精益生产之补充拉系统RelenishmenullSysems中英

Replenishment

PullSystemsManufacturingPullSystemsPurchasePullSystemsBufferLocationsPullSystemPlatformsManualvs.ElectronicPullSystems:HandlingSeasonalityPerformanceMeasuresAppendixRD010402补充拉系统制造拉系统采购拉系统缓冲场所拉系统平台手动vs.电子拉系统：操作的季节性绩效量测附录RD010402LeanSixSigma

ImprovementProcessRoadMapAnalyzeControlImproveDefineIdentifyProblemDevelopListofCustomersDevelopListofCTQ’sfromVoiceoftheCustomerFinalizeProjectFocus

andKeyMetricsCompletePDFMeasureMapBusinessProcessMapValueStreamDevelopData

CollectionPlanConductMeasurement

SystemAnalysisCollectDataConductProcess

CapabilityAnalysisAnalyzeProposeCriticalX’sPrioritizeCriticalX’sVerifyCriticalX’sEstimatetheImpactofEachXonYQuantifytheOpportunityPrioritizeRootCausesConductRootCause

AnalysisonCriticalX’sImproveCriticalX’sConfirmedDevelopPotentialSolutionsSelectSolutionOptimizeSolutionPilotSolutionControlImplementProcess

ChangesandControlsWriteControlPlanCalculateFinalFinancial/ProcessMetricsTransitionProjecttoFutureOwnersIdentifyProjectTranslationOpportunitiesMeasureDefineProjectIDToolsProjectDefinitionFormNetPresentValueAnalysisInternalRateofReturnAnalysisDiscountedCashFlowAnalysisPIPManagementProcessRACIQuadChartsProcessMappingValueAnalysisBrainstormingMulti-VotingTechniquesParetoChartsC&E/FishboneDiagramsFMEACheckSheetsRunChartsControlChartsGageR&RCp&CpkSupplyChainAcceleratorAnalysisMulti-VariBoxPlotsInteractionPlotsRegressionANOVAC&EMatricesFMEABrainstormingPullSystemsSetupReductionTPMProcessFlowBenchmarkingAffinityDOEHypothesisTestingForceFieldTreeDiagramsGanttChartsCheckSheetsRunChartsHistogramsScatterDiagramsControlChartsParetoChartsInteractiveReviewsPoka-YokeRevised1-12-023LearningObjectivesIntroductiontoReplenishmentPullSystemsLearnthebenefitsandapplicationsKnowthedifferencebetweenaManufacturingPullSystemvs.aPurchasePullSystemUnderstandkeyPullparametersandcalculationsIntroductiontothePullPlatformsKnowthekeybufferlocationswithinaprocess4学习目的介绍补充拉系统学习补充拉系统的好处和应用了解制造拉系统和采购拉系统的区别理解拉系统的关键参数及计算方法介绍拉系统的平台了解流程中关键缓冲点的位置5What’sinItforMe?UnderstandwhatReplenishmentPullisandmakeapplicationstoyourenvironmentGainunderstandingonthemanytypesofPullSystems6我学到了什么?了解补充拉系统并并应用于您的工作环境中对各种类型的拉系统增进了解7

IntroductionReplenishmentPullSystemsestablishesstrategicallylocatedbuffersofpartswithinaprocess.RawmaterialManufacturedpartsPurchasedpartsFinishedgoodsDe-couplesthesupplyingprocessfromtheconsumingprocessviathebufferinventory.Partreplenishmentis“triggered”basedonconsumptionversusnetrequirements.Futurerequirementshelpestablishbuffersizing,notactualmaterialrelease.8

