全球运营管理课件new gom8-inventory management.ppt

GOM8,InventoryManagement,GOM8,存货管理,GeneralConcepts,FunctionsofInventories(5)Transitinventories:existbecausematerialsmustbemovedfromonelocationtoanother(alsopipelineinventories)Bufferinventories:toprotectagainsttheuncertaintiesofsupplyanddemand(alsosafetystocks)asagainststockoutAnticipationinventories:suchasapriceincrease,strike,seasonalchange.,一般概念,存货功能(5)运输存货：是由于原料必须从一个地方运输到另外一个地方（包括管道库存）缓冲存货：防止出现不确定的供给和需求造成的脱销（安全库存）预期存货：例如价格上涨，罢工，周期性的变化,GeneralConcepts,Decouplinginventories:betweenmachinesactingasshockabsorbersCycleinventories:lotsizeinventoriesFormsofInventoriesRawmaterialsMaintenance,repair,andoperatingsuppliesWork-in-progress(WIP)Finishedgoods,一般概念,退耦存货：在机器间做减震器循环存货：大量的存货存货的形式：原材料维护和运转供应品在进行中产品产成品,GeneralConcepts,Inventory-relatedCostsOrderingorSetupcostsInventoryCarryingorHoldingCostsCapitalcostsStoragecostsRiskcostsStockoutCostsOpportunityCosts:theovertimerequiredtoincreasecapacity.thecostofidletime.,一般概念,存货相关的成本订货成本存货成本资金成本存储成本风险成本缺货损失机会成本：超时满负荷.停机成本,GeneralConcepts,TypesofInventoryManagementSystemsReorderpointsystemsPeriodicreviewsystemsMRPsystemsReorderpointsystemsAninventorylevelisspecifiedatwhichareplenishmentorderforafixedquantityoftheinventoryitemistobeplaced.ThequantityofinventorytobeorderedisoftenbasedontheeconomicorderquantityTwobinssystem,一般概念,存货管理系统的类型再订货点系统周期性检查系统MRP（物资需求计划）系统再订货点系统库存达到一个预先设置的固定点时需要重新补充库存。库存订货数量依据经济订购量双箱系统,TheABCConcept,PeriodicReviewSystemsTheinventorylevelisreviewedatequaltimeintervalsReorderquantity=maximumlevelon-handinventoryon-orderquantity+demandoverleadtime.PrioritiesforInventoryManagement:TheABCconceptBasedontheannualdollarpurchasesofaninventorieditem.,基本概念,周期性检查系统每间隔一段时间检查库存水平再订货数量最大存货数量当前库存已定购但尚未交货的数量订货至交货这段时间的需求数量存货管理的优先权：基本概念依据存货盘点清单的年货币购买,TheABCConcept,基本概念,TheABCConcept,A:High-valueitems.The15-20percentorsooftheitemsthataccountfor75to80percentofthetotalannualinventoryvalueB.Medium-valueitems.The30to40percentoftheitemsthataccountforapproximately15percentofthetotalannualinventoryvalueC.Low-valueitems.The40to50percentoftheitemsthataccountfor10to15percentoftheannualinventoryvalue.,基本概念,A：数值大的项。大约15到20能够解释75到80的总年度库存值B：数值中的项。30到40可以解释大约15的总年度库存值C：数值小的项。40到50可以解释10到15%的总年度库存值,TheABCConcept,TheAnalysisoftheABCConceptTheAitemsshouldbesubjecttothetightestcontrol,withdetailedinventoryrecordsandaccurate,updatedvaluesoforderquantitiesandreorderpointsBitemsaresubjecttonormalcontrol,withorderquantitiessetbyEOQ,butwithlessfrequentupdatingofrecordsandreviewoforderquantitiesandreorderpoints.Citemsaresubjecttolittlecontrol;ordersareplacedfora6-monthto1-yearsupplysothatrelativelylittlecontrolmustbeexercisedandinventoryrecordscanbekeptsimple.,基本概念,基本概念分析A将会通过详细的库存记录，精确的最新订货数量和再订货点的数值得到最严格的控制B通过经济定购量来确定订购数量，从而达到一般性的控制，但是很少更新库存记录检查订货数量和再订货点。C很少控制；订单是6个月或者1年的供给，所以很少运用相关的控制，库存记录可以简单的保存。