機(jī)械外文翻譯--機(jī)械加工.doc
本科畢業(yè)論文(設(shè)計(jì))相關(guān)中英文翻譯資料資料題目:機(jī)械加工學(xué)生姓名:所在院系:機(jī)電學(xué)院所學(xué)專業(yè):機(jī)電技術(shù)教育完成時(shí)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,andsimilaroperationswhereboresofallkindsaretobefinished.Thesurfacegrindersareforfinishingallkindsofflatwork,orworkwithplainsurfaceswhichmaybeoperateduponeitherbytheedgeofawheelorbythefaceofagrindingwheel.Thesemachinesmayhavereciprocatingorrotatingtables.