会员注册 | 登录 | 微信快捷登录 支付宝快捷登录 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

   首页 人人文库网 > 资源分类 > DOC文档下载

外文翻译实体自由成型制造与快速原型制造.doc

  • 资源星级:
  • 资源大小:2.66MB   全文页数:22页
  • 资源格式: DOC        下载权限:注册会员/VIP会员
您还没有登陆,请先登录。登陆后即可下载此文档。
  合作网站登录: 微信快捷登录 支付宝快捷登录   QQ登录   微博登录
友情提示
2:本站资源不支持迅雷下载,请使用浏览器直接下载(不支持QQ浏览器)
3:本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰   

外文翻译实体自由成型制造与快速原型制造.doc

南通大学毕业设计附录(英文资料翻译)1SOUDFREEFORMFABRICATIONISFFANDRAPIDPROTOTYPING1.1SOUDFREEFORMFABRICATIONISFFMETHODSSeveralmanufacturingprocessesareavailabletomaketheimportanttransitionfromcomputeraideddesignCADtoaprototypepart.Severalnewtechnologiesbegantomaketheirappearanceafter1987.Inthatyear,stereolithographySLAwasfirstintroducedbv3DSystemsInc.,andoverthenextfiveyearsseveralrivalmethodsalsoappeared.TllScreatedthefamilyofprocessesknownassolidfreeformfabricationfSFFl.AswithmostnewtechnologiesatthebeginningofthemarketadoptionS.shapedcurvesinChapter2.theSFFdomainiSaccompaniedbyarela.tiveamountofadvertisinghype.SFFprocessesaresometimesdescribedasPartsondemandFromarttopartDesktopmanufacturingRapidprototypingAtthetimeofthiswriting,stereolithographySLA,selectivelasersinteringSLS,fuseddepositionmodelingFDM,andlayeredobjectmodelingLOMarebeingusedonadaytodaybasisbycommercialprototypingcompanies.Thethreedimensional3一Dprintingprocessincornstarch,plastic,andceramicsisalsobeingusedcommercially.Themethodsloweronthelistshowpromisebutdonotseemtobeingreatusebythirdpartyprototypinghousestomaketheirdailyincome.Castingisaspecialcase.Itisstillusedtomakeoneofakindprototypes.Furthermore,forbatchrunsinthe10to500categoryitisaverycosteffectivemethodtouseonceanoriginalmoldhasbeenmadebyaprocesssuchasstereolithography.Machiningisalsousedtomakeoneofakindorseveralprototypes.1.1.1SummaryofSFFandRapidPrototypingProcessesIndailycommercialuseStereolithographySLASelectivelasersinteringSISLaminatedobjectmodelingLOMFuseddepositionmodelingFDM南通大学毕业设计附录(英文资料翻译)2MoreattheresearchanddevelopmentRDstage3Dprintingincornstarch,plastic,orceramic3DprintingwithplasticsfollowedbyplanarizationusingmachiningSolidgroundcuringsimilartoSLAShapedepositionmodelingracombinationofadditionandsubtractionNonSFFtraditionalMachiningCastingComparisonsdoneintheearly1990sbytheChryslerCorporationrevealedthattheSLAprocesswasaheadofitsrivalnontraditionalprototypingmethodsintermsofcostandaccuracythesestudiesexcludedanevaluationofmachiningandcasting.Followingthetechnicaldescriptionsinthischapter.additionalfiguresandtablesarethusincludedtocomparethesecostsandaccuracies.Overthelastdecade,SLAhasfurtheremergedasthemostusedSFFprocess,especiallyforthegenerationofthemasterpatternsforcastingandinjectionmolding.Atthetimeofthiswriting,SLS,FDM.andLOMhavethemostvisibilityafterSLA.1.1.2TheHistoryofSFFMethodsDuringthelate1970s,MeadandConway1980createdthegroundworkforthefastprototypingofverylargescaleintegratedVLSllcircuits.Designerswereencour.agedtothinkintermsoffivetwodimensional2.Dpatterns.Thesepatternsdefinedthreestackedinterconnectionlayersonametal.oxide.semiconductorfMOSlwaferandtheirmutualconnectionsthroughholes.Thepatternsdescrybedtheactualgeometrvoftheconnectionrunsandviaholesthatonewouldseewhenlookingdownontothecircuitchip,regardlessoftheexactprocessandnumberofmaskingstepsthatwereusedtoimplementthechipseeMOSIS,2000.Inspiredbythissuccess,beginninginthe1970s,severalcompaniestriedtocreatelayeredmanufacturingformechanicalparts.AISObythemid.1980s,severaU.S.governmentstudiesanalyzedthepossibilitiesofamechanicalMOSISMan.ufacturingStudiesBoard,1990Bouldin,1994NSFworkshopI,1994,andII,