会员注册 | 登录 | 微信快捷登录 QQ登录 微博登录 | 帮助中心 人人文库renrendoc.com美如初恋!
站内搜索 百度文库

热门搜索: 直缝焊接机 矿井提升机 循环球式转向器图纸 机器人手爪发展史 管道机器人dwg 动平衡试验台设计

外文翻译--基本的加工工序—切削,镗削和铣削.doc外文翻译--基本的加工工序—切削,镗削和铣削.doc -- 5 元

宽屏显示 收藏 分享

资源预览需要最新版本的Flash Player支持。
您尚未安装或版本过低,建议您

1英文原文BasicMachiningOperationsMachiningtoolshaveevolvedfromtheearlyfoot–poweredlatheEgyptiansandJohnWilkinsonsboringmill.Theyaredesignedtoproviderigidsupportforboththeworkpieceandthecuttingtoolandcuttingtoolandcanpreciselycontroltheirrelativepositionsandthevelocityofthetoolwithrespecttotheworkpiece.Basically,inmetalcutting,asharpenedwedgeshapedtoolremovesarathernarrowstripofmetalfromthesurfaceofaductileworkpieceinthefromofaseverelydeformedchip.Thechipiswasteproductthatisworkpieceinthefromofaseverelydeformedchipisawasteproductthatisconsiderablyshorterthantheworkpiecefromwhichitcamebutwithacorrespondingincreaseinthicknessoftheuncutchip.Thegeometricalshapeofthemachinesurfacedependsontheshapeofthetoolanditspathduringthemachiningopration.Mostmachineoperationsproducepartsofdifferinggeometry.Ifaroughcylindricalworkpiecerevolvesaboutacentralaxisandtoolpenetratesbeneathitssurfaceandtravelsparalleltothecenterofrotation,asurfaceofrevolutionisproduced,andtheoperationiscalledturning.Ifahollowtubeisonthemachinedontheinsideinasimilarmanner,theoperationiscalledboring.Producinganexternalconicalsurfaceofuniformlyvaryingdiameteriscalledtaperturning.Ifthetoolpointtravelsinapathofvaryingradius,acontouredsurfacelikethatofbowlingpincanbeproducedor,ifthepieceisshortenoughandthesupportissufficientlyrigid,acontouredsurfacecouldbeproducedbyfeedingashapedtoolnormaltotheaxisofrotation.Shorttaperedorcylindricalsurfacescouldalsobecontourformed.Flatorplanesurfacearefrequentlyrequired.Theycanbegeneratedbyradialturningorfacing,inwhichthetoolpointmovesnormaltotheaxisofrotation.Inothercases,itismoreconvenienttoholetheworkpiecesteadyandreciprocatethetoolacross,itisseriesofstraightlinecutswithacrosswisefeedincrementbeforeeachcuttingstroke.Thisoperationiscalledplanningandiscarriedoutonashaper.Forlargerpiecesitiseasiertokeepthetoolstationaryanddrawtheworkpieceunderitasinplanning.Thetoolisfedateachreciprocation.Contouredsurfacescanbeproducedbyusingshapedtools.Multipleedgedtoolscanalsobeused.Drillingusesatwinedgedflutedtoolforholeswithdepthsupto5to10timesthedrilldiameter.Whetherthedrillturnsortheworkpiecerotates,relativemotionbetweenthecuttingedgeandtheworkpieceistheimportantfactor.Inmillingoperationsarotarycutterwithanumberofcuttingedgesengagestheworkpiece,whichmovesslowlywithrespecttothecutter.Planeorcontouredsurfacesmaybeproduced,dependingonthegeometryofthecutterandthetypeoffeed.Horizontalorverticalaxesofrotationmaybeused,andthefeedoftheworkpiecemaybeinanyofthethreecoordinatedirections.BasicMachineToolsMachinetoolsareusedtopartofaspecifiedgeometetricalshapeandprecisesizebyremovingmetalfromaductilematerialintheformchips.Thelatterareawasteproductandvaryfromlongcontinuousribbonsofadisposalpointofview,toeasilyhandedwellbrokenchipsresultingfromcastiron.Machinetoolsperformfivebasicmetalremoveprocessesturning,planning,drilling,milling,andgrinding.Allothermetalremovalprocessesaremodificationsofthesefivebasicprocesses.Forexample,