模具专业英语图解教程李东君课件 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.工程图是向别人表达设计师意图的一种抽象的通用语言，它是在工业和工程各个领域最为普遍使用的媒介。2、ThefixedCartesiancoordinatesystemlocatesallpointsonanAutoCADdrawingbydefiningaseriesofpositiveandnegativeaxestolocatepositionsinspace.

固定的笛卡尔坐标系是通过定义一系列用以确定空间位置的正负轴来标记AutoCAD图中的所有点。

动词不定式短语“tolocatepositionsinspace”是“aseriesofpositiveandnegativeaxes”的后置定语，说明“...axes”的作用。“bydefining...inspace”是整句的方式状语，说明标记点的方法。3、Therearemanyviewtypesusedinengineeringdrawing:projection,auxiliary,general,detailed,revolved,half,sectional,explosive,partial,etc..工程图有许多视图类型：投影视图、辅助视图、全视图、细节放大视图、旋转视图、半视图、剖视图、爆炸视图、局部视图等等。4、Thefitbetweentwomatingpartsistherelationshipwhichresultsfromtheclearanceorinterferenceobtained.两个相装配零件间的配合是一种由所产生的间隙或过盈而引发的关系。此句中“whichresults...obtained”是“therelationship”的定语从句。Theprincipalengineeringmaterialscanbedividedintothreemajorcategories:ferrousmaterials,nonferrousmaterialsandnonmetallicmaterials.Ferrousmaterialshaveironasabasemetalandincludetoolsteel,alloysteel,carbonsteelandcastiron.Nonferrousmaterialshaveabasemetalotherthanironandincludealuminum,magnesium,zinc,lead,bismuth,copperandavarietyofalloys.Nonmetallicmaterialsarethosematerialssuchaswoods,plastic,rubbers,epoxyresins,ceramicsanddiamondsthatdonothaveametallicbase.Toproperlyselectamaterial,thereareseveralphysicalandmechanicalpropertiesyoushouldunderstandtodeterminehowthematerialyouselectwillaffectthefunctionandoperationTASK1.2Notes1、Toproperlyselectamaterial,thereareseveralphysicalandmechanicalpropertiesyoushouldunderstandtodeterminehowthematerialyouselectwillaffectthefunctionandoperation.为了恰当地选择材料，我们必须掌握材料的一些物理性能和机械性能，以便确定所选的材料对功能和操作有何影响。此句主干为“therebe”句型，“youshouldunderstand”和“youselect”均为定语从句，“toproperlyselectamaterial”为目的状语，“todeterminehowthematerial…”为结果状语。Notes2、Itisthereforenotsurprisingthat,moldscanbemadefromaverybroadspectrumofmaterials,includingsuchexoticmaterialsaspapermatchandplaster.因此，可制成模具的材料多种多样，包括像纸张、石膏这样的奇异材料，这些都不足为奇。此句为强调句型，强调表语“notsurprising”。Morethan90%byweightofthemetallicmaterialsusedbyhumanbeingsareferrousalloys.Thisrepresentsanimmensefamilyofengineeringmaterialswithawiderangeofmicrostructuresandrelatedproperties.

Themajorityofengineeringdesignsthatrequirestructuralloadsupportorpowertransmissioninvolveferrousalloys.Asapracticalmatter,thesealloysfallintotwobroadcategoriesbasedonthecarboninthealloycomposition.Steelgenerallycontainsbetween0.05and2.0wt%carbon.Thecastironsgenerallycontainbetween2.0and4.5wt%carbon.TASK1.3Notes1、Thisrepresentsanimmensefamilyofengineeringmaterialswithawiderangeofmicrostructuresandrelatedproperties.钢铁是工程材料中的一个巨大家族，它们的微观结构变化很大，性能上有一定关联。句首的“This”指代前句的“ferrousalloys”。2、Themajorityofengineeringdesignsthatrequirestructuralloadsupportorpowertransmissioninvolveferrousalloys.多数要求结构有一定承载力或传递动力的工程设计都会涉及到钢铁。“thatrequirestructural…transmission”为“engineeringdesigns”的定语从句。Notes3、Lowcarbonsteelsarewellsuitedforthefollowingapplications:toolbodies,handles,dieshoesandsimilarsituationswherestrengthandwearresistancearenotrequired.低碳钢比较适宜以下用途：刀具体、手柄、模座以及类似的没有强度和耐磨性要求的位置。“wherestrengthandwearresistancearenotrequired”为“situations”的定语从句。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.铸铁得在对于复杂形状的良好成形性和相比可锻金属而言较差的机械性能之间找到一个平衡点。动词“balance”意为“权衡，平衡”。例如，Youhavetobalancetheadvantagesoflivingdowntownagainstthedisadvantages.——你必须权衡住在市中心的利弊。2、Asignificantsiliconcontent(2to3wt%)promotegraphite(C)precipitationratherthancementite(Fe3C).硅的质量百分比达到2~3%时，可显著促进石墨的析出，抑制渗碳体（Fe3C）的形成。Polymersorplasticsfallintotwomaincategories:thermosettingandthermoplastic.Upontheapplicationofinitialheatthethermosettingplasticssoftenandmelt,andunderpressuretheywillfilleverycreviceofamoldcavity.Uponcontinuedapplicationofheattheypolymerize,orundergoachemicalchange,whichhardensthemintoapermanentlyhard,infusible,andinsolublestate.Afterthistheycannotagainbesoftenedormeltedbyfurtherheating.Thethermoplasticmaterialsarethosewhichsoftenwithheatingandsolidifyandhardenwithcooling.Theycanberemeltedandcooledtimeaftertimewithoutundergoinganyappreciablechemicalchange.TASK1.5Notes1、Acommonsynonymforpolymersis“plastic”,anamederivedfromthedeformabilityassociatedwiththefabricationofmostpolymericproducts.