1995.TheprospectsforamechanicalMOSISwerethusfrequentlylinkedtothefabricationprocessesinthelistsmentionedAshley,1991,1998Heller,1991Kruth,1991Woo,1992,1993AuandWright,1993Kochan,1993Kai,1994UCLA,1994WleissandPrinz,南通大学毕业设计附录(英文资料翻译)31995Coheneta1.,1995Dutta,1995Jacobs,1992,1996Beamaneta1.,1997Kumareta1.,1998Sachseta1.,2000.TheintroductionofthefirstcommercialSFFtechnologystereolithographywasaccompaniedbytheadventoftheSTereoLithography.STLrepresentationofaCADobiect..STUisamodifiedCADformatthatsuitsasubsequentslicingoper.actionandthedownstreamlaser.scanningpathsonaphysicalSLA.FDM.orSLSmachine.IsasoccerballroundTheanswerdependsonhowcarefullythebalIismeas.ured.Nominally,itisaperfectsphere.However.oncloserinspection.theleatherissewntogetherfromabout20littlehexagonalpatchesandafewpentagonalpatchestocreatethecurvature.Inrealityitisanapproximationtoasphere.Likewise.the.STLformatapproximatestheboundarysurfacesofaCADmodelbybreakingitdownintointerconnectedsmalltrianglesaprocesscalledtes.sellation.Eachtriangleisrepresentedbythex/y/zcoordinatesofeachofitsthreever.tices,enumeratedbytheright.handrulethatis.CounterclockwiseccworderasviewedfromtheoutsideofthebodvThevectornormaltothesurfaeeofeachtriangleisalsospecified.1histessellatedsurfaceisstoredasan.STLfile.thisfile.Perhapscontainingupto200,000triangles,issentovertheInternettoaprototypingshop.AsshowninFigure4.1.thistessellatedCADmodelisthenslicedlikeastackofplayingcards.For3DSystemsmachinesthisisknownastheSLIorslicedfile.Otherrapidprototypingmachinesusetheslicingtechniquebuthavetheirownfilecreationdetailsandnames.Eachslicefortheimaginarysoccerballwillthusbeacircle.However.becauseofthetessellationprocedureitwillnotbeaperfectcircle.Theslicingactioncutsthroughthetrianglesontheboundary.Thus,eachcircularsliceordiscwillactuallybeamultisidedpolygonrunninginsidetheboundingcircle.Thenumberofsidesonthisinnerpolygonisofcourserelatedtohowfinelydividedtheoriginaltessellationwasmade.InsidetheSLAmachine.thelaserfirstcreatestheouterboundaryofeachsliceandthenweavesacrosseachsliceinahatchingpatterntocreatethelayer.Thenumberofslicesandthestyleoftheweavingpatternarechosenbyeachrapidpro.Totypingshop.EspeciallyforSLAandSLSacertainamountoftrialanderror.Orcraftspersonship,beginstoplayaroleatthisstage.Thisisreviewedinmoredetailoverthenextfewpages..STL,isnowthestandardexchangeformatforSFFprocesses.However.itisinadequate南通大学毕业设计附录(英文资料翻译)4formanyreasons.First,thefilesarelargeduetothetessellationmethod.Second.thereareredundanciesinthe.STLformat.0neexampleofredundancyisasfollowsthetrianglesarerepresentedbythecounterclockwiserulesothatitisclearinwhichdirectiontheoutersurfacenormalacts.However.ithasalsobecomecustomarytospecifythesurfacevectoraswell.Inconsistencycanbeintroducedasaresultofthisredundancy,andnorulesexistforresolvingit.McMains1996describeshow.STLdoesnotcapturetopologyorconnectivity,makingitdifficulttofixsomeofthecommonerrorsfoundinfilessuchascracks,penetratingorextraneousfaces,andinconsistentsurfacenormalswithoutresortingtoguessingthedesignersoriginalintent.MoregeneraldigitalinterchangeformatshavealsobeenusedwithSFlFTheseincludeACIS1993andIGESHeller,1991.However,asdescribedinNSF1995,problemsarisewiththeseformats,tooOneaspectofongoingresearchisthustoimprovethisrepresentationlanguageMcMainseta1.,1998.1.2CASTINGMETHODSFORRAPIDPROTOTYPING

注意事项

本文(外文翻译实体自由成型制造与快速原型制造.doc)为本站会员(淘宝运营)主动上传,人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知人人文库网([email protected]),我们立即给予删除!

温馨提示:如果因为网速或其他原因下载失败请重新下载,重复下载不扣分。

copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5