机械类毕业设计外文翻译

外文原文

Optionsformicro-holemaking

Asinthemacroscale-machiningworld,holemakingisoneofthemost—ifnotthemost—frequentlyperformedoperationsformicromachining.Manyoptionsexistforhowthoseholesarecreated.Eachhasitsadvantagesandlimitations,dependingontherequiredholediameteranddepth,workpiecematerialandequipmentrequirements.Thisarticlecoversholemakingwiththrough-coolantdrillsandthosewithoutcoolantholes,plungemilling,microdrillingusingsinkerEDMsandlaserdrilling.

HelpfulHoles

Gettingcoolanttothedrilltipwhilethetooliscuttinghelpsreducetheamountofheatatthetool/workpieceinterfaceandevacuatechipsregardlessofholediameter.Butthrough-coolantcapabilityisespeciallyhelpfulwhendeep-holemicrodrillingbecausethetoolsaredelicateandpronetofailurewhenexperiencingrecuttingofchips,chippackingandtoomuchexposuretocarbide'sworstenemy—heat.

Whenapplyingfloodcoolant,thedrillitselfblocksaccesstothecuttingaction.“Somewhereabout3to5diametersdeep,thecoolanthastroublegettingdowntothetip,”saidJeffDavis,vicepresidentofengineeringforHarveyToolCo.,Rowley,Mass.“Itbecomeswisetouseacoolant-feddrillatthatpoint.”

Inaddition,floodcoolantcancausemoreharmthangoodwhenmicroholemaking.“Thepressurefromthefloodcoolantcansometimessnapfragiledrillsastheyenterthepart,”Davissaid.

Thetoolmakeroffersalineofthrough-coolantdrillswithdiametersfrom0.039"to0.125"thatareabletoproduceholesupto12diametersdeep,aswellasmicrodrillswithoutcoolantholesfrom0.002"to0.020".

Havingthrough-coolantcapacityisn'tenough,though.Coolantneedstoflowataratethatenablesittoclearthechipsoutofthehole.Davisrecommends,ataminimum,600to800psiofcoolantpressure.“Itworksmuchbetterifyouhavehigherpressurethanthat,”headded.

Topreventthosetinycoolantholesfrombecomingcloggedwithdebris,Davisalsorecommendsa5pmorfinercoolantfilter.

Anotherrecommendationistomachineapilot,orguide,holetopreventthetoolfromwanderingontopoftheworkpieceandaidinproducingastraighthole.Whenapplyingapilotdrill,it'simportanttoselectonewithanincludedangleonitspointthat'sequaltoorlargerthantheincludedangleonthethrough-coolantdrillthatfollows.Thepilotdrill'sdiametershouldalsobeslightlylarger.Forexample,ifthepilotdrillhasa120°includedangleandasmallerdiameterthanathrough-coolantdrillwitha140°includedangle,“thenyou'recatchingthecoolant-feddrill'scornersandknockingthosecornersoff,”Davissaid,whichdamagesthedrill.

Althoughnotmandatory,peckingisagoodpracticewhenmicrodrillingdeepholes.Davissuggestsapeckingcyclethatis30to50percentofthediameterperpeckdepth,dependingontheworkpiecematerial.Thisclearsthechips,preventingthemfrompackingintheflutevalleys.

LubriciousChill

Tofurtheraidchipevacuation,Davisrecommendsapplyinganoil-basedmetalworkingfluidinsteadofawaterbasedcoolantbecauseoilprovidesgreaterlubricity.Butifashopprefersusingcoolant,thefluidshouldincludeEP(extremepressure)additivestoincreaselubricityandminimizefoaming.“Ifyou'vegotalotoffoam,”Davisnoted,“thechipsaren'tbeingpulledoutthewaytheyaresupposedtobe.”

Headdedthatanotherwaytoenhanceatool'sslipperinesswhileextendingitslifeiswithacoating,suchastitaniumaluminumnitride.TiAlNhasahighhardnessandisaneffectivecoatingforreducingheat'simpactwhendrillingdifficult-to-machinematerials,likestainlesssteel.

DavidBurton,generalmanagerofPerformanceMicroTool,Janesville,Wis.,disagreeswiththeideaofcoatingmicrotoolsonthesmallerendofthespectrum.“Coatingsontoolsbelow0.020"typicallyhaveanegativeeffectoneverymachiningaspect,fromthequalityoftheinitialcuttotoollife,”hesaid.That'sbecausecoatingsarenotthinenoughandnegativelyaltertherakeandreliefangleswhenappliedtotinytools.

