模具專業(yè)英語(yǔ)圖解教程李東君課件 1

1.CoordinatesystemThebasicofallinputAutoCADistheCartesiancoordinatesystem,andthevariousmethodsofinput(absoluteorrelative)relyonthissystem.Inaddition,AutoCADhastwointernalcoordinatesystemstohelpyoukeeptrackofwhereyouareinadrawing:theWorldCoordinateSystem(WCS)andtheUserCoordinateSystem(UCS).ThefixedCartesiancoordinatesystemlocatesallpointsonanAutoCADdrawingbydefiningaseriesofpositiveandnegativeaxestolocatepositionsinspace.2.TypesofviewsTherearemanyviewtypesusedinengineeringdrawing:projection,auxiliary,general,detailed,revolved,half,sectional,exploded,partial,etc..TASK1.1Notes1、Engineeringdrawingisanabstractuniversallanguageusedtorepresentadesigner’sideatoothersandthemostacceptedmediumofcommunicationinallaspectsofindustrialandengineeringwork.工程圖是向別人表達(dá)設(shè)計(jì)師意圖的一種抽象的通用語(yǔ)言，它是在工業(yè)和工程各個(gè)領(lǐng)域最為普遍使用的媒介。2、ThefixedCartesiancoordinatesystemlocatesallpointsonanAutoCADdrawingbydefiningaseriesofpositiveandnegativeaxestolocatepositionsinspace.

固定的笛卡爾坐標(biāo)系是通過(guò)定義一系列用以確定空間位置的正負(fù)軸來(lái)標(biāo)記AutoCAD圖中的所有點(diǎn)。

動(dòng)詞不定式短語(yǔ)“tolocatepositionsinspace”是“aseriesofpositiveandnegativeaxes”的后置定語(yǔ)，說(shuō)明“...axes”的作用。“bydefining...inspace”是整句的方式狀語(yǔ)，說(shuō)明標(biāo)記點(diǎn)的方法。3、Therearemanyviewtypesusedinengineeringdrawing:projection,auxiliary,general,detailed,revolved,half,sectional,explosive,partial,etc..工程圖有許多視圖類型：投影視圖、輔助視圖、全視圖、細(xì)節(jié)放大視圖、旋轉(zhuǎn)視圖、半視圖、剖視圖、爆炸視圖、局部視圖等等。4、Thefitbetweentwomatingpartsistherelationshipwhichresultsfromtheclearanceorinterferenceobtained.兩個(gè)相裝配零件間的配合是一種由所產(chǎn)生的間隙或過(guò)盈而引發(fā)的關(guān)系。此句中“whichresults...obtained”是“therelationship”的定語(yǔ)從句。Theprincipalengineeringmaterialscanbedividedintothreemajorcategories:ferrousmaterials,nonferrousmaterialsandnonmetallicmaterials.Ferrousmaterialshaveironasabasemetalandincludetoolsteel,alloysteel,carbonsteelandcastiron.Nonferrousmaterialshaveabasemetalotherthanironandincludealuminum,magnesium,zinc,lead,bismuth,copperandavarietyofalloys.Nonmetallicmaterialsarethosematerialssuchaswoods,plastic,rubbers,epoxyresins,ceramicsanddiamondsthatdonothaveametallicbase.Toproperlyselectamaterial,thereareseveralphysicalandmechanicalpropertiesyoushouldunderstandtodeterminehowthematerialyouselectwillaffectthefunctionandoperationTASK1.2Notes1、Toproperlyselectamaterial,thereareseveralphysicalandmechanicalpropertiesyoushouldunderstandtodeterminehowthematerialyouselectwillaffectthefunctionandoperation.為了恰當(dāng)?shù)剡x擇材料，我們必須掌握材料的一些物理性能和機(jī)械性能，以便確定所選的材料對(duì)功能和操作有何影響。此句主干為“therebe”句型，“youshouldunderstand”和“youselect”均為定語(yǔ)從句，“toproperlyselectamaterial”為目的狀語(yǔ)，“todeterminehowthematerial…”為結(jié)果狀語(yǔ)。Notes2、Itisthereforenotsurprisingthat,moldscanbemadefromaverybroadspectrumofmaterials,includingsuchexoticmaterialsaspapermatchandplaster.因此，可制成模具的材料多種多樣，包括像紙張、石膏這樣的奇異材料，這些都不足為奇。此句為強(qiáng)調(diào)句型，強(qiáng)調(diào)表語(yǔ)“notsurprising”。Morethan90%byweightofthemetallicmaterialsusedbyhumanbeingsareferrousalloys.Thisrepresentsanimmensefamilyofengineeringmaterialswithawiderangeofmicrostructuresandrelatedproperties.

