Lean Production(精益生产)

Copyright2006JohnWiley&Sons,Inc.BeniAsllaniUniversityofTennesseeatChattanoogaLeanProductionOperationsManagement-5thEditionChapter15RobertaRussell&BernardW.Taylor,IIICopyright2006JohnWiley&Sons,Inc.15-2LectureOutlineBasicElementsofLeanProductionBenefitsofLeanProductionImplementingLeanProductionLeanServicesCopyright2006JohnWiley&Sons,Inc.15-3LeanProductionDoingmorewithlessinventory,fewerworkers,lessspaceJust-in-time(JIT)smoothingtheflowofmaterialtoarrivejustasitisneeded“JIT”and“LeanProduction”areusedinterchangeablyMudawaste,anythingotherthanthatwhichaddsvaluetotheproductorserviceCopyright2006JohnWiley&Sons,Inc.15-4WasteinOperationsCopyright2006JohnWiley&Sons,Inc.15-5WasteinOperations(cont.)Copyright2006JohnWiley&Sons,Inc.15-6WasteinOperations(cont.)Copyright2006JohnWiley&Sons,Inc.15-7BasicElements1.Flexibleresources2.Cellularlayouts3.Pullproductionsystem4.Kanbanproductioncontrol5.Smalllotproduction6.Quicksetups7.Uniformproductionlevels8.Totalproductivemaintenance9.SuppliernetworksCopyright2006JohnWiley&Sons,Inc.15-8FlexibleResourcesMultifunctionalworkersperformmorethanonejobgeneral-purposemachinesperformseveralbasicfunctionsCycletimetimerequiredfortheworkertocompleteonepassthroughtheoperationsassignedTakttimepacesproductiontocustomerdemandCopyright2006JohnWiley&Sons,Inc.15-9StandardOperatingRoutineforaWorkerCopyright2006JohnWiley&Sons,Inc.15-10CellularLayoutsManufacturingcellscomprisedofdissimilarmachinesbroughttogethertomanufactureafamilyofpartsCycletimeisadjustedtomatchtakttimebychangingworkerpathsCopyright2006JohnWiley&Sons,Inc.15-11CellswithWorkerRoutesCopyright2006JohnWiley&Sons,Inc.15-12WorkerRoutesLengthenasVolumeDecreasesCopyright2006JohnWiley&Sons,Inc.15-13PullSystemMaterialispulledthroughthesystemwhenneededReversaloftraditionalpushsystemwherematerialispushedaccordingtoascheduleForcescooperationPreventoverandunderproductionWhilepushsystemsrelyonapredeterminedschedule,pullsystemsrelyoncustomerrequestsCopyright2006JohnWiley&Sons,Inc.15-14KanbansCardwhichindicatesstandardquantityofproductionDerivedfromtwo-bininventorysystemMaintaindisciplineofpullproductionAuthorizeproductionandmovementofgoodsCopyright2006JohnWiley&Sons,Inc.15-15SampleKanbanCopyright2006JohnWiley&Sons,Inc.15-16OriginofKanbana)Two-bininventorysystemb)KanbaninventorysystemReordercardBin1Bin2Q-RKanbanRRQ=orderquantityR=reorderpoint-demandduringleadtimeCopyright2006JohnWiley&Sons,Inc.15-17TypesofKanbanProductionkanbanauthorizesproductionofgoodsWithdrawalkanbanauthorizesmovementofgoodsKanbansquareamarkedareadesignatedtoholditemsSignalkanbanatriangularkanbanusedtosignalproductionatthepreviousworkstationMaterialkanbanusedtoordermaterialinadvanceofaprocessSupplierkanbanrotatesbetweenthefactoryandsuppliersCopyright2006JohnWiley&Sons,Inc.15-18Copyright2006JohnWiley&Sons,Inc.15-19Copyright2006JohnWiley&Sons,Inc.15-20Copyright2006JohnWiley&Sons,Inc.15-21DeterminingNumberofKanbanswhereN=numberofkanbansorcontainersd=averagedemandoversometimeperiodL=leadtimetoreplenishanorderS=safetystockC=containersizeNo.ofKanbans=averagedemandduringleadtime+safetystockcontainersizeN=dL+SCCopyright2006JohnWiley&Sons,Inc.15-22DeterminingNumberofKanbans:Exampled=150bottlesperhourL=30minutes=0.5hoursS=0.10(150x0.5)=7.5C=25bottlesRoundupto4(toallowsomeslack)ordownto3(toforceimprovement)N====3.3kanbansorcontainersdL+SC(150x0.5)+7.52575+7.525Copyright2006JohnWiley&Sons,Inc.15-23SmallLotsRequirelessspaceandcapitalinvestmentMoveprocessesclosertogetherMakequalityproblemseasiertodetectMakeprocessesmoredependentoneachotherCopyright2006JohnWiley&Sons,Inc.15-24InventoryHidesProblemsCopyright2006JohnWiley&Sons,Inc.15-25LessInventoryExposesProblemsCopyright2006JohnWiley&Sons,Inc.15-26ComponentsofLeadTimeProcessingtimeReducenumberofitemsorimproveefficiencyMovetimeReducedistances,simplifymovements,standardizeroutingsWaitingtimeBetterscheduling,sufficientcapacitySetuptimeGenerallythebiggestbottleneckCopyright2006JohnWiley&Sons,Inc.15-27QuickSetupsInternalsetupCanbeperformedonlywhenaprocessisstoppedExternalsetupCanbeperformedinadvanceSMEDPrinciplesSeparateinternalsetupfromexternalsetupConvertinternalsetuptoexternalsetupStreamlineallaspectsofsetupPerformsetupactivitiesinparalleloreliminatethementirelyCopyright2006JohnWiley&Sons,Inc.15-28CommonTechniquesforReducingSetupTimeCopyright2006JohnWiley&Sons,Inc.15-29CommonTechniquesforReducingSetupTime(cont.)Copyright2006JohnWiley&Sons,Inc.15-30CommonTechniquesforReducingSetupTime(cont.)Copyright2006JohnWiley&Sons,Inc.15-31UniformProductionLevelsResultfromsmoothingproductionrequirementsKanbansystemscanhandle+/-10%demandchangesSmoothdemandacrossplanninghorizonMixed-modelassemblysteadiescomponentproductionCopyright2006JohnWiley&Sons,Inc.15-32Mixed-ModelSequencingCopyright2006JohnWiley&Sons,Inc.15-33QualityattheSourceVisualcontrolmakesproblemsvisiblePoka-yokespreventdefectsfromoccurringKaizenasystemofcontinuousimprovement;“changeforthegoodofall”Jidokaauthoritytostoptheproduc