机械外文翻译--机械加工.doc

本科毕业论文（设计）相关中英文翻译资料资料题目：机械加工学生姓名：所在院系：机电学院所学专业：机电技术教育完成时间：MachiningTurningTheenginelathe,oneoftheoldestmetalremovalmachines,hasanumberofusefulandhighlydesirableattributes.Todaytheselathesareusedprimarilyinsmallshopswheresmallerquantitiesratherthanlargeproductionrunsareencountered.Theenginelathehasbeenreplacedintodaysproductionshopsbyawidevarietyofautomaticlathessuchasautomatictracerlathes,turretlathes,andautomaticscrewmachines.Alltheadvantagesofsingle-pointtoolingformaximummetalremoval,andtheuseofformtoolsforfinishedonaparwiththefastestprocessingequipmentonthescenetoday.Tolerancesfortheenginelathedependprimarilyontheskilloftheoperator.Thedesignengineermustbecarefulinusingtolerancesofanexperimentalpartthathasbeenproducedontheenginelathebyaskilledoperator.Inredesigninganexperimentalpartforproduction,economicaltolerancesshouldbeused.TurretLathesProductionmachiningequipmentmustbeevaluatednow,morethaneverbefore,intermsofabilitytorepeataccuratelyandrapidly.Applyingthiscriterionforestablishingtheproductionqualificationofaspecificmethod,theturretlathemeritsahighrating.Indesigningforlowquantitiessuchas100or200parts,itismosteconomicaltousetheturretlathe.Inachievingtheoptimumtolerancespossibleontheturretlathe,thedesignershouldstriveforaminimumofoperations.AutomaticScrewMachinesGenerally,automaticscrewmachinesfallintoseveralcategories；single-spindleautomatics,multiple-spindlerapid,automaticchuckingmachines.Originallydesignedforrapid,automaticproductionofscrewsandsimilarthreadedparts,thenarrowfield,andtodayplaysavitalroleinthemassproductionofavarietyofprecisionparts.Quantitiesplayanimportantpartintheeconomyofthepartsmachinedontheautomaticscrewmachine.Thecostofthepartsmachinedcanbereducediftheminimumeconomicallotsizeiscalculatedandthepropermachineisselectedforthesequantities.AutomaticTracerLathesSincesurfaceroughnessdependsgreatlyuponmaterialturned,tooling,andfeedsandspeedsemployed,minimumtolerancesthatcanbeheldonautomatictracerlathesarenotnecessarilythemosteconomicaltolerances.Insomecases,tolerancesof0.05mmareheldincontinuousproductionusingbutonecut.Groovewidthcanbeheldto0.0125mmonsomeparts.Boresandsingle-pointfinishescanbeheldto0.0125mm.Onhigh-productionrunswheremaximumoutputisdesirable,aminimumtoleranceof0.125mmiseconomicalonbothdiameterandlengthofturn.MillingWiththeexceptionsofturninganddrilling,millingisundoubtedlythemostwidelyusedmethodofremovingmetal.Wellsuitedandreadilyadaptedtotheeconomicalproductionofanyquantityofparts,thealmostunlimitedversatilityofmillingprocessmeritstheattentionandconsiderationofdesignersseriouslywiththemanufactureoftheirproduct.Asinanyotherprocess,partsthathavetobemilledshouldbedesignedwitheconomicaltolerancesthatcanbeachievedinproductionmill.Ifthepartisdesignedwithtolerancesfinerthannecessary,additionaloperationswillhavetobeaddedtoachievethesetolerances-andthiswillincreasethecostofthepart.GrindingGrindingisoneofthemostwidelyusedmethodsoffinishingpartstoextremelyclosetolerancesandfinesurfacefinishes.Currently,therearegrindersforalmosteverytypeofgrindingmachinerequired.Whereprocessingcostsareexcessive,partsredesignedtoworthwhile.Forexample,whereverpossibletheproductioneconomyofcenterlessgrindingshouldbetakenadvantageofbyproperdesignconsideration.Althoughgrindingisusuallyconsideredafinishingoperation,itisoftenemployedasacompletemachiningprocessonworkwhichcanbegrounddownfromroughconditionwithoutbeingturnedorotherwisemachined.Thusmanytypesofforgingsandotherpartsarefinishedcompletelywiththegrindingwheelatappreciablesavingsoftimeandexpense.Classesofgrindingmachinesincludethefollowing:cylindricalgrinders,centerlessgrinders,internalgrinders,surfacegrinders,andtoolexpense.Thecylindricalandcenterlessgrindersortaperwork；thussplines,shafts,andsimilarpartsaregroundoncylindricalmachineseitherofthecommon-centertypeorthecenterlessmachine.Threadgrindersareusedforgrindingprecisionthreadsforthreadgages,andthreadsonprecisionpartswheretheconcentricitybetweenthediameteroftheshaftandpitchdiameterofthreadmustbeheldtoclosetolerances.Theinternalgrindersareusedforgrindingofprecisionholes,cylinderbores,andsimilaroperationswhereboresofallkin