“塑料”是聚合物的一个普通的同义词，这个名字源于多数聚合物产品的制造过程与可塑性的紧密联系。

“anamederived…products”是一个双重过去分词结构，其中“derived…products”修饰“aname”，“associatedwith…products”修饰“thedeformability”。2、Ingeneral,themeltingpointandrigidityofpolymersincreasewithextentofpolymerizationandwithcomplexityofthemolecularstructure.通常，聚合物的熔点和硬度随着聚合程度以及分子结构的复杂程度而增长。Notes3、Uponcontinuedapplicationofheattheypolymerize,orundergoachemicalchange,whichhardensthemintoapermanentlyhard,infusible,andinsolublestate.当继续加热时，热固性塑料发生聚合，即发生化学变化，这使得热固性塑料发硬至永久硬化、很难熔化及很难溶解的状态。4、Plasticscontainingfillerswillcurefasterandholdclosertoestablishedfinisheddimensions,sincetheplasticshrinkagewillbereduced.含有填充物的塑料凝固得更快，并能更精确地达到已制定的最终尺寸，原因在于填充物使塑料的收缩率下降。现在分词短语“containingfillers”后置修饰“Plastics”；连词“since”引导原因状语从句。Annealingmaynotbethemostsuitabletreatmentforlowcarbonsteels,whichafterfullyannealedaretoosoftandrelativelyweak,offeringlittleresistancetocutting,butusuallyhavingsufficientductilityandtoughnessthatacutchiptendstopullandtearthefinishedsurface,leavingacomparativelypoorsurfacequalitythatresultsinapoormachinability.However,themachinabilityofmostofhighcarbonsteelsandalloysteelscanusuallybegreatlyimprovedbyannealing,astheyareoftentoohardandstrongtobeeasilycutatanybuttheirsoftestcondition.Toolsteelisgenerallypurchasesintheannealedcondition.Sometimesitisnecessarytoreworkatoolthathasbeenhardened,andthetoolmustthenbeannealed.Formaximumsoftnessandductilitythecoolingrateshouldbeasslowasallowingthepartstocooldownwiththefurnace.Thehigherthecarboncontent,theslowercoolingratemustbe.TASK1.6Notes1、Thiscombinationofheatingandcontrolledcoolingdeterminesnotonlythenatureanddistributionofthemicroconstituents,whichinturndeterminetheproperties,butalsothegrainsize.加热和被控制的冷却相结合，不仅决定了微观组织的性质和分布还决定了晶粒的大小。其中的微观组织的性质和分布又进而决定了材料的性能。Notes2、Annealingmaynotbethemostsuitabletreatmentforlowcarbonsteels,whichafterfullyannealedaretoosoftandrelativelyweak,offeringlittleresistancetocutting,butusuallyhavingsosufficientductilityandtoughnessthatacutchiptendstopullandtearthefinishedsurface,leavingacomparativelypoorsurfacequalitythatresultsinapoormachinability.退火并不是最适合低碳钢的热处理方法。经过完全退火的低碳钢硬度过低，强度相对也小，使得其对切削的阻力小，但是由于其有足够的塑性和韧性导致切屑会拉伤和磨损已加工表面，从而导致比较差的表面质量，进而切削加工性也差。

“which”至句末是非限制性定语从句，修饰“lowcarbonsteels”。在这个从句中，

“offering…”、“having…”和“leaving…”是三个递进关系的现在分词短语作结果状语；“having…”中是“so…that”句型，“leaving…”中“that”引导的定语从句修饰“acomparativelypoorsurfacequality”。Notes3、Withmostofthemediumcarbonforgingsteels,alloyedandunalloyed,normalizingishighlyrecommendedafterforgingandbeforemachiningtoproducemorehomogeneousstructures,andinmostcases,improvedmachinability.对于多数中碳钢，无论其是否加入合金，极力推荐在其锻造后和机加工前进行正火处理，从而产生更为均匀的组织，而且在多数情况下可改善切削加工性。Notes4、Althoughthisprocesssoftenssteel,itdiffersconsiderablyfromannealinginthattheprocesslendsitselftoclosecontrolofthephysicalpropertiesandinmostcasesdosenotsoftenthesteeltotheextentthatannealingwould.

尽管（回火）这种方法也使钢软化，但它与退火有很大差别，因为（回火）这种方法适于精确地控制材料物理性能，而且多数情况下回火钢没有退火钢那么软。

“inthat…annealingwould.”是由“inthat”引导的原因状语从句，说明回火和退火之间的的两个差异。“inthat”意思为“因为”，“lenditselfto”为习惯用法，意思为“适合于…”。

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