《模具专业英语》-Unit 8 Electrodischarge Machines

DialogueSteven:Hi,MrLee!CouldIaskyouaquestion?MrLee:Sure,goahead!Steven:What’syouropinionaboutstampingdies?Iwillattendameetingnextweek，soIwantyoutogivemeahint，maybethecontentincludesitMrLee:Well,mentionedstampingdies,theyareconstructedofseveralbasiccomponents，includingdieplates,shoes,diesets,guidepins,bushingsSteven:Ok,Ihavewrittenthemdown.Whatelse?

下一页返回DialogueMrLee:Diesalsoneedstripper,pressure，drawingpadsandthedevicesusedtosecurethem:spools，shoulderbolts，keepers，retainers，andgas，coil，orurethanespringsSteven:Great!Thankyouverymuch!Ithinkthat’senoughformyexamMrLee:Ithinkso.Wishyouhaveahighscore上一页返回TextElectrodischargeCuttingMachinesWhenapplyingtheelectrodischargemachining(EDM)process,thematerialiserodedasaresultofanelectricaldischargebetweentoolandwork.Duetotheresultantshort-lived,butveryhigh,temperaturerises,metalparticlesatthepointofdischargearemolten,partiallyvaporizedandremovedfromthemeltbymechanicalandelectromagneticforces.Theworkingmediumisadielectric,whichwashestheerodedmaterialawayandsimultaneouslyactsasacoolantEDMisacopyingprocesswherethereisnocontactbetweentoolandwork.AndthereissomeerosionofthetoolinEDM,whichmustbeallowedforinthetooldesigntoensureaccuracyofmachining.下一页返回TextElectrodischargeCuttingMachinesAnimportantapplicationofthespark-erosionprocessisthecuttingofmetalbywire-electrodes.TheprocessisusedfortheproductionofaperturesincuttingtoolsandthemanufactureoftoolelectrodesforEDM.Fig8-1illustratestheprinciple.Thecuttingtoolisathincopperorbrasswire,whichenterstheworkduringcuttingwithoutphysicalcontact.Thissufferswearasaresultoftheactionofsparkerosion,andforthisreasonfreshwireisconstantlysupplied.TheapparatusrequiredforwirefeedingcanbeseeninFig8-2.Thedegreeofwiretension,therateofwireconsumptionandthereachofthewiresupportarmsareadjustedinaccordancewiththeworktobedoneandthesizeoftheworkpiece.Theworkingmediumforelectrodischargecuttingisusuallyde-ionizedwater,whichisfedtotheworkareawiththeuseofflushingjets.上一页下一页返回TextElectrodischargeCuttingMachinesAccordingtotherequiredcontouroftheworkpiece,thetablewiththeworkclampedtoitandtheslidewiththewirefeedunitmustbesuitablypositioned.Therelativeadvanceofthecuttingtooltotheworkdoesnothaveaconstantvelocity,butmustbevariedinaccordancewiththeconditionsexistinginthegapthroughouttheprocess,dependingontheprocessofthecut,aswasthecaseinelectrodischargemachining上一页下一页返回TextElectrodischargeCuttingMachinesNewWordsandExpressionsErodevt&vi腐蚀；侵蚀dischargev放出，排出，释放；n放电，流出particlen颗粒，微粒vaporizev（使）汽化；（使）蒸发Electromagneticadj电磁的dielectricn电介质，绝缘材料；adj电介质的，绝缘的上一页下一页返回TextElectrodischargeCuttingMachinescoolantn冷却剂（液）aperturen隙；缝apparatusn机械，设备，装置，仪器ionizevt使电离，离子化flushingn冲洗，净化Gapn裂口；间隙contourn外形，轮廓，略图inaccordancewith与……一致，依照上一页下一页返回TextElectrodischargeCuttingMachinesSparkerosion电火花腐蚀flushingjet冷却喷头Electrodischargecutting电火花切割wireelectrodes线电极toolelectrode工具电极上一页返回SupplementaryReadingElectron-BeamCuttingInstallationInelectron-beamcutting,theworkmaterialisvaporizedasaresultofabeamofacceleratedelectronsimpingingonapointofcontact.Withinafewmilliseconds,achanneliscutintotheworkmaterial.Thevaporpressureforcesthemoltenmetalintheimmediatevicinityoutofthechannel.Thedepthdiameterandformofthecutcanbecontrolledthroughthecharacteristicsofthebeam.下一页返回SupplementaryReadingElectron-BeamCuttingInstallationApartfromtheactualworkchamber,ahigh-voltagesource(upto150kV)isrequired,asaredevicesforthepositioningoftheelectronbeamandtheworkinrelationtoit.Theprocesstakesplaceinavacuuminordertoavoidtheenergy-absorbingcollisionoftheelectronswithairmolecules.ThebeammaybedeflectedsidewaysandfocusedthroughtheuseofasystemofmagneticlensesanddeflectioncoilsThepowerdensitymaybeupto106kW/cm2withaminimumbeamdiameterof2μm上一页下一页返回SupplementaryReadingElectron-BeamCuttingInstallationLaserCuttingMachineLasercuttingusestheerosioneffectofhigh-energylightbeams.Asinthecaseofelectron-beamcutting,theworkmaterialisvaporizedatthepointofimpact.Accordingtothelasermaterialused,differentiationismadebetweensolidandgaslasersWithsolidlasers(e.gruby,neodymium-yttrium-aluminum-garnet),theexcitementofalightemissionisachievedwiththeuseofaflashlight(pumplight),andwhenusingagaslaser(e.gCO2,He-Ne)throughtheprovisionofahighvoltage.Alenssystemfocusesthemonochromatichigh-energylight.Thepowerdensityachievableatthepointofcontactwiththeworkmaybeupto107kW/cm2