However,workcontinuesonthedevelopmentofthinnercoatings,andBurtonindicatedthatPerformanceMicroTool,whichproducesmicroendmillsandmicroroutersandresellsmicrodrills,isworkingonaprojectwithotherstocreateasubmicron-thicknesscoating.“We'reprobably6monthsto1yearfromtestingitinthemarket,”Burtonsaid.

ThemicrodrillsPerformanceoffersarebasicallycircuit-boarddrills,whicharealsoeffectiveforcuttingmetal.Allthetoolsarewithoutthrough-coolantcapability.“Ihadacustomerdrilla0.004"-dia.holeinstainlesssteel,andhewasamazedhecoulddoitwithacircuit-boarddrill,”Burtonnoted,addingthatpeckingandrunningatahighspindlespeedincreasethedrill'seffectiveness.

TherequirementsforhowfastmicrotoolsshouldrotatedependonthetypeofCNCmachinesashopusesandthetooldiameter,withhigherspeedsneededasthediameterdecreases.(Note:Theequationforcuttingspeedissfm=tooldiameterx0.26xspindle

哈尔滨理工大学2008届本科生毕业设计（论文）外文翻译

哈尔滨理工大学2008届本科生毕业设计（论文）外文翻译

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speed.)

Althoughrelativelylow,5,000rpmhasbeenusedsuccessfullybyBurton'scustomers.“Werecommendthatourcustomersfindthehighestrpmatthelowestpossiblevibration—thesweetspot,”hesaid.

Inadditiontominimizingvibration,aconstantandadequatechiploadisrequiredtopenetratetheworkpiecewhileexertinglowcuttingforcesandtoallowtheraketoremovetheappropriateamountofmaterial.Ifthedrilltakestoolightofachipload,therakefacewearsquickly,becomingnegative,andtoollifesuffers.Thisapproachisoftentemptingwhendrillingwithdelicatetools.

“Ifthecustomerdecideshewantstobabythetool,hetakesalighterchipload,”Burtonsaid,“and,typically,thecuttingedgewearsmuchquickerandcreatesaradiuswherethelandofthatradiusiswiderthanthechipbeingcut.Heendsupusingitasagrindingtool,tryingtobumpmaterialaway.”Fortoolslargerthan0.001",Burtonconsidersachiploadunder0.0001"tobe“babying.”Ifthedrilldoesn'tsnap,prematurewearcanresultinabysmaltoollife.

Toomuchrunoutcanalsobedestructive,buthowmuchisdebatable.BurtonpointedoutthatPerformancepurposelydesignedamachinetohave0.0003"TIRtoconductin-house,worst-casemillingscenarios,addingthatthecompanyisstillabletomilla0.004"-wideslot“dayinanddayout.”

Headded:“Youwouldthinkwith0.0003"runoutandachiploadathirdthat,say,0.0001"to0.00015",thetoolwouldbreakimmediatelybecauseoneflutewouldbetakingtheentireloadandthenthebackendoftheflutewouldberubbing.

Whendrilling,heindicatedthatupto0.0003"TIRshouldbeacceptablebecauseoncethedrillisinsidethehole,thecuttingedgesontheendofthedrillcontinuecuttingwhilethenoncuttinglandsontheODguidethetoolinthesamedirection.Minimizingrunoutbecomesmorecriticalasthedepth-to-diameterratioincreases.Thisisbecausetheflutesarenotabletoabsorbasmuchdeflectionastheybecomemoreengagedintheworkpiece.Ultimately,toomuchrunoutcausesthetoolshanktoorbitaroundthetool'scenterwhilethetooltipisheldsteady,creatingastresspointwherethetoolwilleventuallybreak.

TakingaPlunge

Althoughstandardmicrodrillsaren'tgenerallyavailablebelow0.002",microendmillsthatcanbeusedto“plunge”aholeare.“Whenpeoplewanttodrillsmallerthanthat,theyuseourendmillsandareprettysuccessful,”Burtonsaid.However,theholescan'tbeverydeepbecausethetoolsdon'thavelongaspect,ordepth-to-diameter,ratios.Therefore,a0.001"-dia.endmillmightbeabletoonlymakeaholeupto0.020"deepwhereasadrillofthesamesize

cangodeeperbecauseit'sdesignedtoplacetheloadonitstipwhendrilling.Thistransfersthepressureintotheshank,whichabsorbsit.

