jit准时生产方式_characteristics of jit environment

JIT History Thistext sideaPhilosophicalchangeTaiichiOhno ToyotaJust in TimemanufacturingistheeliminationofallwasteandcontinuousimprovementofproductivityWastemeansanythingotherthantheminimumamountofequipment parts space material andworkers timeabsolutelynecessarytoaddvaluetotheproduct JIT Thelong termresultofeliminatingwasteisacost efficient quality oriented fast responseorganizationthatisresponsivetocustomerneedsAddingvaluetoaproductdoesnotmeanaddingcost Usersarenotconcernedwiththemanufacturer scostbutonlywiththepricetheymustpayandthevaluetheyreceive Manyactivitiesincreasecostwithoutaddingvalueand asmuchaspossible theseactivitiesshouldbeeliminated Waste AnythingintheproductcyclethatdoesnotaddvaluetotheproductiswasteManagementisresponsibleforestablishingpoliciesforthemarketsegmentsthecompanywishestoserveandfordecidinghowbroadorspecializedtheproductlineistobe Standardization Standardizationreducestheplanningandcontroleffortneeded thenumberofitemsrequired andtheinventorythathastobecarried The ideal productisonethatmeetsorexceedscustomerexpectations makesthebestuseofmaterial andcanbemanufacturedwithaminimumofwaste WasteinManufacturing Toyotaidentifiedsevenimportantsourcesofwasteinmanufacturing Thefirstfourrelatetothedesignofthemanufacturingsystemandthelastthreetotheoperationsandmanagementofthesystem 1 Theprocess Consistent minimumscrap leastcost2 Methods wastedmovement timeandeffort ietools3 Movement storingcomponents4 Productdefects rework badqualitycustomer5 Waitingtime workerand ormaterial6 Overproduction excessinventory7 Inventory excess InventoriesroleinJIT Batchof1000partsQualityReworkSlowsCIPBatch100IncreasedresponsivenessLessinspectionBetterquality Ch15 6 2000byPrentice HallIncRussell TaylorOperMgt3 e StandardOperatingRoutine CharacteristicsofJITEnvironment Flowmanufacturing onlycertainitemsCellularmanufacturing functionallayoutandworkcelllayoutProcessflexibility workerandmachineflexibility Quickchangeover shortensetupsReducedEOQ queue MLT WIPImprovedqualityandprocessflow Ch15 8 2000byPrentice HallIncRussell TaylorOperMgt3 e ManufacturingCellWithWorkerRoutes Enter Worker1 Worker2 Worker3 Exit Key ProductrouteWorkerroute Machines TQM Qualityisimportantfortworeasons Ifqualityisnotpresentinwhatissuppliedtothecustomerandtheproductisdefective thecustomerwillbedissatisfied Ifaprocessproducesscrap itcreatesdisruptedschedulesthatdelaysupplyingthecustomer increasesthecostoftheproduct Manufacturingmustensurethattheprocessiscapableofproducingtherequiredqualityconsistentlyandwithasclosetozerodefectsaspossible Thebenefitsofagoodqualityprogramarelessscrap lessrework lessinventory betteron timeproduction timelydeliveries andmoresatisfiedcustomers Totalproductivemaintenance is preventivemaintenancepluscontinuingeffortstoadapt modify andrefineequipmenttoincreaseflexibility reducematerialhandling andpromotecontinuousflow Uniformplantloading meansthattheworkdoneateachworkstationshouldtakeaboutthesametime Balancingtheline whichmeansthatthetimetakentoperformtasksateachworkstationonthelineisthesameorverynearlyso Theresultwillbenobottlenecksandnobuildupofwork in processinventory Pullsystem Startsattheendofthelineandpullsproductfromtheprecedingoperationasneeded Theprecedingoperationdoesnotproduceanythingunlessasignalissentfromthefollowingoperationtodoso Thesystemforsignalingdemanddependsonthephysicallayoutandconditionsintheplant ThemostwellknownsystemistheKanbansystem Thedetailsvary butitisbasicallyatwo bin fixed order quantity order pointsystem Validschedule Theschedulesetstheflowofmaterialscomingintothefactoryandtheflowofworkthroughmanufacturing Tomaintainanevenflow theschedulemustbelevel Inotherwords thesameamountshouldbeproducedeachday Mixed modelscheduling Meansthatsomeofeverythingismadeeachdayintheproportionstomeetdemand Ifdemandshiftsbetweenmodels theassemblylinecanresponddaily MasterProductionScheduleLeveledMasterProductionSchedule Linearity isachievingtheplan nomore nolessandisusuallyreachedbyschedulingtolessthanfullcapacity SupplierPartnerships TrustLong termcommitmentSharedvision TotalEmployeeInvolvement AsuccessfulJITenvironmentcanbeachievedonlywiththecooperationandinvolvementofeveryoneintheorganizationOperatorsmusttakeresponsibilityforimprovingprocesses controllingequipment correctingdeviations andbecomingvehiclesforcontinuousimprovement Employeesmustbeflexibleinthetaskstheydo InaJITenvironment moreemphasisisplacedontheleadershiprole Managersandsupervisorsmustbecomecoachesandtrainers developthecapabilityofemployees andprovidecoordinationandleadershipforimprovements EffectsofMPCinJITEnvironment Forecasting isshortenedlead time PP Supplierrelationships improvedmaterialflow MPS seeslide14Shorterlead timesreducetimefences greatercustomerserviceandclosertomaketoorderenvironment MRP reductiontodailytimebucketsNoinventory nonettingandsometimesnooffsettingBOM SareflattenedorsimplifiedCapacity leveledInventorymanagement increasetransactions backflushing postdeduct ThePullSystem MRPisapushsystem meaningthatthematerialneedsarecalculatedaheadoftimeandpushedouttotheproductionsystemsasaproductionorder Thepullsystemunderlyingconceptisnottopreplanandgenerateschedules buttoreacttothefinalcustomerorderandproduceonlywhatisneededtosatisfydemandandthemonlywhenitisneeded CalBerkeleyVideo Ch15 10 2000byPrentice HallIncRussell TaylorOperMgt3 e KanbanProductionControlSystem KanbancardindicatesstandardquantityofproductionDerivedfromtwo bininventorysystemKanbanmaintainsdisciplineofpullproductionProductionkanbanauthorizesproductionWithdrawalkanbanauthorizesmovementofgoods Ch15 11 2000byPrentice HallIncRussell TaylorOperMgt3 e ASampleKanban MachiningM 2 AssemblyA 4 Partno 7412Description Sliprings From To Boxcapacity25BoxTypeAIssueNo 3 5 Ch15 22 2000byPrentice HallIncRussell TaylorOperMgt3 e InventoryHidesProblems PoorQuality UnreliableSupplier MachineBreakdown InefficientLayout BadDesign LengthySetups Ch15 23 2000byPrentice HallIncRussell TaylorOperMgt3 e LowerLevelsOfInventoryToExposeProblems PoorQuality UnreliableSupplier MachineBreakdown InefficientLayout BadDesign LengthySetups WhichtoChoose MRP ERP Kanban orTheoryofConstraints Becauseoftheforward lookingnatureofMRP itcanbeveryeffectiveinanenvironmentwithagreatdealofvariabilityanduncertainty MRP smajordisadvantageisthatitishighlydatadependent bothaccurateandtimely JITandKanbanworkb