介绍补充拉系统在流程中关键的地方建立了零部件的缓冲区.原材料制造零件采购零件成品通过缓冲库存将供应过程和消耗过程联系起来.零件的补充是基于消耗的实际需求而被触发的.未来需求帮助确定缓冲量的大小，而不是决定于实际材料的发放.9ReplenishmentPullSystemBenefitsEfficiency:ApullsystemcanattainthesamethroughputasapushsystemwithlessaverageWIP(andtherefore,ashortercycletime).EaseofControl:PullsystemsrelyonsettingeasilycontrollableWIPlevels,versusreleaseratesforpushsystems(maintainingconstantthroughputismuchmoredifficult).Robustness:PullsystemperformanceisdegradedmuchlessbyerrorsinWIPlevelsthanbyacomparablepercenterrorinthroughput.QualityImprovement:LowWIP(andassociatedcycletime)systemsaremoresensitivetoquality(andthereforeforceproblemresolution)andfacilitateit(byimprovingfeedbackandlearningcycles).10补充拉系统的的好处效率:一个个拉系统可以以获得和推系系统一样的产产能而平均WIP水准却更少(因此，周期时时间更短).易于控制:和和推系统的的放料相比，，拉系统依靠靠设置更容易易控制WIP水平(推系统难以保保证更持续稳稳定的产能).敏锐性:拉拉系统对比推推系统在同样样的WIP水平差错更少少.质量改善:底WIP（与周期时间相相关联）系统统对于质量（（因为要压迫迫问题解决））更加敏感且且有助于推动动它（通过改改善反馈和学学习周期）.11ReplenishmentPullSystemDesignDriversComponentpartshavedifferent““characteristics”Dollarvolumevariesparttopart,drivesneedforpartstratification(impactsorderfrequency)Demandprofiles(peaksandvalleys),orvariability,isdifferentfordifferentpartsLeadtime(replenishmenttime)variesparttopartDemandisdynamicandchangesovertimeSeasonality,rampup/down,engineeringchangesdriveneedtoresizeKanbansystem(typicallymonthly)Designtrade-offsmanageriskSafetystock(designedasprotectionagainstvariability),reducespartshortagesbutincreasesinventoryHoldingsemi-finishedinventoryvolumesmoothesdemandatthatbuffer,butaddscycletime12补充拉系统的的设计驱动因因素各零部件具有有不同的“特特征”零件与零件间间的价值量不不同，使零件件需求层次不不同（影响订订货频率）需求轮廓（高高峰和低峰）），或变化因因零件不同而而不同交货期（补充充时间）件与与件的不同需求是动态的的，且随时间间的变化而变变化季节性的、需需求上升/下下降、工程变变更等需要调调整看板系统统（一般为月月度调整）设计协定，管管理风险安全库存(为预防变化性性而设计),减少零件短缺缺但增加了库库存保留半成品库库存，虽然让让需求在缓冲冲区流动平滑滑，但是增加加了周期时间间13WhentoUseReplenishmentPullLeadtimeisgreaterthancustomerexpectationwindowRepetitiveproductofferingRelativelyconsistentdemand(lowvariability)Note:GenericPullsystemsshouldalwaysbeusedwhenareplenishmentpullsystemisimplemented.14何时使用补充充拉系统交货期比客户户期望的大得得多反复性的产品品供应相对稳定的需需求（底变异异）注:当补充拉拉系统被采用用时，普通拉拉系统必定也也是在使用的的.15ManufacturingPullvs.

PurchasePullKeyDifferencesPurchasePullSystemExternallycontrolledMultiplesuppliersandlocationsControlledbyminorderquantitiesContinualcommunicationtovendorstoaddresscostandshippingissuesRelianceonvendor(s)forshippingfrequencyandorderedquantitiesManufacturingPullSystemInternallycontrolledOnesupplierandonelocationControlledbymanufacturingprocessInternaldailycommunicationtoaddressissuesRelianceoninternalresourcesforchanges(quantities,priorityofshoporders,etc.)16制造拉系统和和采购拉系统统的主要不同同采购拉系统外部控制多个供应商和和供应位置以最小的订单单数量控制不断的与供应应商交流，忙忙于成本和交交货事宜依赖于供货方方的交货频率率和数量制造拉系统内部控制一个供应商和和一个供货地地点通过制造流程程来控制内部的日常交交流来解决问问题依赖于内部资资源的变化（（质量、车间间内部指令等等）17ReplenishmentPullSystemParametersThereisvirtuallynodifferenceinthesupportingpullsystemcalculationsforthetwotypesofparts,butwepresentthemseparatelyforclarity.ManufacturingPullSystemsDemandManufacturingCycleTime(MCT)CycleTimeInterval(CTI)SafetyStock(SS)PurchasePullSystemDemandLeadTime(LT)OrderFrequency(OF)SafetyStock(SS)18补充拉系统的的参数事实上，对于于这两种类型型的拉系统计计算并没有本本质的区别，，这里为了识识别清楚而分分开制造拉系统需求制造周期时间间(MCT)周期时间间隔隔(CTI)安全库存(SS)采购拉系统需求交货期(LT)订单频率(OF)安全库存(SS)19Manufacturing