Performanceoffersendmillsassmallas5microns(0.0002")butisn'tkeenonincreasingthatline'ssales."Whenpeopletrytobuythem,IveryseriouslytrytotalkthemoutofitbecausewedorftlikemakingthemJBurtonsaid・Partoftheproblemwithtoolsthatsmallisthecarbidegrainsnotonlyneedtobesubmicroninsizebutthesizealsoneedstobeconsistent,inpartbecausesuchatooliscomprisedoffewergrains."The5-micronendmillprobablyhas10grainsholdingthecoretogether/'Burtonnoted・

Headdedthathehasseencarbidepowdercontaining0.2-microngrains,whichisabouthalfthesizeofwhat^commerciallyavailable,butitalsocontainedgrainsmeasuring0.5and0.6microns."Itjustdoesn'thelptohavesmallgrainsifthey'renotuniform.”

Microvaporization

ElectricaldischargemachiningusingasinkerEDMisanothermicro-holemakingoption.Unlike,whichcreatesmallholesforthreadingwirethroughtheworkpiecewhenwireEDMing,EDMsforproducingmicroholesareconsiderablymoresophisticated,accurateand,ofcourse,expensive・

Forproducingdeepmicroholes,atubeisappliedastheelectrode.ForEDMingsmallerbutshallowerholes,asolidelectrodewire,orrod,isneeded・“Wetrytousetubesasmuchaspossible/9saidJeffKiszonas,EDMproductmanagerforMakinoInc.?AuburnHills,Mich.“Butatsomepoint,nobodycanmakeatubebelowacertaindiameter.^^Headdedthatsomesuppliersoffertubesdownto0.003nindiameterformakingholesassmallas0.0038”・Thetube'sflushingholeenablescreatingaholewithahighdepth-to-diameterratioandhelpstoevacuatedebrisfromthebottomoftheholeduringmachining.

OnesuchsinkerEDMforproducingholesassmallas0.00044"(1ljim)isMakino9sEdge2sinkerEDMwithfine-holeoption.InJapan,themachinetoolbuilderrecentlyproducedeightsuchholesin2minutesand40secondsthrough0.0010n-thicktungstencarbideattheholelocations.Theelectrodewasasilver-tungstenrod0.00020"smallerthantheholebeingproduced,toaccountforsparkactivityinthegap・

Whenproducingholesofthatsize,therod,whilerotating,isdressedwithachargedEDMwire.Thefine-holeoptionincludesaW-axisattachment,whichholdsadiethatguidestheelectrode,aswellasamiddleguidethatpreventstheelectrodefrombendingorwobblingasitspins.Withtheoption,themachineisappropriatefordrillingholediameterslessthan0.005n.

AnothersinkerEDMformicro-holemakingistheMitsubishiVAIOwithafine-holejigattachmenttochuckandguidethefinewireappliedtoerodethematerial."It'sastandard

EDM,butwiththatattachmentfixedtothemachine,wecandomicroholedrilling,”saidDennisPowderly,sinkerEDMproductmanagerforMCMachinerySystemsInc.,WoodDale,Ill.HeaddedthattheEDMisalsoabletocreateholesdownto0.0004"usingawirethatrotatesatupto2,000rpm.

TurntoTungsten

EDMingistypicallyaslowprocess,andthatholdstruewhenitisusedformicrodrilling.“It'sveryslow,andthefinerthedetails,thesloweritis,”said,presidentandownerofOptimationInc.TheMidvale,Utah,companybuildsProfile24PiezoEDMsformicromachiningandalsoperformsmicroEDMingonacontract-machiningbasis.

Optimationproducestungstenelectrodesusingareverse-polarityprocessandmachinesandring-lapsthemtoassmallas10pmindiameterwith0.000020"roundness.Applyinga10ym-dia.electrodeproducesaholeabout10.5pmto11pmindiameter,andblind-holesarepossiblewiththecompany'sEDM.Theworkpiecethicknessforthesmallestholesisupto0.002",andthethicknesscanbeupto0.04"for50pmholes.

