外文翻译--研究逆向工程中的应用工程技术 英文版.pdf

JournalofMaterialsProcessingTechnology1392003472–475ResearchintotheengineeringapplicationofreverseengineeringtechnologyYuZhangCIMSApplicationandResearchCenter,SchoolofMechanicalandAutomationEngineering,KunmingUniversityofScienceandTechnology,Kunming650093,Yunnan,PRChinaAbstractBasedonpreviousresearchonreverseengineeringREtechnology,theengineeringapplicationofREisexploredinthispaper.TheapplicationenvironmentofREisbuiltwithcoordinatemeasurementmachineCMMandCAD/CAMsoftware.Takingacoredieoftheinletofadieselengineasanexample,thispaperdescribestheprocessesofRE,fromobjectdigitization,CADmodelreconstructiontoNCmachining.MeasurementdataareacquiredbyscanningthephysicalobjectusingathreedimensionalCMM.Throughprocessingofmeasurementdata,theauthorssucceedincreatingaCADmodelofthedieandmachiningthedie,gainingagoodresult.©2003ElsevierScienceB.V.Allrightsreserved.KeywordsReverseengineeringProductdevelopmentCAD/CAM1.IntroductionNowadays,competitivepressurehasreachedthepoint,whererapidproductdesignandoptimizationneedtobeembracedwithintheproductdevelopmentcycle.Ashortleadtimeinproductdevelopmentisstronglydemandedtosatisfyneeds,resultingfromtheglobalizationofmanufacturingactivitiesandthechangesinmarketrequirements.Inengineeringareassuchasaerospace,automotives,shipbuildingandmedicine,itisdifficulttocreateaCADmodelofanexistingproductthathasafreeformsurfaceorasculpturedsurface.Inthesecases,reverseengineeringREisanefficientapproachtosignificantlyreducetheproductdevelopmentcycle.REreferstotheprocessesinwhichdesignersacquireadesignconceptofaproductfromdigitizationofaphysicalmodel,andcreatetheCADmodeltorealizeapproximationtothephysicalmodelthemodelcreatedcanbereused,modifiedandoptimized5.ByREtechnology,thegeometricshapeofanexistingpartorproductismeasured.BasedonthismeasurementdataacompleteandcomplexCADmodeliscreated.REhastwokeytechnologies,i.e.digitizationofaphysicalmodelandcreationofitsCADmodel.Emailaddresszhangyupublic.km.yn.cnY.Zhang.2.WorkingprocessesofREDifferingfromthetraditionaldesignideaandmethod,REtechnologyenablesonetostartadesignfromanexistingproductmodelbycombiningcomputertechnology,measurementtechnologyandCAD/CAMtechnology.REhasbeenofinterestinmanydifferentbranchessuchasautomotives,shipbuilding,electronics,andmedicine.Itisoftenusedincasessuchasthefollowing3iWhereaprototypeofthefinalproducthasbeenmodeledmanuallyandthereforenoCADmodeloftheprototypeexists,e.g.claymodelinautomotiveindustry.iiWhereaCADisintroducedinacompanyandallexistingproductsmustbemodeledinordertohaveafullydigitalarchive.Particularly,theCADmodelofacomplexshapedpartismodeledbecauseitisdifficulttocreateitsCADmodeldirectly.iiiWherecomplexshapedpartsmustbeinspectedandthereforetheREmodelcreatedwillbecomparedtoanexistingCADmodel.TheREprocesscanprincipallybeseenasaprocesschainthatiscomposedofthreemainoperationsasfollows5iDigitizationoftheobjectThethreedimensionalshapeoftheproductisacquiredbyanyappropriatemeasurementmethod.09240136/03/–seefrontmatter©2003ElsevierScienceB.V.Allrightsreserved.doi10.1016/S0924013603005132Y.Zhang/JournalofMaterialsProcessingTechnology1392003472–475473Fig.1