Management for Professionals For furthervolumes: http://www.springer.com/series/10101 . Christoph Karrer Engineering Production Control Strategies A Guide to Tailor Strategies that Unite the Merits of Push and Pull ChristophKarrer McKinsey&Company,Inc. Sophienstr.26 80333Mu¨nchen Germany Email:[email protected] ISSN2192-8096 e-ISSN2192-810X ISBN978-3-642-24141-3 e-ISBN978-3-642-24142-0 DOI10.1007/978-3-642-24142-0 SpringerHeidelbergDordrechtLondonNewYork LibraryofCongressControlNumber:2012933113 #Springer-VerlagBerlinHeidelberg2012 Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthematerialis concerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,broadcasting, reproductiononmicrofilmorinanyotherway,andstorageindatabanks.Duplicationofthispublication orpartsthereofispermittedonlyundertheprovisionsoftheGermanCopyrightLawofSeptember9, 1965,initscurrentversion,andpermissionforusemustalwaysbeobtainedfromSpringer.Violations areliabletoprosecutionundertheGermanCopyrightLaw. Theuseofgeneraldescriptivenames,registerednames,trademarks,etc.inthispublicationdoesnotimply, evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevantprotective lawsandregulationsandthereforefreeforgeneraluse. Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) Foreword Today’s global supply chains are getting more and more complex. At the same time,thedemandoncustomerserviceandthecostpressurecontinuetoincrease.In thischallengingenvironment,productioncontrolstrategies(PCS)playamajorrole. They manage the physical material flow on the shopfloor and are therefore a key driverfordeliveryperformance,inventorylevels,andultimatelyproductioncost. Identifying and customizing suitable control strategies is a challenging task, especiallywhenproductionsystems have tocope withvariabledemands, forecast error,andunstableprocesses. The focus of this book lies on helping companies with complex and discrete productionsystems totailoraproduction controlstrategytotheir needs.Thereby, the mutual merits of “push” and “pull” systems are taken into account,leading to hybridstrategies.Consequently,thebookaddressespractitionerswhoareinterested inlookingbehindthescenesandintothephysicsofproductioncontrol. A real-life case study demonstrates the practical applicability of the presented framework. I would like to thank the company and the involved managers for enablingthiscooperation. Moreover,IwouldliketoexpressmygratitudetoProf.Dr.Hans-OttoGu¨nther and PD Dr.-Ing. Knut Alicke for their support, our fruitful discussions, and for beinginspirationalmentors. Iwouldalsoliketothankmyfamilyfortheirconstantsupportandunderstanding duringthecreationofthisbook.Idedicatethisbooktothem. Munich,Germany ChristophKarrer Customers require on-time delivery at a minimal cost. As a result, companies are constantly under pressure to cut costs and uphold high levels of service. A major factor for success in achieving these objectives is the right production control strategy, one in which two approaches compete in practical application – push andpull. In push systems, external signals trigger production orders; these signals typi- callytaketheformofsophisticated,detailed,planningandschedulingalgorithmsin environmentswithintegratedplanningsystems.Apullsysteminitiatesaproduction v vi Foreword order internally. The consumption of parts of the next step in the value chain triggers the release of a signal (for example, a Kanban card), which is then translatedintoaproductionorder. Bothproduction controlapproacheshave clearbenefitsanddisadvantages,and should, therefore, be combined. Many companies have already implemented pull systems as a part of their Lean manufacturing philosophy; this control strategy is easy to apply, and it limits work in process. Companies with strong planning systems prefer push systems to, for example, leverage the forecast. Unfortunately thepushandpullapproachesareoftenappliedinaverydogmaticwaythatdoesnot capturethebenefitsofeither. Inhisexcellentbook,ChristophKarrerpresentsamethodforcombiningthetwo approaches.Heprovidesasoundtheoreticalfoundationforverifyingthebenefitsof usingafractionoftheexistingforecasttocontroltheproductionsystem.Theresults arepromising;costandinventorycanbereducedsignificantly,andahighlevelof service retained. Thebeautyofhis approach is itsrelative simplicityinpractice – thereisnoneedforsysteminvestmentorradicalchangesinproductioncontrol.In addition,theKanbansystem–oftenalreadyinplace–canbeleveragedinorderto implementtheapproach. Karrer’s book is aimed at practitioners who contend with high fluctuations in demandandwhowouldliketofurtherreducetheircostsafterimplementingalean or an integrated planning system. His approach is a breakthrough – it combines Lean manufacturing (“pull”) and “algorithmic” detailed planning and scheduling (“push”),andwillfurtherboostsystemperformance. Karlsruhe,Germany PDDr.