成组技术外文文献翻译机械加工工艺方面外文翻译中英文翻译.docx
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成组技术外文文献翻译机械加工工艺方面外文翻译中英文翻译.docx
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成组技术外文文献翻译机械加工工艺方面外文翻译中英文翻译
成组技术外文文献翻译、机械加工工艺方面外文翻译、中英文翻译
外文原文:
GroupTechnology
GrouptechnologyGTisaveryimportantmethodologyintoday’smanufacturingsignificant.Thereasonforthisisthatgrouptechnology,whenutilizedtoitsfullestextent,canaffectmostareasofmanufacturing,includingdesign,processplanning,scheduling,routing,factorylayout,procurement,qualityassurance,machinetoolutilization,tooldesign,producibilityengineering,andassembly.
1Introduction
Grouptechnologyisasimpleconceptthatisusedwidelyinvariousforms.Foravarietyofreasons,itislogicaltocollectandassociatethingsbasedonfeaturesthattheyhaveincommon.Thisapproachisfamiliartoeveryoneforplants,animals,andchemicals.Suchorganizationalstructureshavealsobeenusedforhardwareandotherobviouslysimilarproductswithinthemanufacturingworld.Grouptechnologyrepresentsstructuredcategorizationofparticularvaluetothemanufacturingcommunity.Itisalreadywidelyused;perhaps50%ofmanufacturingcompaniesusesomeformofGT.
Bathorlotproductionsuffersfrommanyinefficienciesduetopartvarietyandthegeneral-purposenatureflexibilityrequirementsofmachinetoolsinuseontheshopfloor.Infact,aCincinnatiMilacronstudyshowedthat95%ofthetimeapartspendsontheshopfloorisidletime,theother5%isdividedbetweensetupandteardownofthemachinetool.Thefuturebreakdownofthe5%ofon-machinetimewasdevelopedbyDunlap.Basedonthisestimate,only24%ofthe5%istimewhichactuallyinvolvescutting;i.e.,partsarebeingmachinedduringonly1.2%ofthetotaltimespentinmanufacturing.Grouptechnologymakespossibletheapplicationofseveralmethodsofanalysiswhichassistinmakingbatchproductionmoreefficientbyreducingpartvarietyviapartfamiliesandimprovingthroughoutandwork-in-processinventory.Itisforthisreasonthatgrouptechnologyisbecomingakeyconceptinmanufacturing.
2Definition
Manufacturingphilosophytosome,fundamentalbuildingblockformoreefficientproductiontomost,grouptechnologyisasimpleconceptwhichutilizes/exploitssimilaritiesformoreefficientproductioninbathmanufacturing.Grouptechnologyusuallyclassifiespartsintheformofacodewhichisassignedtoeachpartbasedonitsshapeorproductionprocessingcharacteristics.Inuse,codingpartsassistsinthecontrolofplanningandprocessing.Thisaddedcontrol,whichexploitssimilarities,leadstoeconomiesintheoverallmanufacturingprocess.Theactualoperatorontheshopfloormayneverknowthiscode,butdesigners,engineers,andplannersfinditaninvaluabletool,allowingthemtodomoreproductiveandusefulanalysis.
3GeneralBenefits
Inpractice,grouptechnologyisreallynothingmorethananinformation/indexingsystem.However,becauseofitsfocusonpartdesignandprocessingsimilarities,analysisispossiblewhichcreatesmanufacturingeconomiesofscale,encouragesstandardization,andeliminatesduplicationindesignandprocessplanning.
Massproductionenjoysthebenefitsofwhatarecalledeconomiesofscale.Economiesofscaleachievedbyprocessingalargenumberofpartsoverthesameworkstationsorequipment.Thisresultinlesslaborperpart,moreefficientmachineutilization,andafasterturnoverofinventory.Batchproductioninthepasthasnotenjoyedeconomiesofscalebecauseoftheneedtoremainflexibleforchangingparttypesandproducts.However,bygroupingpartsintofamiliesbasedontheirsimilarities,muchofthemanufacturingprocessingofthesepartscanbedoneonentirefamilies.Thisincreasesthenumberofpartsprocessedwiththesameequipmentconditions,therebypermittingsomeoftheeconomiesofscaleofmassproduction.
Standardizationisachievedinbothdesignandpartprocessplanning.Essentially,grouptechnologycreatesanefficientdesignretrievalsystemsincepartshavebeencodebasedonshape.Similardesignarelocatedquicklyandaspectssuchasparttolerancesandproducibilitycanbebetterunderstood,moreeasilyapplied,andkeptmoreconsistentfromdesigntodesign.Whenstandardizedprocessplanesaredevelopedandincludeinthegrouptechnologycode,newpartsandrepeatorderscanfollowsimilarprocessingroutesthroughtheshopfloor,simplifyingschedulingandflowthroughtheshop.
Grouptechnologyeliminatesduplication.Inbothdesignandprocessplanning,thereismuchles“reinventingofthewheel”sincethereissufficientretrievalofstandarddesignsandprocessplans.
4ApplicationofGTinProcessPlanning
AlthoughmanyareasofbusinessoperationcanbenefitfromGT,manufacturing,theoriginalapplicationarea,continuestobetheplacewhereGTismostwidelypracticed.Twoimportanttasksinmanufacturingplanningandmanufacturingengineeringareschedulingandprocessplanning.Jobschedulingsetstheorderinwhichpartsshouldbeprocessedandcandetermineexpectedcompletiontimesforoperationandorders.Processplanning,ontheotherhand,decidesthesequenceofmachinestowhichapartshouldberoutedwhenitismanufacturedandtheoperationsthatshouldbeperformedateachmachine.Processplanningalsoencompassestool,jig,andfixtureselectionaswellasdocumentationofthetimestandardsrunandsetuptimeassociatedwitheachoperation.Processplanningcandirectlyaffectschedulingefficiencyand,thus,manyoftheperformancemeasuresnormallyassociatedwithmanufacturingplanningandcontrol.
