面向负荷的生产控制与JIT.ppt

Load-orientedmanufacturingcontroljust-in-timeproductionforjobshops,ProductionPlanningLoadconversionfactordepreciationfactor=plannedoutput/Loadlimit=planningperiodplannedleadtime+planningperiodLimitingandbalanceworkinprocessbyorderrelease.,PlannedInv.(I),(D),Loadlimit,Plannedleadtime,Today,PlannedInv.(Buffer),Plannedoutput(capacity),(D),PlannedRelease(I),IdealReleasedCurve,Fullload,ConvertedLoad,Figure6.Derivationofconversionusingtheloadlimit,Aconsideringtheavailablecapacitiesofashort-termplanningperiods(12Week)PlannedorderswerescheduledbackwardSelectsperiodicallythoseoftheplannedordersStep1.EstablishurgentordersStep2.ReleasewotrkableordersTimelimit,3.Basicconceptinload-orientedmanufacturingcontrol3.3Techniqueofload-orientedorderrelease,.,IfcapacitiesisneededLoad-orientedreleaserequireappreciatedecision,c,b,a,a,c,a,b,b,a,c,Planningperiod,Timelimit,today,TimeDays,Due,Overdue,Future,Non-Urgent,Order4,3,1,2,Workable,Workable,Unworkable,Omissible,A,B,C,Workcenters,LoadHours,Loadlimit,ReleasedLoad,RemainingLoad,Figure7.StepsofLoad-orientedorderrelease,3.Basicconceptinload-orientedmanufacturingcontrol3.4Techniqueofload-orientedorderentry,TheideasofLoad-orientedorderentryistoavoidoverloadedweeksChecksthescheduledoperationdatesagainstavailablecapacitiesforamidtermplanninghorizon(ex12weeks)Realisticduedatesareofferedandtheexpectedbottlenecksareindicated.InitiationcapacitychangesinadvanceifpossibleOverloadweeksFreedate,.,.,CumulativeLoad,CumulativeCapacity,Backlog,OverloadWeeks,Underloadweeks,Planninghorizon,Today,Timeweek,FreeDate,OverloadPortion83%,TotalLoad100%,Loadhour,Figure8.Cumulativeloadandcapacityofaworkcenter,.,.Cisacriticalworkcenter,A,B,C,D,E,A,B,C,D,E,OverloadWeeks,Today,Timeweek,Workcenter,A,B,C,D,E,FreeDate,OrderLeadTime,OperationLeadTime,RealisticReleaseDate,RealisticDeliveryDate,PlanningHorizon,Figure9.Establishingarealisticdeliverydateofanorder,4.Overviewofaload-orientedmanufacturingcontrolsystem,1.Routingdata2.Orderdata3.Itemdata4.Shopcalendar5.Capacitydata6.Transactiondata7.Controldata:detailedtablesforw/candfreedefinablegroup,.,.,ShopCalendar,CapacityData,PlanningData,TransactionData,ItemData,OrderData,RouteingData,PROGRAMTransactionData,PROGRAMControlData,PROGRAMShopCalendar,ProgramGraphsReports,PROGRAMOperationSequencing,PROGRAMOrderRelease,PROGRAMOrderEntry,DIALOGCapacities,DIALOGOperationComplete,DIALOGOrderRelease,DIALOGOrderEntry,CapacitiesEntries,CapacitiesRelease,CapacitiesSequences,GraphsReports,ControlData,CONTROLSYSTEM(PC),BASICSYSTEM(HOST),PLANNINGSYSTEM(PC),Figure10.Load-orientedmanufacturingcontrolsystemshowingthedataflow,5.Exampleofthecontrolsystem,1.Themethodofbasicthroughputdiagramsisextended(Figure1withdiagrams)2.OperationThroughputElement3.Plannedandactualaverageleadtimearecomputedforeachinventoryaswellasaveragedue-datedev.Forrelease,input,outputanddelivery,Entry,Release,Input,Output,Delivery,Disposition,Indirect,Direct,Downstream,Upstream,Open,Cycle,Totalleadtime,Waitafteroperation,Transport,Waitbeforeoperation,Setup,Run,Interoperationtime,Processtime,DirectLoadtime,.,4.Pump-buildingfactorycharacteristicsproducts9000pumpsManufacturedparts26000differentitemsManpower(Jobshop)180personsWorkcenters130(mainly2shifts)Orders350perweekOperations4,5perorder(Max20)Runtimes3,7peroperationLotsizes30perorder(1-1000)Factorybegantoworkwiththenewsystemin1987Improvement(compared1991with1987)Inventorywastwiceashighin1987Mostdeliveryhigherthanin1987Cycleleadtime(releasedelivery)werecutfromalmost8weeksto5weeksDue-datedeviations4.5to1week(lateness)Totalleadtime(entrydelivery)14weeksto9weeks,Conclusion,Load-orientedmanufacturingcontrolsystemenablesthefactory1.