,TheABCConcept,2050100PercentageofTotalItems,1009075,PercentageofTotalDollarUsage,A,B,C,基本概念,2050100各个项目的占比,1009075,总资金的使用比例,A,B,C,TheEconomicOrderQuantity(EOQ),EOQAppliestoinventoryitemsthatarereplenishedinbatchesorordersandarenotproducedanddeliveredcontinuously.Onlycarryingcostsandopportunitycostsareconsidered.ThebasicEOQmodelRageofdemandisconstant(e.g.50perday)Shortagesarenotallowed,经济定购量,EOQ应用于存货的分批或者订购，不是连续的产出和交货。只考虑运输费用和机会成本。基本的经济订货量模型需求量的变化是固定的（例如每天50）不允许缺货,TheEconomicOrderQuantity(EOQ),Leadtimesareknownwithcertainty,sostockreplenishmentcanbescheduledtoarriveexactlywhentheinventorydropstozero.Purchaseprice,orderingcost,andper-unitholdingcostareindependentofquantityordered.Itemsareorderedindependentlyofeachother.VariablesQ=orderquantityU=annualusageCO=costtoplaceoneorderCH=annualholdingcostperunit,经济订购量,订货到交货的时间是确定已知的，可以安排为刚好到存货减少到0的时候交货。采购费用，订货成本，单位保管费用与订货数量无关各项之间无关变量Q=订购数量U=年度使用CO=一次订货成本CH=每年单位存储成本,TheEconomicOrderQuantity(EOQ),Example:Awaterdistributorsells10005-gallonbottlespermonth(30days)andpurchaseinquantitiesof2000perorder.Leadtimeforthereceiptofanorderis6days.Thecostaccountingdepartmenthasanalyzedinventorycostsandhasdeterminedthatthecostofplacinganorderis$60andtheannualcostofholdingone5-gallonbottleininventoryis$10,经济定购量,例子：一个水批发商每个月（30天）卖出1000瓶5加仑的水，每次定购2000。订货到交货收到的时间是6天。成本会计部门分析了存货成本，得出每次定购成本是60$，每年存储1瓶5加仑的水的存货的成本是10$,TheEconomicOrderQuantity(EOQ),Answer:Firsttodeterminetwoseparateannualcosts:totalannualholdingcostandtotalannualorderingcostTheorderingcostisdeterminedbyCo.Thecosttoplaceoneorder($60),andthenumberofordersplacedperyear.Sincethedistributorsells12,0005-gallonbottlesperyearandorders2000perorder,itmustplacesix(i.e.,12,000/2000)foratotalorderingcostof$360(6ordersperyearx$60perorder),经济定购量,解：首先分清两个年费用：总年存储成本和总订购成本订购成本由Co决定，每次定购成本（60$），每年订购的次数。因为这个批发商每年销售12000瓶5加仑的水，每次订购2000瓶，因此需要定购6次（12000/2000），总的订购成本为$360(6$60),TheEconomicOrderQuantity(EOQ),Sincetherateofdeclineininventoryisconstant(i.e.,1000permonth),theaveragelevelis1000units,orsimplythearithmeticaverageofthetwolevels:(2000+0)/2=1000.Hencetheannualholdingcostis$10,000($10/unitx1000units)or,TAC=$360+$10,000=$10,360,经济订购量,因为存货减少率是常数（每个月1000），平均水平是1000个单位或者简单的两个水平的算术平均（2000+0）/21000。因此年存储费用为$10000（$101000）或者,TAC=$360+$10,000=$10,360,150010,000500,500100001500200025000,EOQ,Cost($),Q(units)Graphofannualinventorycosts,TACAnnualholdingcost,(CH/2)QAnnualordercost,(UCO)/Q,About400bottlesperorder,TheEconomicOrderQuantity(EOQ),Isthisthebestpolicyorcanitbeimproved?,经济订购量,这是最好的策略吗？能够改进吗？,150010,000500,500100001500200025000,EOQ,费用($),Q(单位)年存货成本图,TAC年存储费用,(CH/2)Q年订购费用,(UCO)/Q,大约每次订购400瓶,TheEconomicOrderQuantity(EOQ),WecanfindanequationforEOQbysettingthetwocostsequaltooneanotherandsolvingforthevalueofQ,Obviouslywecannotorderafractionofabottle,theorderQuantitywouldberoundedto380units.,经济订购量,我们发现通过经济订购量模型可以设置两个成本的等式，从而解出Q的值,显然我们不能订零点几瓶，所以订购的数量可以是380瓶,TheEconomicOrderQuantity(EOQ),Thetotalannualcost(TAC)ofthispolicy