外文翻譯-新工具使新機(jī)器設(shè)計(jì)最優(yōu)

外文譯文院（系）：機(jī)電學(xué)院專業(yè)：機(jī)電技術(shù)教育姓名：杜顯峰學(xué)號(hào)：20040315033指導(dǎo)老師：陳錫渠 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.翻譯新工具使新機(jī)器設(shè)計(jì)最優(yōu)當(dāng)加工鋁時(shí)，我們主要關(guān)心的是：鋁粘住加工切削邊緣的傾向；保證有好的碎片排屑形成切削邊緣；和保證工具有足夠的中心強(qiáng)度來(lái)承受切削力而不被破壞。技術(shù)發(fā)展，比如：MakinoMAG系列，已經(jīng)使工具商重新考慮任何工藝水平的機(jī)器技術(shù)。用正確的加工和編程思路是很重要的。材料，涂料和幾何形狀是與減小我們所關(guān)注問(wèn)題相關(guān)系的工具設(shè)計(jì)的三個(gè)因素。如果這些因素不能一起很好的配合，成功的調(diào)整磨削是不可能的。為了成功進(jìn)行高速鋁加工，理解這三個(gè)因素是很必要的。使組合邊緣最小化當(dāng)加工鋁時(shí)，一個(gè)失敗的切削工具模式是，被加工的材料粘住工具切削邊緣。這種情況會(huì)很快削弱工具的切削能力。由粘著的鋁形成的組合邊緣會(huì)導(dǎo)致工具變鈍，以至不能切削材料。工具材料選擇和工具涂料選擇是被工具設(shè)計(jì)者用來(lái)減小組合邊緣出現(xiàn)的主要工藝。亞微米微粒碳化物材料要求很高的鈷濃度來(lái)獲得良好的微粒結(jié)構(gòu)和材料強(qiáng)度屬性。隨著溫度的升高，鈷與鋁發(fā)生反應(yīng)，鈷使鋁與暴露的工具材料碳化物相粘合。一旦鋁開始粘住工具，鋁會(huì)在快速的在工具上形成組合邊緣，使工具不可用。在切削的進(jìn)程中，減小鋁粘合著的工具的暴露碳化物的秘訣就是找到正確的碳化物的平衡來(lái)提供足夠的材料強(qiáng)度。在加工鋁時(shí)，為了減小粘附，使用能提供足夠硬度的紋理粗糙的碳化物來(lái)獲得平衡，來(lái)使變鈍變慢。工具涂料當(dāng)嘗試減小組合邊緣時(shí)，第二個(gè)應(yīng)該考慮的工具設(shè)計(jì)因素是工具涂料。工具涂料的選擇包括：TiN,TiAIN,AITiN，鉻氮化物，鋯氮化物，鉆石和鉆石般的涂料（DLC）。擁有這么多的選擇，航空航天磨削商店需要知道在鋁的高速加工應(yīng)用中哪一種工作最有效。TiN,TiCN,TiAIN,和AITiN工具的PVD涂裝應(yīng)用進(jìn)程使這些選項(xiàng)不合適鋁的應(yīng)用。PVD涂裝進(jìn)程建立了兩個(gè)使鋁粘住工具的模式---表面的粗糙程度和鋁與工具涂料之間的化學(xué)反應(yīng)。PVD進(jìn)程形成了一個(gè)表面，這表面是比底層材料更粗糙的。由這個(gè)進(jìn)程形成的表面“凹凸”使工具中的鋁在凹處快速集結(jié)。由于涂料有金屬晶體和鐵晶體特征，PVD涂料是可以和鋁發(fā)生化學(xué)反應(yīng)的。一種TiAIN涂料通常是包含鋁的，這鋁很容易和相同材料的切削表面粘合。表面粗糙度和化學(xué)反應(yīng)特性將會(huì)導(dǎo)致工具和工作片體粘在一起，以致形成組合表面。OSGTapandDie主導(dǎo)的試驗(yàn)中，人們發(fā)現(xiàn)在高速加工鋁時(shí)，一個(gè)沒(méi)有涂染過(guò)紋理粗糙的碳化物的工具的表面優(yōu)于用TiN,Ticn,TiAIN,或者ALTiN涂染過(guò)的工具。這