外文翻译-新工具使新机器设计最优

外文译文院（系）：机电学院专业：机电技术教育姓名：杜显峰学号：20040315033指导老师：陈锡渠 NewtoolsmaximizenewmachinedesignsTheprimarytoolingconcernswhenmachiningaluminumare:minimizingthetendencyofaluminumtosticktothetoolcuttingedges;ensuringthereisgoodchipevacuationformthecuttingedge;andensuringthecorestrengthofthetoolsissufficienttowithstandthecuttingforceswithoutbreaking.TechnologicaldevelopmentssuchastheMakinoMAG-Seriesmachineshavemadetoolingvendorsrethinktheanystate-of-the-artmachinetechnology.Itisvitaltoapplytherighttoolingandprogrammingconcepts.Materialscoatingsandgeometryarethethreeelementsintooldesignthatinterrelatetominimizetheseconcerns.Ifthesethreeelementsdonotworktogether,successfulhigh-speedmillingisnotpossible.Itisimperativetounderstandallthreeoftheseelementsinordertobesuccessfulinthehigh-speedmachiningofaluminum.MinimizeBuilt-UpEdgeWhenmachiningaluminum,oneofthemajorfailuremodesofcuttingtoolsthematerialbeingmachinedadherestothetoolcuttingedge.Thisconditionrapidlydegradesthecuttingabilityofthetool.Thebuilt-upedgethatisgeneratedbytheadheringaluminumdullsthetoolsoitcannolongercutthroughthematerial.Toolmaterialselectionandtoolcoatingselectionarethetwoprimarytechniquesusedbytooldesignerstoreduceoccurrenceofthebuilt-upedge.Thesub-microngraincarbidematerialrequiresahighcobaltconcentrationtoachievethefinegrainstructureandthematerial’sstrengthproperties.Cobaltreactswithaluminumatelevatedtemperatures,whichcausesthealuminumtochemicallybondtotheexposedcobaltofthetoolmaterial.Oncethealuminumstartstoadheretothetool,itquicklyformsabuilt-upedgeonthetoolrenderingitineffective.Thesecretistofindtherightbalanceofcobalttoprovideadequatematerialstrength,whileminimizingtheexposedcobaltinthetoolsforaluminumadherenceduringthecuttingprocess.Thisbalanceisachievedusingcoarse-grainedcarbidethatprovidesatoolofsufficienthardnesssoastonotdullquicklywhenmachiningaluminumwhileminimizingadherence.ToolcoatingsThesecondtooldesignelementthatmustbeconsideredwhentryingtominimizethebuilt-upedgeisthetoolcoating.ToolcoatingchoicesincludeTiN,TiAIN,AITiN,chromenitrides,zirconiumnitrides,diamond,anddiamond-likecoatings(DLC).Withsomanychoices,aerospacemillingshopsneedtoknowwhichoneworksbestinanaluminumhigh-speedmachiningapplication.ThePhysicalVaporDeposition(PVD)coatingapplicationprocessonTiN,TiCN,TiAIN,andAITiNtoolsmakesthemunsuitableforanaluminumapplication.ThePVDcoatingprocesscreatestwomodesforaluminumtobondtothetools――thesurfaceroughnessandthechemicalreactivitybetweenthealuminumandthetoolcoating.ThePVDprocessresultsinsurfacethatisrougherthatthesubstratematerialtowhichitisapplied.Thesurface”peaksandvalleys”createdbythisprocesscausesaluminumtorapidlycollectinthevalleysonthetool.Inaddition,thePVDcoatingischemicallyreactivetothealuminumduetoitsmetalliccrystalandioniccrystalfeatures.ATiAINcoatingactuallycontainsaluminum,whicheasilybondswithacuttingsurfaceofthesamematerial.Thesurfaceroughnessandchemicalreactivityattributeswillcausethetoolandworkpiecetosticktogether,thuscreatingthebuilt-upedge.IntestingperformedbyOSGTapandDie,itwasdiscoveredthatwhenmachiningaluminumatveryhighspeeds,theperformanceofanuncoatedcoarse-grainedcarbidetoolwassuperiortothatofonecoatedwithTiN,Ticn,TiAIN,orALTiN.Thistestingdoesnotmeanthatalltoolcoatingswillreducethetoolperformance.ThediamondandDLCcoatingsresultinaverysmoothchemicallyinertsurface.Thesecoatingshavebeenfoundtosignificantlyimprovetoollifewhencuttingaluminummaterials.Thediamondcoatingswerefoundtobethebestperformingcoatings,butthereisaconsiderablecostrelatedtothistypeofcoating.TheDLCcoatingsprovidethebestcostforperformancevalue,addingabout20%-25%tothetotaltoolcost.But,thiscoatingextendsthetoollifesignificantlyascomparedtoanuncoatedcoarse-grainedcarbidetool.GeometryTheruleofthumbforhigh-speedaluminummachiningtoolingdesignsistomaximizespaceforchipevacuation.Thisisbecausealuminumisaverysoftmaterial,andthefederateisusuallyincreasedwhichcreatesmoreandbiggerchips.TheMakinoMAG-Seriesaerospacemillingmachines,suchastheMAG4,requireanadditionalconsiderationfortoolgeometry-toolstrength.TheMAG-Seriesmachineswiththeirpowerful80-hpspindleswillsnapthetoolsiftheyarenotdesignedwithsufficientcorestrength.Ingeneral,sharpcuttingedgesshouldalwaysbeusedtoavoidaluminumelongation.Asharpcuttingedgewillcreatehighshearingandalsohighsurfaceclearance,creatingabettersurfacefinishandfinishandminimizingchatterorsurfacevibration.Theissueisthatitispossibletoachieveasharpercuttingedgewiththefine-grainedcarbidematerialthanthecoarsegrainedmaterial.Butduetoaluminumadherencetothefine-grainedmaterial,itisnotpossibletomaintainthatedgeforverylong.CoarsecompromiseThecoarsegrainedmaterialappearstobethebestcompromise.Itisastrongmaterialthatcanhaveareasonablecuttingedge.Testresultsshowitisabletoachieveaverylongtoollifewithgoodsurfacefinish.Themaintenanceofthecuttingedgeisimprovedusinganoilmistcoolantthroughthetool.Mistinggraduallycoolsdownthetools,eliminatingthermalshockproblems.Thehelixangleisanadditionaltoolgeometryconsideration.Traditionallywhenmachiningaluminumafoolwithahighhelixanglehasbeenused.Ahighhelixangleliftsthechipawayfromthepartmorequickly,butincreasesthefrictionandheatgeneratedasresultofthecuttingaction.Ahighhelixangleistypicallyusedonatoolwithahighernumberofflutestoquicklyevacuatethechipfromthepart.Whenmachiningaluminumatveryhighspeedstheheatcreatedbytheincreasedfrictionmaycausethechipstoweldtothetool.Inaddition,acuttingsurfacewithahighhelixanglewillchipmorerapidlythatatoolwithalowhelixangle.Atooldesignthatutilizesonlytwoflutesenablesbothalowhelixangleandsufficientchipevacuationarea.ThisistheapproachthathasproventobethemostsuccessfulinextensivetestingperformedbyOSGwhendevelopingthenewtoolingline,theMAXAL.翻译新工具使新机器设计最优当加工铝时，我们主要关心的是：铝粘住加工切削边缘的倾向；保证有好的碎片排屑形成切削边缘；和保证工具有足够的中心强度来承受切削力而不被破坏。技术发展，比如：MakinoMAG系列，已经使工具商重新考虑任何工艺水平的机器技术。用正确的加工和编程思路是很重要的。材料，涂料和几何形状是与减小我们所关注问题相关系的工具设计的三个因素。如果这些因素不能一起很好的配合，成功的调整磨削是不可能的。为了成功进行高速铝加工，理解这三个因素是很必要的。使组合边缘最小化当加工铝时，一个失败的切削工具模式是，被加工的材料粘住工具切削边缘。这种情况会很快削弱工具的切削能力。由粘着的铝形成的组合边缘会导致工具变钝，以至不能切削材料。工具材料选择和工具涂料选择是被工具设计者用来减小组合边缘出现的主要工艺。亚微米微粒碳化物材料要求很高的钴浓度来获得良好的微粒结构和材料强度属性。随着温度的升高，钴与铝发生反应，钴使铝与暴露的工具材料碳化物相粘合。一旦铝开始粘住工具，铝会在快速的在工具上形成组合边缘，使工具不可用。在切削的进程中，减小铝粘合着的工具的暴露碳化物的秘诀就是找到正确的碳化物的平衡来提供足够的材料强度。在加工铝时，为了减小粘附，使用能提供足够硬度的纹理粗糙的碳化物来获得平衡，来使变钝变慢。工具涂料当尝试减小组合边缘时，第二个应该考虑的工具设计因素是工具涂料。工具涂料的选择包括：TiN,TiAIN,AITiN，铬氮化物，锆氮化物，钻石和钻石般的涂料（DLC）。拥有这么多的选择，航空航天磨削商店需要知道在铝的高速加工应用中哪一种工作最有效。TiN,TiCN,TiAIN,和AITiN工具的PVD涂装应用进程使这些选项不合适铝的应用。PVD涂装进程建立了两个使铝粘住工具的模式---表面的粗糙程度和铝与工具涂料之间的化学反应。PVD进程形成了一个表面，这表面是比底层材料更粗糙的。由这个进程形成的表面“凹凸”使工具中的铝在凹处快速集结。由于涂料有金属晶体和铁晶体特征，PVD涂料是可以和铝发生化学反应的。一种TiAIN涂料通常是包含铝的，这铝很容易和相同材料的切削表面粘合。表面粗糙度和化学反应特性将会导致工具和工作片体粘在一起，以致形成组合表面。OSGTapandDie主导的试验中，人们发现在高速加工铝时，一个没有涂染过纹理粗糙的碳化物的工具的表面优于用TiN,Ticn,TiAIN,或者ALTiN涂染过的工具。这