MapFuture Value Stream MapJ T. Black –1, 21. Form CellsSequentialoperations, decoupleoperator frommachine, parts infamilies, single pieceflow within cell2. Reduce SetupExternalize setup toreduce down-timeduring changeover,increases flexibilityTPS CellToyota Cell, one part is produced for every trip around the cellJ T. BlackStandardized FixturesJ T. Black – 3, 43. Integrate qualitycontrolCheck part quality atcell, poke-yoke, stopproduction whenparts are bad4. Integrate preventivemaintenanceworker maintainsmachine , runs slowerJ T. Black – 5, 65. Level and balanceProduce to Takttime, reduce batchsizes, smoothproduction flow6. Link cells- KanbanCreate “pull” system– “Supermarket”SystemBalancing and Leveling• Balanced line: each process has the samecycle time. Match process time toassemble time, match production rate torate of demand (Takt time)• Leveled Line: each product is produced inthe needed distribution. The process mustbe flexible to do this.J T. Black – 7, 87.Reduce WIPMake system reliable,build in mechanismsto self correct8. Build VendorprogramPropagate low WIPpolicy to yourvendors, reducevendors, make on-time performance partof expectationSome Basics Concepts of TPSSmooth Flow and Produce to Takt TimeProduce to OrderMake system “observable” and correctproblems as they occurIntegrate Worker SkillsInstitutionalize changeTwo Examples;Takt TimePull SystemsTakt Time:demand time intervalDemandProduct Time AvailableTimeTakt =Calculate Takt Time per month, day,year etc. Available time includes allshifts, and excludes all non-productive time (e.g. lunch, clean-upetc). Product demand includes over-production for low yields etc.Takt TimeAutomobile Assembly Line; Available time = 7.5 hr X 3shifts = 22.5 hrs or 1350 minutes per day. Demand =1600 cars per day. Takt Time = 51 secAircraft Engine Assembly Line; 500 engines per year.2 shifts X 7 hrs => 14 hrs/day X 250 day/year = 3500hrs.Takt time = 7 hrs.Engines shipped over a 3 month periodat aircraft engine factory “B”0246810127-Jun 15-Jun 23-Jun 30-Jun 7-Jul 15-Jul 24-Jul 31-Jul 7-Aug 15-Aug 24-Aug 31-AugW e e k sengines shipped per weekmonth 1month 2month 3Factory “B”Engines shipped over a 3 month periodat aircraft engine factory “C”01234567may june july augustw ee k sengines shippedFactory “C”On-time performance of engineplantsA B C0%20%40%60%80%100%engines deliveredA B ContimelateontimeontimelatePush and Pull SystemsMachinesParts Orders1 2 3 4Push Systems –Order (from centralized decision process) arrives at the front of thesystem and is produced in
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