外文翻译--制造分析.doc

论文翻译MANUFACTURINGANALYSIS:HOWMUCHFLEXIBILITY?Inadditiontoproductionsystemsthatfabricateveryhighqualityproducts,atlowcost,andwithultrarapiddelivery,manystrategicplannersandeconomistspointtotheneedforflexibility.PublicationsfromJapan(Yoshio,1994；Ohsono,1995)expressasimilarview,andthemorerecentJ.D.Powerscomparativesurveysonautomobilesindicatethat"nowthatothersareclosingthequalitygap,theJapanesehavetocompeteinotherareas"(seeRechtin,1994；andtheannualJ.D.Powersreportseries).Emphasisisthusplaceonthesecombinedfactorsofquality,cost,delivery,andflexibility(QCDF).Theabilitytoreacttosmallerlotsizesandthequestforultrarapiddeliveryaremajorconconcerns,culminatinginthepossbilityofathree-daycar(Iwataetal.,1990_.Inanidealsituation,oncethevariousmarketsectorshavebeenestablished,productionwillsettleintoagrooveandbeconstantlyrefinedandimprovedbutwithnomajorupheavals.Unfortunately,inrecentyears,manufacturershavenotbeenabletorelyonlongperiodsofuninterruptedproductionbecauseeventsintheworldeconomyhaveforcedrapidchangesinconsumerdemandandtherangeofconsumerpreferences.HenryFord"sfavoriteaphorism-thathiscutomerscouldhaveanycolorofcartheywantedaslongasitwasblack-isinsharpcontrasttotodaysrangeofconsumerpreferences.Thishasledtotheproposalbysomeacademicsthatmanufacteringcanbebuiltfor"customizedmassproduction."Thissoundsniceonfirsthearing.Howerver,forproductslikeautomobiles,thedegreeofcustomizationcangoonlysofarforagivenbatchsizeandpricepoint.OnlyhyperwealthyCEOsandmoviestarscangetprecisecustomizationinproductslikeautomobiles.Nevertheless,anabilitytobepreparedforanysuddenmarketshiftsisbecomingmoreofanissue.Asnewequipmentispurchased,manufacturingcompaniesmustdecidebetweenharwarethatisdedicatetoonlyafewtasksandisthusrelativelyinexpensive,andmorecostlybutmoreversatileequipmentthatmightperformunforeseentasksinthefuture.Themethodologiesforanalyzingcapitalexpenditures,returns=on-investment(ROI),anddepreciationsaregiveninmanytexts(seeParkin,1992).thesecanbeusedtoanalyzetheROIfornewmachinerythathasbeenidentifiedasusefulandisthereforeabouttobepurchased.However,sincetodaysmarkettrendsaresouncertain,suchanalysesdonothelptopredictthespecificsystemstoinstallinthefirtplace.Thehopeisthatsomeoftheengineeringsolutionswillprovidemuchmoreflexiblemachineryforonlyamodestincreaseincost(Greeenfeldetal.,1989).Inthisway,theinvestmentdilemnamightbelesscritical.Theprecedingdiscussionsemphasizethatflexibilityisamainchallengeforthecontinuedgrowthofamewcompany.Themainquestionis:Canadesignandfabricationsystemthatisfirstsetuptorespondtoonemarketsectorbequicklyreconfiquredtorespondtotheneedsofanothermarketsector,orevenanotherproduct,andbejustasefficient?Today,theanswertothisquestionis"probablynot."Forexample,ifamachineshopiswellequippedwithlathesbuthasnoverticalboringmachines,therewillbeanaturallimitonachievabletolerances.Itisunlikelythatitwillbeabletosuddenlyjumpfromtrucktransmissionstohelicopterteansmissions.Andeveninthereversescenario,ifashophasdedicateditselftoprecisionboring.itisunlikelythattheequipmentandthecraftspeoplewillbeabletobrquicklyredeployedinacost-effectivemannertoroutineproductionproceduresandlessdemandingtolerances；theircompetitiveadvantagewouldbelost.Thesesamecomparisonscanbemadeforsemiconductormanufacturing.Manufacturerswhoarecurrentlyfocusingonthehigh-volumeproductionofmemorychipswillnotreadilyswitchtoapplication-specificdevicesorveceversa.Thegeneralconclusionmaybedrawnthattodaysmanufacturingtools-specificallymanufacturingsystems-arestilltoodedicatedtospecificmachinetools,robots,andmanuvacturingsystems-arestilltoodedicatedyospecificmarketsectorsandarenotflexibleenough.Thisgeneralneedforflexibl,reconfigurablemanufacturingsystemswasofcourseakeyaspectofCIMiitsoriginalxonception.Merchant(1980)ledanumberofindustyforecastsbetween1969and1971thatrefinedthedetailsandneedsoftheCIMphilosophy.However,theseforecastsoverestimatedtherateatwhichflexiblemanufacturingsystemsangrelatedtechnologywouldbeasorbedintofactories.Duringthe1970sand1980s,machinesexchanged”handshakes”whentaskswerecompleted.Ifthesetaskswerecompletesproperlyandontim,thenaflexiblemanufacturingsystem(FMS)continuedtooperatesatisfactorily.However,ifthemachineswentseriouslyoutofbounds,thenthecommunicaationsbrokedownandtoofrequenthumaninterventionwasneededtomaketheFMSefficient.Duringthisera,theexperiencesofseveralresearchanddevelopmentgroupsshowedthattheinadequacyofcellcommunicationsoftwarewasprobablythekeyimpedimenttotheindustrialacceptanceofCIM(Harrington,1973；Merchant,1980；Bjorke,1979).Ofinterestwasthatbythelate1980s.thereviewarticlesonCIMwereadvocatingmuchsmallerFMSsofonlythreeorfourmaxhinesasthemostefficientwayofutilizingthecellconcept.Allthesetrenssuggestesmoresophisticatedcomputer-andsensorbasedtechniquesatthefactoryfloor.asdescribedlater.2.6.1DesignforFlexibility(Reuse)Designforflexibilityintheautomobileindustrycanpayoffinabigwayifthereissomereusabilityoffixturefamilies.Theautomatedassemblylineswheretheframes,doors,andchassisareasembledwithrobotsandweldedtogetherareobviouslyintenselyexpensive.Thesearesualltwo_story-highlinesasbigasmanyfootballfieldswhererobots,fixtures,andalignmentcradlesbringthebodycomponentstogetherforweldingandassemblu.Theintensecostoftheselinesishardtopicturewithoutavisittoastandardautomobileplant.Thekeyissueistomaximizetheuseandreuseofthesefixuringlines.Ifdesigerswereallowedtotalfreedom,eachvehicleinthefamilumightrequirespecialtooling,Thiswouldnotallowcost-effectivemanufacturing.Asmintionedearlier.thisfactorplacesanimportantresponsibilityonthedesigner.Inanidealsituationthenewlydesignedcomponentwillbemadeonexisigfactory-floormachinery,readilyleadingtoan“off_the-shelf”automationsolution,Inthebestcase,existingfixturesandevensomepartsofexistingdieswillalsoreused.Somecompanies,thosewithsmallerbatchsizes,mightuseamixedproductionline.Asoneviewssuchaline,severalbodystylesgoby:perhapsthemixisassimpleasregularsedansandstationwagons.butthemixcanoftenbestretchedbeyondthistodufferentcarsofmoreorlessthesamesize.Withgooddesignformultipleusability,manyofthehardfixturesandrobotscahbeusedgorallthedifferingvehiclesinthefamily.Also,withgoodcooperationbetweenmanufacturinganddesign,theexistingrobotsandfixturesmightevenbeableto“upwardlyconstrainthevehicledesignspace”foorfuturevehickes.Therefore,viewedacrossseveralyearsandmorethanonefamilyofvehickes,automationcostsarerelativelylowerperindevidualvehicle2.62ConcludingRemarks:designAestheticsversusManufacturingJusttokeepaproperperspectiveatthecloseofthissubsection,itmustveemphasizedthatdesignformanufacturability(orflxibility)hastobeprudentlyapp；iedwiththeperceivedenduserconstantlyinmind,TheJapanesearticlesconcernedwithTQM(Yoshio,1994；Iwataetal.,1990；see