機械外文翻譯--機械加工.doc

本科畢業(yè)論文（設計）相關中英文翻譯資料資料題目：機械加工學生姓名：所在院系：機電學院所學專業(yè)：機電技術教育完成時間：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