c物流專業(yè)英語（第5版） 電子課件 h5

InventoryManagement

Chapter5ChapterOutlineConceptofInventoryPurposesofInventoryTypesofInventoryManufacturerinventoryWholesalerinventoryRetailerinventory

PartIConceptandTypesofInventoryPartII

InventoryManagementStrategiesMaterialRequirementsPlanning(MRP)DistributionRequirementsPlanning(DRP)Vendor-managedInventory(VMI)Just-in-timeInventoryManagementPartIIISupplementaryReading

Casestudy:JITintheSmogCo.ProductionSystemPerformanceMeasureforProductionSystemChangestoCustomerRequirementsTraditionalReactiontoCustomerDemandsforBetterService

PartI

ConceptandTypesofInventoryConceptofInventoryInventoryiscostly：

Inventoryisalargeandcostlyinvestment.Bettermanagementoffirminventoriescanimprovecashflowandreturnoninvestment.Theinventoryrequirementsofafirmdependonthenetworkstructureandthedesiredlevelofcustomerservice.Theoretically,afirmcouldstockeveryitemsoldinafacilitydedicatedtoserveeachcustomer.Fewbusinessoperationscouldaffordsuchalargeinventorycommitmentbecausetheriskandtotalcostwouldbeprohibitive.Theobjectiveistoachievethedesiredcustomerservicewiththeminimuminventory,consistentwithlowesttotalcost.PurposesofInventoryEconomiesofscale:

Facilitateseconomiesofscale.Managementmaydecide,forexample,topurchaselargequantitiesofaniteminordertoqualifyforadiscount.Orlowertransportationcostsmayberealizedbyshippinglargerquantitiesatonetime.Similarly,alongproductionrunmaysignificantlyreducemanufacturingcosts.Ineverycase,inventoryisbeingutilizedasawaytoobtainsavingsinotherpartsofthelogisticssystem.

Balancingsupplyanddemand:Offersameansofbalancingsupplyanddemand.Somefirmscanonlyselltheirproductsatcertaintimesoftheyear.Inordertoutilizetheirfixedinvestmentinbuildingsandequipmentandmaintainaskilledlaborforce,managersmaydecidedtoproduceallyearandstorethefinishedgoodsuntilthesellingseasonarrives.

Ensuringcustomerdemands:

Providesprotectionfromuncertaindemand.Despitemanagement’sbestforecastingefforts,demandcanneverbeknownwithabsolutelycertainty.Similarly,transportvehiclesbreakdown,rawmaterialsmaysuddenlybeunavailable.Andmanufacturinglinesmaystop.Forallofthesereasons,inventoryisutilizedtoensurethatcustomerneedsaremetevenwhentheproductionprocessitselfisinterrupted..Inventoryenablesspecialization:Inventoryenablesspecialization:Specialization.Inventorymakesitpossibleforafirm’splantstospecializeintheproductsthatitmanufactures.Thefinishedproductscanbeshippedtofieldwarehouseswheretheyaremixedtofillcustomerorders.Theeconomiesthatresultfromthelongerproductionrunsandfromsavingsintransportationcostmorethanoffsetsthecostofadditionalhandling.Inventoryisheldthroughoutthesupplychain:

Inventoryasabuffer.Inventoryisheldthroughoutthesupplychaintoactasabufferforthefollowingcriticalinterfaces

Supplies-procurement(purchasing)

Procurement-production

Production-marketing

Marketing-distribution

Distribution-intermediary

Intermediary-consumer/userSymptomsofpoorinventorymanagement:

Excessiveinventory.Excessiveinventoriesmaycompensatefordeficienciesinbasicdesignofalogisticsnetworkandtosomedegreeinferiormanagement.However,excessiveinventoryusedasacrutchwillultimatelyresultinhigherthannecessarytotallogisticscost.Symptomsofpoorinventorymanagementaredescribedasfollowing

.