PullSystems制造拉系统ManufacturingStrategicBuffer(On-Site)3-4WeekManufacturingCycleTime2Week“CustomerExpectation”ReplenishmentSignalConsumptionManufacturingPullSystemBasedonconsumptionOn-handquantityfunctionofdemandvariability,leadtime,orderfrequency,desiredservicelevelPartshortagesandexpeditingreducedInventoryreduced(bettermix)22生产制造战略缓冲3-4周制造周期时间间2周“客户户的的期期望望””补充充信信号号消耗耗制造造拉拉系系统统补充充基基于于消消耗耗现有有数数量量与与需需求求变变量量、、交交货货时时间间、、订订单单频频次次、、期期望望的的服服务务水水平平成成函函数数关关系系零件件短短缺缺减减少少/消消除除库存存减减少少（（更更合合理理的的产产品品组组合合））23ManufacturingPullSystemParametersDemand(averageweeklyoraveragedailyusage)Basedoneitherhistory,forecast(backlog)orcombinationRecalculatedfrequentlyinordertocapturechangesintrendsManufacturingCycleTime(MCT)Timefromwhenarelease(workorder)issenttothemanufacturingflooruntilpartsarereceived(replenishmenttime)CycleTimeInterval(CTI)Representsthefrequency(days),thataspecificpartismanufactured-drivestheorderquantity(batchsize)thatwewouldliketobuildChangingCTIallowstrade-offsbetweentransactions,capacityandinventorySafetyStock(SS)Partsrequiredtocompensateforvariation(i.e.,demand,quality,downtime)24制造造拉拉系系统统的的参参数数需求求(平均均每每周周或或平平均均每每天天的的用用量量AWU或ADU)基于于历历史史、、预预测测（（订订单单））或或两两者者的的结结合合多次计算算以掌握握变化的的趋势制造周期期时间(MCT)从工单发发出到制制造车间间开始，，直到收收到零件件（补充充时间））的时间间周期时间间间隔(CTI)表示某一一零件的的制造频频率（天天），驱驱动我们们将要制制造的订订货数量量（批数数量）改变CTI允许在交交易、能能力和库库存间平平衡安全库存存(SS)为预防变变化（如如需求、、质量、、停机））而设置置的零件件需求25Demand(DMD)DMDistheusageoveraperiodoftime.Ensurethatthedemandiscalculatedinthesameunitsastheothercomponents(i.e.,weeks,days,etc.).Onehastobecarefulwhenusingonlyhistoricalusageforaveragedemandasitmaynotreflectcomingchangesinthebusiness-i.e.,productmix,volumeincreases,etc.Typically,somecombinationof:HistoricalUsageForecastedDemandLookAheadWindowareusedifthepartsseeseasonalityorothervolumeswings.DMDisusuallythemostdifficultnumbertopindowninpullcalculations.26需求(DMD)DMD是指某段时间间内的用量，，确保需求的的计算和其他他零件的计算算使用相同的的单位(如周、天等).需要注意的是是当用以往用用量做为平均均需求时，可可能不能反映映出未来的业业务变化-如如：产品种类类、需求量增增加时、一般般的应用组合合为：历史的用量预测的需求未来的趋势用来发现季节节性或其他原原因的产量变变化，DMD通常是拉系统统中计算最困困难的数据.27ManufacturingCycleTime(MCT)MCTisthetimefromworkreleaseintothemanufacturingprocessuntilcompletion/movementintoshipping/finishedgoods.Itismeasuredas:ItisveryimportanttoconfirmthattheMCTcalculationaboveholdstrueviaasamplingofhistoricalworkorderdatafromtheshopfloor.28制造周期时间间(MCT)MCT是从工作指令令发出到制造造工序中，直直到完成后续续工序或成品品为止的时间间，计算如下下:这里非常重要要的一点是要要确认使用从从现场收集的的真实数据而而不是以往的的抽样数据.29MCTExits=30units/dayWIP=SumofallInventorywithinPhysicalworkarea=100unitsMCT=100units/30unitsperdayMCT=3.3daysManufacturingCycleTime(MCT)30MCTExits=30units/dayWIP=在实际工作区区域里的库存存总数=100unitsMCT=100units/30unitsperdayMCT=3.3days制造周期时间间(MCT)31CycleTimeInterval(CTI)CTIisthefrequencythataspecificpartismanufactured(drivesbatchsizeororderquantity).Itismeasuredas:32周期时间间隔隔(CTI)CTI是某个零件被被生产的频率率(驱动批数量或或订单数量).