第七章供应链综合计划

Chapter7AggregatePlanningintheSupplyChainLearningObjectivesIdentifythedecisionsthatarebestsolvedbyaggregateplanningUnderstandtheimportantofaggregateplanningasasupplychainactivityDescribetheinformationneededtoproduceanaggregateplanExplainthebasictrade-offstoconsiderwhencreatinganaggregateplanFormulateandsolvebasicaggregateplanningproblemusingMicrosoftExcelOutlineRoleofaggregateplanninginasupplychainTheaggregateplanningproblemAggregateplanningstrategies(三种策略)AggregateplanningusinglinearprogrammingImplementinglinearprogrammingforaggregateplanningusingMicrosoftExcelImplementingaggregateplanninginpracticeRoleofAggregatePlanninginaSupplyChainCapacityhasacost,leadtimesaregreaterthanzeroQuestion–Shouldacompanyinvestinaplantwithlargecapacitythatisabletoproduceenoughtosatisfydemandeveninthebusiestmonth?–Shouldacompanybuildasmallerplantbutincurthecostsofholdinginventorybuiltduringslowperiodinanticipationofdemandinlatermonths?ThesearetypesofquestionsthataggregateplanninghelpscompaniesanswerRoleofAggregatePlanninginaSupplyChainAggregateplanning(总体计划):–processbywhichacompanydeterminesideallevelsofcapacity,production,subcontracting,inventory,stockouts,andpricingoveraspecifiedtimehorizonThegoalistosatisfydemandwhilemaximizeprofit–供应链综合计划之上，是供应链战略；–供应链综合计划之下，是企业资源计划；–综合计划介于之间。对上细化，对下驱动内部供应链，驱动“企业资源计划”。RoleofAggregatePlanninginaSupplyChainAggregateplanningisanimportantsupplychainissueTobeeffective,itrequiresinputsfromthroughoutthesupplychain,anditsresultshaveatremendousimpactsonsupplychainperformance.–Collaborativeforecastsarecreatedbymultiplesupplychainenterprisesandareanimportantinputforaggregateplanning–Manyconstraintsinaggregateplanningcomefromsupplychainpartnersoutsidetheenterprise–TheoutputfromaggregateplanningisalsoofvaluetobothupstreamanddownstreampartnersRoleofAggregatePlanninginaSupplyChainThemainobjectiveofaggregateplanneristoidentifythefollowingoperationalparametersoverthespecifiedtimehorizon:–Productionrate(生产率):thenumberofunitstobecompletedperunittime(suchasperweekorpermonth)–Workforce(劳动力数量):thenumberoftheworkers/unitsofcapacityneededforproduction.–Overtime(加班量):theamountofovertimeproductionplanned.–Machinecapacitylevel(机器生产能力):thenumberofunitsofmachinecapacityneededforproduction.RoleofAggregatePlanninginaSupplyChain–Subcontracting(转包合同):thesubcontractedcapacityrequiredovertheplanninghorizon.–Backlog:demandnotsatisfiedintheperiodinwhichitarisesbutcarriedovertofutureperiod.–Inventoryonhand(现有库存):theplannedinventorycarriedoverthevariousperiodsovertofutureperiods.AllsupplychainstagesshouldworktogetheronanaggregateplanthatwilloptimizesupplychainperformanceTheAggregatePlanningProblemGiventhedemandforecastforeachperiodintheplanninghorizon(计划期),determinetheproductionlevel(生产水平),inventorylevel(库存水平),andthecapacitylevel(生产能力水平)foreachperiodthatmaximizesthefirm’s(supplychain’s)profitovertheplanninghorizonSpecifytheplanninghorizon(typically3-18months)SpecifythedurationofeachperiodInformationNeededforinAggregatePlanDemandforecastineachperiodProductioncosts(生产成本)–laborcosts,regulartime($/hr)andovertime($/hr)–subcontractingcosts($/hror$/unit)–costofchangingcapacity:hiringorlayoff($/worker)andcostofaddingorreducingmachinecapacity($/machine)Labor/machinehoursrequiredperunitInventoryholdingcost(库存成本)($/unit/period)Stockoutorbacklogcost(库存缺货或积压成本）($/unit/period)Constraints:limitsonovertime,layoffs,capitalavailable,stockoutsandbacklogs.ConstraintsfromsupplierstotheenterpriseOutputsofAggregatePlanProductionquantityfromregulartime,overtime,andsubcontractedtime；Inventoryheld；Backlog/stockoutquantity；WorkforceHired/Laidoff；Machinecapacityincrease/decrease；Apooraggregateplancanresultinlostsales,lostprofits,excessinventory,orexcesscapacityFundamentalTradeoffsinAggregatePlanningCapacity(regulartime,overtime,subcontract)InventoryBacklog/lostsalesBasicStrategies（三种基本策略）ChasestrategyTimeflexibilityfromworkforceorcapacityLevelstrategyAggregatePlanningStrategiesThesestrategiesinvolvetrade-offsamongcapitalinvestment,workforcesize,workhours,inventory,andbacklogs/lostsalesChasestrategy(追逐战略）–usingcapacityastheleverTimeflexibility（弹性时间）fromworkforceorcapacitystrategy–usingutilizationastheleverLevelstrategy(水平战略）–usinginventoryastheleverMixedstrategy–acombinationofoneormoreofthefirstthreestrategiesChaseStrategyProductionrateissynchronizedwithdemandbyvaryingmachinecapacityorhiringandlayingoffworkersasthedemandratevariesExpensiveifcostofvaryingcapacityishighNegativeeffectonworkforcemorale（联想裁员案例，目前外企和银行都采用外包的方式应对）ResultsinlowlevelsofinventoryShouldbeusedwheninventoryholdingcostsarehighandcostsofchangingcapacityarelowTimeFlexibilityStrategyCanbeusedifthereisexcessmachinecapacityWorkforceiskeptstable,butthenumberofhoursworkedisvariedovertimetosynchronizeproductionanddemandCanuseovertimeoraflexibleworkschedule（很多企业采用这种策略，比如四大）Requiresflexibleworkforce,butavoidsmoraleproblemsofthechasestrategyLowlevelsofinventory,lowerutilizationShouldbeusedwheninventoryholdingcostsarehighandcapacityisrelatively