Lossofcustomers

Increasingnumberofback-orders

Increasinginvestmentininventorywithbackordersremainingconstant

Increasingnumberoforderscanceled

Periodiclackofsufficientstoragespace

Deterioratingrelationshipswithintermediaries,astypifiedbydealercancellationsanddecliningorders

LargequantitiesofobsoleteitemsTypesofinventoryManufacturer’sinventoryislongterm:ManufacturerinventoryForamanufacturer,inventoryriskislongterm.Themanufacturer’sinventorycommitmentstartswithrawmaterialandcomponentparts,includeswork-in-process,andendswithfinishedgoods.Inaddition,finishedgoodsareoftenpositionedinwarehousesinanticipationofcustomerdemand.Insomesituations,manufacturersarerequiredtoconsigninventorytocustomerfacilities.Ineffect,thispracticeshiftsallinventoryrisktothemanufacturer.Althoughamanufacturertypicallyhasanarrowerproductlinethanaretailerorwholesaler,themanufacturer’sinventorycommitmentisdeepandoflongdurationWholesaler’sinventoryhasaeconomicfunction：

Wholesalerinventory

Awholesalerpurchaseslargequantitiesfrommanufacturersandsellssmallerquantitiestoretailers.Theeconomicfunctionofawholesaleristhecapabilitytoprovideretailcustomerswithassortedmerchandisefromdifferentmanufacturersinspecificquantities.Whenproductsareseasonal,thewholesalermayberequiredtotakeaninventorypositionfarinadvanceofthesellingseason,thusincreasingdepthanddurationofrisk.responsibilitybacktowholesalers.Oneofthegreatestchallengesofwholesalingisproduct-lineexpansiontothepointwherethewidthofinventoryriskapproachestheretailers,whiledepthanddurationofriskremaintraditionalforthewholesalers.Inrecentyears,retailclientshavealsoforcedalargeincreaseindepthanddurationbyshiftinginventory.Retailerinventoryriskiswide:

Retailerinventory

Foraretailer,inventorymanagementisaboutbuyingandsellingspeed.Theretailerpurchasesawidevarietyofproductsandassumesasubstantialriskinthemarketingprocess.Retailerinventoryriskcanbeviewedaswidebutnotdeep.Duetothehighcostofstorelocation,retailersplaceprimeemphasisoninventoryturnoveranddirectproductprofitability.Inventoryturnoverisameasureofinventoryvelocityandiscalculatedastheratioofannualsalesdividedbyaverageinventory.Althoughretailersassumeapositionofriskonavarietyofproducts,theirpositiononanyoneproductisnotdeep.Riskisspreadacrossmorethan30,000StockKeepingUnits(SKUs)inatypicalsupermarket.Adiscountstoreofferinggeneralmerchandiseandfoodoftenexceeds25,000SKUs.Afull-linedepartmentstoremayhaveasmanyas50,000SKUs.Thesearecontractswherespecifiedquantitiesofcargohavetobecarriedbetweenspecifiedportswithinaspecifictimeframeforanagreeduponpaymentperunitofcargo.Trampoperatorsusuallycontroltankersanddrybulkcarriers.Bothlinerandtrampoperatorstrytomaximizetheirprofitspertimeunit.Industrialoperatorsusuallyownthecargoesshippedandcontrolthevesselsusedtoshipthem.Howdoesretailertrytoavoidrisk:

Facedwiththiswidthofinventory,retailersattempttoreduceriskbypressingmanufacturersandwholesalerstoassumegreaterandgreaterinventoryresponsibility.Specialtyretailers,incontrasttomassmerchandisers,normallyexperiencelesswidthofinventoryriskasaresultofhandlingnarrowerassortments;however,theymustassumegreaterriskwithrespecttodepthanddurationofinventoryholding.Ifabusinessplanstooperateatmorethanonelevelofthedistributionchannel,itmustbepreparedtoassumerelatedinventoryrisk.Forexample,thefoodchainthatoperatesaregionalwarehouseassumesriskrelatedtothewholesaleroperationoverandabovethenormalretailoperations.