计算如下:33ABACABCTI(A)CTI(B)RawMaterialFinishedGoods100100100DmdA=15units/dayBatchA=20YieldA=90%CTIACTI=(20unitsx.90)/15unitsperday=1.2daysCTIBCTI=(10unitsx.90)/10unitsperday=0.9daysCTICCTI=(15unitsx.95)/5unitsperday=2.85daysCalculatingCycleTimeInterval(CTI)DmdB=10units/dayBatchB=10YieldB=90%DmdC=5units/dayBatchC=15YieldC=95%34ABACABCTI(A)CTI(B)原材料成品100100100需求A=15units/day批A=20良品率A=90%CTIACTI=(20unitsx.90)/15unitsperday=1.2daysCTIBCTI=(10unitsx.90)/10unitsperday=0.9daysCTICCTI=(15unitsx.95)/5unitsperday=2.85days计算周期时间间间隔(CTI)需求B=10units/day批B=10良品率B=90%需求C=5units/day批C=15良品率C=95%35DemandDemandSafetyStock(SS)SSisproductrequiredtoguardagainst:ProcessVariabilityDemandVariabilityLeadTime/MCTVariabilityQualityProblems36DemandDemand安全库存(SS)SS是为对付下列列情况的产品品需求而设定定的:过程变化需求变化交货期/MCT变化质量问题37SafetyStock(SS)SSisafunctionof:Demandvariability(standarddeviation:)Desiredservicelevel(stockoutcoverage)ManufacturingCycleTime(MCT)Manufacturingon-timeperformance()Therearemanywaystocalculatesafetystock,wewilluseonebasedonempiricalcomputationsandexperience.KeyAssumption:Thedemandprofileisnormallydistributed.50%84%98%50%+50%+SafetyStock=*servicelevel*(MCT)where=0.7CoefficientVariation=s/x38安全库存(SS)SS是下列因素的的函数:需求变化(标准偏差:)期望的服务水水准(库存不短缺的的覆盖面积)制造周期时间间(MCT)制造时间的准准时率()有多种方法法计算安全全库存，我我们这里使使用其中一一种经验公公式.重要假定:需求形形式遵循正正态分布。。50%84%98%50%+50%+安全库存=*服务水准准*(MCT)这里=0.7变异系数CV=s/x=Sigma/AverageDemand（CV<0.75,用数量计算算WIP，0.75-1.33,用等价物数数量或时间间，>1.33,用用时间表表示，详见见W306GenericPullSystem章节纵轴是顾客客需求量横轴是时间间序列39SafetyStock(SS):ServiceLevelServiceLevel:Theservicelevelisessentiallythenumberofstandarddeviations,relativetothemean,carriedassafetystock.Itis,literally,thecalculatednumberoftimesthatyouexpectastockouttooccur.50%84%98%DemandaboveandbelowthemeanServiceLevel=1meansthatonestandarddeviationofsafetystockiscarried,andonaveragetherewillbenostockouts84%ofthetime(50%belowmean+34%)ServiceLevel=2meansthattwostandarddeviationsofsafetystockiscarried,andonaveragetherewillbenostockouts98%ofthetime(50%belowmean+48%)andsoon...40安全库存(SS):服务水平服务水平:服务水平本本质上指相相对需求平平均值而言言的标准差差的倍数，，在安全库库存中表示示.按字面理解解，就是你你认为出现现库存短缺缺发生的时时间的计算算50%84%98%需求高于或或低于平均均值服务水准=1意指只有1个标准差差的库存，，平均库存存不出现短短缺的次数数将有84%（50%均值值以下+34%)服务水准=2意意指只有有2个标准准差的库存存，平均库库存不出现现短缺的次次数将有98%（50%均值值以下+48%)等等41SafetyStock(SS):ServiceLevel42DateUsage4-Jan995-Jan1006-Jan1007-Jan998-Jan9811-Jan10012-Jan10113-Jan9914-Jan10215-Jan10318-Jan9919-Jan9820-Jan9721-Jan10022-Jan10125-Jan10226-Jan10427-Jan10128-Jan99UsageCount29-Jan989611-Feb989722-Feb969843-Feb1009964-Feb10210075-Feb10110168-Feb10310249-Feb102103210-Feb101104111-Feb10012-Feb99均值15-Feb101100.0316-Feb9717-Feb100标准差18-Feb991.8519-Feb102AverageDailyUsage929496981001021041061/4/011/11/011/18/011/25/012/1/012/8/012/15/01UnitsCountofUsages01234567896979899100101102103104Count安全库存(SS):服务水平43SafetyStock(SS):ServiceLevelRecallthatweassumeourdemandcanberepresentedbyanormaldistribution:1=1.85=68.27%2=3.70=95.45%MeanBut,wearealwayscoveredwhendemandisLOWERthanthemean,soat:ServiceLevel=1whichis:

