JIT-32p.ppt

1,JIT,ISQA459MelliePullman,2,Just-In-Time(JIT)Defined,JITcanbedefinedasanintegratedsetofactivitiesdesignedtoachievehigh-volumeproductionusingminimalinventories(rawmaterials,workinprocess,andfinishedgoods).JITalsoinvolvestheeliminationofwasteinproductioneffort.JITalsoinvolvesthetimingofproductionresources(e.g.,partsarriveatthenextworkstation“justintime”).,3,TheJapaneseApproachtoProductivity,EliminationofwasteEffortsconcentratedonshopfloorRespectforpeopleQualityimprovementfocus,4,WasteinOperations,(1)Wastefromoverproduction(2)Wasteofwaitingtime(3)Transportationwaste(4)Inventorywaste(5)Processingwaste(6)Wasteofmotion(7)Wastefromproductdefects,5,JITDemand-PullLogic,6,MinimizingWaste:FocusedFactoryNetworks,Coordination,SystemIntegration,7,TraditionalConveyance,A,B,C,A,C,B,SporadicandInfrequentDeliveriesfromIndividualSuppliers,8,Mixed-LoadDelivery,A,B,C,ABC,RegularandFrequentDeliveriesfromManySuppliers,9,MinimizingWaste:GroupTechnology,UsingDepartmentalSpecializationforplantlayoutcancausealotofunnecessarymaterialmovement.,Saw,Saw,Lathe,Press,Press,Grinder,Lathe,Lathe,Saw,Press,HeatTreat,Grinder,10,MinimizingWaste:GroupTechnology,RevisingbyusingGroupTechnologyCellscanreducemovementandimproveproductflow.,Press,Lathe,Grinder,Grinder,A,2,B,Saw,HeatTreat,Lathe,Saw,Lathe,Press,Lathe,1,11,MinimizingWaste:UniformPlantLoading,NotuniformJan.UnitsFeb.UnitsMar.UnitsTotal1,2003,5004,3009,000,UniformJan.UnitsFeb.UnitsMar.UnitsTotal3,0003,0003,0009,000,Supposeweoperateaproductionplantthatproducesasingleproduct.Thescheduleofproductionforthisproductcouldbeaccomplishedusingeitherofthetwoplantloadingschedulesbelow.,Howdoestheuniformloadinghelpsavelaborcosts?,or,12,MixedBatchExample,Companyproducesthreeproductswithamixedmodelassemblyline.Operates16hoursperdayfor250days/yr.DeterminethemixedmodelMPSforadailybatch.DetermineminimumbatchMPSandthemixscheduleforaday.,13,Calculations,Foreveryunitof#3(minimumbatch),weneedtwiceasmany#2and4timesAsmany#1soforminimumbatch:Produceduringeachdayproduce#1,1,1,1,2,2,3-repeated20times,14,MixedBatchExample,Companyproducesfourproductswithamixedmodelassemblyline.Operates8hoursperdayfor250days/yr.DeterminethemixedmodelMPSforadailyandhourlybatch.Determinemixscheduleforaday.,15,MinimizingWaste:Just-In-TimeProduction,16,MinimizingWaste:InventoryHidesProblems,Example:Byidentifyingdefectiveitemsfromavendorearlyintheproductionprocessthedownstreamworkissaved.,Example:Byidentifyingdefectiveworkbyemployeesupstream,thedownstreamworkissaved.,17,MinimizingWaste:KanbanProductionControlSystems,StoragePartA,StoragePartA,MachineCenter,AssemblyLine,MaterialFlowCard(signal)Flow,Withdrawalkanban,Productionkanban,18,DeterminingtheNumberofKanbansNeeded,Settingupakanbansystemrequiresdeterminingthenumberofkanbans(orcontainers)needed.Eachcontainerrepresentstheminimumproductionlotsize.Anaccurateestimateoftheleadtimerequiredtoproduceacontaineriskeytodetermininghowmanykanbansarerequired.,19,TheNumberofKanbanCardSets,k=Numberofkanbancardsets(asetisacard)d=AveragenumberofunitsdemandedoversometimeperiodL=leadtimetoreplenishanorder(sameunitsoftimeasdemand)S=SafetystockexpressedasapercentageofdemandduringleadtimeC=Containersize,20,ExampleofKanbanCardDetermination:ProblemData,Aswitchassemblyisassembledinbatchesof4unitsfroman“upstream”assemblyareaanddeliveredinaspecialcontainertoa“downstream”control-panelassemblyoperation.Thecontrol-panelassemblyarearequires5switchassembliesperhour.Theswitchassemblyareacanproduceacontainerofswitchassembliesin2hours.Safetystockhasbeensetat10%ofneededinventory.,21,ExampleofKanbanCardDetermination:Calculations,Alwaysroundup!,22,JITRequirements:DesignFlowProcess,LinkoperationsBalanceworkstationcapacitiesRe-layoutforflowEmphasizepreventivemaintenanceReducelotsizesReducesetup/changeovertime,23,JITRequirements:ImproveProductDesign,StandardproductconfigurationStandardizeandreducenumberofpartsProcessdesignwithproductdesignQualityexpectations,24,RespectforPeople,LevelpayrollsCooperativeemployeeunionsSubcontractornetworksInvertedpyramidmanagementstyleSmallgroupinvolvementactivities,25,JITRequirements:TotalQualityControl,WorkerresponsibilityMeasureSQCEnforcecomplianceFail-safe(Poke-yoke)methodsAutomaticinspection,26,POKE-YOKEsaddressMistakes,DamagedpartsMissingpartsReversedpartsWrongpartsWrongsizeorshapeWrongchemicalpropertiesWrongphysicalpropertiesWrongitemshippedWronglabelWrongpackageDamagedfinishedproduct,OmittingapartOmittingaprocessPerformingaprocessincorrectlyPerformingaprocessonthewrongpartPerformingaprocessinimproperenvironmentalconditionsPerformingthewrongprocessSettingupequipmentincorrectlySettingupaworkpieceincorrectlyAdjustingequipmentincorrectlyToolingsetupincorrectlyToolingadjustedincorrectlyInstallingwrongpartInstallingpartincorrectly,DEFECTS,MISTAKES,27,JITRequirements:WorkwithVendors,ReduceleadtimesFrequentdeliveriesProjectusagerequirementsQualityexpectations,28,JITRequirements:ReduceInventoryMore,LookforotherareaswhereinventoryhidesStoresTransitCarouselsConveyors,29,MRPandJIT,MRPisaplanningsystemthatdoesnotdodetailedshopfloorschedulingMRPrequiresfixedleadtimeswhichmightactuallyvarywithbatchsizeJITexcelsatrapidlymovingsmallbatchesofmaterialthroughthesystem,30,MRPSmallBucketApproach,MRP“buckets”arereducedtodailyorhourlyThemostcommonplanningperiod(timebucket)forMRPsystemsisweeklyPlannedreceiptsareusedinternallytosequenceproductionInventoryismovedthroughtheplantonaJITbasisCompletedproductsaremovedtofinishedgoodsinventorywhichreducesrequiredquantitiesforsubsequentplannedordersBackflushingbasedontheBOMisusedtodeductinventorythatwasusedinproduction,31,MRPBalancedFlow,UsedinrepetitiveoperationsMRPplansare