NewWordsandPhrasesPartII

InventoryManagementStrategiesMaterialRequirementsPlanning(MRP)HowdoesMRPwork:MRPdealsspecificallywithsupplyingmaterialsandcomponentpartswhosedemanddependsuponthedemandforaspecificendproduct.Essentially,MRPbeginsbydetermininghowmuchofthefinalproductcustomersdesire,andwhentheyneedit.ThenMRPbreaksdownthetimingandneedforcomponents(allofwhichcouldhavedifferentleadtimes)baseduponthatscheduledend-productneed.AnMRPsystemconsistsofasetoflogicallyrelatedprocedures,decisionrules,andrecords,whicharedesignedtotranslateamasterproductionscheduleintotime-phasednetinventoryalsore-plansnetrequirementsasaresultofchanges.MRPminimizesinventorytotheextentthatthemasterproductionscheduleaccuratelyreflectswhatisneededtosatisfycustomerdemand.Iftheproductionscheduledoesnotmatchdemand,thecompanywillhavetoomuchofsomeitemsandtoolittleofothers.Becausethemasterproductionscheduledrivestheneedforparts,MRPissaidtobeapullsystem.Inotherwords,theproductionschedule“pulls”componentsthroughthesysteminordertomeetmanufacturingneeds.DistributionRequirementsPlanning(DRP)HowdoesDRPwork:

DRPisamoresophisticatedplanningapproachthatconsidersmultipledistributionstagesandthecharacteristicsofeachstage.DRPisthelogicalextensionofmanufacturingrequirementsplanning,althoughthereisonefundamentaldifferencebetweenthetwotechniques.MRPisdeterminedbyaproductionschedulethatisdefinedandcontrolledbytheenterprise.

ComparingDRPwithMRP:Ontheotherhand,DRPisguidedbycustomerdemand,whichisnotcontrollablebytheenterprise.So,whileMRPgenerallyoperatesinadependentdemandsituation,DRPoperatesinanindependentenvironmentwhereuncertaincustomerdemanddeterminesinventoryrequirements.Themanufacturingrequirementsplanningcomponentcoordinatestheschedulingandintegrationofmaterialsintofinishedgoods.MRPcontrolsinventoryuntilmanufacturingorassemblyiscompleted.DRPthentakescoordinationresponsibilityoncefinishedgoodsarereceivedintheplantwarehouse.Vendor-managedinventory(VMI)Vendor-ManagedInventory(VMI)isanapproachtoinventoryandorderfulfillmentwherebythesupplier,notthecustomer,isresponsibleformanagingandreplenishinginventory.Thisappearsatfirstsighttocountertheprincipleofpullscheduling,becausetheprecedingprocess(themanufacturer)isdecidinghowmanyandwhentosendtothenextprocess(theretailer).Inpractice,thebasisonwhichdecisionswillbemadeisagreedwiththeretailerbeforehand,andisbasedontheretailer’ssalesinformation.UnderVMI,thesupplierassumesresponsibilityformonitoringsalesandinventory,andusesthisinformationtotriggerreplenishmentorders.Ineffect,supplierstakeoverthetaskofstockreplenishment.Potentialbenefits:TheimmediatebenefitofVMIisaccesstodataon:

customersales;inventorylevelsatthecustomers.Ononeside,thismayhelpthesuppliertoprovidebettercontrolofthesupplychainandsodeliverbenefitsforboththecustomerandthemselves.Ontheotherside,havingthesuppliertakethedecisiononthereplenishmentaimstominimizetheimpactofdemandamplification.Inthelongerterm,suppliersshouldintegratedemandinformationintotheirorganizationanddevelopthecapabilitytodriveproductionwithit.Thishelpstoreplacethetraditionalpushschedulingwithpullscheduling,basedonmeetingknowndemandinstantaneouslyoutofmanufacturing.PotentialProblemsinsettingupaVMIsystem:OtherthanthepracticaldifficultiesofsettingupaVMIsystem,anumberofproblemscanpreventtheabovebenefit:

Unwillingnesstosharedata.Retailersmaybeunwillingtosharetheirmarketingplansandproductrangestrategieswithmanufacturers.

Seasonalproducts.ThebenefitsofVMIarequicklyawayinfashionandseasonalproducts,especiallyapparel.

Investmentandrestructuringcosts.AdoptingaVMIapproachincursahighinvestmentbythecustomerandsupplier,andalsotakestimeandeffort.

Retailervulnerability.VMIwillmaketheretailermoredependentonthem.