-Ing.KnutAlicke MasterExpertSupplyChainManagement McKinsey&Company,Stuttgart The quest for a good production control strategy (PCS) is as old as industrial production.Extensiveresearchinthefieldhasledtomanyinnovationsthatenable today’s production systems. The availability of affordable computer technology, which led to the introduction of IT-based planning systems, was an important milestone. Another important step was marked by the diffusion of the Lean manufacturing philosophy from Toyota, comprising the famous Kanban control system. However, due to the large variety of existing control strategies and the complexityoftoday’sindustrialpractice,itisdifficultforpractionerstoselectand continuouslyupdatetheirPCS. Theengineeringframeworkpresentedinthisbookoffersvaluablesupport.The strength of the approach is its integrated and practice oriented perspective. The problem is approached from a systems engineering angle, taking findings from currentresearchintoaccount.Theresultingstrategiescombinemeritsof“push”and “pull”systemsandyetremaininlinewiththephilosophyofLeanmanufacturing. Berlin,Germany Prof.Dr.Hans-OttoGu¨nther DepartmentofProductionManagement TechnicalUniversityofBerlin Contents 1 Introduction ................................................................ 1 1.1 NeedforaPCSEngineeringFramework .............................. 1 1.2 SuitableIndustrialContextforApplication ............................ 2 1.3 StructureoftheBook ................................................... 3 2 ProductionControlStrategies(PCS) ..................................... 7 2.1 FundamentalConceptsandCoherences ................................ 7 2.1.1 PCSintheBroaderContextofProductionPlanning andControl ....................................................... 7 2.1.2 ThePush/PullEnigmaandTheirBasicImplementations ....... 8 2.1.3 TheOrderPenetrationPoint .................................... 12 2.1.4 TheInfluenceofthePCSonOperationalPerformance ........ 12 2.2 ReviewofCurrentResearchonPCS .................................. 15 2.2.1 SegmentationofLiterature ..................................... 15 2.2.2 PCSMethodDevelopment ..................................... 16 2.2.3 PCSSelection ................................................... 27 2.2.4 PCSImplementation ............................................ 32 2.2.5 RelatedDesignQuestions ...................................... 33 2.3 SynthesisandPositioningoftheFollowingWork .................... 35 3 AQueuingNetworkBasedFrameworkforPCSEngineering ........ 37 3.1 DesignDriversandInitialComplexityReduction .................... 37 3.1.1 StructuringDesignDrivers ..................................... 37 3.1.2 ComplexityReductionbyDefiningPlanningSegments ....... 38 3.2 GenericModelFormulation ........................................... 41 3.2.1 Notation ......................................................... 41 3.2.2 QueuingNetworkRepresentationofPlanningSegments ...... 41 3.2.3 BasicProperties ................................................. 44 3.2.4 AnalysisoftheResultingSolutionSpace ...................... 46 vii viii Contents 3.3 MappingProductionSystemVariability .............................. 48 3.3.1 AnIntegratedApproachtoStochasticModeling ofProductionSystemVariability ............................... 48 3.3.2 DefinitionofaMeasureforProductionSystemVariability ... 51 3.4 MappingofDemandVariability ...................................... 53 3.4.1 StochasticModelingofDemandVariability ................... 53 3.4.2 Excursion:PossibleInvolvementofCustomers ................ 57 4 NumericalOptimizationofControlParametersAlong aPCSEngineeringProcess ............................................... 59 4.1 ObjectiveFunctionDesign ............................................ 59 4.1.1 SelectionofValuationMeasures ............................... 59 4.1.2 ValueAnalysis .................................................. 60 4.2 ImplementationofaSupportingSimulationFramework ............. 65 4.2.1 IntroductiontoDiscrete-EventSimulationandthe Platform‘AnyLogic’ ............................................ 65 4.2.2 ImplementationofPlanningSegments ......................... 67 4.2.3 ImplementationoftheDemandModel ......................... 69 4.2.4 ImplementationoftheProductionSystemModel ............. 70 4.3 APCSEngineeringProcesstoOptimizeProduction ControlParameters .................................................... 72 4.3.1 ApproachandProcessOverview ............................... 72 4.3.2 Step1–KiDetermination ...................................... 75 4.3.3 Step2–OPPjDetermination ................................... 