外文翻译计算机集成制造的定义精品.docx

外文翻译计算机集成制造的定义精品.docx

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外文翻译计算机集成制造的定义精品

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英文原文

IntroductiontoComputerIntegratedManufacturing

CIMdefinedComputerintegratedmanufacturing（CIM）isthetermusedtodescribethemodemapproachtomanufacturing.AlthoughCIMencompassesmanyoftheotheradvancedmanufacturingtechnologiessuchasCNC;CAD/CAM,robotics,andjust-in-time（JIT）deliuery,itismoreth~anewtech.nolomlor.a~c~ncept.~puterintegrated:

manufacturingisanentirelynewapproachtomanufacturing,anewwayofdoingbusiness.

TounderstandCIM,itisnecessarytobeginwithacomparisonofmodernandtraditionalmanufacturing.Modemmanufacturingencompassesalloftheactivitiesandprocessesnecessarytoconvertrawmaterialsintofinishedproducts,deliverthemtothemarket,andsupporttheminthefield.Theseactivitiesincludethefollowing:

1.Identifyinganeedforaproduct.

2.Designingaproducttomeettheneeds.

3.Obtainingtherawmaterialsneededtoproducetheproduct.

4.Applyingappropriateprocessestotransformtherawmaterialsintofinishedproducts,

5.Transportingproductstothemarket.

6.Maintainingtheproducttoensureproperperformanceinthefield.

Thisbroad,modernviewofmanufacturingcanbecomparedwiththemorelimitedtraditionalviewthatfocusedalmostentirelyontheconversionprocesses.Theoldapproachexcludedsuchcriticalpreconversionelements'asmarketanalysisreseach,development,anddesign,aswellassuchafter-conversionelementsasproductdeliveryandproductmaintenance.Inotherwords,intheoldapproachtomanufacturing,onlythoseprocessesthattookplaceontheshopfloorwereconsideredmanufacturing.Thistraditionalapproachofseparatingtheoverallconceptintonumerousstand-alonespecializedelementswasnotfundamentallychangedwiththeadventofautomation.

WithCIM,notonlyarethevariouselementsautomated,buttheislandsofautomationarealllinkedtogetherorintegrated.Integrationmeansthatasystemcanprovidecompleteandinstantaneoussharingofinformation.Inmodernmanufacturing,integrationisaccomplishedbycomputers.CIM,then,isthetotalintegrationofallcomponentsinvolvedinconvertingrawmaterialsintofinishedproductsandgettingtheproductstothemarket.

HistoricalDevelopmentofCIM

ThetermcomputerintegratedmanufacturingwasdevelopedinI974byJosephHarringtonasthetitleofabookhewroteabouttyingislandsofautomationtogetherthroughtheuseofcomputers.IthastakenmanyyearsforCIMtodevelopasaconcept,butintegratedmanufacturingisnotreallynew.Infact,integrationiswheremanufacturingactuallybegan.Manufacturinghasevolvedthroughfourdistictstages:

Manualmanufacturing.

Mechanization/Specialization

Automation.

Integration.

ManualManufacturing

Manualmanufacturingusingsimplehandtoolswasactuallyintegratedmanufacturing.

Allinformationneededtodesign,produce,anddeliveraproductwasreadilyavailablebecauseitresidedinthemindoftheonepersonwhoperformedallofthenecessarytasks,Thetoolofintegrationintheearliestyearsof,manufacturingwasthehumanmindofthecraftsmanwhodesigned,produced,anddeliveredtheproduct,Anexampleofintegratedmanualmanufacturingisthevillageblacksmithproducingaspecialtoolforalocalfarmer.Theblacksmithwouldhaveinhismindalloftheinformationneededtodesign,produce,anddeliverthefarmer'stools.Inthisexample,allelementsofmanufacturingareintegrated.

Mechanization/Specialization

Withtheadventoftheindustrialrevolution,manufacturingprocessesbecamebothspecializedandmechanized.Insteadofonepersondesigning,producing,anddeliveringaproduct,workersand/ormachinesperformedspecializedtaskswithineachofthesebroadareas.Commtmicationamongtheseseparateentitieswasachievedusingdrawings,specifications,joborders,processplans,andavarietyofothercommunicationaids.Toensurethatthefinishedproductmatchedtheplannedproduct,theconceptofualitycontrolwasintroduced

Thepositivesideofthemechanization/specializationstagewasthatitpermittedmassproduction,interchange,abilityofparts,differentlevelsofaccuracy,anduniformity.Thedisadvantageisthatthelackofintegrationledtoagreatdealofwaste.

Automation

Automationimprovedtheperformanceandenhancedthecapabilitiesofbothpeopleandmachineswithinspecializedmanufacturingcomponents.Forexample,CADenhancedthecapabilityofdesignersanddrafters.CNCenhancedthecapabilitiesofmachinistsandcomputer-assistedplanners.Buttheimprovementsbroughtonbyautomationwereisolatedwithinindividualcomponentsorislands.Becauseofthis,automationdidnotalwaysliveuptoitspotential.

Tounderstandthelimitationsofautomationwithregardtooverallproductivityimpro-vement,considerthefollowinganalogy.Supposethatvarioussubsystemsofanautomobile（i.e.,theengine,steering,brakes）wereautomatedtomakethedriver'sjobeasier.Automaticacceleration,deceleration,steering,andbrakingwouldcertainlybemoreefficientthanthemanualversions.However,considerwhatwouldhappenifthesevariousautomatedsubsystemswerenottiedtogetherinawaythatallowedthemtocommunicateandshareaccurateup-to-dateinformationinstantlyandcontinually.Onesystemmightbeattemptingtoacceleratetheautomobilewhileanothersystemwasattemptingtoapplythebrakes.Thesamelimitationsapplyinanautomatedmanufacturingsetting.Theselimitationsarewhatledtothecurrentstageinthedevelopmentofmanufacturing,integration.

Integration.

Withtheadventofthecomputerage,manufacturinghasdevelopedfullcircle.Itbeganasatotallyintegratedconceptand,withCIM,hasonceagainbecomeone.However,therearemajordifferencesinthemanufacturingintegrationoftodayandthatofDesignhasevolvedfromamanualprocessusingsuchtoolsassliderulesofmanufacturingarelinkedtogetherthroughthemanualeraofthepast.First,theinstrumentofintegrationinthemanualerawasthehumanmind.Theinstrumentofintegrationinmodernmanufacturingisthecomputer.Second,processesinthemodernmanufacturingsettingarestillspecializedandautomated.

AnotherwaytoviewthehistoricaldevelopmentofClMisbyexaminingthewaysinwhichsomeoftheindividualcomponentsofCIMhavedevelopedovertheyears.Suchcomponentsasdesign,planning,andproductionhaveevolvedbothasprocessesandinthetoolsandequipmentusedtoaccomplishtheprocesses.pencils,scales,anderasersintoanautomatedprocessknownascomputer-aideddesign（CAD）.Processplanninghasevolvedfromamanualprocessusingplanningtables,diagrams,andchartsintoanautomatedprocessknownascomputer-aidedprocessplanning（CAPP）.Productionhasevolvedfromamanualprocessinvolvingmanuallycontrolledmachinesintoanautomatedprocessknownascomputer-aidedmanufacturing（CAM）.

Theseindividualcomponentsofmanufacturingevolvedovertheyearsintoseparateislandsofautomation.However,communicationamongtheseislandswasstillhandledmanually.Thislimitedthelevelofimprovementinproductivitythatcouldbeaccomplishedintheoverallmanufacturingprocess.Whentheseislandsandotherautomatedcomponentscomputernetworks,theselimitationscanbeovercome.

MRP&CIM

Materialrequirementsplanning（MRP）isanimportantconceptwithadirectrelationshiptoCIM.Itisaprocessthatcanbeusedtocalculatetheamountofrawmaterialsthatmustbeobtainedinordertomanufactureaspecifiedlotofacertainproduct.Materialrequirementsplanninginvolvesusingthebillofmaterial,productionscheduleandinventoryrecordtoproduceacomprehensive,detailedscheduleoftheraw,materialsandcomponentsneededforajob.

Asmanufacturingtechnologyhasevolvedfromautomationtointegration,MRPhasalsoevolved.TheacronymMRPnowmeansmanufacturingresourcesplanning.Thisbroaderconceptgoesbeyonddeterminingmaterialrequirementstoalsoencompassfinancialtrackingandaccounting.ThemodemversionofMRPisparticularlywellsuitedtotheintegratedapproachrepresentedbyCIM.InthisapproachMRPcanbeaneffectiveinventoryplanningandcontroltool.

KeyconceptsrelatingtoMRPinclude:

1.independentanddependentdemand;2.leadtimes;and3.common-useitems.Independentdemandresourcesarethosethatarenottiedtoanyotherresource,Theystandalone.Dependentdemandresourcesaretieddirectlytootherresources.Receivingadependentresourcewithouttheotherresourcesitrequiresdoesnogood.Inmanufacturing,resourcesaremorelikelytobedependentthanindependent.Rawmaterials,in-procuressparts,components,andsubassembledsareallpartoftheoverallmanufacturinginventory.

Leadtimesareoftwotypes:

1.orderingleadtimeand2.manufacturingleadtime.Orderingleadtimeisthetotalamountoftimebetweeninitiatingapurchaseorderandreceivingtheorder.Manufacturingleadtimeisthetotalamountoftimerequiredtoperformallthestepsnecessarytoproduceagivenpart.

Leadtimesareimportantbecausetheyareusedindevelopingtheschedulesfororderingmaterialsandproducingproducts.TheyarealsowhereMRPismostlikelytobreakdown.Resourceplannersdependontheleadtimesprovidedtothembyotherpersonnel.Ifthesetimesarepaddedorinaccurate,theMRPresultswillbeequallyinaccurate.Common-useitemsareitemsusedinproducingmorethanjustoneproduct.Forexample,thesametypeofaluminumsheetmightbeusedinproducingseveraldifferentparts.TheintegratedapproachofMRPallowsplannerstoidentifycommon-useitemsforanumberofdifferentproductsandusethisinformationtosavemoneybyorderinginquantity.

Manufacturingresou