外文翻译--运用磨削中心弹性砂轮的一种曲面高效抛光技术.doc

外文资料HighProductiveTechniqueforPolishingFreeSurfacewithElasticBallTypeWheelonGrindingCenterPolishingisanimportantfinishingprocessindieandmoldmanufacturing.Handpolishingtakeslongtimeandmuchlabor.Effortsaremadetoautomatethepolishingprocesswhilekeepingaccuracy.Recentlygrindingcentershavebeendeveloped，whichareusedforfreesurfacepolishinginthepresentwork.Thenewpolishingtechniqueappliesthesamecuttinglocusasusedinthecuttingprocesstoremoveonlycuspheighteffectively,keepingtheformaccuracygeneratedinthecuttingprocess.1IntroductionDieandmoldconstructedwithvariousfreesurfacesareimportantinmanufacturing.Inmachiningofdieandmold,ittakesalongtimetofinishthecurvedsurface.Thereforeefficientmachiningandfinishingtechniquesaredesired.Recentlygrindingcenters(GC)aredevelopedforgrindingofvarioustypesofmachineparts.GCissuitableforfreesurfacegrindingandfinishingofdieandmoldwithelasticballtypewhee1.Freesurfacegrindingisdifficultwithmanyproblemstobesolved.Forexample,itisdifficulttodecidethegrindingconditionsforcurvedsurfacehavingvariousradiiofcurvature.Alsoitisdifficulttodecidethetoolpassaddingtheselectionofasuitablewhee1.Forthisreason,studiesoffreesurfacegrindingarerare.AbasicstudyoffreesurfacegrindingwithaballtypewheelisconductedandnewtechniquesforpolishingfreesurfacebyGCdevelopedwithelasticballtypewhee1.2ConceptofNewPolishingTechniqueUsuallyfreesurfaceofdieandmoldismachinedwithbal1endmillwithamachiningcenter(MC).Onamachinedsurface,cuspheightisproducedduetopickfeedofballendmil1.Inapolishingprocess，itisimportanttoremovethiscuspheightwithoutdecreasingmachinedformaccuracy.Themainpointsofthisnewpolishingtechniqueareasfollows:(1)Polishingisconductedwiththesamemachinetoolusedinthecuttingprocess；(2)Elasticballtypewheelisusedinpolishing,whichisexchangedbyautomatictoolchanger(ATC)；(3)Inpolishingprocess，thesamecuttinglocus(CL)asusedinthecuttingprocessisappliedeffectively；(4)Astheelasticwheelisincontactwithwidearea,itispossibletotakelargeamountofpickfeed；(5)Inthepolishingprocess，onlycuspheightisremovedinordertokeepformaccuracyproducedinthecuttingprocesswithballendmill.Theserequirementswillleadtoahighproductivepolishingprocessandachieveautomaticpolishing.Tomakethistechniquesuccessfulthebasicpolishingprocessmustbeunderstoodandoptimalpolishingconditionselected,whichdoesnotdecreasetheformaccuracygeneratedinthecuttingprocess.Togetthepolishingcharacteristics,manybasicexperimentswerecarriedout.3PolishingCharacteristicsofAnEelasticBallTypeWheelDependingonthePrestonsexperience,itisknownthattheamountofremovalinapolishingprocessisinproportiontothepolishingpressureandspeed.Inordertoknowthepolishingcharacteristicsofelasticballtypewheel,basicexperimentswereconducted.Theexperimentalsetupandconditionsareshowninthispaper.Aperipheralspeedofballtypewheelchangesdependingontheactingpositionduetoitsdifferentrotationalradius.Theactingpositionisrepresentedwithanangle.PolishingexperimentswereconductedunderdifferentpolishingconditionsbychangingsettingdepthofcutcontactinganglefeedrateandYoungsmodulusofelasticwheelontheinclinedfiatsurfaceshowstherelationbetweenactualandsettingdepthofcutfor=30.Itisknownthattheactualdepthofcut,isverysmallcomparedwiththesettingdepthofcut.Also,theactualdepthofcutdosenotincreaseforsettingdepthofcutlagerthan10um.Thereasonisthatthecontactingpressuredoesnotincreaseduetotheincreaseofcontactingareabyelasticdeformationshowtheincreaseofcontactingwidthandnumberofcontactcusps.ThisisacharacteristicphenomenonforelasticwheelhavingsmallYoungsmodulus.Itisrecognizedthatroughnessofthecoarsesurfacegeneratedinthecuttingprocessisimprovedbypolishingandonlycuspheightisremovedinpolishingwithoutdecreaseofformaccuracy.Polishingparameterswereobtainedexperimentallybychangingthepolishingspeedfeedratecontactingpressure.4SimulationAnalysisofPolishedSurfaceTodevelopthispolishingmethodintovarioustypesofworkpieces,itisnecessarytoestimatethepolishedsurfaceinsimulations.Usingapolishingparameter,theremovalamountcanbeobtainedandpolishedsurfacecanbeestimated.Anelasticballtypewheelcontactswithamachinedsurfacethathastriangularcuspsgeneratedbycutting.Thepressuredistributionatthecontactingareaisobtainedwiththefiniteelementmethod.Gettingthepolishingparameterfrompolishingconditions,theamountofremovalshowsaflowchartofestimation.Anestimatedandactua