配送与运输策划外文翻译.docx

配送与运输策划外文翻译.docx

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配送与运输策划外文翻译

外文翻译

原文

DistributionandTransportPlanning

MaterialSource:

BernhardFleischmann

UniversityofAugsburg,DepartmentofProductionandLogistics,

Universitatsstrabe16,86135Augsburg,Germany

PlanningSituations

TransportSystems

Transportprocessesareessentialpartsofthesupplychain.Theyperformtheflowofmaterialsthatconnectsanenterprisewithitssuppliersandwithitscustomers.Theintegratedviewoftransport,productionandinventoryholdingprocessesischaracteristicofthemodernSCMconcept.

Theappropriatestructureofatransportsystemmainlydependsonthesizeofthesingleshipments:

Largeshipmentscangodirectlyfromthesourcetothedestinationinfulltransportunits,e.g.trucksorcontainers.Smallshipmentshavetobeconsolidatedinatransportnetwork,whereasingleshipmentistransshippedonceorseveraltimesandthetransportisbrokenattransshipmentpoints（TPs）.Aparticularlyeffectiveconsolidationofsmallshipmentsisachievedbyalogisticsserviceprovider（LSP）,whocancombinethetransportsfrommanysenders.

Theconsolidationoftransportflowsdecreasesthetransportcost.Asthecostofasingletripofacertainvehicleonacertainrouteisnearlyindependentoftheload,ahighutilizationoftheloadingcapacityisadvantageous.Moreover,therelativecostperloadingcapacitydecreaseswithincreasingsizeofthevehicles.Butevenwithastrongconsolidationofshipmentstofullloads,e.g.byanLSP,thesmallershipmentscauserelativelyhighercost,becausetheconsolidationrequiresdetourstodifferentloadingplaces,additionalstopsandtransshipment（seeFleischmann（1998,pp.65））.

Thefollowingtransportprocessesoccurinasupplychain:

•Thesupplyofmaterialsfromexternalsuppliersorfromanownremotefactorytoaproductionsite.Bothcasesareidenticalfromtheviewpointoflogistics.

•Thedistributionofproductsfromafactorytothecustomers.Thedistributionsystemdependsonthetypeofproducts:

–Investmentgoods,e.g.machinesorequipmentforindustrialcustomers,areshippedonlyonceorseldomonacertaintransportlink.

–Materialsforproductionarealsoshippedtoindustrialcustomers,butregularlyandfrequentlyonthesamepath.

–Consumergoodsareshippedtowholesalersorretailers,ofteninverysmallordersizes（withanaveragebelow100kginsomebusinesses）,

requiringaconsolidationofthetransports.

Notethatthetransportofmaterialsfromfactorytofactoryispartofthedistributionfunctionofthesupplieraswellaspartoftheprocurementfunctionofthereceiver.Transportplanningisusuallytheresponsibilityofthesupplier.Butthereareimportantexceptions,e.g.intheautomotiveindustry,wherethemanufacturercontrolsthetransportsfromhissuppliers.Inthiscase,transportplanningoccursontheprocurementsideaswell.

AnLSPmayconsolidatethetransportflowsofseveral”shippers”,operatinginseparatesupplychains,inhisownnetwork.Thenheisresponsibleforplanninghowthetransportsareexecuted,i.e.bywhichvehiclesalongwhichroutes.However,thedecisionsonthetransportorders,i.e.thequantity,sourceanddestinationofeveryshipment,remainataskoftheAPSoftheshipper.Usually,itisnotpracticabletoincludetheflowsofallothershippersofanLSPintotheAPS.However,theadditionalflowshaveanimpactonthetransportcostandshouldbetakenintoaccountimplicitlybyappropriatetransportcostfunctions.

DistributionSystems

Atypicaldistributionsystemofaconsumergoodsmanufacturercomprisestheflowofmanyproductsfromseveralfactoriestoalargenumberofcustomers.ProductsmadetostockareoftenshippedfirsttocentralDCsonforecast.Thedeliveriesofthecustomerordersmaythenusethefollowingdistributionpaths:

ShipmentsmaygodirectlyfromthefactoryorfromaDCtothecustomer,withasingleorder.Thissimplestformofdistributionisonlyefficientforlargeordersusingupthevehicle.SmallerorderscanbeshippedjointlyintoursstartingfromthefactoryorDCandcallingatseveralcustomers.AstrongerbundlingofsmallshipmentsisachievedbyajointtransportfromtheDCtoaTPanddeliveryinshortdistancetoursfromthere.Figure12.1illustratesthedifferentdistributionpaths.

Thetransportofmaterialsforproduction,asfarascontrolledbythesupplier,ismostlydoneindirectshipments.Arecentconceptforthesupplyofstandardmaterialsisthevendormanagedinventory（VMI）,wherethesupplierdecidesontimeandquantityoftheshipmentstothecustomerbuthastokeepthestockinthecustomer’swarehousebetweenagreedminimumandmaximumlevels.Inthiscase,thecustomer’swarehousehasthesamefunctionasaDC,sothattheplanningofVMIsupplyissimilartotheDCreplenishment.