Someofthelargestproductivitygainshavebeenreportedinthecreationofprocessplansthatdeterminehowapartshouldbeproduced.Withcomputer-aidedprocessplanningCAPPandGTitispossibletostandardizesuchplans,reducethenumberofnewones,andstore,retrieve,edit,andprintthemoutveryefficiently.
Processplanningnormallyisnotaformalprocedure.Eachtimeanewpartisdesigned,aprocessplannerwilllookatthedrawinganddecidewhichmachinetoolsshouldprocesstheparts,whichoperationsshouldbeperformed,andinwhatsequence
Therearetworeasonswhycompaniesoftengenerateexcessprocessplans.First,mostcompanieshaveseveralplanners,andeachmaycomeupwithadifferentprocessplanfortheverysamepart,Second,process;planningisdevelopedwiththeexistingconfigurationofmachinetoolsinmind.Overtime,theadditionofnewequipmentwillchangethesuitabilityofexistingplans.Rarelyarealterationstooldprocessplansmade.Onecompanyreportedlyhad477processplansdevelopedfor523differentgears.Acloselookrevealedthatmorethan400oftheplanscouldbeeliminated.ProcessplanningusingCAPPcanavoidtheseproblems.
ProcessplanningwithCAPPtakestwodifferentforms;
Withvariant-basedplanning,onestandardizedplanandpossiblyoneormorealternateplansiscreatedandstoredforeachpartfamily.WhentheplannerenterstheGTcodeforapart,thecomputerwillretrievethebestprocessplan.Ifnoneexists,thecomputerwillsearchforroutingsandoperationsforsimilarparts.TheplannercanedittheschemeontheCRTscreenbeforeprintout.
Withgenerativeplanning,whichcanbutdoesnotnecessarilyrelyoncodedandclassifiedparts,thecomputerformstheprocessplanthroughaseriesofquestionsthecomputerposesonthescreen.Theendproductisalsoastandardizedprocessplan,whichisthebestplanforaparticularpart.
Thevariant-basedapproachreliedonestablishedplansenteredintothecomputermemory,whilethegenerativetechniquecreatestheprocessplansinteractively,relyingonthesamelogicandknowledgethataplannerhas.Generativeprocessplanningismuchmorecomplexthanvariant-basedplanning;infact,itapproachestheartofartificialintelligence.Itisalsomuchmoreflexible;bysimplychangingtheplanninglogic,forinstance,engineerscanconsidertheacquisitionofanewmachinetool.Withthevariant-basedmethod,theengineersmustlookoverandpossiblycorrectallplansthatthenewtoolmightaffect.
CAPPpermitscreationanddocumentationofprocessplansinafractionofthetimeitwouldtakeaplannertodotheworkmanuallyandvastlyreducesthenumberoferrorsandthenumberofnewplansthatmustbestored.Whenyouconsiderthatplansnormallyarehandwrittenandthatprocessplannersspendasmuchas30%oftheirtimepreparingthem,CAPP’Scontributionofstandardizedformatsforplansandmorereadabledocumentsisimportant.CAPP,ineffect,functionsasadvancedtexteditor.Furthermore,itcanbelinkedwithanautomatedstandarddatasystemthatwillcalculateandrecordtheruntimesandthesetuptimesforeachoperation.
CAPPcanleadtolowerunitcoststhroughproductionofpartsinanoptimalway.Thatis,costsavingscomenotonlyviamoreefficientprocessplanningbutalsothroughreducedlabor,material,tooling,andinventorycosts.
GTcanhelpinthecreationofprogramsthatoperatenumericallyNCmachinery,narearelatedtoprocessplanning.Forexample,aftertheengineersatOtisEngineeringhadformedpartfamiliesandcells,thetimetoproduceanewNCtapedroppedfrombetween4and8hoursto30minutes.ThecompanytherebyimprovedthepotentialforuseofNCequipmentonbatcheswithsmallmanufacturingquantities.
编者:
吴非晓等
《机械英语2》
外语教学与研究出版社2002.7
译文:
成组技术
在当今的制造环境下,尤其是对批量生产来说,成组技术(GT)是一个很重要的生产方式而且它正变得越来越重要。
其原因在于,当成组技术发挥最大作用的时候,能够影响大多数的制造领域,其中包括设计、工艺规划、调度、路线、工厂布局、采购、质量保证、车床应用、刀具设计、生产能力设计及组装。
1简介
成组技术是一个以各种形式广泛应用的简单概念。
基于各种原因,我们有理由根据事物的共同特征把它们收集并联系在一起。
对于植物、动物和化合物来说,每个人都很熟悉这种方法。
在制造业内,这种组织结构也被用于硬件和其它明显相似的产品中。
成组技术对于生产团体来说,代表着具有具体价值的组织分类。
它早就被广泛应用,大约有50%的生产企业在使用某种形式的成组技术。
由于零件多种多样以及生产车间使用的车床的通用特性(灵活性要求),造成了批量和规模生产效率差的情况很多。
一份辛辛那提麦尔克伦的研究表明,实际上一个零件花费在生产车间的时间有95%是闲置的,另外5%的时间在车床的装配和拆卸之间进行分配。
Dunlap
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