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READINGMATERIALUnit9TEXTMachineToolsMachinetoolsaremachinesforcuttingmetals.Themostimportantofmachinetoolsusedinindustryarelathes,drillingmachinesandmillingmachines.Otherkindsofmetalworkingmachinesarenotsowidelyusedinmachiningmetalsasthesethree.Thelatheiscommonlycalledthefatheroftheentiremachinetoolfamily.Forturningoperations,thelatheusesasinglepointcuttingtool,whichremovesmetalasittravelspasttherevolvingwork-piece.Turningoperationsarerequiredtomakemanydifferentcylindricalshapes,suchasaxes,gearblanks,pulleys,andthreadedshafts.Boringoperationsareperformedtoenlarge,finish,andaccuratelylocateholes.Drillingisperformedwitharotatingtoolcalledadrill.Mostdrillinginmetalisdonewithatwistdrill.Themachineusedfordrillingiscalledadrillpress.Operations,suchasreamingandtapping,arealsoclassifiedasdrilling.Reamingconsistsofremovingasmallamountofmetalfromaholealreadydrilled.Tappingistheprocessofcuttingathreadinsideaholesothatacapscreworboltmaybethreadedintoit.Millingremovesmetalwitharevolving,multiplecuttingedgetoolscalledmillingcutter.Millingcuttersaremadeinmanystylesandsizes.Somehaveasfewastwocuttingedgesandothershave30ormore.Millingcanproduceflat,angledsurfaces,groves,slots,gearteeth,andotherprofiles,dependingontheshapeofthecuttersbeingused.Shapingandplaningproduceflatsurfaceswithasinglepointcuttingtool.Inshaping,thecuttingtoolonashaperreciprocatesormovesbackandforthwhiletheworkisfedautomaticallytowardsthetool.Inplaning,thework-pieceisattachedtoaworktablethatreciprocatespastthecuttingtool.Thecuttingtoolisautomaticallyfedintothework-pieceasmallamountoneachstroke.Grindingmakesuseofabrasiveparticlestodothecutting.Grindingoperationsmaybeclassifiedasprecisionornon-precision,dependingonthepurpose.Precisiongrindingisconcernedwithgrindingtoclosetolerancesandverysmoothfinish.Non-precisiongrindinginvolvestheremovalofmetalwhereaccuracyisnotimportant.LEARNTOSPEAK

Mr.Zhang:Hello,Mr.Cheng,whatareyoudoing?Mr.Cheng:Iammachiningapart!Mr.Zhang:Thisisalathe,isn’tit?Mr.Cheng:Yes.Itisamediumsizelathe.Mr.Zhang:Whatcanitdo?Mr.Cheng:Cylindricalparts,hole,andendsurfacecanbemadeonit.Mr.Zhang:What’sthat?Mr.Cheng:Itisamillingmachine.Mr.Zhang:Isthisamillingcutter?Mr.Cheng:Yes,itis.Itisaendmillingcutter.Mr.Zhang:Whatkindsofworkcanitdo?Mr.Cheng:Itcanproduceplane,slotandcamsurface.Mr.Zhang:Thankyouforyourhelp.Mr.Cheng:Mypleasure.NEWWORDSANDEXPRESSIONSlathe [leIT] n.車床vt.用車床加工drill [drIl] n.鉆床v.鉆孔mill [mIl] n.銑床，銑刀vt.銑，銑削ream [ri:m] v.鉸孔tap [tAp] v.攻螺紋thread [Wred] n.螺紋，線v.車螺紋turn [t:n] v.車削cylindrical [sI5lIndrIk(E)l]adj.圓柱(體，形)的blank [blANk] n.毛坯，坯料pulley [5pJlI] n.皮帶輪，滑輪bore [bC:(r)] n.膛孔enlarge [In5lB:dV] v.擴大finish [5fInIF] n.精加工，粗糙度 v.表面拋光，完成shaper [5FeIpE(r)] n.牛頭刨床planer [5pleInE(r)] n.龍門刨床slot [slBt] n.縫，狹槽reciprocate [rI5sIprEkeIt] v.來回往復運動stroke [strEJk] n.沖程，行程abrasive [E5breIsIv] adj.摩擦(損)的particle [5pB:tIk(E)l] n.微粒precision [prI5sIV(E)n] n.精度consistof 包含，包括， 由……組成backandforth 來回，往復beattachedto 連接于，固定于beconcernedwith 與……有關(guān)系singlepointtool 單刃刀具NOTES1．