模具专业英语 教学课件 作者 王浩钢 14456第16章.ppt

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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