AfterworkingwithlasersandthenwithaformerEDMbuildertofindabetterwaytoproduceprecisemicroholes,JorgensendecidedthebestapproachwasDIY.“Weliterallystartedwithacleansheetofpaperanddidalltheelectronics,allthesoftwareandthewholemachinefromscratch,”hesaid.Includingthesoftware,themachinecostsintheneighborhoodof$180,000to$200,000.

Muchofthecompany'scontractwork,whichisprovidedatashoprateof$100perhour,involvesmicroEDMingexoticmetals,suchasgoldandplatinumforX-rayapertures,stainlesssteelforopticalapplicationsandtantalumandtungstenfortheelectron-beamindustry.JorgensensaidtheprocessisalsoappropriateforEDMingpartiallyelectricallyconductivematerials,suchasPCD.

“Thecustomernormallydoesn'tcaretoomuchaboutthecost,”hesaid.“We'vedonepartswherethere's$20,000[intimeandmaterial]involved,andyoucanputthewholejobunderneathafingernail.Wedoeverythingunderamicroscope.”

LightCutting

Besidescarbideandtungsten,lightisanappropriate“toolmaterial”formicro-holemaking.Althoughmostlaserdrillingisperformedintheinfraredspectrum,theSuperPulsetechnologyfromTheExOneCo.,Irwin,Pa.,usesagreenlaserbeam,saidRandyGilmore,thecompany'sdirectoroflasertechnologies.Unlikethefemtosecondvariety,Super-Pulseisananosecondlaser,anditsgreenlightoperatesatthe532-nanometerwavelength.Thetechnologyprovideslaserpulsesof4to5nanosecondsinduration,andthosepulsesaresentinpairswithadelayof50to100nanosecondsbetweenindividualpulses.Thebenefitsofthisapproacharetwofold.“Itgreatlyenhancesmaterialremovalcomparedtoothernanosecondlasers,”Gilmoresaid,“andgreatlyreducestheamountofthermaldamagedonetotheworkpiecematerial”becauseofthepulses'shortduration.

TheminimumdiameterproducedwiththeSuperPulselaseris45microns,butoneofthemostcommonapplicationsisforproducing90pmto110pmholesindieselinjectornozzlesmadeoflmm-thickHseriessteel.Gilmorenotedthatthoseholeswillneedtobeinthe50pmto70pmrangeasemissionstandardstightenbecausesmallerholesininjectornozzlesatomizedieselfuelbetterformoreefficientburning.

Inaddition,thetechnologycanproducenegativelytaperedholes,withasmallerentrancethanexitdiameter,topromotebetterfuelflow.

Anothercommonapplicationisdrillingholesinaircraftturbinebladesforcooling.Althoughtheturbinematerialmightonlybel.5mmto2mmthick,Gilmoreexplainedthattheholesaredrilledata25°entryanglesotheair,asitcomesoutoftheholes,hugstheairfoilsurfaceanddragstheheataway.Thatmeanstheholetraversesupto5mmofmaterial.“Temperatureiseverythinginaturbine”hesaid,“becauseinanaircraftengine,thehotteryoucanruntheturbine,thebetterthefueleconomyandthemorethrustyouget.”

Tofurtherenhancethetechnology'scompetitiveness,ExOnedevelopedapatent-pendingmaterialthatisinjectedintoahollow-bodycomponenttoblockthelaserbeamandpreventback-wallstrikesafteritcreatestheneededhole.Afterlasermachining,theenduserremovesthematerialwithoutleavingremnants.

“Oneofthebugaboosingettinglasersacceptedinthedieselinjectorcommunityisthatlighthasanastyhabitofcontinuingtotraveluntilitmeetsanotherobject,”Gilmoresaid.“Inadieselinjectornozzle,thatdamagestheinteriorsurfaceoftheoppositewall.”

Althoughthe$650,000to$800,000priceforaSuper-Pulselaserishigherthanamicro-holemakingEDM,Gilmorenotedthatlaserdrillingdoesn'trequireelectrodes.“Alasersystemisusinglighttomakeholes,”hesaid,“soitdoesn'thaveaconsumable.”

Dependingontheapplication,mechanicaldrillingandplungemilling,EDMingandlasermachiningallhavetheirplaceintheexpandingmicromachininguniverse.“Peoplewantmorepackedintosmallerspaces,”saidMakino'sKiszonas.

