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ID:50055235
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页数:28页
时间:2020-03-08
《模具专业英语 教学课件 作者 王浩钢 14456第16章.ppt》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、Lesson16MachineToolsThepurposeofanymachinetoolistoremovemetal.Eachmachinetoolremovesmetalinadifferentway.it.①Forexample,inonetype(thelathe)metalisremovedbyasinglepointtoolastheworkisrotated,whereasinanothertype(themillingmachine)acutterisrotatedandmetali
2、sremovedastheworkisprogressedbeneath.Whichmachinetoolistobeusedforaparticularjobdependstoalargeextentuponthetypeofmachiningrequired.Thereis,however,acertainamountofoverlappingandsomemachinetoolscanbeutilizedforseveraldifferentoperationsbutitmustnotbeassu
3、medthattheparticularmachinetoolisrestrictedtotheoperationshown.Themachinetoolswhichwillbefoundinthemoderntoolroomareasfollows:(i)Lathesforturning,boringandscrewcutting,etc.Theprimarypurposeofthelatheistomachinecylindricalforms.Thecontourisgeneratedbyrota
4、tingtheworkwithrespecttoasingle-pointcuttingtool.(ii)Cylindricalgrindingmachinesfortheproductionofprecisioncylindricalsurfaces.Thecylindricalgrindingmachineisusedforprecisiongrindingcylindricalmouldparts.Metalisremovedbytheactionofabrasivegrindingwheelwh
5、ichisbroughtintocontactwithacontra-rotatingworkpiece.(iii)Shapingandplanningmachinesforthereductionofsteelblocksandplatestotherequiredthicknessandfor‘squaringup’theseplates②.Astheprimarypurposeofashapingmachineistoproduceflatsurfaces,thismachinetoolisuse
6、dintheinitialpreparationofmouldblocks.Theworkpieceismountedonatableandareciprocatingsingle-pointtoolremovesmetalinaseriesofstraightcuts.(iv)Surfacegrindingmachinesfortheproductionofprecisionflatsurfaces.Anexcellentsurfacefinishcombinedwithaccuracycanbeac
7、hievedonhardorsoftsteelwiththesurfacegrindingmachine.Theworkpieceismountedonatablewhichisreciprocatedbeneatharotatingabrasivegrindingwheelandmetalisremovedinaseriesofstraightcuts.(v)Millingmachinesfortherapidremovalofmetal,formachiningslots,recesses,bori
8、ngholes,machiningsplines,etc.Millingisanoperationinwhichmetalisremovedfromaworkpiecebyarotatingmillingcutter.Theworkpiececanbemovedinthreedirectionsatrightanglestoeachotherwithrespecttothecutter.Thethreedirectionsarelongit
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