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《机电专业英语 教学课件 作者 杨寿智 刘水平 Lesson 11.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、Lesson11CNCMachinesTextCNCstandsforComputerNumericalControlandhasbeenaroundsincetheearly1970's.Priortothis,itwascalledNC,forNumericalControl.Intheearly1970'scomputerswereintroducedtothesecontrols,hencethenamechanges.Whilepeopleinmostwalksoflifehaveneverheardofthisterm,
2、CNChastouchedalmosteveryformofmanufacturingprocessinonewayoranother.Ifyou’llbeworkinginmanufacturing,it’slikelythatyou’llbedealingwithCNConaregularbasis.CNCmachinestypicallyreplace(orworkinconjunctionwith)someexistingmanufacturingprocesses.Asstated,CNChastouchedalmoste
3、veryfacetofmanufacturing.ManymachiningprocesseshavebeenimprovedandenhancedthroughtheuseofCNC.TherearemanytypesofCNCMachine.Let'slookatsomeofthespecificfieldsandplacetheemphasisonthemanufacturingprocessesenhancedbyCNCmachineusage.TypesofCNCmachinesInthemetalremovalindus
4、try:Machiningprocessesthathavetraditionallybeendoneonconventionalmachinetoolsthatarepossible(andinsomecasesimproved)withCNCmachiningcentersincludeallkindsofmilling(facemilling,contourmilling,slotmilling,etc.),drilling,tapping,reaming,boring,andcounterboring.Insimilarfa
5、shion,allkindsofturningoperationslikefacing,boring,turning,grooving,knurling,andthreadingaredoneonCNCturningcenters.Thereareallkindsofspecial"off-shoots"ofthesetwomachinetypesincludingCNCmillingmachines,CNCdrillandtapcenters,andCNClathes.Grindingoperationsofallkindslik
6、eoutsidediameter(OD)grindingandinternaldiameter(ID)grindingarealsobeingdoneonCNCgrinders.CNChasevenopenedupanewtechnologywhenitcomestogrinding.Contourgrinding(grindingacontourinasimilarfashiontoturning),whichwaspreviouslyinfeasibleduetotechnologyconstraintsisnowpossibl
7、e(almostcommonplace)withCNCgrinders.Fig1.1Horizontal-spindleMachiningCenterandpartFig1.2TurningCenterInthemetalfabricationindustry:Inmanufacturingterms,fabricationcommonlyreferstooperationsthatareperformedonrelativelythinplates.Thinkofametalfilingcabinet.Alloftheprimar
8、ycomponentsaremadeofsteelsheets.Thesesheetsareshearedtosize,holesarepunchedinappropriateplaces,andthesheetsarebent(fo