哈尔滨理工大学2008届本科生毕业设计（论文）外文翻译

中文翻译

微孔的加工方法

正如宏观加工一样，在微观加工中孔的加工也许也是最常用的加工之一。孔的加工方法有很多种，每一种都有其优点和缺陷，这主要取决于孔的直径、深度、工件材料和设备要求。这篇文章主要介绍了内冷却钻头钻孔、无冷却钻孔、插铣、电火花以及激光加工微孔的几种方法。

易于孔加工的操作

无论孔有多大，在加工时将冷却液导入到刀尖，这都有助于排屑并能降低刀具和工件表面产生的摩擦热。尤其是在加工深细孔时，有无冷却对加工的影响更大，因为深细孔加工的刀具比较脆弱，再加上刀具对切屑的二次切削和切屑的堆积会积累大量的热，而热量是碳化物刀具的主要“天敌”，它会加快刀具的失效速度。

当使用外冷却液时，刀具本身会阻止切削液进入切削加工位置。“也就是到3-5倍的直径深度后切削液就会很难流入到刀尖。”副哈维工具有限公的副总工程师杰夫戴维斯说，“这时，就应该选用带有内冷的钻头。”

另外，在加工小孔时采用外冷却液的冷却方式产生的利要大于弊，“当钻头进入工件时，已经流入孔的冷却液产生的压力有时会缴坏钻头。”戴维斯说。

刀具生产商提供的标准钻头的直径从0.039到0.125英寸，能加工深度小于12倍直径的深孔，同时提供直径从0.002到0.020英寸的不带内冷的钻头。

尽管有内冷能力，但还是不够的，冷却液还需要一定的流动速度从而能够将切屑清出孔外。戴维斯强调，冷却液的最低压力应为600-800磅/平方英寸，“加工状况还会随着所施压力的增加而提高。”他补充道。

为了防止这些冷却液通口被杂物堵塞，戴维斯还推荐在钻头上加一5口m孔径或更加精密的冷却液滤清器。

另外，他还推荐在加工孔时有必要在工件的上方先加工一个定心或导向孔，以防止刀具偏斜，并有助于保证所加工孔的垂直度。当选用定心钻时，应使选择的定心钻刀尖上的坡口角小于等于其后内冷钻的破口角。定心钻的直径还要稍微大一些。例如，如果定心钻的坡口角为120°，内冷却钻头的坡口角为140°，并且定心钻的直径小于内冷却钻的直径，“在加工时内冷却钻的拐角处会与定心孔干涉而容易脱落，”戴维斯说，“这将导致钻头损坏。”

虽然没加强调，但是加工细深孔时，啄式进给是一种很好的加工方式。戴维斯建议，根据工件的材料的不同，每次啄式进给的深度最好为孔径的30%—50%。这种加工方式便于排出切屑，使切屑不在加工的孔中堆积。

润滑及冷却

为了更加有助于排屑，戴维斯推荐在金属加工中用油基金属切削液代替水基冷却液因为油具有较高的润滑效果。但是如果车间更加青睐于使用水基冷却液，液体中应该包括EP（极压）添加剂，增加润滑和减少发泡。“如果产生很多泡沫，”戴维斯说，“切屑就不会按着预定的方式排出。”

他还补充到，另一种提高润滑并且提高刀具寿命方法是刀具涂层，例如氮铝化钛（TiAlN）°TiAlN具有很高的硬度，当钻削像不锈钢这样的难加工金属材料时，带有TiAlN涂层的刀具能有效地减少热量冲击。

威斯康星州简斯维尔微型刀具公司的总经理大卫伯顿，对微加工刀具的小批量涂层有不同的看法，他说：“对直径小于0.020英寸的刀具涂层，会对从刀具的加工质量到刀具的寿命等每一加工方面都产生消极影响”。因为小刀具的涂层不能够做得足够薄，这样涂层就会改变刀具的前角和后角，从而不利于加工。

不过，更薄涂层的开发正在继续，伯顿表示，现在微型刀具公司除了生产销售微型铣刀、刨刀和微型钻头外，还在和其他公司合作致力于开发一种亚细微涂层。伯顿说：“我们计划这种图层刀具会在六个月到一年的时间内上市。”

微型钻公司的产品主要是用于电路板加工的钻头，但也可用于有效的切削金属。所有的刀具都没带有内冷能力。“我有一个客户想要在不锈钢上面钻一个0.004英寸的孔，他当时非常惊讶这能用一把加工电路板的钻头完成。”伯顿还补充说，“采用啄式进给并选择高的主轴速度可以提高钻头的效率。”