1*=68.27%/2+50.0%=84.14%Andat:ServiceLevel=2whichis:

2*=95.45%/2+50.0%=97.73%Tosummarize:ServiceLevel=1gives84%stockoutcoverageServiceLevel=2gives98%stockoutcoverageServiceLevelof1=84%stockoutcoverageServiceLevelof2=98%stockoutcoverage44安全库存(SS):服务水平假定我们的的需求可以以用正态分分布1=1.85=68.27%2=3.70=95.45%均值值但是是，，当当需需求求比比平平均均值值低低时时，，我我们们总总是是出出现现短短缺缺，，所所以以:服务水平=1意意味着:

1*=68.27%/2+50.0%=84.14%在:服务水平=2意味着:

2*=95.45%/2+50.0%=97.73%总结:服务水平=1覆盖盖84%库存不短缺服务水平=2覆盖盖98%库存不短缺服务水平1=84%库存短短缺率服务水平2=98%库存短短缺率45BOHWorkOrders(SumWO)MCTMaxLoop*=(MCT*Dmd)+(CTI*Dmd)+SSMinKanban/TriggerPoint=(MCT*Dmd)+SSOrderIf:(BOH*+SumWO)<=TriggerPointOrderQty=MaxKanban-(BOH*+SumWO)CTISSMCTManufacturedPartsAvgBOH*BalanceOn-Hand(BOH)MaxLoop=MaxKanbanMaxMinBasicPullFormulasforManufacturedParts46现有余额=BOH订单数量=OOQMCT最大看板数量量MaxLoop*=(MCT*Dmd)+(CTI*Dmd)+SS最小看板/触发点MinKanban/TriggerPoint=(MCT*Dmd)+SS如果:(BOH*+SumWO)<=TriggerPoint触发点时就生生产订单数量=最大看板板数量-(BOH*+SumWO)CTISSMCT制造的零件AvgBOHBalanceOn-Hand(BOH)顾客过程中的的现有余量MaxLoop=MaxKanban最大看板数量量MaxMin制造件的拉系系统基本公式式47OtherKeyParametersforManufacturedPartsBatchSizePerformanalyticalbatchsizingEnsurepulldesignmeetscapacitylimitationsofprocessMinimum/Maximum/MultipleOrderQuantitiesChallengebasedonBatchSizingandcapacityanalysisaboveMaybebaseduponcontainerquantity–caution48制造零件的其其他关键参数数批量实施批数量的的分析确保拉动设计计满足过程的的能力限制最小/最大/多订单数量基于以上批量量和能力分析析而挑战还可能基于容容器数量–警戒49Example:ManufacturingReplenishmentPullSystemPartNumber“XYZ”hasthefollowingdata:CTI =15daysMCT =30daysSafetyStock =100partsDemand =4.0parts/dayDeterminetheMaxLoop(Kmax)MaxLoop=(MCTxDemand)+(CTIxDemand)+SS=(____x_______)+(___x_______)+(__)=__________50举例:制造补充拉系系统零件“XYZ”已经有了如下下数据:CTI =15天MCT =30天安全库存= 100个需求 =4.0个个/天决定最大看板板数(Kmax)MaxLoop=(MCTxDemand)+(CTIxDemand)+SS=(____x_______)+(___x_______)+(__)=__________51PurchasePullSystems采购拉系统StrategicBuffer(on-site)8WeekVendorLeadTime1-2WeekManufacturingCycleTime2Week“CustomerExpectation”ReplenishmentSignal““PurchaseOrder”ConsumptionVendorManufacturingPurchasePullSystemBasedonconsumptionOn-handquantityfunctionofdemandvariability,leadtime,orderfrequency,desiredservicelevelPartshortagesreduced/eliminated(reducingexpediting)Inventoryreduced(bettermix)54战略缓冲(on-site)8周供应商交货期期1-2周制造周期时间间2周“客户期望”补充信号：““采购订单””消耗供应商制造流程采购拉系统补充基于消耗耗现有数量与需需求变量、交交货时间、订订单频次、期期望的服务水水平成函数关关系零件短短缺减减少/消除除库存减减少（（更合合理的的产品品组合合）55PurchasePullSystemParametersDemand(averageweeklyordailyusage)Basedoneitherhistory,forecast(backlog)orcombinationRecalculatedfrequentlyinordertocapturechangesintrendsLeadTime(LT)Timefromwhenarelease(PO)issenttothesupplieruntilpartsarereceived(replenishmenttime)OrderFrequency(OF)Representstheorderfrequency(days),ororderquantity(units)thatwewouldliketopurchaseChangingOFallowstrade-offsbetweentransactions,capacityandinventorySafetyStock(SS)Partsrequiredtocompensateforvariation(I.e.demand,quality,vendordelivery)56PurchasePullSystemParameters需求(平均每每周或或平均均每天天的用用量)基于历历史、、预测测（订订单））或两两者的的结合合多次计计算以以掌握握变化化的趋趋势交货期期(LT)从发出出一个个订单单给供供应商商到零零件接接受的的时间间（补补充时时间））订单频频率(OF)表现我我们所所喜欢欢的订订单的的频率率（天天）,或订单单的数数量（（单位位）改变订订单的的频率率可以以使订订单处处理、、能力力和库库存之之间有有一定定的缓缓冲余余地安全库库存(SS)用于应应付变变化（（如：：需求求量、、质量量、供供应商商交付付等））的零零件需需求57LTisthetimetoreplenishapartfromasupplieroncetheparthasbeenconsumed.Itshouldinclude:POGeneration+SupplierLT+Transportation+Receiving/InspectionOFisthefrequencythataspecificpartisordered(drivesorderquantity)SupplierLeadTime(LT)andOrderFrequency(OF)GenerateandMail/FaxPOReceiveandLog/EnterPOPrepareandShipProductTransportProductReceiveandInspectProductLT58LT是从供供应商商那里里补充充零件件直到到该零零件被被消耗耗的时时间，，包括括以下下内容容：PO生成+供应商LT+运输+接受受/检检验OF是指某一一零件的的订货频频次（决决定驱动动定货数数量的变变化）供应商交交货期(LT)和

