Chapter 5 Operations Planning and Control

Chapter5OperationsPlanningandControlContentsIntroduction12OverviewofOperationsPlanningandControl3TechniquesforDemandforecasting4TechniquesforOperationsPlanning5TechniquesforInventoryPlanningandControlContents7DispatchingandProgressControl8MRPSystem9JustInTime(JIT)Manufacturing6TechniquesforOperationsSchedulingIntroductionAlargeportionofmodernindustryconsistsoffabricationandassemblyprocesses.Aplantthatmanufacturestelevisionsets,radios,andstereos.Thisplantmustpurchasematerials,andperhapsparts,convertthesematerialsintospecificcomponents,thenassemblethecomponentsintotheseveralproductsofferedtotheconsumers.Thisgreatlyoversimplifiedprocessisrepresentedasfollows:StorageStoragePlantFabricationAssemblyStorageTelevisionSets,Radios,StereosAluminum,Plastic,Glass,etcOverviewofOperationsPlanningandControl------DemandForecasting(Ⅰ)Demandhistoriesofexistingproducts(especially,tradeinformation)Marketingprograms(anticipatingdemandvariationsresultfromadvertisingandpromotionscheme)Externaleconomicfactors(generaleconomichealthofthenation)InputTherecognitionofdecliningdemandforaproductAstatementofexpecteddemandquantitiesfortheseveralproductsoversomeplanningperiodOutputOverviewofOperationsPlanningandControl------OperationPlanning(Ⅱ)Demandforecasting(itprovidesthebasisfordeterminingtheactivitylevel)Theengineerfactorsthatconcernsnewproducts,modificationstoexistingproducts,ormodificationstotheproductionprocessFinancialcontrolthatconcernsmonetaryconstrainsandbudgetlimitationsInputRelativelyshortterm(usuallyoneyearorless)planning,whichconsistsprimarilytheallocationofavailableresourcestoproductionrequirementsLong-rangeplanningofplantexpansionandnewfacilityacquisitionOutputExternalperturbationswhichincludesemergencyorders,canceledorders,laborstrikes,etcOverviewofOperationsPlanningandControl------InventoryPlanningandControl(Ⅲ)InventoryPlanningInventoryplanningdeterminesthematerialrequirements(components,parts,rawmaterial,assemblies,supplies,etc.)necessarytosatisfytheoperationsplanTheapprovedoperationsplanfromoperationsplanning.Specifically,theoperationsplanmustprovideatime-phasedoutlineoftheplant’sactivitiesintermsofproductionforthemarketTheoperationplanisextendedintothenet,time-phasedrequirementsforcomponents,parts,rawmaterial,assembles,andsupplies.TherequirementsareforwardedtoinventorycontrolOverviewofOperationsPlanningandControl------InventoryPlanningandControl(Ⅲ)Inventorycontroldeterminestheproperinventorylevels,reorderpoints,safetysticks,andthelikeInventoryControlTime-phasedrequirementsfromtheinventoryplanningfunctionSalesordersfromsalesMaterialrequisitionsfromdispatchingOrdersquantitiesReorderspointsSafetystockofrawmaterialandpurchasedpartsManufacturingbatchsizesSafetystockofassemblies,fabricatedparts,andfinishedpartsOverviewofOperationsPlanningandControl------OperationsScheduling(Ⅳ)RequestsforfabricationandassemblyfrominventorycontrolCorrectiveactionintheformofupdatedprioritiesandscheduleadjustmentsofproductionorderscurrentlyinprocessInputDetailedoperationssequencesforindividualworkactivities,aswellas,startandstoptimesforalloperations,arereleasedtodispatchingOutputThisfunctionisattheheartoftheentireoperationplanningandcontrolsystem,sinceitisherethatcompromisesmustbemadebetweeneconomicbatchsizes,duedates,resourceconstraints,manpowerleveling,andfacilityutilization.HerealsocorrectionsaremadefornonstandardprocessbehaviorOverviewofOperationsPlanningandControl------DispatchingandProgressControl(Ⅴ)Diagram2CorrectionActionShort-termcorrectiveactionisperformedhere.Specificdecisionsaremaderegardingoperatingproblems.Thesedecisionsincludeexpeditingcriticaljobs,determiningnewpriorities,balancingworkloadsbetweenworkcenters,etcDispatching(Scheduling)Itisresponsibleforinitializingproduction,thatis,forreleasingworkorderstooperationsattheappropriatetime.Materialisrequisitionedfrommaterialcontrol,andarrangementaremadeforchangingtheproductionprocessovertothenewproductionitemDataAcquisitionDataareacquiredfromdifferentprocessingpointsontheshopfloor.Specificdataincludetheprogressofworkinproduction,thestatusofworkwaitingprocessing,thestatusofproductionfacilities,andtheavailabilityofrequiredworkersMeasuresofEfficiencyShort-termcorrectiveactionisperformedhere.Controlparametersaremaintainedtowhichmeasuresofplantperformancearerelated.Actualperformanceiscomparedwithplanedperformanceforsuchmeasuresofeffectivenessasproductionoutput,etcOverviewofOperationsPlanningandControl------InterfaceThisfunctiondeterminesandreportstheeffectsofthecompany’sactivitiesuponitsfinancialpositionBasicresearchoriginatesideasfornewproductsessentiallyindependentlyofmarketconsiderationsPurchaseordersarereceivedfrominventorycontrolIdeasfornewproductsandmodificationofexistingproductsareconsolidatedbythisfunctionProductionordersreachtheshopfloorthroughthedispatchingfunction…..SpecificconfigurationsforallmodelsintheproductionlineareformalizedhereOperationsPurchasingProductInnovationEngineeringFinancialBasicResearchInterfaceTechniquefordemandforecastingThismethodgeneratesnextperiod’sforecas