微加工刀具要使用多高的转速，这主要依赖于车间所使用的数控机床和刀具的直径所需的转速随刀具直径的增加而加快（注：切削速度公式为sfm=刀具直径X0.26X主轴转速）。

虽然相对较低，但伯顿的客户也成功地应用过每分钟5000转的加工速度。伯顿说：“我们建议我们的用户找到一个震动最小的最高转速——最佳加工速度。”

为了减少震动，在用小的切削力通过刀具的前倾面去除适当的金属时，应使渗入到工件中的切削载荷连续而充足，如果钻头承受的切削载荷太轻，刀具前倾面的磨损速度就会加快，刀具变钝，从而影响刀具的使用寿命。这在加工细孔时应更加注意。

“用户们常常使用较轻的切削载荷来延长刀具的使用寿命，”伯顿说，“这恰恰会加快切削刃的磨损，并在刀刃宽出切屑的位置形成圆弧，刀具会变得像磨削工具一样把材料强行除掉，只能成为报废刀。”伯顿认为，直径大于0.001英寸的刀具切削抗力小于0.0001〃时，切削力抗力就已经太小了，即使刀具不会断裂，过早的摩擦也会导致刀具寿命缩短。

太多的跳动也可能是破坏性的，但是影响有多少还值得商榷。伯顿指出，公司打算设计一台具有0.0003英寸偏差的机器，用以建立室内最坏情况下的铣削场景，还将能够加工0.004英寸宽的槽，“这迟早会实现的”。

他还补充：“你还可以试想一下0.0003英寸的跳动和只有正常水平三分之一的切削载荷，也就是说0.0001〃到0.00015,刀具将会立即破坏，因为刀具的一个排屑槽会承受所有的载荷，然后排屑槽的后面就会破坏。”

他还指出，在钻孔时，小于0.0003英寸的偏差是可接受的，因为当钻头深入孔内时，钻头末端的切削刃在外圆柱非加工表面的引导下会继续切削。偏差的最小值随着深度和直径比值的增加而迅速减少，这是因为当钻头越深入工件，排屑槽的吸震能力越差。最后强烈的跳动导致刀柄绕着刀具的轴线转动，而刀尖还仍然保持稳定，从而产生使刀具最终断裂的集中应力。

插铣

虽然通常没有直径小于0.002英寸的标准微型钻头，但可以用微型端铣刀来“冲”孔。“每当人们想加工一个小于0.002英寸的孔时，他们可以选用端铣刀，效果也不错。”伯顿说到。但是这样加工的孔不能太深，因为刀具体不长，没有大的深度直径比率。因此一把直径为0.001英寸的端铣刀只能加工最深0.020英寸的孔，而同样直径的钻头可以加工得更深，因为钻头的设计使载荷全部作用在刀尖上，进而传到刀柄上被吸收。

市面上能提供最小5微米（0.0002英寸）的端铣刀，但是并没有大量销售。“当人们想买这样的刀具时，我非常严肃的试着说服他们不要买，因为我们不喜欢制作这样的刀具。”伯顿说到。这种刀具的主要问题是，不但这种刀具的硬质合金齿处于亚细微尺寸，而且当一把刀有多个齿时，每个齿的尺寸还要保持一致。伯顿道：“一把直径5微米的端铣刀在其基体上就夹持大约10个刀齿。”

他还补充说，他曾经看到过带有0.2微米齿的粉末冶金硬质合金刀具，这是商业上能提供齿的尺寸的一半，但它还包括0.5和0.6微米的小齿。“如果齿的尺寸不统一，小齿是发挥不出作用的”。

坠电火花加工

应用坠电火花的电火花加工是另一种微孔加工方式。这不同于将放电导线穿过工件的电火花加工方式，应用坠电火花加工的微孔更加精密和精确，但同时花费也会很高。

坠电火花加工深细孔时，要用一个导电管作为电极。加工小而浅的孔时，需要用到一根导线或棒，“我们尽量用导管做电极，”位于密歇根州的牧野公司总经理JeffKiszonas说道，导管的排渣孔能使加工的孔有大的深度直径比，并能够在加工中将孔底的熔渣排除孔外。他又补充道“但是另一方面，没人能制出小于一定直径的导管。”一些供应商能提供直径小于0.003英寸的导管可以加工出0.0038英