78 4.3.4 Step3–FCTjandSijDetermination ........................... 79 5 InvestigationofthePush/PullIntegration .............................. 85 5.1 InfluencingFactorsandRulesfortheDecisionamong PushandPull .......................................................... 85 5.1.1 HypothesisandExperimentDesign ............................ 85 5.1.2 DeterminationofRelevantFactorsandDerivation ofDecisionRules ............................................... 88 5.2 Closed-FormDeterminationofthePush/PullIntegration ParametersFCT*andS%* ............................................ 90 5.2.1 HypothesisandExperimentDesign ............................ 90 5.2.2 DerivationofaClosed-FormParameterization forHybridControl .............................................. 92 5.2.3 ExtensiontotheMulti-ProductCase ........................... 95 5.3 AnalysisofthePerformanceIncreaseAchievable withtheHybridStrategy ............................................... 96 5.3.1 DriversfortheRelevanceoftheDecisionamong HybridandPureStrategies ..................................... 96 5.3.2 DerivationofaDemandVariabilityMeasuretoCharacterize EnvironmentsThatFavorHybridStrategies ................... 99 5.4 SummaryofInsights .................................................. 101 Contents ix 6 CaseStudyfromtheElectronicsManufacturingIndustry ........... 103 6.1 CaseIntroductionandSpecificChallenges .......................... 103 6.1.1 IntroductiontotheBusinessandManufacturingProcess ..... 103 6.1.2 IdentificationoftheImprovementNeed andSpecificChallenges ....................................... 104 6.2 ModelDevelopmentandParameterization ........................... 106 6.2.1 ProductionSystemModel ..................................... 106 6.2.2 ParameterizationofPlanningSegments ....................... 107 6.2.3 ParameterizationoftheDemandModel ....................... 108 6.3 PCSDesign ........................................................... 109 6.3.1 StrategyDerivation ............................................ 109 6.3.2 ImpactEvaluation ............................................. 111 6.4 ImplicationsandImplementationHints .............................. 114 7 ConclusionandFurtherResearch ...................................... 117 7.1 ResearchSummary ................................................... 117 7.2 LimitationsandFurtherResearchDirections ........................ 119 8 Appendix .................................................................. 121 8.1 ListofFigures ........................................................ 121 8.2 ListofTables ......................................................... 123 8.3 ListofAbbreviations ................................................. 124 8.4 ListofNotations ...................................................... 125 8.5 ComplexProductionSystems ........................................ 128 8.6 LiteratureReview ..................................................... 128 8.7 DelimitationagainstOtherGenericPCS ............................. 133 8.8 EvolutionoftheMaximumSizeReductionoftheSolution Space .................................................................. 134 8.9 SimulationModelImplementation ................................... 135 8.9.1 PlanningSegmentGraphicalRepresentation .................. 135 8.9.2 DemandModel:GraphicalRepresentation .................... 135 8.9.3 JavaCodeExecutedatForecastArrival (Event‘FCarrival’) ............................................ 137 8.10 PCSEngineeringProcess:NumericalOptimization ofModelParameters ................................................ 138 8.10.1 SetupsforExperimentsandIllustrations .................... 138 8.10.2 InfluenceofOver-CapacityontheMTFVersus MTSDecision ............................................... 139 8.10.3 ConvertingUtilityImprovementsintoWIPReductions .... 141 8.11 InvestigationofthePush/PullIntegration .......................... 142 8.11.1 GraphicalRepresentationofExperimentalSetup inAnylogic .................................................. 142 x Contents 8.11.2 ExperimentsandResultstoDetermineInfluencing FactorsforUpstreamControl ............................... 147 8.11.3 ExperimentsandResultstoDetermineClosed-Form SolutionsforFCT*andS%* ................................ 148 8.11.4 ExtensiontoArbitraryForecastErrorDistributions ........ 157 8.11.5 ExperimentalSetupfortheExtensiontothe Multi-ProductCase .......................................... 161 8.11.6 AnalysisofDriversfortheImpactMagnitude ............. 161 8.12 AnylogicModelofCaseStudy ..................................... 165 8.13 UsedSoftwareProducts ............................................. 169 8.14 AbouttheAuthor .................................................... 170 References .................................................................. 171