An integrated approach to design for manufacturing

ORIGINALARTICLEAnintegratedapproachtodesignformanufacturingandassemblybasedonreductionofproductdevelopmenttimeandcostP.Selvaraj&P.Radhakrishnan&M.AdithanReceived:24August2007/Accepted:20May2008/Publishedonline:12June2008#Springer-VerlagLondonLimited2008AbstractTimeandcostreductionduringproductdevel-opmentisimportanttomeetthecompetitivenessinthemarket.DesignforManufactureandAssembly(DFMA)playsakeyroleinproductdevelopment,especiallyinindustrieslikeaerospace,whereinvarietyincomponentgeometryismore.PartscountreductionisoneofthebasicprinciplesofDFMA.DesignforManufacture(DFM)considerationsleadtosimplificationandstandardizationofdesignandmanufacturingprocesses.Italsofacilitatesintegrationoffunctionandformandoptimizesthework-flow.ThispaperoutlinestheDFMAconsiderationstosheetmetalpartsconsideringfactorssuchasstandardizationofgeometricshapesandintegralpartdesignthroughpartscountreduction.Amethodologyforintegrationofpartsispresented,whichispartlyinteractive,toevolveanintegraldesignfromamultipartsub-assembly.Themethodpro-posedisappliedtoasheetmetalpartssub-assembly,anditalsocomparesthetimeandcostofmanufactureandassembly.KeywordsDesignforManufactureandAssembly.Integratedpartdesign.Productdevelopment.TimeandcostreductionNomenclatureBENDRELIEFAcutoutcalledthebendreliefisprovidedintheloftbetweeneachpairofadjacentactiveedges(havingflanges),inordertoavoidinterfer-ences/crackinitiationatthejunctionbetweenadjacentflangesofasheetmetalcomponentCADComputeraideddesignCAMComputeraidedmanufactureCNCComputernumericalcontrolCUTOUTSTheseareholes,withavarietyofshapesandsizesprovidedonthePrincipalFlatSurface(PFS)ofthesheetmetalcomponent(havingfilletedcornerstoavoidstresssingularities)DFMDesignforManufactureDFMADesignforManufactureandAssemblyDONHOLESTheseareflanged‘lighteningholes’generallymadeinsheetmetalcompo-nentsforeffectingmaterialandweighteconomyintheregionsoflowstressDPADigitalprototypeassemblyFLANGEFlangeisa(plane/curved)surface,partofsheetmetalcomponent,whichisattachedtoanedgeofthePFSwithafilletconnecting(andisproducedbybendingthesheetalongtheedgecontour)JOGGLEUniquegeometryshapeincorporatedinsheetmetalcomponentstoenableIntJAdvManufTechnol(2009)42:13–29DOI10.1007/s00170-008-1580-8P.Selvaraj(*)AeronauticalDevelopmentAgency,P.B.No.1718,VimanapuraPost,Bangalore560017,Indiae-mail:[e-mail],Peelamedu,Coimbatore641004,Indiae-mail:[e-mail],Vellore632014,Indiae-mail:[e-mail]lap/butteachotherLOFTLoftisatwo-dimensionalgeometrycontourgivingtheexactshapeandsizeoftheblankrequiredtoformasheetmetalcomponent.Italsocon-tainsthedesignandproductionfeaturesrequiredtofabricatethepartPFSPrincipalflatsurfaceisaplanarsurface,andthisisthepartofsheetmetalcomponentsurface,whichisheldintactduringtheformingprocessPILOTHOLESTheseareholesmadeonflangestofacilitateattachmenttootherparts.Ingeneral,onlythesecentersaremarked,asbothpartsaredrilledtogetherPRIMARYSMPARTAsheetmetalcomponentonwhichmajorityofothersheetmetalpartsareassembledtomakethesheetmetalpartsassemblyPLMProductlifecyclemanagementTOOLING(LOCAT-ING)HOLESThesearecircularholesdrilledonthePFSofthesheetmetalcomponentinordertofacilitateproperlocatingandgrippingofthesheetmetalduringthemanufacturingprocesses1IntroductionThesuccessfulcompletionofanyprojectintermsofscheduleandcostdependsonshorteningtheleadtimerequiredtodeveloptheproduct.Partscountreductionthroughintegrationofpartsresultsinutilizationofleanresourcesintermsoftime,tools,machines,operations,material,people,etc.DesignforManufacture(DFM)considerationsensureminimizingthenumberofjigsandfixtures,reductioninthenumberandvarietyofcuttingtools,minimizationoftolerancestackup,andassemblymismatch.DFMmethodologyinvolvesconsideringdesigngoalsandmanufacturingconstraintssimultaneouslyinordertoidentifyandalleviatemanufacturingproblemswhiletheproductisbeingdesigned,therebyreducingtheleadtimeandimprovingtheproductquality.TheDFMphilosophyfocusesonthetechniques,practices,andattitudesthatcauseaproducttobedesignedfortheminimummanufacturingcost,achievementofhighmanu-facturedquality,andtheoptimumlifecyclesupport(serviceability,reliability,andmaintainability).Thecon-ceptsofDesignforAssembly(DFA),concurrentorsimultaneousengineering,andothersystematicdesignapproacheswhichcausethedesignertoconsiderallelementsofproductlifecyclefromconceptthroughdisposalarespecificallyincludedwithinthisdefinition.TheapplicationofDFMprincipleseliminates,simplifies,andstandardizesthedesignandmanufacturingactivitieswhereverpossible.Itfocusesonimprovingthedesignprocess,structuralchange,andfacilitatesintegrationoffunction,form,andfabrication.Italsosimplifiesandoptimizestheworkflow.HaleviandWeillhighlightedthedesignfactorsthathavethechoiceofamanufacturingprocess[1].SelvarajandRadhakrishnanhaveexplainedtheDFMfactorsspecifictoaircraftstructuralcomponents[2].TheadventofCAD/CAMsystemhasprovidedtheopportunityofbetterintegrationofCADandDFM[3].Effectiveanalysisofthemanufacturabilityofadesignrequiresembeddedmanufac