第三章-预备知识1-工艺设计capp

ProcessEngineering,IE550-ManufacturingSystemsFall2008Dr.R.A.Wysk,Chapter6.PROCESSENGINEERING,Processplanningisalsocalled:manufacturingplanning,processplanning,materialprocessing,processengineering,andmachinerouting.Whichmachiningprocessesandparametersaretobeused(aswellasthosemachinescapableofperformingtheseprocesses)toconvert(machine)apiecepartfromitsinitialformtoafinalformpredetermined(usuallybyadesignengineer)fromanengineeringdrawing.Theactofpreparingdetailedworkinstructionstoproduceapart.Howtorealizeagivenproductdesign.,PRODUCTREALIZATION,ProductdesignProcessplanningOperationprogrammingVerificationSchedulingExecution,Process,machineknowledge,Schedulingknowledge,PROCESSPLANNING,Design,MachineTool,SchedulingandProductionControl,ProcessPlanning,PROBLEMSFACINGMANUFACTURINGINDUSTRY,Fact:Only11%ofthemachinetoolsintheU.S.areprogrammable.Morethan53%ofthemetal-workingplantsintheU.S.donothaveevenonecomputer-controlledmachine.Someproblems:CannotjustifythecostLackofexpertiseinusingsuchmachinesToosmallabatchsizetooffsettheplanningandprogrammingcostsSource:Kelley,M.R.andBrooks,H.,TheStateofComputerizedAutomationinUSManufacturing,J.F.KennedySchoolofGovernment,HarvardUniversity,October1988.,Potentialbenefitsinreducingturnaroundtimebyusingprogrammablemachinetoolshavenotbeenrealizedduetotime,complexityandcostsofplanningandprogramming.,DOMAIN,One-of-a-kindandSmallbatchObjectives:Lead-time,CostApproaches:processselection,useexistingfacilities.MassproductionObjective:CostApproaches:processdesign,optimization,materialsselection,facilitiesdesign,Howdoweprocessengineer?,Howcanwemakeit?Howmuchdoesitcost?Howlongwillittakeustocompleteit?Howreliablewillitbe?Howcanwerecycleit,Howcanwemakeit?,Isthislikesomethingelsethatwevedone?Yes;Whatmethodswereused?No;Designanewprocess,Whatmethodswereused?,MachiningmethodsPressworkingWelding/fabricationCastingPowdermaterialsLayereddepositionOthers,Welding/fabrication:Additivetechniques,+,+,=,InitialStock,WeldAdd-on,WeldAdd-on,FinalProduct,MachiningMethods:Subtractivetechniques,-,=,InitialStock,Slotting,Drilling,FinalProduct,-,=,Casting:FormMethods,=,ENGINEERINGDESIGNMODELING,CSGMODEL,B-REPMODEL,INTERACTIONOFPLANNINGFUNCTIONS,GEOMETRICREASONING,PROCESSSELECTION,CUTTERSELECTION,MACHINETOOLSELECTION,SETUPPLANNING,FIXTUREPLANNING,CUTTERPATHGENERATION,global2.Newcomponentscanbeplannedaseasilyasexistingcomponents;3.Ithaspotentialforintegratingwithanautomatedmanufacturingfacilitytoprovidedetailedcontrolinformation.,KEYDEVELOPMENTS,1.Thelogicofprocessplanningmustbeidentifiedandcaptured.2.Theparttobeproducedmustbeclearlyandpreciselydefinedinacomputer-compatibleformat3.Thecapturedlogicofprocessplanningandthepartdescription,PRODUCTREPRESENTATION,GeometricalinformationPartshapeDesignfeaturesTechnologicalinformationTolerancesSurfacequality(surfacefinish,surfaceintegrity)SpecialmanufacturingnotesEtc.FeatureinformationManufacturingfeaturese.g.slots,holes,pockets,etc.,INPUTREPRESENTATIONSELECTION,Howmuchinformationisneeded?Dataformatrequired.Easeofusefortheplanning.Interfacewithotherfunctions,suchas,partprogramming,design,etc.Easyrecognitionofmanufacturingfeatures.Easyextractionofplanninginformationfromtherepresentation.,WHATINPUTREPRESENTATIONS,GTCODELinedrawingSpeciallanguageSymbolicrepresentationSolidmodelCSGB-Repothers?Featurebasedmodel,SPECIALLANGUAGE,AUTAP,CIMS/PROREPRESENTATION,GARIREPRESENTATION,(F1(typeface)(directionxp)(quality120)(F2(typeface)(directionyp)(quality64)(F3(typeface)(directionym)(qualityrough)(H1(typecountersunk-hole)(diameter1.0)(countersik-diameter3.0)(starting-fromF2)(opening-intoF3)(distanceH1F13.0)(countersink-depthF2H10.5),CONCEPTOFFEATURE,Manufacturingisfeaturebased.Feature:1a:thestructure,form,orappearanceesp.ofapersonb:obs:physicalbeauty.2a:themakeuporappearanceofthefaceoritspartsb:apartoftheface:LINEAMENT3:aprominentpartorcharacteristic4:aspecialattractionWebstersNinthNewCollegiateDictionary,FEATURESINDESIGNANDMANUFACTURING,Ahighlevelgeometrywhichincludesasetofconnectedgeometries.Itsmeaningisdependentupontheapplicationdomain.,DesignFeaturevsManufacturingFeature,DESIGNFEATURES,ForcreatingashapeForprovidingafunction,Slotfeature,MANUFACTURINGFEATURES,ForprocessselectionForfixturing,Endmillaslot,DrillingRoundholeTurningRotationalfeatureEndmillingPlanesurface,Hole,profile,slotpocketBallendmillFreeformsurfaceBoringCylindricalshellReamingCylindricalshell.,Manufacturingisfeaturebased.,MANUFACTURINGFEATURES(cont.),?,DATAASSOCIATEDWITHDESIGNFEATURES,MechanicalEngineeringPartDesignFeatureTypeDimensionLocationToleranceSurfacefinishFunction,DATAASSOCIATEDWITHMANUFACTURINGFEATURES,FeaturetypeDimensionLocationToleranceSurfacefinishRelationswithotherfeaturesApproachdirections,Featureclassificationsarenotthesame.,FEATURERECOGNITION,Extractanddecomposefeaturesfromageometricmodel.SyntacticpatternrecognitionStatetransitiondiagramandautomataDecompositionLogicGraphmatchingFacegrowing,DIFFICULTIESOFFEATURERECOGNITION,Potentiallylargenumberoffeatures.Featuresaredomainanduserspecific.Lackofatheoryinfeatures.Inputgeometricmodelspecific.Basedonincompletemodels.Computationalcomplexityofthealgorithms.Existingalgorithmsarelimitedtosimplefeatures.,DESIGNWITHMANUFACTURINGFEATURES,Makethedesignprocessasimulationofthemanufacturingprocess.Featuresaretoolsweptvolumesandoperatorsaremanufacturingprocesses.,Design,ProcessPlanning,Barstock-Profile-Borehole,Turnprofile,DrillholeBorehole,PROSANDCONSOFDESIGNWITHMANUFACTURINGFEATURES,Concurrentengineering-designersareforcedtothinkaboutmanufacturingprocess.Simplify(eliminate)processplanning.Hinderthecreativethinkingofdesigners.Usethewrongtalent(designerdoingprocessplanning).Interactionoffeaturesaffectsprocesses.,Pros,Cons,BACKWARDPLANNING,PROCESSKNOWLEDGEREPRESENTATION,PredicatelogicProductionrulesSemanticNetsFramesObjectOrientedProgramming,SOMERESEARCHISSUES,Partdesignrepresentation:informationcontents,dataformatGeometricreasoning:featurerecognition,featureextraction,toolapproachdirections,featurerelationsProcessselection:backwardplanning,toleranceanalysis,geometriccapability,processknowledge,processmechanicsToolselection:size,length,cutlength,shanklength,holder,materials,geometry,roughing,andfinishingtools,SOMERESEARCHISSUES(continue),Fixturedesign:fixtureelementmodel,fixturingknowledgemodeling,stabilityanalysis,friction/cuttingforceToolpathplanning:algorithmsforfeatures,gaugingandinterferenceavoidancealgorithms,automatedpathgenerationSoftwareengineeringissues:datastructure,database,knowledgebase,planningalgorithms,userinterface,softwareinterface,AFEATUREBASEDDESIGN/PROCESSPLANNINGSYSTEM,GeometricReasoning,Application-SpecificFeatures(e.g.manufacturingfeatures)blindslot,throughslot,step,etc.approachdirection,feeddirectionfeaturerelations:precedenceandintersectiontype,Manufacturing-OrientedDesignFeatureshole,straightslot,T-slot,circularslot,pocketcounterbore,sculpturedsurfacecavity,Principle:Providedesignerwiththefreedomtodescribeshape-avoidconstrainingmanufacturingplanningorrequiringdetailedmanufacturingknowledge.,SOMEAUTOMATEDPROCESSPLANNINGEFFORTS,U.Mass,Dixon:Features-baseddesignformanufacturinganalysisofextrusions,castings,injectionmoldingASU,Shah:TheoryoffeaturesstudyforCAM-I;Feature-mappingshellStanford,Cutkosky:feature-baseddesign,processplanning,fixturingsystems.Helsinki,Mantyla:systemsfordesignMAMOURsystem.SDRC,Chung