Unit-3-Lesson-7PPT课件

ProfessionalEnglishforMechanicalEngineeringLecturer:XiaobinCui*PartIIInterchangeabilityandMeasurementLesson7WorkingDrawing*Lesson7WorkingDrawingWorkingdrawingarethedrawingsfromwhichadesignisimplemented.Allprinciplesoforthographicprojectionandtechniquesofgraphicscanbeusedtocommunicatethedetailsofaprojectinworkingdrawings.Adetaildrawingisaworkingdrawingofasinglepart(ordetail)withinthesetofworkingdrawings.Definitionsworkingdrawing工作图,施工图orthographic[,ɔ:θəʊ'ɡræfik]adj.正投影的orthographicprojection正投影detaildrawing详图零件图在工作图中，所有正交投影法则和图形技术均可用来表达设计的细节。*Lesson7WorkingDrawingSpecificationsarethewritteninstructionsthataccompanyworkingdrawings.Whenthedesigncanberepresentedonafewsheets,thespecificationsareusuallywrittenonthedrawingstoconsolidatetheinformationintoasingleformat.Definitionsspecifications[,spεsəfə'keʃən]n.技术要求当设计在多张图纸上表达时，通常在工作图上注明技术要求，从而确保图纸信息的统一性。consolidate[kən'sɔlideit]vt.巩固，统一，整理*Allpartsmustinteractwithpartstosomedegreetoyieldthedesiredfunctionfromadesign.Beforedetaildrawingsofindividualpartsaremade,thedesignermustthoroughlyanalyzetheworkingdrawingtoensurethatthepartsfitproperlywithmatingparts,thatthecorrecttolerancesareapplied,thatthecontactsurfacesareproperlyfinished,andthatthepropermotionispossiblebetweentheparts.Lesson7WorkingDrawingYield产生，形成matingparts配合件tolerance['tɔlərəns]n.公差；规定公差在绘制单个零部件的详图之前，设计人员必须对工作图进行充分分析，以确保零部件之间的配合良好、采用正确的公差、可对接触面进行合理的加工，以及零部件之间能够产生合理的运动。Requirements*Muchoftheworkinpreparingworkingdrawingsisdonebythedrafter,butthedesigner,whoisusuallyanengineer,isresponsiblefortheircorrectness.Itisworkingdrawingsthatbringproductsandsystemsintobeing.Workingdrawingsarelegalcontractsthatdocumentthedesigndetailsandspecificationsasdirectedbytheengineer.Thereforedrawingsmustbeasclear,precise,andthoroughaspossible.Lesson7WorkingDrawingbring…intobeing使出现，实现，产生，建立工作图的许多准备工作是由绘图员来完成的，而图纸的正确性则要由设计者负责，设计者通常是师。Requirements*Revisionsandmodificationsofaprojectatthetimeofproductionorconstructionaremuchmoreexpensivethanwhendoneinthepreliminarydesignstages.Poorlyexecutedworkingdrawingsresultinwastedtimeandresourcesandincreaseimplementationcosts.Tobeeconomicallycompetitivedrawingsmustbeaserror-freeaspossible.Lesson7WorkingDrawing生产或施工中修订和更改设计方案所需成本要比初步设计阶段高很多。Requirements*TheinchisthebasicunitoftheEnglishsystem,andvirtuallyallshopdrawingsintheU.S.aredimensionedininches.Themillimeteristhebasicunitofthemetricsystem.Metricabbreviation(mm)afterthenumeralsisomittedfromdimensionsbecausetheSIsymbolnearthetitleblockindicatesthatallunitsaremetric.Lesson7WorkingDrawingabbreviation[ə,bri:vi'eiʃən]n.缩写，缩写词titleblock标题栏由于在标题栏附近的国际单位制（SI）符号标明所有单位为公制，因此尺寸数字后面的单位缩写（mm）要省略标注。Requirements**Someworkingdrawingscarrybothinchandmillimeterdimensions,usuallythedimensionsinparenthesesorbracketsaremillimeters.Theunitsmayalsoappearasmillimetersfirstandthenbeconvertedandshowninbracketsasinches.Convertingfromoneunittotheotherresultstofractionalround-offerrors.Andexplanationoftheprimaryunitsystemforeachdrawingshouldbenotedinthetitleblock.Lesson7WorkingDrawingparenthesis[pə'renθisis]n.圆括号bracket[‘brækit]n.方括号有些图纸的尺寸单位既有英寸也有毫米，通常在圆括号或方括号中的尺寸以毫米为单位.fractional['frækʃənl]adj.