Themajorityofengineeringdesignsthatrequirestructuralloadsupportorpowertransmissioninvolveferrousalloys.Asapracticalmatter,thesealloysfallintotwobroadcategoriesbasedonthecarboninthealloycomposition.Steelgenerallycontainsbetween0.05and2.0wt%carbon.Thecastironsgenerallycontainbetween2.0and4.5wt%carbon.TASK1.3Notes1、Thisrepresentsanimmensefamilyofengineeringmaterialswithawiderangeofmicrostructuresandrelatedproperties.鋼鐵是工程材料中的一個(gè)巨大家族，它們的微觀結(jié)構(gòu)變化很大，性能上有一定關(guān)聯(lián)。句首的“This”指代前句的“ferrousalloys”。2、Themajorityofengineeringdesignsthatrequirestructuralloadsupportorpowertransmissioninvolveferrousalloys.多數(shù)要求結(jié)構(gòu)有一定承載力或傳遞動(dòng)力的工程設(shè)計(jì)都會(huì)涉及到鋼鐵?！皌hatrequirestructural…transmission”為“engineeringdesigns”的定語(yǔ)從句。Notes3、Lowcarbonsteelsarewellsuitedforthefollowingapplications:toolbodies,handles,dieshoesandsimilarsituationswherestrengthandwearresistancearenotrequired.低碳鋼比較適宜以下用途：刀具體、手柄、模座以及類似的沒(méi)有強(qiáng)度和耐磨性要求的位置。“wherestrengthandwearresistancearenotrequired”為“situations”的定語(yǔ)從句。Castironshavefourgeneraltypes.Whiteironhasacharacteristicwhite,crystallinefracturesurface.LargeamountsofFe3Careformedduringcasting,givingahard,brittlematerial.Grayironhasagrayfracturesurfacewithafinelyfacetedstructure.Asignificantsiliconcontent(2to3wt%)promotegraphite(C)precipitationratherthancementite(Fe3C).Thesharp,pointedgraphiteflakescontributetocharacteristicbrittlenessingrayiron.Byaddingasmallamount(0.05wt%)ofMgtothemoltenmetalofthegrayironcomposition,spheroidalgraphiteprecipitatesratherthanflakesareproduced.Ductilityisincreasedbyafactorof20,andstrengthisdoubled.Amoretraditionalformofcastironwithreasonableductilityismalleableiron,whichisfirstcastaswhiteironandthenheattreatedtoproducenodulargraphiteprecipitates.TASK1.4Notes1、Thecastironmustbalancegoodformabilityofcomplexshapesagainstinferiormechanicalpropertiescomparedtowroughtalloys.鑄鐵得在對(duì)于復(fù)雜形狀的良好成形性和相比可鍛金屬而言較差的機(jī)械性能之間找到一個(gè)平衡點(diǎn)。動(dòng)詞“balance”意為“權(quán)衡，平衡”。例如，Youhavetobalancetheadvantagesoflivingdowntownagainstthedisadvantages.——你必須權(quán)衡住在市中心的利弊。2、Asignificantsiliconcontent(2to3wt%)promotegraphite(C)precipitationratherthancementite(Fe3C).硅的質(zhì)量百分比達(dá)到2~3%時(shí)，可顯著促進(jìn)石墨的析出，抑制滲碳體（Fe3C）的形成。Polymersorplasticsfallintotwomaincategories:thermosettingandthermoplastic.Upontheapplicationofinitialheatthethermosettingplasticssoftenandmelt,andunderpressuretheywillfilleverycreviceofamoldcavity.Uponcontinuedapplicationofheattheypolymerize,orundergoachemicalchange,whichhardensthemintoapermanentlyhard,infusible,andinsolublestate.Afterthistheycannotagainbesoftenedormeltedbyfurtherheating.Thethermoplasticmaterialsarethosewhichsoftenwithheatingandsolidifyandhardenwithcooling.Theycanberemeltedandcooledtimeaftertimewithoutundergoinganyappreciablechemicalchange.TASK1.5Notes1、Acommonsynonymforpolymersis“plastic”,anamederivedfromthedeformabilityassociatedwiththefabricationofmostpolymericproducts.

