会员注册 | 登录 | 微信快捷登录 QQ登录 微博登录 | 帮助中心 人人文库renrendoc.com美如初恋!
站内搜索 百度文库

热门搜索: 直缝焊接机 矿井提升机 循环球式转向器图纸 机器人手爪发展史 管道机器人dwg 动平衡试验台设计

外文翻译--精密模具用的纳米级研磨表面研发 英文版.pdf外文翻译--精密模具用的纳米级研磨表面研发 英文版.pdf -- 10 元

宽屏显示 收藏 分享

资源预览需要最新版本的Flash Player支持。
您尚未安装或版本过低,建议您

中國機械工程學刊第二十七卷第六期第707715頁民國九十五年JournaloftheChineseSocietyofMechanicalEngineers,Vol.27,No.6,pp.7077152006707TheStudyofNanometerGradeGrindingSurfaceforPrecisionMoldsHoHuaChung,K.L.YangandHsinTzuLiaoKeywordsPrecisiongrinding,Surfaceroughness,Grindingspeed.ABSTRACTTheSKHmoldsteelswerepreprocessed,groundbytheprecisesharpeningstonetohaveRa1015μmforsubsequentprecisegrindingallowance,andthenpreciselygroundbytheCBNgrindingwheel.Theinfluenceofthemainaxelrotationspeedandthesamplehardnessonthegrindingsituationwasdiscussedinthisstudy.TheresultshowsthatthesurfaceroughnessofthelowhardnessSKH51moldsteelcouldbeimprovedmarkedlyasrotationspeedincreased.Onthecontrary,thereisnoobviousimprovementforthehighhardnessSKH59moldsteel.Withincreasingrotationspeed,thesurfaceroughnessofworkpiecesimprovedsignificantlyduetotheincreasingofgrindingforce.However,athighrotationspeed,itwasunabletogetfurtherimprovementsincethegrindingforcenearlyremainingthesamelevel,causingthelessimprovementonthesurfaceroughnessofworkpieces.INTRODUCTIONCuttingmachiningtechnologyisamongthemosteffectivemethodsformoldmachining.Atpresent,machiningbyusingCNClatheswithmillingturretandendmillingmachininginaleadingCNCmachinecenterarethemostcommonmethodsforproductsmachining.However,aftertheroughmachining,thesurfaceofthemoldisextremelyrough.Tosmooththemoldsurface,itshouldbetreatedagainbythefinishmachiningandhandpolishing.Thisprocessreliesonexperiencedtechnician,anditcostsalongtime.Moreover,theprecisionandthequalityofmoldsaredifficulttobefurtherenhancedbythemanualoperation.Therefore,themaingoalofhighspeedmoldprocessingistoobtainthehighprecisionoffreecurvesurface,toshortenthepolishingoperationtime,andtolowerthemanufacturingcost.Especially,intherecentyears,thecombinationofhighspeedmoldprocessingwithhighhardnessmaterialsisusuallyusedinthemoldindustrytoenhancethecompetitivenessofprocessingtechnology.Inordertoobtainsubmicrongrade107108mshapeaccuracyandnanometergrade109msurfaceroughness,diamondmilling,diamondlathing,anddiamondgrindingareusuallyusedinultraprecisionmachining.ComputersimulationdonebyHasegawaandMiyazimapointedoutthattheimprovementofsurfaceroughnessofworkpieceswouldreachasaturationvalueunderalongtimepolish,anditshardtobefurtherimproved.Weckdevelopedanultraprecisionmachiningbyusingadiamondcuttingtool,bywhichthesurfaceroughnessofworkpiecescouldbereducedtobelow5nm.Asaconsequence,themanufacturedminiaturecomponentscouldalsobeappliedinthesemiconductorindustry.Takeuchidevelopedafiveaxleultraprecisionmachine,whichhavehydropressureballscrewsandaservomotorwithinitscap.Thismachineusuallyattachedasuperresolutionopticalencoderwith6,400millionpulsesperrevolution.Thesurfaceroughnesscouldbereducedtoabout50nmunderextremelowfeedingrate,becausetherewerenofrictionforceandbacklashquestions.Itisnecessaryformachiningtoolstohaveexcellentdynamiccharacteristicsandhighrigidityespeciallyformachinigbrittlematerials.PatentTetraformCdevelopedbyStephensonandCorbettreportedthatthesurfacefinishwasproducedbetterthan10nmbyusinga76μmCBNwheelandtheelectrolyticinprocessdressingELIDassistedgrinding.CombinationofthehighrigidityPaperReceivedAugust,2006.RevisedNovember,2006.AcceptedNovember,2006.AuthorforCorrespondenceHoHuaChungCorrespondingAuthorAssociateProfessor,DepartmentofMechanicalandAutomationEngineering,KaoYuanUniversity,KaohsiungCounty,Taiwan82101,R.O.C.,Emailhohuacc.kyu.edu.twAssistantProfessor,DepartmentofElectronicsEngineering,KaoYuanUniversity,KaohsiungCounty,Taiwan82101,R.O.C.,Emailklyangcc.kyu.edu.twAssociateProfessor,DepartmentofBiochemicalEngineering,KaoYuanUniversity,KaohsiungCounty,Taiwan82101,R.O.C.,Emailhtliawcc.kyu.edu.twJ.CSMEVol.27,NO.62006708machineandmanufacturingprocess,theremovingrateofultraprecisionmachiningcouldbeincreasedsignificantly.Shapeaccuracyandsurfaceroughnessarealsoveryimportantinthesemiconductorindustry.Surfaceroughnessdemandingforsiliconwaferisaboutatnanometergrade.Surfaceroughnessforoptoelectronicsandmemorydevicesisanimportantfactordirectlyaffectingtheperformanceofproduct.Inbrief,thecurrenttrendsinultraprecisemachiningaretoachievenanometergrademillingandturninginhardenedsteels,toimprovetheprecisionofproducts,toextendthelifeofprecisionmolds,andtoreductionofsurfaceroughnessofworkpieces.Inordertosaveenergyandenvironmentalconservation,surfaceroughnessindegreeofnanometeroffastenersfortransmissionpartsusedinvehicleshasincreaseditsessentiality.Atpresent,hardenedmoldsteel,whichisacommonprecisionfastenermaterial,isusuallymanufacturedbyprecisegrinding.Inthefuture,highefficiencyprecisegrindingandvariantnanometerhardturningtechnologieswillbedevelopedforgrindingprecisionmolds.Inthisresearch,SKHtoolsteelsarechosenasthemoldworkpieces,andtheeffectofgrindingspeed,materialhardness,grindingforceandfeedingrateonthesurfaceroughnessofworkpiecewillbestudied.EXPERIMENTMETHODEquipmentalsetupInthisstudy,ahighrotationspeedmicrogrinderinstallingtheperipheralmeasurementsystemandmanykindsofdifferentprocessingequipmentsuchasnumericalcontrollathe/millingmachine,fourthaxlewereusedtoconducttheresearch.AsillustratedinFig.1,theoperationproceduresofthishighrotationspeedautomaticprecisemicrogrinderwereshowed.Firstly,afterheattreatment,thehighhardnessmaterialwaspretreatedbydiamondmachininganddiamondcutting.Secondly,thesurfaceroughnessofworkpieceswasreducedtoRa1015μmforsubsequentprecisegrindingallowance.Thirdly,matchingCBNgrindingwheelatFigure1Schematicillustrationofhighrotationspeedmicrogrinder.H.H.Chungetal.TheStudyofNanometerGradeGrindingSurface.709highrotationspeed,XYZaxleandthefourthaxlereciprocationwithmoves,thecurvedsurfaceandlinegrindingtruncatingbythediamondscribingtool,andconstructingtheoutlineofgrindingtruncatingbytheCAD/CAMwithparametersobtainedfromexperiments,theunwantedpartofthesurfaceofworkpiecewasremovedandtheincisiveextremelyhardultramicrondiamondburrorabrasiveparticleswererevealed.Finally,themovementpathofgrindingwheelproducedbythediamondscribingtoolwasduplicatedtotheheattreatedmoldtoolsteeltohavethemicrometergradeprecisecontacttypegrindingandthenthesurfaceroughnesscanreachbelow50nm.ExperimentalprocedureThreetypesofmoldtoolsteelsSKH51,SKH55andSKH59werechosenastheworksamples,andthenweremarkedwithdifferentcolorsinclassified.Theprocessingofworksampleswascarriedonasthefollowingsteps1CuttingRoughcuttingtoclosetothesamplelength.2RoughmachiningContourmachiningbythediscorcylindergrindingwheel.TrimmingTrimtwosidesofthecuttingend.3CNCroughlatheLathetheouterdiameterfromthelatheprogram.4CNCroughmillingShapemillingfromthemillingprogram.5ThermaltreatmentWorksampleswereaustenizedat1165oC,1200oCand1165oC,respectively,andthenquenched.Subsequently,thesampleswereannealedat560oCthreetimestoobtaintheRockwellhardnessof60,63and67HRc.ThechemicalcompositionsofthesamplesweresummarizedinTable1.6PrecisionlathingLathetostandardlength.7PrecisiongrindingGrindedtothegeometryasillustratedinFigure2,andthencleanedbeforeconductingtheexperiment.Theworkpeiceswereusingacetoneplacedinanultrasoniccleanercleanedforseveralminutes,andthenthesurfaceroughnessweremeasuredbythesurfaceroughnessmeasurementinstrument.TheworkpeiceswerefixedonthespeedmicrogrinderwithsuperhighrotationspeedFig.1.Inordertoinvestigatetheinfluenceofthecuttingspeedandthesamplehardnessonthegrindingsituation,theoperationvariableswererotationspeed,depthofcut,horizontalfeedingrate,coolingjet,concentrationandtemperatureofgrindingslurry.ThedetailedexperimentalconditionwasaslistedinTable2.Table1ElementsanalysisofthemoldtoolsteelsafterthermaltreatmentChemicalCompositionwtTestsampleCCrMoWVCoSKH511.073.562.032.591.76SKH551.113.922.162.831.745.51SKH591.173.573.990.591.149.34Figure2Thegeometryoftheprecisiongrindedhexagonpunch.Table2TheexperimentalconditionsforthegrindingprocessofmoldtoolsItemConditionsTestsamplematerialSKH51,SKH55,SKH59GrindingwheelCBN80N75B11V26,d125mmRotationspeedrpm5000,6500,7000,8000,9000Worktablevelocitymm/min90150Optimumdepthofcutmm0.030.2GrindingslurrytemperatureoCInput2829Output3031Grindingslurryconcentrationoriginalgrindingfluid/water397CoolingjetVolumetricflowrate20m3/h,pressure8barJ.CSMEVol.27,NO.62006710Undereachkindofrotationspeed,depthofcut,feedingrate,grindingforce,thevibrationfrequency,andthegrindingtemperatureofgrindingslurryweredeterminedbythehighprecisionloadcell,thedigitalstoragevibrationsmeasuringmeterandthenoncontactthermometer.Aftergrinding,thesurfacemorphologyofworkpieceswasexaminedbythescanningelectronmicroscopeSEM.Moreover,anenergydispersionspectroscope,theRockwellhardnesstester,andthesurfaceroughnessmeasurementinstrumentwerealsousedtocharacterizethegrindingmechanismofSKHsteelprocessingsurface.Finally,theprocessingefficiencyofhardvehiclemillandprecisiongrindingwasassessedviatheexperimentalresult.RESULTSANDDISCUSSIONSSurfaceBehaviorofCBNGrindingWheelThemajorpurposeofhighspeedmoldprocessingistoobtainthehighaccuracyfreecurvedsurface,toreducethepolishingtime,andtolowerthecost.ThehighefficientgrindingisbytheCBNgrindingwheel,thehighmainaxlerotationspeed,andthehighrateofmovementanddeeperentering.Itscuttingquantitywasseveralhundredtimesthanthetraditionalgrinderandthegrindingwheelshapeisallthesamefromthebeginningtoendduringtheperiodofthewholegrindingprocess.Therefore,thenanometergradegrindingsurfacecouldbeobtainedbyomittingtherepairingandmaintainingprocedureofgrindingwheelandthechangeofcuttingcondition.ThehardnessofthemoldsurfacewasusuallyhigherthanHRc60andthegeneralcuttingtoolcouldnotprocessitwhenitssurfacewashardenedafterheattreatment.Moreover,therequestofmoldprecisionandsurfacesmoothnesswastoohightobeestablishedbythegeneralcuttingtool.TheCBNgrindingwheelwasthebestmethodusedfortheprecisionprocessingofmoldsurfacebecauseithadthemulticuttingsangleandtheregenerationproperty.Figure3showstherelationshipbetweengrindingforceandcuttingspeedfordifferentSKHmoldsteelmaterialswhenthefeedingrateandthedepthofcutweremaintainedat150mm/minand0.05mm,respectively.ForthethreekindsofSKHmoldsteelmaterials,itisclearthatthegrindingforcedecreasedFigure3Thevariationofgrindingforceasafunctionofcuttingspeedundertheconditionofthefeedingrateof150m/minandthefeedamountof0.05mm.markedlywhenthecuttingspeedwasincreasedfrom2000to2750m/minandthenapproachedasaturationvalue.ThisresultisduetothefactthattheheatgeneratedfromthegrindingofmoldtoolcanbeeasilydissipatedformCBNgrindingwheelitselfandnottransfertotheworkpiecebecauseCBNhashighthermalconductivity.Therefore,alongwithanincreasingofcuttingspeed,thecuttingtemperaturewaseasytoconcentrateonthegrindingparticlesofCBNgrindingwheelandleadingtoreducethegrindingforcegradually.Ontheotherhand,itwasalsofoundfromFigure3that,underthesamevalueofcuttingspeed,thegrindingforceofSKH59moldsteelissmallerthanthatofSKH51andSKH55duetothehighercarboncontentandthehigherhardness.ThisresultcanbeexplainedbythephenomenonthatSKH59haslowersofttemperatureandthecarbidecanbeseparatedafterquenching.Theseparatedcarbideaffectsthefrictionfactorofcuttingsurfaceandthenleadingtoreducethegrindingforce.Theanalysisoftheseparatedmaterialwillbefurtherdiscussedinthenextsection.AspinwallandNgstudiedthevariationofgrindingforcewithcuttingspeedforAISIH13moldsteelwithdifferenthardenabilityandtheresultshowedthat,withthesamecuttingconditionandthesamematerial,thegrindingforcewasnotnecessarilylargeforthehigherhardenabilityworkpiece.Intheaspecttogrindingforce,thecuttingtemperaturewillincreasetosomedegreewithanincreasingofcuttingspeedandthentheheatconcentratesonthegrindingparticlesoftheCBNgrindingwheel.Whenthequantityofconcentrated
编号:201311171917547885    大小:2.20MB    格式:PDF    上传时间:2013-11-17
  【编辑】
10
关 键 词:
教育专区 外文翻译 精品文档 外文翻译
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
0条评论

还可以输入200字符

暂无评论,赶快抢占沙发吧。

当前资源信息

4.0
 
(2人评价)
浏览:26次
英文资料库上传于2013-11-17

官方联系方式

客服手机:17625900360   
2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   

相关资源

相关资源

相关搜索

教育专区   外文翻译   精品文档   外文翻译  
关于我们 - 网站声明 - 网站地图 - 友情链接 - 网站客服客服 - 联系我们
copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5