.WorkingprocessesofRE.iiProcessingofmeasureddataThethreedimensionaldataacquiredisprocessedinordertofulfilltherequirementsofthefollowingoperation.iiiCreationofaCADmodelAcompleteCADmodeloftheproductmustbebuiltinordertorepresentallrelevantdataoftheproduct.Fig.1showstheworkingprocessesofRE.ThewholeprocessofREshouldbecomputeraided.3.EngineeringapplicationofREBasedonprincipleofREtechnologymentionedabove,theauthorsappliedREtechnologyinthedesignandmanufacturingofthedieofadieselengine.Takingthecoredieoftheinletofadieselengineasanexample,thispaperdescribestheREprocesses,fromobjectdigitization,CADmodelreconstructiontoNCmachining.Theinletisthekeypartinadieselengine.Itinfluencesthecharacteristicofthedieselenginetoagreatextent.BecausetheinlethasverycomplexshapeseeFig.2,itisdifficulttocreateadigitalmodeloftheinlet,aswellastomanufacturethecoredieoftheinlet.TheauthorshavethereforetakenitasanexampletoresearchtheengineeringapplicationofREtechnology.Fig.2.The3Dmodeloftheinlet.3.1.EnvironmentofRETheenvironmentofREisalocalareanetworkLAN,whichisbuiltwithtwoworkstations,twoNTworkstations,threesetsofPC,acoordinatemeasurementmachineCMMandthreeNCmachines.ThehardwareplatformusesleveldispositionofworkstationsandPCs.ThemainapplicationsoftwareutilizedistheUnigraphicsCAD/CAE/CAMintegratedsystemandKUMmeasurementsoftwareprovidedbythezesscompany.TheoperatingsystemsutilizedareHPUX10.2onworkstationsandWindowsNTonPCs.Fig.3showstheenvironmentofRE.Withcomputernetwork,theREprocesses,i.e.objectdigitization,processingofmeasurementdata,creationofaCADmodel,andNCmachining,arerealizedinaintegratedenvironmentoncomputers.Fig.3.EnvironmentofRE.474Y.Zhang/JournalofMaterialsProcessingTechnology1392003472–475Fig.4.NCmeasurementandsurfacereconstructionofthecoredieoftheinlet.3.2.DigitizationofthedieGenerally,themethodsofmeasurementofthreedimensionalgeometryproductdataaredividedintotwoclasses,i.e.tactilemeasurementandopticalmeasurement.TheCMMisageneraltactilemeasurementdevice,andisbeingwidelyusedinindustrialenterprises1,2.TheauthorsmeasurethegeometricshapeofthedieandacquiremeasurementdatausingCMMandKUMmeasurementsoftwarewithalinearscanmode.ThephysicalmodelofthedieisscannedonCMMusinga5mmdiameterprobewithastepoveracrossthemodelof5mminthefirstareaand1mminthecomplexareaseeFig.4a.ThenumberofmeasurementpointsisautomaticallydeterminedbyCMMaccordingtothecurvaturechangeofthesurfacemeasuredonthetactilepoint.Inordertoavoidtrackslip,theprobestartstomeasurethesurfaceat4mmawayfromtheboundaryofthesurfacebeingmeasured.Onaverage,thereareabout1600measurementpointsacquiredforeachscancurve.3.3.ProcessingofmeasurementdataTheresultofamechanicaltracingprocessisastructuredpointsequenceswithalargenumberofpointsandalinestructure4.TheoutputdataoftheCMMarecoordinatevaluesofthecenteroftheprobeandnormalvectorsintheX,YandZdirectionatthepositionofthetactilepoint.Additionally,theoutputformatofthemeasurementdatadoesnotaccordwiththedemandsofthecreationofaCADmodel.Thusonemustprocessthemeasurementdata.Theauthorhaveselfdevelopedaprogramtorealizethetransformationoftheformatofthemeasurementdata.First,theformatofthemeasurementdataoutputmustbetransformedintoaformatthatcanbeacceptedbyUnigraphicssoftware.Thenthemeasurementdataoutofthecontroltolerancemustbefilteredoutandinteractivelyprocessedinavisualizedway.ThedataprocessedcanbeuseddirectlyforthecreationofaCADmodelofthedie.3.4.CreationofaCADmodelofdieTheCADmodeliscreateddirectlyfrommeasurementdatausingUnigraphicsCAD/CAE/CAMsoftwareafterprocessingofmeasurementdataandtransformingofthedataformat.TherearetwowaysinthecreationoftheCADmodelfrommeasurementdatausingfreeformfeaturemodeling.Oneiscalledthecurvemode.Inthisway,theconstructioncurvesaregeneratedfrommeasurementdatafirst,andthenthesurfacecanbecreatedthroughtheconstructioncurvemeshgenerated.Anotheroneiscalledthesurfacemode,thesurfaceisgenerateddirectlyfrommeasurementdata2.Becausethemeasurementdataoutputarethecoordinatevaluesofthecenteroftheprobe,thesurfacegeneratedfrommeasurementdataisasurfaceoffsetfordistance,whichequalstheradiusoftheprobe,awayfromactualsurfacemeasured.Thusonehastooffsetthissurface.Thesurfacegeneratedisanalyzedthroughashadingsurfaceandsurfaceanalysisfunctioninordertocheckitscontinuityandsmoothness,aswellastheerrorsbetweenthesurfacegeneratedandthemeasurementpoints.Themaximumerroris0.2mm,whichisacceptable.3.5.NCmachiningofthedieAftertheCADmodelofthedieiscreatedcompletely,onecandeterminetheNCmachiningprocessplanningandgeneratethecutterlocationforamanufacturingapplication.FurthermachiningcodesaregeneratedthroughNCpostprocessing.Finally,thedieismachinedbyanNCmachinetoolusingitsCADmodelcreated.Fig.4showstheresultsofNCmeasurementandsurfacereconstructionofthecoredieoftheinlet,whilstFig.5showsthegeneratedCADmodelofthecoredieoftheinlet.Fig.5.ThegeneratedCADmodelofthecoredieoftheinlet.Y.Zhang/JournalofMaterialsProcessingTechnology1392003472–4754754.ConclusionBasedonpreviousresearchonREtechnology,theauthorshaveexploredtheengineeringapplicationofREtechnologyinthedesignandmanufacturingofacomplexproduct.Takingadieoftheinletofadieselengineasanexample,theyhavedescribedthewholeprocesses,fromobjectdigitization,CADmodelreconstructiontoNCmachining,andhavegainedagoodresult.REisanefficientapproachtosignificantlyreducetheproductdevelopmentcycleandensureproductqualitykinthedesignandmanufacturingofaproductthathasacomplexsurface.REtechnologyisnottocopyanexistingproductbuttoacquireadesignconceptfromaexistingphysicalmodelandcreateacompletedigitalproductmodelandfurthertooptimizetheproductdesign.References1Y.Ke,F.Li,Studyonreversedesignengineeringofcomplexsurfaceproducts,inProceedingsoftheCIRPInternationalSymposiumonAdvancedDesignandManufactureintheGlobalManufacturingEra,HongKong,August21–22,1997,pp.741–746.2H.Xiang,Y.Liu,S.Sun,Rapidreconstructionbasedoncoordinatemeasurementmethodforcomplexshapedparts,inProceedingsoftheInternationalConferenceonAdvancedManufacturingTechnology99,Xian,PRChina,June16–19,1999,pp.618–620.3Q.Ni,H.Wang,Y.Zhang,R.Zhao,Theanalysistokeytechnologyinreverseengineeringbasedphysicalobject,Mech.Des.19964–7inChinese.4H.Josef,Werner,ReverseEngineering,Teubner,Stuttgart,1996.ISBN3519026333.5Y.Zhang,Y.Fan,X.Chu,Principleandkeytechnologiesofreverseengineering,J.KunmingUniv.Sci.Technol.244199942–46inChinese.