机械外文翻译中英文 机床 模具 机械 材料.doc

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1、机械外文翻译中英文机床模具机械材料========================================第1页附录附录1英文原文BasicMachiningOperationsandCuttingTechnologyBasicMachiningOperationsMachinetoolshaveevolvedfromtheear1yfoot-poweredlathesoftheEgyptiansandJohnWiIkinsosboringmill.Theyaredesignedtoproviderigidsupportforboththew

2、orkpieceandthecuttingtoolandcanpreciseiycontroltheirrelativepositionsandthevelocityofthetoolwithrespecttotheworkpiece・Basically,inmetalcutting,asharpenedwedge-shapedtoolremovesarathernarrowstripofmetalfromthesurfaceofaductileworkpieceintheformofaseverelydeformedchip・Thechipisaw

3、asteproductthatisconsiderablyshorterthantheworkpiecefromwhichitcamebutwithacorrespond!ngincreaseinthicknessoftheuncutchip・Thegeometricalshapeofworkpiecedependsontheshapeofthetoolanditspathduringthemachiningoperation.Mostmachiningoperationsproducepartsofdifferinggeometry.Ifaroug

4、hcylindricalworkpiecerevolvesaboutacentralaxisandthetoolpenetratesbeneathitssurfaceandtravelsparalleltothecenterofrotation,asurfaceofrevolutionisproduced,andtheoperationiscalledturning・Ifahollowtubeismachinedontheinsideinasimilarmanner,theoperationiscalledboring・Producinganexte

5、rnalconicalsurfaceuniformlyvaryingdiameteriscalledtaperturning,ifthetoolpointtravelsinapathofvaryingradius,acontouredsurfacelikethatofabowlingpincanbeproduced;or,ifthepieceisshortenoughandthesupportissufficientlyrigid,acontouredsurfacecouldbeproducedbyfeedingashapedtoolnormalto

6、theaxisofrotation.Shorttaperedorcylindricalsurfacescouldalsobecontourformed・Flatorplanesurfacesarefrequentlyrequired・Theycanbegeneratedbyradialturningorfacing,inwhichthetoolpointmovesnormaltotheaxisofrotation.Inothercases,itismoreconvenienttoholdtheworkpiecesteadyandreciprocate

7、thetoolacrossitinaseriesofstraight-linecutswithacrosswisefeedincrementbeforeeachcuttingstroke・Thisoperationiscalledplanningandiscarriedoutonashaper・Forlargerpiecesitiseasiertokeepthetoolstationaryanddrawtheworkpieceunderitasinplanning・Thetoolisfedateachreciprocation.Contouredsu

8、rfacescanbeproducedbyusingshapedtools・Multiple-edgedto