Lackofstandardprocedures.Customersmayaskfordifferenttaggingmethodsorlabeling.Withmanyindustrialproductsthereisnobar-codestandard.

Systemmaintenance.Itneedsalotmaintenancetotheinventoryrecorderrorsduetoincorrectpartcounts,mislabeling,damage,lossandtheft.

Australia,Austria,Belgium,Canada,Chile,CzechRepublic,Just-in-timeInventoryManagementJITConcept:

Intheearly1970s,ToyotaMotorManufacturingadoptedJITsystem,anewproductionstrategythatusedlittleinventory,shortenedcycletimes,improvedquality,andeliminatedwasteandcostsinthesupplychain.ItwasalsoadoptedbyAmericanandEuropeanautomakersinresponsetothegrowingsuccessoftheirJapanesecompetitors.LaterJITconceptspreadtootherindustriessuchascomputers,andbecamepopularinmanufacturingstrategiesaroundtheworld.Just-In-Timeisaphilosophyofcontinuousandforcedproblemsolving.WithJIT,suppliesandcomponentsare“pulled”throughasystemtoarrivewheretheyareneededwhentheyareneeded.Whengoodunitsdonotarrivejustasneeded,a“problem”hasbeenidentified.ThismakesJITanexcellenttooltohelpoperationsmanagersaddvaluebydrivingoutwasteandunwantedvariability.BecausethereisnoexcessinventoryorexcesstimeinaJITsystem,costsfromunneededinventoryareeliminatedandthroughputimproved.Consequently,thebenefitsofJITareparticularlyhelpfulinsupportingstrategiesofrapidresponseandlowcost.AdvantagesofJIT:Moreinventoryturns.Becausethereislessstockonhand,theinventorythatismaintainedstaysforashorterperiodoftime.Betterquality.HighqualityproductsmustbereceivedwithaJITsystem,otherwisetheentirebenefitproductionprocesscollapses.Lesswarehousespace.Whenthereislessinventory,fewerand/orsmallerwarehousesarerequired.DisadvantagesofJIT:Riskofstock-outs.Whenfirmseliminateinventory,theriskofstockingoutcanrise.Increasedpurchasingcosts.Theoretically,JITmeansobtainingsmalleramountsmorefrequently,whichgenerallywillnotgetpurchasingdiscountsassociatedwithbuyinglargequantitiesatonetime.Smallchannelmembersmaysuffer.JITmayallowstrongorganizationstoshifttheirinventorytosmallerfirmsinthechannel.Environmentalissues.JITcanleadtohigherlevelsoftrafficcongestionandairpollutionbecauseofadditionaltransportationrequired.

ZeroInventoryJITcaseinrestaurant:

JITisalsoestablishedpracticeinrestaurants,wherecustomersexpectit,andanecessityintheproducebusiness,wherethereislittlechoice.

PacificPre-CutProduce,a$14millionfruitandvegetableprocessingcompanyinTracy,California,holdsinventorytozero.Buyersareinactionintheveryearlyhoursofthemorning.At6a.m.,productioncrewsshowup.Ordersforveryspecificcutsandmixturesoffruitandvegetablesaladsandstir-fryingredientsforsupermarkets,restaurants,andinstitutionalkitchenspourinfrom8a.m.until4p.m.

Shippingbeginsat10p.m.andcontinuesuntilthelastorderisfilledandloadedat5a.m.thenextmorning.Inventoriesareonceagainzero,thingsarerelativelyquiet,andthentheroutinestartsagain.PacificPre-CutProducehasaccomplishedacompletecycleofpurchase,manufacture,andshippinginabout24hours.VPBobBorzonecallstheprocesstheultimateinmass-customization.“Webuyeverythingasabulkcommodity,thensliceanddiceittofittheexactrequirementsoftheenduser.Thereare20differentstir-frymixes.Somecustomerswantthesnowpeasclippedonbothends,somejustonone.Somewantonlyredbellpeppersinthemix,someonlyyellow.Youtailortheproducttothecustomer’srequirements.You’retryingtomeettheneedofalotofendusers,andeachrestaurantandretailerwantstolookdifferent.”NewWordsandPhrases

