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生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.111.1JIT准时生产的实质•Motive:exposesandeliminateswaste,andcontinuingimprovement•NeedtoreducecostTraditionalMethod(Push)SellerDrivenModernMethod(Pull)CustomerDrivenSellingPriceProfit=Cost+(SELLER)SellingPrice-Cost=PROFIT(MARKET)生产与运作管理ProductionandOperationsManagementHangzhou,©CaoMinTypesofWaste•Overproduction•Waiting•Transportation•Inventory•Inefficientprocessing•Unnecessarymotion/movement•Productdefects凡是超出增加产品价值所绝对必要的最少量的设备、材料、零件和工作时间的部分，都是浪费Wasteis‘anythingotherthantheminimumamountofequipment,materials,parts,space,andworker’stime,whichareabsolutelyessentialtoaddvaluetotheproduct.’—ShoichiroToyodaPresident,Toyota生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.3InventoryHidesProblemsinProductionandOperationsManagementQualityProblemsMaterialShortagesMachineBreakdownsWorkloadImbalancesWorkerAbsenteeismOut-of-SpecMaterialsQualityProblemsWIPInventoryProblemsinProductionwaterlevelmustbereduced生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.4JITphilosophy•JustinTime:producingwhatthenextdownstreamworkstationsneed–JITisamanagementphilosophyofcontinuousandforcedproblemsolving.–Suppliesandcomponentsare‘pulled’throughsystemtoarrivewheretheyareneededwhentheyareneeded.–delivertherightproduct,inrightqualityandrightstatus,intherightquantity,attherightprice,intherightplace,attherighttime,torightpeople,withoutanywaitinganddisjointfromthesupplierstointernalprocess.•Goals:zeroinventory,zerodefects,zerosetups,zerowaste–shortentheresponsetimetocustomerneed–continuingwasteelimination生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.5JIT:stocklessproduction•aidealstandard,alimitwithzero–actualproductioncanneartoitillimitably,butnevertouchit.–improvementbecomescontinuingbecauseofthelimit•amethodcontinuingimprovement–reduceinventory--exposeproblemsandbottlenecks--solvetheproblems--reduceinventory--......aprocessofinfiniteloop生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.611.2KanbanSystem•Whatiskanban?–developedatToyota1950stomanagelinematerialflows.–Kanban(Kan=card,Ban=signal)•simplemovementsystem–“cards”tosignal&communicatereorderinformation–boxes/containerstotake“lots”ofpartsfromoneworkstationtoanother.•Serveronlydeliverscomponentstoclientworkstationas&whenneeded(called/pulled).•minimisestorageintheproductionarea.•Workstationsonlyproduce/delivercomponentswhencalled(theyreceivecard+emptycontainer).•Thework-stationproducesenoughtofillthecontainer•Kanban=anauthorizationtoproducemoreinventory•Wethuslimittheamountofinventoryinprocess.生产与运作管理ProductionandOperationsManagementHangzhou,©CaoMinJITandDemand-PullCustomerSupplierSupplierSupplierSupplierFinalAssemblyFabricFabricFabricFabricSubassSubassCall(Kanban)&PullCall(Kanban)&PullCall(Kanban)&Pull•Pushsystem:materialispushedintodownstreamworkstationsregardlessofwhetherresourcesareavailable•Pullsystem:materialispulledtoaworkstationjustasitisneededPushversusPull生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.8Toyotadual-cardKanbansystem•ProductionKanban:theneedtopurchasemoreparts•ConveyanceKanban:theneedtowithdrawpartsfromoneworkcenteranddeliverthemtothenextworkcenter•Notallcompaniesusethekanbancardsfortheirpullsystems.Manycompaniessimplyuselabelstoidentifythatacontainerisemptyoruseareasintheirwarehousesorproductiondepartmentstoidentifyacontainerisemptyandneeds.生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.9FunctionofKanban•Providesproductionand/ortransportationinformation.•Preventsoverproductionandexcessivetransportation.•Servesasaworkorderindicatingwhathasbeenproducedandidentifiesthephysicalproduct•Revealsexistingproductionproblemsandmaintainsinventorycontrol生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.10ProcessFinalAssembly(F)ProcuctionKanbanWS:A-14PartNr.:NK-200406Partname:BraceParttyp:KEI-7066ContainerCapacityTypeNr.14M-1113412WS:A-14PartNr.:NK-200406Partname:BraceParttyp:KEI-7066PrecedingProcessLatheMachiningNextProcessComponentAssembly(E)ConveyanceKanbanContainerCapacityTypeNr.14M-1113412生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.11DiagramofKanbancontrolupstreamWS#1downstreamWS#2WIPinventorypartsflowProductionkanbanandemptycontainerProductionkanbanandfullcontainerConveyancekanbanandemptycontainerConveyancekanbanandfullcontainer生产与运作管理ProductionandOperationsManagementHangzhou,2020/1/24©CaoMinNr.12RulesofKanban•Kanbanmustbeattachedtotheactualcontainersofparts•PartsarenevertobeproducedorconveyedwithoutaKanban•ThedownstreamprocessdrawsonlywhatisrequiredbytheKanbanfromupstreamprocesses.•TheupstreamprocessproducesitemsinthequantityandthesequenceindicatedbytheKanban.•Neversenddefectiveproductstodownstreamprocesses生产与运作管理ProductionandOperationsManagementHangzhou,©CaoMinCSdL)(1+=kcapacityofcontainerExpecteddemandduringleadtime+safetystock=k=No.ofkanbansincardsetd=AverageNo.ofunitsdemandedovertheperiodL=leadtimetoreplenishorder(sameunitsoftimeasdemand)S=Safetys