Forturningoperations,thelatheusesasinglepointcuttingtool,whichremovesmetalasittravelspasttherevolvingwork-piece.為了進行車削，當工件旋轉(zhuǎn)經(jīng)過刀具時，車床用一把單刃刀具進行切削?！癋orturningoperation”作狀語，表目的，有“為了進行切削”之意。“which”引導非限制性定語從句，修飾“asingle-point-cuttingtool”?！癮singlepointcuttingtool”切不可直譯為“單點刀具”，而應譯為“單刃刀具”。2．Tappingistheprocessofcuttingathreadinsideaholesothatacapscreworblotmaybethreadedintoit.攻螺紋就是在孔內(nèi)壁上加工螺紋，以使螺釘或螺栓旋進孔內(nèi)。在英文翻譯成中文時，不必要把所有的英文一一對應翻譯成中文。如本句中“process”在譯成中文時就不必譯成“過程”，只要把句子的含義表達清楚就可以了。3．Inshaping,thecuttingtoolonashaperreciprocatesormovesbackandforthwhiletheworkisfedautomaticallytowardsthetool.用牛頭刨床進行加工時，刀具在機床上往復運動，而工件朝向刀具自動進給。用“or”連接的詞或詞組在地位上相等，有時表示的是同一個含義。本句中的“reciprocates”和“movesbackandforth”表達的是同一個含義?！癿ovesbackandforth”是對“reciprocates”的詳細說明。EXERCISES1．DiscussthefollowingquestionsinEnglish:(1)?Howdoesthelatheworkinmachiningawork-piece?(2)?Whatkindsofmethodsaretherewhenwecutathreadinthesurfaceofawork-piece?(3)?Whatkindsofmachinetoolisthemostusefulmachinetoolinmachining?2．UseEnglishforreplacingChineseoruseChineseforreplacingEnglish.(1)機床(2)車床(3)圓柱型零件(4)?Tapping(5)?Reaming(6)?Multiplecuttingedgetool3．Placea“T”aftersentencesthataretrueandan“F”afterthosethatarefalse.(1)?Themostimportantmachinetoolsusedinindustryarelathesanddrillingmachines.()(2)?Thelatheisoftencalledthefatheroftheentiremachinetoolfamily.()(3)?Millingmachinecannotbeusedtoproduceahole.()(4)?Shapingcanproducegroves.()(5)?Grindingcanformaverysmoothfaceatwork-piece.()4．TranslatethefollowingtextintoChinese:Thelatheisoneofthemostimportantmachinesinamachineshop.Varioustypesoflathesaredesignedandproducedfordifferentpurposes.Themaintypesofthemareenginelathes,benchlathes,verticallathesturretlathes,andsoon.Theenginelatheismostlyusedinmachineshops.Itcanperformvariousturningoperationsand,inaddition,drilling,threading,boring,andotheroperations.Thebenchlatheismountedonaworkbench.Itissmallerinsize.Lathesofthistypeareusedtomachinesmallparts.Theverticallatheischaracterizedbyitsverticalspindle.Itissuitableforturningheavyandshortwork-pieces.READINGMATERIALAggregateMachineToolsAnaggregatemachinetoolisahighlyefficientautomatic.Itisanaggregationofstandardcomponents,suchaspowertransmissionunits,rotarytables,millingheads,beds,columnsaswellassomespecialcomponents.Theaggregatemachinetoolmadeitsfirstappearanceinthefifties,butithasrapidlydevelopedintoaveryimportantbranchofthemachinetoolindustry.Manyfactoriesaredesigningandmakingvariousaggregatemachinetoolstoincreasetheirproduction.Forinstance,aplantinTalienhassuccessfullydesignedandbuiltanumericallycontrolledaggregatemachine,whichemploystwentythreepowertransmissionunitswithtwohundredandseventeenspindles.Withthehelpofthismachine,theproductivityofthisplantisraisedbyfourteentimes.Aggregatemachinetoolsareincreasinginnumberandvariety.Theyhavefoundwideapplicationinourmachinebuildingindustry.PROFESSIONALWORDSANDPHRASESaggregate [5A^rI^eIt] adj.組合的aggregation [A^rI5geIF(E)n] n.聚集，集合體standard [5stAndEd] n.標準well [wel] adv.好appearance [E5pIErEns] n.出現(xiàn)branch