分数的，小数的round-off四舍五入，抹去零头Requirements**TitleBlocksInpractice，titleblocksusuallycontainthetitleorpartname,drafter,date,scale,company,andsheetnumber.Otherinformation,suchastolerances,checkers,andmaterials,alsomaybegiven.Anymodificationsorchangesaddedafterthefirstversiontoimprovethedesignisshownintherevisionblocks.Dependingonthecomplexityoftheproject,asetofworkingdrawingsmaycontainfromonetomorethanahundredsheets.Therefore,givingthenumberofeachsheetandthetotalnumberofsheetsinthesetoneachsheetisimportant(forexample,sheet2of6,sheet3of6,andsoon).Lesson7WorkingDrawingTitleBlocks**PartsListThepartnumbersandpartnamesinthepartslistcorrespondtothosegiventoeachpartdepictedontheworkingdrawings.Inaddition,thenumberofidenticalpartsrequiredisgivenalongwiththematerialusedtomakeeachpart.Ifallworkingdrawingsinasetarethesamescale,youneedtoindicateitonlyonceintitleblockoneachsheet.Ifseveraldetaildrawingsonaworkingdrawingaredifferentscales,indicatethemonthedrawingundereachsetofviews.Inthiscase,indicate,“asshown”inthetitleLesson7WorkingDrawingpartlist零件明细表，材料清单asshown如图所示PartList*blockoppositescale.Whenadrawingisnotaccordingtothescale,placetheabbreviationNTS(nottoscale)inthetitleblock.PartNamesandNumbersGiveeachpartanameandnumber,usinglettersandnumbers1/8-in.(3mm)high.Placepartnumbersinsidecircles,calledballoons,havingdiametersapproximatelyfourtimestheheightofthenumber.Placepartnumbersneartheviewstowhichtheyapply,sotheirassociationwillbeclear.Lesson7WorkingDrawingnottoscale不按比例partnumber零部件序号将部件序号置于直径约四倍数字高度的圆内，称为带圆圈的数字。PartListPartNamesandNumbers*Onassemblydrawings,balloonsareespeciallyimportantbecausethesamepartsnumbersareusedinthepartslist.Peoplewhocheckdrawingsmusthavespecialqualificationsthatenablethemtoidentifyerrorsandtosuggestrevisionsandmodificationsthatresultinabetterproductatalowercost.Lesson7WorkingDrawing图纸审核员必须具有专业任职资格，才能识别错误，并能提出修订和修改方案，从而以相对较低的成本生产出较高质量的产品。PartNamesandNumbersCheckandRevision*Acheckermaybechiefdrafterexperiencedindraftingandmanufacturingprocessesortheengineerordesignerwhooriginatedtheproject.Inlargecompanies,personnelinthevariousshopsinvolvedinproductionreviewthedrawingstoensurethatthemostefficientproductionmethodsarespecifiedforeachpart.Lesson7WorkingDrawing在大型公司，与生产相关的各部门要有专人对图纸进行复审，以确保每个零部件均已指定最有效生产方法。CheckandRevision*Checkersneverchecktheoriginaldrawing;instead,theymarkcorrectionswithacoloredpencilonablue-lineprint.Theyreturnthemarked-upprinttothedrafterwhorevisestheoriginalandmakesanotherprintforfinalapproval.Checkersinspectaworkingordetaildrawingforcorrectnessandsoundnessofdesign.Inaddition,theyareresponsibleforthedrawing’scompleteness,quality,readability,andclarity.Inadditiontotheindividualrevisionrecords,draftersshouldkeepalogofallchangesmadeduringaproject.Astheprojectprogresses,thedraftershouldrecordthechanges,dates,andpeopleinvolved.Lesson7WorkingDrawinglog[lɔɡ,lɔ:ɡ]n.（工程、试验等的）工作CheckandRevision*Suchalogallowsanyonereviewingtheprojectinthefuturetounderstandeasilyandclearlytheprocessusedtoarriveatthefinaldesign.Calculationsoftenaremadeduringadrawing’spreparation.Iftheyarelostorpoorlydone,theymayhavetoberedone;thereforetheyshouldbeapermanentpartofthelog.Lesson7WorkingDrawing这样的记录可让将来的任何一位审查人员能够清楚容易地了解达到最终设计的整个进程。CheckandRevision*****