机械工程英语考试资料

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1、1•段落英译汉(1)Ultrasonicmachining(USM)isamechanicalmetalremovalprocessforbrittlematerialswhichuseshighfrequencyoscillationsofashapedtoolusinganabrasiveslurry.Thetermultrasonicreferstothefrequencyrangeabovetheaudiblerangeandisabove16kHz.超声加工(USM)通过高频振荡的:E作

2、头和研磨液来去除材料。超声是指频率高于人耳可听到的频率上限的声音，一般高于16KHzoAschematicdiagramoftheultrasonicmachiningset-upisshowninFig.15.3.Thetransducergeneratesthehighfrequencyvibrationsoftheorderof2030kHzwithanamplitudeoftheorderof0.02mm.Thisvibrationistransmittedtothetoolmadeofs

3、oftmaterialthroughamechanicalcouplerknownasthetoolholder.Thetoolshapeisaclosecomplementaryshapeofthefinalsurfacetobegenerated.超声设备略图如图15.3所示，变频器产生20~30kHz的，振幅0.02mm的波,它通过由软材料制成的称为刀架的连接物传到刀具上，刀具则和最终所期望得到的腔非常均合。Thetoolwhileoscillatingwouldbepressedagain

4、sttheworkpieceandfedcontinuously.Aslurryofabrasivegrainssuspendedinaliquidisfedintothecuttingzoneunderpressure.Theslurryisabout30%inconcentration.Abrasiveparticlesaredrivenintotheworksurfacebytheoscillatingtool.Theforceistypicallyabout150,000timesthew

5、eightoftheindividualgrains.Asmallcraterisformedattheimpactsiteofthegrain,iftheworkpieceisbrittle.Averylargenumberofsuchsmalleratersremovesufficientlylargematerialfromtheworkpiece.振动的刀具向工件施压并连续进给，研磨浆也就拍打在加工区域上了。研磨浆一般调到30%的浓度，研磨粒则被振动头推往加工面，其力可达研磨粒自重之十五万

6、倍，从而在工件上砸出小坑。若工件易碎，许多这样的小坑会迅速去除许多材料。Asthematerialisremoved,thetoolisgraduallyadvancedintotheworkpiecebyaservomechanismsuchthataconstantgapismaintainedbetweenthetoolandtheworkpiece.Finallytheshapeofthetoolisimpressedintotheworkpiece.材料去除后，伺服机构又推动振动头进给，

7、使工件与振动头间有定宽的缝。最终，振动头形状压入工件形成腔。ThematerialremovalratesinUSMarerelativelysmall,butinmaterialswhicharebrittle,thisistheonlywaytoproduceeconomicallycomplexcavitieswithoutbreakingtheworkpiece.Sincethereisnodirectcontactbetweentheworkpieceandthetool，fragile

8、workpiecescanbeconvenientlyusedinUSM.超声加工的切除率相对低，但这是唯一能经济地在易碎材料上制复杂形腔的办法，由于刀具并不直触工件，超声加工得以在易碎件上应用。(1)Electropolishingisanelectrochemicalprocesssimilarto,butthereverseof,electroplating.Theelectropolishingprocesssmoothesandstreamlinesthemicrosco