订单单频率(OF)产生和Mail/FaxPO供应商收收到并记记录/输输入PO供应商准准备及发发运货物物产品运输输收料和产品检验验LT59PartClassificationdrivesa64%reductionintransactions,with12.5%lessinventory!OrderFrequencyABCPartClassificationManytimesitisfinanciallyadvantageoustosetdifferentorderfrequenciesfordifferent““classes””ofparts.ThisisusuallyperformedviathePareto(80/20)Analysisusingstandardand/orextendedcosts:60零件分类类法让事事务处理理量被减减少64%，库库存被减减少12.5%订单频率率ABC零件分类类大多数情情况下，，出于财财务考虑虑/根据据不同零零件“分分类”设设定为为不同的的订货频频次，一一般采用用柏拉图图（80/20）分析析，其标标准/附附加成本本：61PurchasePartSafetyStockSizingSSisafunctionof:Demandvariability()DesiredservicelevelSupplierleadtime(LT)Supplieron-timeperformance()KeyAssumption:Thedemandprofileisnormallydistributed.50%84%98%CoefficientVariation=s/xSafetyStock=*servicelevel*(MCT)where=0.762采购件的的安全库库存规模模SS是以下内内容的函函数:需求变化化()期望的服服务水平平供应商交交货时间间(LT)供应商准准时交货货表现()重要假设设:需求的曲曲线呈正正态分布布50%84%98%变量系数数=s/x安全库存存=*服务水水平*(MCT)这里=0.763PurchaseLeadTimeand