boringisinternalturningreaming,tapping,andcounterboringmollifydrilledholesandarerelatedtodrillinghobblingandgearcuttingarefundamentallymillingoperationshacksawingandbroachingareafromofplanningandhoninglapping,superfinishing,polishing,andbuffingarevariantsofgrindingorabrasiveremovaloperations.Therefore,thereareonlyfourtypesofbasicmachinetools,whichusecuttingtoolsofspecificcontrollablegeometry.Thegrindingprocessformschips,butthegeometryoftheabrasivegrainisuncontrollable.Theamountandrateofmaterialremovedbythevariousmachiningprocessesmaybelarge,asinheavyturningoperations,orextremelysmall,asinlappingorsuperfinishingoperationswhereonlythehighspotsofasurfaceareremoved.Amachiningtoolperformsthreemajorfunctions1.itrigidlysupportstheworkpiceoritsholderandthecuttingtool2.itprovidesrelativemotionbetweentheworkpiceandthecuttingtool3.itprovidesarangeoffeedsandspeedsusuallyrangingfrom4to32choicesineachcase.2SpeedandFeedsinMachiningSpeeds,feeds,anddepthpfcutarethethreemajorvariablesforeconomicalmachining.Othervariablesaretheworkandtoolmaterials,coolantandgeometryofthecuttingtool.Therateofmetalremovalandpowerrequiredformachiningdependuponthesevariables.Thedepthsofcut,feed,andcuttingspeedaremachinesettingthatmustbeestablishedinanymetalcuttingoperation.Theyallaffecttheforces,thepower,andtherateofmetalremoval.Theycanbedefinedbycomparingthemtotheneedleandrecordofaphonograph.ThecuttingspeedVisrepresentedbythevelocityoftherecordsurfacerelativetotheneedleinthetonearmatanyinstant.Feedisrepresentedbytheadvanceoftheneedleradiallyinwardperrevolution,oristhedifferenceinpositionbetweentwoadjacentgrooves.Thedepthofcutisthepenetrationoftheneedleintotherecordorthedepthofthegrooves.TurningonlathecentersThebasicoperationsoperationsperformedonanenginelatheareillustratedinfig.113.thoseoperationsperformedonexternalsurfaceswithasinglepointcuttingtoolarecalledturning.Exceptfordrilling,reaming,andtapping,theoperationsoninternalsurfacesarealsoperformedbyasinglepointcuttingtool.Allmachiningoperate,includingturningandboring,canbeclassifiedasroughing,finishing,orsemifinishing.Theobjectiveofaroughingoperationistoremovethebulkofthematerialasrapidlyandasefficientlyaspossible,whileleavingasmallamountofmaterialontheworkpieceforthefinishingoperation.Finishingoperationsareperformedtoobtainthefinalsize,shape,andsurfacefinishontheworkpiece.Sometimesasemifinishingoperationwillprecedethefinishingoperationtoleaveasmallpredeterminedanduniformamountofstockontheworkpiecetoberemovedbythefinishingoperation.Generally,longerworkpiecesareturnedwhilesupportedononeortwolathecenters.Coneshapedholes,calledcenterholes,whichfitthelathecentersaredrilledintheendoftheworkpieceusuallyalongtheaxisofthecylindricalpart.Theendoftheworkpieceadjacenttothetailstockisalwayssupportedbyatailstockcenter,whileendneartheheadstockmaybesupportedbyaheadstockcenterorheldinachuck.Theheadstockendoftheworkpiecemaybeheldinafourjawchuck,orinacollettypechuck.Thismethodholdstheworkpiecefirmlyandtransfersthepowertotheworkpiecesmoothlytheadditionalsupporttotheworkpieceprovidedbythechucklessensthetendencyforchattertooccurwhencutting.Preciseresultcanbeobtainedwiththismethodifcareistakentoholdtheworkpieceaccuratelyinthechuck.Verypreciseresultscanbeobtainedbysupportingtheworkpiecebetweentwocenters.Alathedogisclampedtotheworkpiecetogethertheyaredrivenbythedriverplatemountedonthespindlenose.Oneendoftheworkpieceismachinedthentheworkpiececanbeturnedaroundinthelathetomachinetootherend.Thecenterholesintheworkpieceserveaspreciselocatingsurfacesaswellasbearingsurfacestocarrytheweightoftheworkpieceandtoresistthecuttingforces.Aftertheworkpiecehasbeenremovefromthelatheforanyreason,thecenterholeswillaccuratelyaligntheworkpiecebackinthelatheorinanotherlathe,orinacylindricalgrindingmachine.Theworkpiecemustneverbeheldattheheadstockendbybothachuckandalathecenter.Whileatfirstthoughtthisseemslikeaquickmethodofaligningtheworkpieceinthechuck,thismustnotbedonebecauseitisnotpossibletopressevenlywiththejawsagainsttheworkpiecewhileitisalsosupportedbythecenter.Thealignmentprovidedbythecenterwillnotbemaintainedandthepressureofthejawsmaydamagethecenterhole,thelathecenter,andperhapseventhelathespindle.Compensatingorfloatingjawchucksusedalmostexclusivelyonhighproductionworkprovideanexceptiontothestatementsmadeabove.Thesechucksarereallyworkdriversandcannotbeusedforthesamepurposeasordinarythreeorfourjawchicks.Whileverylargediameterworkpiecearesometimesmountedontwocenters,theyarepreferablyheldattheheadstockendbyfaceplatejawstoobtainthesmoothpowertransmissionmoreover,largelathedogsthatareadequatetotransmitthepowernotgenerallyavailable,althoughtheycanbemadeasaspecial.Faceplatejawsarelikechuckjawsexceptthattheyaremountedonafaceplate,whichhaslessoverhangfromthespindlebearingsthanalargechuckwouldhave.BoringTheobjectiveofboringaholeinalatheis31、Toenlargethehole2、Tomachinetheholetothedesireddiameter3、Toaccuratelylocatethepositionofthehole4、ToobtainasmoothsurfacefinishintheholeThemotionoftheboringtoolisparalleltotheaxisofthelathewhenthecarriageismovedinthelongitudinaldirectionandtheworkpiecerevolvesabouttheaxisofthelathe.Whenthesetwomotionsarecombinedtoboreahole,itwillbeconcentricwiththeaxisofrotationofthelathe.Thepositionoftheholecanbeaccuratelylocatedbyholdingtheworkpieceinthelathesothattheaxisaboutwhichtheholeistobemachinedcoincideswiththeaxisofrotationofthelathe.Whentheboringoperationisdoneinthesamesetupoftheworkthatisusedtoturnandfaceit,practicallyperfectconcentricityandperpendicularitycanbeachieved.Theboringtoolisheldinaboringbarwhichisfedthroughtheholebycarriage.Variationsofthisdesignareused,dependingonthejobtobedone.Theleadangleused,ifany,shouldalwaysbesmall.Also,thenoseradiusoftheboringtoolmustnotbetoolarge.Thecuttingspeedusedforboringcanbeequaltothespeedforturning.However,whenthespindlespeedofthelatheiscalculated,thefinished,orlargest,borediametershouldbeused.Thefeedrateforboringisusuallysomewhatlessthanforturningtocompensatefortherigidityoftheboringbar.Theboringoperationisgenerallyperformedintwostepsnamely,roughboringandfinishboring.Theobjectiveoftheroughboringoperationistoremovetheexcessmetalrapidlyandefficiently,andtheobjectiveofthefinishboringoperationistoobtainthedesiredsize,surfacefinish,andlocationofthehole.Thesizeoftheholeisobtainedbyusingthetrialcutprocedure.Thediameteroftheholecanbemeasuredwithinsidecalipersandoutsidemicrometercalipers.BasicMeasuringInstrument,orinsidemicrometercaliperscanbeusedtomeasurethediameterdirectly.Coredholesanddrilledholesaresometimeseccentricwithrespecttotherotationofthelathe.Whentheboringtoolentersthework,theboringbarwilltakeadeepercutononesideoftheholethanontheother,andwilldeflectmorewhentakingthisdeepercut,withtheresultthattheboredholewillnotbeconcentricwiththerotationofthework..Thiseffectiscorrectedbytakingseveralcutsthroughtheholeusingashallowdepthofcut.Eachsucceedingshallowcutcausestheresultingholetobemoreconcentricthanitwaswiththepreviouscut.Beforethefinale,finishcutistaken,theholeshouldbeconcentricwiththerotationoftheworkinordertomakecertainthatthefinishedholewillbeaccuratelylocated.Shoulders,grooves,contours,tapers,andthreadsarealsoboredinsideofholes.Internalgroovesarecutusingatoolthatissimilartoexternalgroovingtool.Theprocedureforboringinternalshoulderisverysimilartotheprocedureforturningshoulders.Largershouldersarefacedwiththeboringtoolpositionedwiththenoseleading,andusingthecrossslidetofeedthetool.Internalcontourscanbemachinedusingatracingattachmentonalathe.Thetracingattachmentismountedonthecrossslideandthestylusfollowstheoutlineofthemasterprofileplate.Thiscausesthecuttingtooltomoveinapathcorrespondingtotheprofileoftheprofileplate.Thus,theprofileonthemasterprofileplateisreproducedinsidethebore.Themasterprofileplateisaccuratelymountedonaspecialslidewhichcanbepreciselyintwodirections,inordertoalignthecuttingtoolinthecorrectrelationshiptothework.Thislathehascamlocktypeofspindlenosewhichpermitsittotakeacutwhenrotatingineitherdirection.Normalturningcutsaretakenwiththespindlerotatingcounterclockwise.Theboringcutistakenwiththespindlerevolvinginaclockwisedirection,orbackwards.Thispermittheboringcuttobetakenonthebacksideoftheborewhichiseasiertoseefromtheoperatorspositionfrontofthelathe.Thisshouldnotbedoneonlatheshavingathreadedspindlenosebecausethecuttingforcewilltendtounscrewthechuck.MillingMillingisamachiningprocessforremovingmaterialbyrelativemotionbetweenaworkpieceandarotatingcutterhavingmultiplecuttingedges.Insomeapplications,theworkpieceisheldstationarywhiletherotatingcutterismovedpastitandagivenfeedratetraversed.Inotherapplications,boththeworkpieceand4cutteraremovedinrelationtoeachotherandinrelationtothemillingmachine.Morefrequently,however,theworkpieceisadvancedatarelativelylowrateofmovementorfeedtoamillingcutterrotatingatacomparativelyhighspeed,withthecuteraxisremaininginafixedposition,acharacteristicfeatureofthemillingprocessisthateachmillingcuttertoothtakesitsshareofthestockintheformofsmallindividualchips.Millingoperationsareperformedonmanydifferentmachines.Sinceboththeworkpieceandcuttercanbemovedrelativetooneanother,independentlyorincombination,awidevarietyofoperationscanbeperformedbymilling.Applicationsincludetheproductionofflatorcontouredsurfaces,slots,grooves,recesses,threads,andotherconfigurations.Millingisoneofthemostuniversal,yetcomplicatedmachiningmethods.Theprocesshasmorevariationsinthekindsofmachinesused,workpiecemovements,andtypesoftoolingthananyotherbasicmachiningmethod.Importantadvantagesofremovingmaterialbymeansofmillingincludehighstockremovalrates,thecapabilityofproducingrelativelysmoothsurfacefinishes,andthewidevarietyifcuttingtoolsthatareavailable.Cuttingedgesofthetoolscanbeshapedtoformanycomplexsurface.Themajormillingmethodsareperipheralandfacemillinginaddition,anumberofrelatedmethodsexistthatarevariationsofthesetwomethods,dependinguponthetypeofworkpieceorcutter.PeripheralMillingOnperipheralmilling,sometimescalledslabmilling,themilledsurfacegeneratedbyteethorinsertslocatedintheperipheryofthecutterbodyisgenerallyinaplaneparalleltothecutteraxis.Millingoperationswithformrelievedandformedprofilecuttersareincludedinthisclass.Thecrosssectionofthemilledsurfacecorrespondstotheoutlineorcontourofthemillingcutterorcombinationofcuttersused.Peripheralmillingoperationsareusuallyperformedonmillingmachineswiththespindlepositionedhorizontally,however,theycanalsobeperformedwithendmillsonvertiaslspindlemachines.Themillingcuttersaremountedonanarborwhichisgenerallysupportedattheouterendforincreasedrigidity,particularlywhen,becauseoftheconditionsofthesetup,thecutterorcuttersarelocatedatsomedistancefromthenoseofthespindle.Peripheralmillingshouldgenerallynotbedoneiftheperipheralmillingshouldgenerallynotbedoneifthepartcanbefacemilled.FaceMillingFacemillingisdoneonbothhorizontalandverticalmillingmachines.Themilledsurfaceresultingfromthecombinedactionofcuttingedgeslocatedontheperipheryandfaceofthecutterisgenerallyatrightanglestothecutteraxis.Themilledsurfaceisflat,withnorelationtothecontouroftheteeth,exceptwhenmillingisdonetoashoulder.Generally,facemillingshouldbeappliedwhereverandwheneverpossible.Chipthicknessinconventionalupfacemillingvariesfromaminimumattheentranceandexitofthecuttertoothtoamaximumalongthehorizontaldiameter.Themilledsurfaceischaracterizedbytoothandrevolutionmarks,asinthecaseofperipheralmillingcutters.Theprominenceofthesemarksiscontrolledbytheaccuracyofgrindingthefacecuttingedgeoftheteeth,orbytheaccuracyofthebody/insertcombinationinindexablecuttersandofmountingthecuttersothatitrunstrueonthemachinespindle.Itisalsocontrolledbytherigidityofthemachineandworkpieceitself.Whenthelengthofthefacecuttingedgeislessthanthefeedperrevolutionortheamounttheworkhasmovedinonerevolutionofthecutter,aseriesofroughlycirculargroovesorridgesresultsonthemilledsurface.Similarmarkingisproducedbythetrailingteethdragonthemilledsurfaceofthework.Thisisknownasheeldrag.Infacemilling,itisimportanttoselectacutterwithadiametersuitedtotheproposedwidthofcutifbestresultsaretobeobtained.Cutsequalinwidthtothefullcutterdiametershouldbeavoided,ifpossible,sincethethinchipsectionatentryoftheteethresultsinacceleratedtoothwearabrasionplusatendencyforthechiptoweldorsticktothetoothorinsertandbecarriedaroundandrecut.Thisisdetrimentaltosurfacefinish.Agoodratioofcutterdiametertothewidthoftheworkpieceorproposedpathofcutis53.
编号:201311171603187085    大小:55.50KB    格式:DOC    上传时间:2013-11-17
  【编辑】
5
关 键 词:
教育专区 外文翻译 精品文档 外文翻译
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
0条评论

还可以输入200字符

暂无评论,赶快抢占沙发吧。

当前资源信息

4.0
 
(2人评价)
浏览:35次
英文资料库上传于2013-11-17

官方联系方式

客服手机:17625900360   
2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   

相关资源

相关资源

相关搜索

教育专区   外文翻译   精品文档   外文翻译  
关于我们 - 网站声明 - 网站地图 - 友情链接 - 网站客服客服 - 联系我们
copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5