上一页下一页返回SupplementaryReadingElectron-BeamCuttingInstallationNewWordsandExpressionsAcceleratevt&vi加速，增速vicinityn接近，附近，临近vacuumn真空，空间collisionn碰撞，冲突，抵触Deflectvt&vi偏离，偏斜，转向monochromaticadj单色的，一色的electron-beam电子束high-voltage高压solidlaser固体激光器gaslaser气体激光器

上一页返回TranslatingSkill(8):被动语态的译法Ⅰ译成汉语主动句

1原主语仍译为主语当英语被动句中的主语为无生命的名词，又不出现由介词by引导的行为主体时，常可译成汉语的主动句，原句的主语在译文中仍为主语。这种把被动语态直接译成主动语态的句子，实际是省略了“被”字的被动句，因为汉语里表示被动意义的句子可以不用“被”字，而采取主动语态的形式。2把原主语译成宾语，而把行为主体或相当于行为主体的介词宾语译成主语下一页返回TranslatingSkill(8):被动语态的译法3在翻译某些被动语态时，增译适当的主语使译文通顺流畅（1）增译逻辑主语。（2）某些要求复合宾语的动词（如believe,consider,find,know,see,think等）用于被动语态时，翻译时也常可加上不确定的主语。（3）由it作形式主语的被动句型。这实际是上述句型的一种变体，意义完全相同，译文中有时也可加不确定主语。上一页下一页返回TranslatingSkill(8):被动语态的译法现将这类常见句型及其汉译列举如下：Itisgenerallyacceptedthat一般认为，大家公认Itisallegedthat人们断言Itisassertedthat有人主张（断定）Itisbelievedthat据信，人们（大家）相信Itisclaimedthat有人（人们）主张，人们要求Itisdeclaredthat据宣称，人们宣称Itcannotbedeniedthat不可否认Itisestimatedthat据估计（推算）Ithasbeenfoundthat已经发现，实践证明Itmustbekeptinmindthat必须记住上一页下一页返回TranslatingSkill(8):被动语态的译法Itisknownthat众所周知Ithasbeenob