On-TimePerformance50%84%98%Unitsperweek(demand)SafetyStock=*servicelevel*(LT)Example:Threepartshavethesamevariability(s/x=1.2),andastandarddeviationof75.PartAhasaleadtimeof5days,PartBhasaLTof20days,whilePartChasaleadtimeof40days.Assumingadesiredservicelevelof98%and=0.7,whatistherequiredsafetystockofeach?Answer:SSA=75x2x(5^.7)=462unitsSSB=75x2x(20^.7)=1221unitsSSC=75x2x(40^.7)=1984unitsLeadtimereductionbecomesacrucialpartofaninventorymanagementstrategy!64采购交货货期和按按时交交货表现现50%84%98%件每周(需需求)安全库存存=*服务水水平*(LT)举例:三种零件件有相同同的变量量系数(s/x=1.2),标准差为为75.零件A的交货时时间是5天,零件B的交货时时间是20天,零件C的交货时时间为40天.假设期望望的服务务水平为为98%，，=0.7,那么每种种零件要要求的安安全库存存是多少少?回答:SSA=75x2x(5^.7)=462unitsSSB=75x2x(20^.7)=1221unitsSSC=75x2x(40^.7)=1984units减少交货货时间成成为库存存管理策策略的关关键部分分65DemandVariability:ImpactonSafetyStockHowmuchsafetystockisrequiredofeachitem,givenadesiredfillrateof98%?(assumethereplenishmentleadtimeis5daysforallparts)ADUA=15StdDevA=75SSA=____units(safetystockalgorithm)____units/15units/day=___daysSSADUB=10StdDevB=75SSB=____units(safetystockalgorithm)____units/10units/day=___daysSSADUC=5StdDevC=75SSC=____units(safetystockalgorithm)____units/5units/day=___daysSSTypicalapproachattemptstomaintainasimilarinventoryonallitems.Thisapproachdrivestoomuchinventoryonsome,andnotenoughonothers.DemandProfile66需求的可变变性:对对安全库存存的影响对于每项产产品需要多多少安全库库存？,给给定98%的期望望供给率？？(假设对于每每项产品的的补充交货货时间为5天)ADUA=15标准差A=75SSA=____件(安安全库存计计算式)____件/15件/天=___天SSADUB=10标准差B=75SSB=____件(安安全库存计计算式)____件/10件/天=___天SSADUC=5标准差C=75SSC=____件(安全库存存计算式)____件/5件/天=___天SS一般的方法法是对所有有的产品项项目尽量保保持同样的的库存.这这种方方法可能对对某些产品品来说库存存太多，而而对另外的的产品又不不够。需求变化图图67BasicPullFormulasforPurchasedPartsBOHPurchasedOrders(SumPO)SLTMaxLoop*=(LT*Dmd)+(OF*Dmd)+SSMinKanban/TriggerPoint=(LT*Dmd)+SSOrderIf:(BOH*+SumPO)<=TriggerPointOrderQty=MaxKanban–(BOH*+SumPO)OFSSLTPurchasedPartsAvgBOH*BalanceOn-Hand(BOH)MaxLoop=MaxKanbanMaxMin68采购零件拉拉系统的基基本公式现存余额BOH采购定单SLTMaxLoop*（拉系统环里里的最大库库存）=(LT*Dmd)+(OF*Dmd)+SSMinKanban/TriggerPoint拉系统环里里的最小库库存/触发发点=(LT*Dmd)+SS如果:(BOH*+SumPO)<=TriggerPoint触发点时就就订货订单数量=MaxKanban–(BOH*+SumPO)OFSSLT采购的零件件AvgBOH*BalanceOn-Hand(BOH)策略缓冲中中的库存数数量MaxLoop=MaxKanbanMaxMin69Example#1:PurchasePullSystemPurchasePartNumber““11111”hasthefollowingdata:OF =10daysLT =20daysSafetyStock=50partsDemand=2.0parts/dayDeterminetheMaxLoop(Kmax)MaxLoop=(OFxDemand)+(LTxDemand)+SS=(____x______)+(___x______)+(__)=________DeterminetheMinKanban/TriggerPoint(Kmin)MinKanban=(LTxDemand)+SS=(___x______)+(__)=________BONUSQUESTION:IftheBOH=50partsandtheSumPO’’s=50parts,shouldwereplenishandifsohowmuch?70举例例#1:采购购拉拉系系统统采购购件件““11111””已已知知以以下下数数据据:OF=10天LT=20天安全全库库存存=50天天需求求=2.0件件/天天决定最大看板板数量(Kmax)MaxLoop=(OFx需求)+(LTx需求)+SS=(____x______)+(___x______)+(__)=________决定最小看板板数量/触触发点(Kmin)MinKanban=(LTx需求)+SS=(___x______)+(__)=________有奖问答:如如果BOH=50件，SumPO’’s=50件,我们要要补充吗？如如果要，补充充多少？71举例#1:采购拉系统（（答案）采购件“11111””已知以下下数据:OF =10天LT =20天安全库存= 50天天需求 =2.0件件/天决定最大看板板数量(Kmax)MaxLoop=(OFx需求)+(LTx需求)+SS=(_10_x__2__)+(_20__x__2___)+(50*2)=___160_____决定最小看板板数量/触触发点(Kmin)MinKanban=(LTx需求)+SS=(_20_x___2__)+(50*2)=___140____有奖问答:如如果BOH=50件，SumPO’’s=50件,我们要要补充吗？50+50<140,需需要补充160-50-50=60，72Usingthedataonthepreviousslide,calculate

thefollowing:WhatistheHighestBufferInventory?______WhatistheLowestBufferInventory?______SSQuantityLTQuantity__________________TriggerPointBuffer

MaxLoopOFQuantityExample#1:PurchasePullSystem(Cont.)73用前面的数据据，计算下列列：最高的缓冲库库存是多少?______最低的缓冲库库存是多少?______SS数量LT数量__________________触发点缓冲