“塑料”是聚合物的一個(gè)普通的同義詞，這個(gè)名字源于多數(shù)聚合物產(chǎn)品的制造過(guò)程與可塑性的緊密聯(lián)系。

“anamederived…products”是一個(gè)雙重過(guò)去分詞結(jié)構(gòu)，其中“derived…products”修飾“aname”，“associatedwith…products”修飾“thedeformability”。2、Ingeneral,themeltingpointandrigidityofpolymersincreasewithextentofpolymerizationandwithcomplexityofthemolecularstructure.通常，聚合物的熔點(diǎn)和硬度隨著聚合程度以及分子結(jié)構(gòu)的復(fù)雜程度而增長(zhǎng)。Notes3、Uponcontinuedapplicationofheattheypolymerize,orundergoachemicalchange,whichhardensthemintoapermanentlyhard,infusible,andinsolublestate.當(dāng)繼續(xù)加熱時(shí)，熱固性塑料發(fā)生聚合，即發(fā)生化學(xué)變化，這使得熱固性塑料發(fā)硬至永久硬化、很難熔化及很難溶解的狀態(tài)。4、Plasticscontainingfillerswillcurefasterandholdclosertoestablishedfinisheddimensions,sincetheplasticshrinkagewillbereduced.含有填充物的塑料凝固得更快，并能更精確地達(dá)到已制定的最終尺寸，原因在于填充物使塑料的收縮率下降?，F(xiàn)在分詞短語(yǔ)“containingfillers”后置修飾“Plastics”；連詞“since”引導(dǎo)原因狀語(yǔ)從句。Annealingmaynotbethemostsuitabletreatmentforlowcarbonsteels,whichafterfullyannealedaretoosoftandrelativelyweak,offeringlittleresistancetocutting,butusuallyhavingsufficientductilityandtoughnessthatacutchiptendstopullandtearthefinishedsurface,leavingacomparativelypoorsurfacequalitythatresultsinapoormachinability.However,themachinabilityofmostofhighcarbonsteelsandalloysteelscanusuallybegreatlyimprovedbyannealing,astheyareoftentoohardandstrongtobeeasilycutatanybuttheirsoftestcondition.Toolsteelisgenerallypurchasesintheannealedcondition.Sometimesitisnecessarytoreworkatoolthathasbeenhardened,andthetoolmustthenbeannealed.Formaximumsoftnessandductilitythecoolingrateshouldbeasslowasallowingthepartstocooldownwiththefurnace.Thehigherthecarboncontent,theslowercoolingratemustbe.TASK1.6Notes1、Thiscombinationofheatingandcontrolledcoolingdeterminesnotonlythenatureanddistributionofthemicroconstituents,whichinturndeterminetheproperties,butalsothegrainsize.加熱和被控制的冷卻相結(jié)合，不僅決定了微觀組織的性質(zhì)和分布還決定了晶粒的大小。其中的微觀組織的性質(zhì)和分布又進(jìn)而決定了材料的性能。Notes2、Annealingmaynotbethemostsuitabletreatmentforlowcarbonsteels,whichafterfullyannealedaretoosoftandrelativelyweak,offeringlittleresistancetocutting,butusuallyhavingsosufficientductilityandtoughnessthatacutchiptendstopullandtearthefinishedsurface,leavingacomparativelypoorsurfacequalitythatresultsinapoormachinability.退火并不是最適合低碳鋼的熱處理方法。經(jīng)過(guò)完全退火的低碳鋼硬度過(guò)低，強(qiáng)度相對(duì)也小，使得其對(duì)切削的阻力小，但是由于其有足夠的塑性和韌性導(dǎo)致切屑會(huì)拉傷和磨損已加工表面，從而導(dǎo)致比較差的表面質(zhì)量，進(jìn)而切削加工性也差。

“which”至句末是非限制性定語(yǔ)從句，修飾“l(fā)owcarbonsteels”。在這個(gè)從句中，

“offering…”、“having…”和“l(fā)eaving…”是三個(gè)遞進(jìn)關(guān)系的現(xiàn)在分詞短語(yǔ)作結(jié)果狀語(yǔ)；“having…”中是“so…that”句型，“l(fā)eaving…”中“that”引導(dǎo)的定語(yǔ)從句修飾“acomparativelypoorsurfacequality”。Notes3、Withmostofthemediumcarbonforgingsteels,alloyedandunalloyed,normalizingishighlyrecommendedafterforgingandbeforemachiningtoproducemorehomogeneousstructures,andinmostcases,improvedmachinability.對(duì)于多數(shù)中碳鋼，無(wú)論其是否加入合金，極力推薦在其鍛造后和機(jī)加工前進(jìn)行正火處理，從而產(chǎn)生更為均勻的組織，而且在多數(shù)情況下可改善切削加工性。Notes4、Althoughthisprocesssoftenssteel,itdiffersconsiderablyfromannealinginthattheprocesslendsitselftoclosecontrolofthephysicalpropertiesandinmostcasesdosenotsoftenthesteeltotheextentthatannealingwould.

盡管（回火）這種方法也使鋼軟化，但它與退火有很大差別，因?yàn)椋ɑ鼗穑┻@種方法適于精確地控制材料物理性能，而且多數(shù)情況下回火鋼沒(méi)有退火鋼那么軟。

“inthat…annealingwould.”是由“inthat”引導(dǎo)的原因狀語(yǔ)從句，說(shuō)明回火和退火之間的的兩個(gè)差異?！癷nthat”意思為“因?yàn)椤保發(fā)enditselfto”為習(xí)慣用法，意思為“適合于…”。

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