PartIII

SupplementaryReadingCasestudy:JITintheSmogCo.ProductionSystemPerformancemeasureforproductionsystemSmogCo.isasmallsupplierofwell-engineeredcomponents.Itproducesarangeofproductsgroupedintofamilies.Productionofoneofthehighervolumeproductfamilieshasbeenorganizedintoaflowprocessmadeupoffoursteps,whichfollowoneaftertheotherinsequence.Changeoverfromoneproducttoanotherissimple,buttakesaround10minutespermachine.Tominimizedelayscausedbychangeovers,productstendtobemadeinbatches.Thesebatchesmovefromonesteptothenext,wheretheyqueueonafirstin,firstoutbasistobeworkedon,afterwhichtheymovetothenextstep.ThisprocessisshowninFigure1.Keymeasuresoftheperformance：Keymeasuresoftheperformanceofthisprocessaretheutilizationofpeopleandofmachines.Theobjectiveistokeeputilizationofbothashighaspossible.FredHollis,theSmogproductionmanager,feltpleasedwithperformanceashelookedoutacrossthefactory.Hewaspleasedbecausehismachinesandpeoplewerebusy,therewereplentyoffinishedgoodsonhand,whichthesalesteamcouldusetosupplycustomers,andtherewasstocktocalluponifproductdemandincreased.Everythingseemedtobeundercontrol.Changestocustomerrequirements

Consistentdemandareclosetorealdemand：Themotivationtochangefromthecurrentsystemhasbeenlowinthepast,astheprocessatSmogCo.isareliableone,whichhasworkedwellforthecompany.Thebigthreecustomers,whotakethree-quartersofsales,tendtoorderthesamethingsinsimilarquantitiesoneweekinadvanceofdelivery.Withaproductionleadtimeofthreeweeks,SmogCo.usesaforecasttoscheduleproductionandmakesurethatfinishedgoodsstockswillbeavailabletomeetpredicteddemand.Consistentdemandmeansthatforecastsareoftenclosetorealdemand,sostockoutsarerare.Infacttheonlytimethisoccurredwasanincidentacoupleofyearsago,whenakeymachinewentdownandaspareparttookalongtimetosource.Currentinventorylevelsnowincludesafetystocktoprovidecoveragainstasimilarprobleminthefuture.Movegoodwhicharesoldslowly：

Whenthecompanyfoundthatcertainfinishedgoodsweresellingslowly,thesalesteamwasparticularlygoodatfindingawaytomovethem.Sometimespriceswerecut;atothertimessalesusedspecialpromotions.Ifproductionwastoohigh,ortheforecastwasabitoptimistic,thentherewerewaysofsellingsurplusstock,andthesalesteamseemedtoenjoythechallenge.Recently,however,thiswell-understoodpositionbegantochange.Themaincustomersstartedtouseanumberofnewstrategiestocompetewitheachother.Firstoneandthenasecondofthemannouncedthatitwillbereducingthecall-offtimeforitsproductsfromoneweektotwoworkingdays.Atthesametimetheyarealllookingfora5percentcostreduction,andaredemandingqualityimprovement.TheprojectteamatVoAwassearchingforameanstodealwiththelimitationsofcurrentpushsystem.Asadesignprincipleforthenewdistributionsystem,theprojectteamhadrejectedbothoftheabovementionedassumptions.Thenewsystemhadtoservetheenduser’srequirementsasitskeyperformancemeasure.Thenewsystemwouldhavetobe,firstandforemost,responsivetoenduserchoicesandsimultaneouslymoreefficientthanthecurrentsystem.Fromthesenewprinciplesthefollowingperformancecriteriawereestablishedthatthereengineeredprocesswouldhavetomeet:TraditionalreactiontocustomerdemandsforbetterserviceStockswereincreasedtocoverproductionproblems：ThecombinationofdemandsforbetterservicescausedSmogmanagementsomeconcern.Theobviousresponsetothechangesinorderingpatternswastoincreasestocklevelstocaterforunexpectedvariationsindemand.Thisapproachhadworkedbefore,whenitwasusedtojustifythesafetystocksthatcoveredproductionproblems.Itseemedworthtryingagain,sostockswereincreased.Ov