外文翻译--激光切割陶瓷砖的速度：理论和经验值的比较.doc

徐州工程学院毕业设计外文翻译学生姓名学院名称机电工程学院专业名称机械设计制造及其自动化指导教师原文：Lasercuttingspeedsforceramictile:atheoretical-empiricalcomparisonI.Black*DepartmentofMechanicalandChemicalEngineering,Heriot-WattUniversity,Riccarton,EdinburghEH144AS,UKReceived21October1997；accepted24March1998AbstractThispaperpresentsacomparisonoftheoretically-predictedoptimumcuttingspeedsfordecorativeceramictilewithexperimentally-deriveddata.Fourwell-establishedtheoreticalanalysesareconsideredandappliedtothelasercuttingofceramictile,i.e.Rosenthalsmovingpointheat-sourcemodelandtheheatbalanceapproachesofPowell,SteenandChryssolouris.Thetheoreticalresultsaresubsequentlycomparedandcontrastedwithactualcuttingdatatakenfromanexistinglasermachiningdatabase.Empiricalmodelsdevelopedbytheauthoraredescribedwhichhavebeensuccessfullyusedtopredictcuttingspeedsforvariousthicknessesofceramictile.#1998ElsevierScienceLtd.Allrightsreserved.Keywords:CO2laserCeramicmaterialsAdvancedcuttingprocessesLasermodelingCuttingspeeds1.ListofsymbolsAAbsorptivityaThermaldi.usivity(m2/s)CSpecificheat(J/kgK)dCuttingdepth(mm)EcutSpecificcuttingenergy(J/kg)kThermalconductivity(W/mK)JLaserbeamintensity(W/m2)LLatentheatofvaporisation(J/kg)lLengthofcut(mm)nCoordinatenormaltocuttingfrontPLaserpower(W)PbLaserpowernotinteractingwiththecuttingfront(W)QHeatinput(J/s)RRadialdistance(mm)rBeamradius(mm)sSubstratethickness(mm)ScritCriticalsubstratethickness(mm)TTemperature(C)T0Ambienttemperature(C)TPPeaktemperature(C)TSTemperatureattopsurface(C)tTime(s)VCuttingspeed(mm/min)VoptOptimumcuttingspeed(mm/min)wKerfwidth(mm)X,Y,ZCoordinatelocationx,y,zCoordinatedistance(mm)ConductivelossfunctionRadiativelossfunctionConvectivelossfunctionAnglebetweenZ-coordinateandx-coordinate(rad)nCoordinateparalleltobottomsurfaceAngleofinclinationofcontrolsurfacew.r.t.X-axis(rad)vCouplingcoecientTranslatedcoordinatedistance(mm)Density(kg/m3)Angleofinclinationofcontrolsurfacew.r.t.Y-axis(rad)2.IntroductionLasercuttingofadecorativeceramictilehasitsownsetofcharacteristicproblemsincludingburnout,striations,drossandout-of-flatness,whichallaffectthefinishqualityofacutedge1-3.Atypicalcutmayhavesomeorallofthesefeaturesdependingonthetypeofceramictilebeingprocessedandonthesettingofthevariousset-upparameters.Inaproductionenvironment,cuttingspeedsneedtobeoptimisedinordertoreducein-cuttimeswithouttoomuchsignificantdegradationofcut-edgequality.Anoptimumcuttingspeedcanbedefinedasthatwhichwillproducefull-through-cutting(FTC)withminimalmicro-crackingbothinthesurfaceglazeandinthetilesubstrate.Therefore,itcanbearguedthatthecuttingspeednecessarytoraiseapproximatelyacuboidofmaterialofdimensionsl,wandstothematerialsmeltingorfusiontemperaturewouldbeequaltothecuttingspeedthatwilljustcutthematerial；highercuttingspeedswillnotallowFTCandontheotherhandslowercuttingspeedswillresultinthematerialabsorbingmoreheatandreachinghighertemperaturesthanisnecessarytocutthetile.Thesehighertemperatureswillalsoresultingreaterthermalgradientsandresidualstresses,withthesubsequentproblemsofmicro-crackinginthesurfaceglazetogetherwithexcessdross.Striationmarkswillalsobeexaggeratedatslowercuttingspeedsandthiswillalsoreducecutfinishquality.Itshouldalsobenotedthatthevarioustheoreticalapproachesoutlinedinthispaperrelateonlytolasercuttingincontinuouswave(CW)mode.3.Theoreticalapproaches3.1.CalculatingVoptusingmovingpointheat-sourceAnalysisAtitssimplestlevel,lasercuttingcanbeconsideredtobeamovingpointheat-sourceproblemwherethepointheatsourceisassumedtobethelaserbeamfocusedonthematerialtobecutmovingataconstantcuttingspeed.Therefore,itisnotunreasonabletoutilisetheheat-flowsolutionsdet