ProcurementLogisticsSystems

Ifamanufacturercontrolsthetransportsofmaterialsfromhissuppliers,hecanusevariouslogisticsconcepts,whichdifferinthestructureofthetransportationnetworkandinthefrequencyoftheshipments.Theymayoccurinparallelfordifferentclassesofmaterialsforthesamereceivingfactory.

Cyclicalprocurementinintervalsofafewdaysuptoweekspermitstobundlethetransportflowintolargershipments,butgeneratescyclestockatthereceivingfactory.JITprocurementwithatleastdailyshipmentsavoidstheinboundmaterialpassingthroughthewarehouse.Instead,itcanbeputonabufferareaforashorttime.Ifthearrivalsareevensynchronizedwiththeproductionsequence,thematerialcanbeputimmediatelytotheproductionlinewhereitisconsumed.Thelattercaseiscalledsynchronizedprocurementinthefollowing.

Thefollowingtransportconceptsexistforprocurement:

•Directtransportsfromthesupplieraresuitableforcyclicalsupplyand,ifthedemandissufficientlylarge,alsofordailysupply.Onlyifthedistanceisveryshort,directtransportsmaybeusedforsynchronizedprocurement.

•AregionalLSPcollectsthematerialsintoursfromallsuppliersinhisdefinedarea,consolidatesthemataTPandshipstheminfulltruckstothereceivingfactory.Thisconceptpermitsfrequentsupply,uptodaily,evenfromremotesupplierswithlowvolume.Thetrunkhaulagecanalsobecarriedoutbyrail,iftherearesuitableconnections.

•AnLSPwarehouseclosetothereceivingfactorysuitsforsynchronizedprocurement:

TheLSPisresponsibleforsatisfyingtheshort-termcallsfromthereceiverbysynchronizedshipments.Thesuppliershavetokeepthestockinthewarehousebetweenagreedminimumandmaximumlevelsbyappropriateshipments,likeintheVMIconcept.

Models

TransportandInventory

Transportplanninghasastrongimpactontheinventoryinthesupplychain.Itdirectlycreatestransportlot-sizingstockandtransitstock（seeSect.2.4）andinfluencesthenecessarysafetystock.Thelot-sizingstockresultsfromthedecisiononthetransportfrequencies.Unfortunately,thepresentAPSdonot（yet）supporttheoptimizationofmid-termtransportplanningwithregardtoinventory.Nevertheless,thissectionpresentssomegenericplanningmodels,sincetheresultingfrequenciesandinventoriesarealsoimportantdataforotherAPSmodules.Whensettingthesedata,thefollowingrelationshipsshouldbetakenintoaccount.AreviewofcombinedtransportationandinventoryplanningisgivenbyBertazziandSperanza（1999）.

TransportationandSafetyStocks

Inadistributionsystemforproductsmadetostock,thesafetystocksthatarenecessaryforguaranteeingacertainservicelevel,dependonthestrategyofthetransportsbetweenthefactoryandtheDCs（seeSilveretal.（1998,Chap.12.4））:

InastrongpushsystemanyproductionlotisdistributedimmediatelytotheDCs.Amodificationconsistsinretainingsomecentralsafetystockatthefactorywarehousewhichisdistributedincaseofimminentstock-outatsomeDC.Inapullsystem,transportsaretriggeredbythelocalstockateveryDC,whenitreachesadefinedreorderpoint.Inapushsystem,globalinformationonthedemandandstocksituationateveryDCisrequiredforthecentralcontrol.Butalsoinapullsystem,globalinformationcanimprovethecentralallocationofstockincaseofabottleneck.InanAPS,suchglobalinformationshouldbeavailableforthewholesupplychain.

Thepushsystemcorrespondstothecaseofsynchronizedproductionanddistributionandthusrequireslesscyclestock,butingeneralhighertotalsafetystockormorecross-shipmentsbetweentheDCs.ThelocalsafetystockataDChastocoverthelocaldemanduncertaintyduringthetransportleadtime,thetotalsystemsafetystockhastocoverthetotaldemanduncertaintyduringtheproductionlead-timeandcycletime.Inaconsumergoodsdistributionsystem,thetransportcycletimeisusuallyveryshort,asaDCisusuallyreplenisheddaily,buttheproductioncycletimemaylastweekstomonths,ifmanyproductsshareaproductionline.Therefore,thesystemsafetystockcalculationshouldbebasedonaperiodicreviewmodelwiththereviewperiodequaltotheproductioncycle.

Deployment

Thegeneraltaskofdeploymentistomatchtheshort-termdemandwiththeavailableandexpectedstockforthenextdayorfewdays.Asthesourcelocations（factories,suppliers）,wherestockisavailable,areingeneraldifferentfromthedemandlocations（DCs,customers）,ithastobedecidedhowmuchtoshipfromwhichsourcelocationtowhichdemandlocation.

DeliveringKnownCustomerOrders

Inamake-to-ordersituation,thecompletionoftheordersinduetimeistheresponsibilityofproductionplanningandscheduling.Deploymentcanonlydealwithcompletedordersreadyfordelivery,andtheshipmentsizeisfixedby