MaxLoopOF数量举例#1:采购拉系统74Demand=7parts/daySafetyStock(SS)=10partsVendorLeadTime(LT)=10daysOrderFrequency(OF)=5daysExample#2:PurchasePullSystemSSQuantityLTQuantity__________________TriggerPointBuffer

MaxLoopOFQuantityUsingthedatatotheleft,calculatethefollowing:Whatisthevendorleadtimequantity=________?Whatisthetriggerpoint=_________?Whatisthetypicalorderquantity=________?Whatisthetypical(avg)BOH(bufferinventory)=_________?75需求=7件/天天安全库存(SS)=10件供应商交货期期(LT)=10天订单频率(OF)=5天举例#2:采购拉系统SS数量LT数量__________________触发点缓冲

MaxLoopOF数量用左边的数值值计算下列：：供应商的交货货期数量是多多少=________?触发点是多少少=_________?典型的订货数数量是多少=________?典型的(平平均)BOH(缓冲库存)是是多少=_________?76需求=7件/天天安全库存(SS)=10件供应商交货期期(LT)=10天订单频率(OF)=5天举例#2:采购拉系统SS数量LT数量__________________触发点缓冲

MaxLoopOF数量用左边的数值值计算下列：：供应商的交货货期数量是多多少=__7*10______?触发点是多少少=___7*10+10______?典型的订货数数量是多少=__5*7______?典型的(平平均)BOH(缓冲库存)是是多少=7*10+10?77PullSystemsPullSystemPlatformsManualvs.ElectronicPullSystems:HandlingSeasonalityPerformanceMeasures拉系统拉系统平台人工VS电子拉系统:处处理季节性绩效量测PullSystemPlatformsVisualCardSystemsElectronicSystems2-Bin/AsynchronousSynchronous80拉系统统平台台目视卡卡系统统电子系系统2-Bin/不同步步的同步的的81目视卡卡系统统该方法法使用用卡片片流经经整个个制造造过程程，并并返回回到拉拉系统统板上上通过过目光光就可可以看看到零零件的的情况况82ReplenishmentPullDemandCalculationPartsClassificationABCClassificationSafetyStockCalculationsOrderFrequencySystemPlatformPCBasedModulesElectronicThisapproachuseselectronicsystem(typicallyintegratedwithMRP)toresizepartquantitiesandtogeneratereplenishmentsignalswithouttheuseofcards.83补充充拉拉系统统需求求计计算算零件件分分类类ABC分类类安全全库库存存计计算算订单单的的频率率问题题解解答答绩效效监监督督系统统平平台台基于于模模块块化化的的PC电子子的的该方方法法使使用用电电子子系系统统(一一般般都都与与MRP集成成)来调调整整零零件件库库存存的的大大小小规规模模，，产产生生补补充充信信号号，，而而不不需需要要用用卡卡片片84PrimaryStorage12LineSide12-Bin/AsynchronousEmptybinreturnstoprimarystorageBinisfilledFullbinreturnstoline85初始的库库存12生产线侧侧12-Bin/异步的空箱回到到初始库库存处箱子被填填满填满的箱箱子回到到生产线线上86AssemblyA2daysAssemblyB2daysAssemblyC2daysAssemblyD2daysSubAssyY6days8DayCycleTimeSubAssyX2daysSynchronousPull87组装A2天组装B2天组装C2天组装D2天半成品Y6天8天的的周期时时间半成品X2天同步的拉拉系统88Manualvs.ElectronicPullSystemsFewpartnumbersSteady/predictabledemandFewsuppliersFrequent(daily)deliversfromsuppliersVerydisciplinedworkforceManypartnumbersErraticorseasonaldemandManysuppliersInfrequentdeliveriesfromsuppliersDisciplinedworkforce/accurateinventoryFewpartnumbersSteady/predictabledemandSimpleprocessflowLimitedvariationinstandardpacksizeVerydisciplinedworkforceManypartnumbersErraticorseasonaldemandComplexprocessflowManyvariationsinstandardpacksizeDisciplinedworkforce/accurateinventoryPurchasingManufacturingNote:CombinationofElectronicandManualisacceptableManualElectronic89人工VS电子的拉拉系统零件数量量少稳定的/可预测测的需求求少数几个个供应商商频繁的(每日)发货从供供应商良好培训训的工人人很多零件件数量不确定的的或季节节性的需需求很多供应应商很少的交交货从供供应商良好培训训的工人人/准确确的库存存零件数量量少稳定的/可预测测的需求求简单的流流程标准包装装限制变变化良好培训训的工人人很多零件件数量不确定的或季季节性的需求求复杂的流程标准包装变化化很大良好培训的工工人/准准确的库存采购制造Note: