计算机辅助制造外文文献翻译、中英文翻译

IntegratedComputerAidedManufacturing1.INTRODUCTIONToday’sindustrycompetesinatrulyinternationalmarketplace.Efficienttransportationnetworkshavecreateda“worldmarket”inwhichweparticipateonadailybasis.Foranyindustrialcountrytocompeteinthismarket,itmusthavecompaniesthatprovideeconomichigh-qualityproductstotheircustomersinatimelymanner.Theimportanceofintegratingproductdesignandprocessdesigntoachieveadesignforproductionsystemcannotbeoveremphasized.However,evenonceadesignisfinalized,manufacturingindustriesmustbewillingtoaccommodatetheircustomersbyallowinglast-minuteengineering-designchangeswithoutaffectingshippingschedulesoralteringproductquality.MostU.S.-basedmanufacturingcompanieslooktowardCAD/CAMandCIMtoprovidethisflexibilityintheirmanufacturingsystem.Today,theuseofcomputersinmanufacturingiscommon.Manufacturingsystemarebeingdesignedthatnotonlyprocesspartsautomatically,butalsomovethepartsfrommachinetomachineandsequencetheorderingofoperationsinthesystem.Figure1containsaplotoftheeconomicregionsofmanufacturing.ItshouldbenotedthatmanualhandcraftedgoodswillalwayshaveamarketintheUnitedStatesaswellasabroad.Thisisalsotrueofindustrialproducts—therewillcontinuetobeaneedforspecialone-of-a-kinditems.Thespectrumofone-of-a-kindgoodsthroughhigh-volumegoodsdictatesthatavarietyofmanufacturingmethodsbeusedtomeetourvariousindustrialneeds.Someofthesesystemswilllooklikethefactoriesthatourgrandparentslaboredin,whereasotherswilltakeonafuturisticlook.Inthefollowingsections,adiscussionofflexiblemanufacturingsystemsispresented.Figure1Volumeversusvarietyregionsforeconomicmanufacturing(CourtesyofCincinnatiMilacron.)2.FLEXIBLEMANUFACTURINGSYSTEMSAflexiblemanufacturingsystem,orFMSastheyaremorecommonlyknown,isareprogram-ablemanufacturingsystemcapableofproducingavarietyofproductsautomatically.SinceHenryFordfirstintroducedandmodernizedthetransferline,wehavebeenabletoperformavarietyofmanufacturingoperationsautomatically.However,alteringthesesystemstoaccommodateevenminorchangesintheproducthasbeenquitetaxing.Wholemachinesmighthavetobeintroducedtothesystemwhileothermachinesorcomponentsaremodifiedorretiredtoaccommodatesmallchangesinaproduct.Intoday’scompetitivemarketplace,itisnecessarytoaccommodatecustomerchangesorthecustomerwillfindsomeoneelsewhowillaccommodatethechanges.Conventionalmanufacturingsystemshavebeenmarkedbyoneoftwodistinctfeatures:Jobshoptypesystemswerecapableofproducingavarietyofproduct,butatahighcost.Transferlinescouldproducelargevolumesofaproductatareasonablecost,butwerelimitedtotheproductionofone,two,orveryfewdifferentparts.Theadventofnumericalcontrol(NC)androboticshasprovideduswithreprogrammingcapabilitiesatthemachinelevelwithminimumsetuptime.NCmachinesandrobotsprovidethebasicphysicalbuildingblocksforre-programmablemanufacturingsystems.2.1.FMSEquipment2.1.1MachinesInordertomeettherequirementsofthedefinitionofanFMS,thebasicprocessinginthesystemmustbeautomated.Becauseautomationmustbeprogrammableinordertoaccommodateavarietyofproduct-processingrequirements,easilyalterableaswellasversatilemachinesmustperformthebasicprocessing.Forthisreason,CNCturningcenters,CNCmachiningcenters,androboticworkstationscomprisethemajorityofequipmentinthesesystems.Thesemachinesarenotonlycapableofbeingeasilyreprogrammed,butarealsocapableofaccommodatingavarietyoftoolingviaatoolchangerandtool-storagesystem.ItisnotunusualforaCNCmachiningcentertocontainto12ormoretools(right-handturningtools,left-handturningtools,boringbars,drills,andsoon).TheautomatictoolchangerandstoragecapabilitiesofNCmachinesmakethemnaturalchoicesformaterial-processingequipment.Partsmustalsobemovedbetweenprocessingstationsautomatically.Severaldifferenttypesofmaterial-handlingsystemsareemployedtomovethesepartsfromstationtostation.Theselectionofthetypeofmaterial-handlingsystemisafunctionofseveralsystemfeatures.Thematerial-handlingsystem,first,mustbeabletoaccommodatetheloadandbulkofthepartandperhapsthepartfixture.Large,heavypartsrequirelarge,powerfulhandlingsystemssuchasrollerconveyorsguidedvehiclesortrack-drivenvehiclesystems.Thenumberofmachinestobeincludedinthesystemandthelayoutofthemachinesalsopresentanotherdesignconsideration.Ifsinglematerialhandlermustbeatleastaslargeasthephysicalsystem.Arobotisnormallyonlycapableofaddressingoneortwomachinesandload-and-unloadstation.Aconveyororautomaticguidevehicle(AGV)systemcanbeexpandedtoincludemilesoffactoryfloor.Thematerial-handlingsystemmustalsobecapableofmovingpartsfromonemachinetoanotherinatimelymanner.Machinesinthesystemwillbeunproductiveiftheyspendmuchoftheirtimewaitingforpartstobedeliveredbythematerialhandler.Ifmanypartsareincludedinthesystemandtheyrequirefrequentvisitstomachines,thenthematerial-handlingsystemmustbecapableofsupportingtheseactivities.Thisusuallycanbeaccommodatedbyusingeitheraveryfasthandlingdeviceofbyusingseveraldevicesinparallel,forexample,insteadofusingasinglerobottomovepartstoallthemachinesinthesystem,arobotwouldonlysupportasinglemachine.2.1.2Toolingandfixtures.VersatilityisthekeytomostFMSs,andassuchthetoolingusedinthesystemmustbecapableofsupportingavarietyofproductsorparts.TheuseofspecialformingtoolsinanFMSisnottypicalinpractice.Thecontoursobtainedbyusingformingtoolscanusuallybeobtainedthroughacontour-controlNCsystemandastandardmill.Thestandardmillthencanbeusedforavarietyofpartsratherthantoproduceasinglespecialcontour.Aneconomicofthecostandbenefitsofanyspecialtoolingisnecessarytodeterminethebesttoolingcombination.However,becauseNCmachineshavealimitedoftoolsthatareaccessible,veryspecialtoolsshouldbeincluded.OneofthecommonlyneglectedaspectsofanFMSisthefixturingused.Becausefixturesarepartofthetoolingofthesystem,onecouldarguethattheyshouldalsobestandardforthesystem.Workoncreating“flexiblefixtures”thatcouldbeusedtosupportavarietyofcomponentshasonlyrecentlybegun.SeeChapter5.OneuniqueaspectofmanyFMSsisthatthepartisalsomovedaboutthesysteminthefixture(orpalletfixture).Fixturesaremadetothesamedimensionssothatthematerial-handlingsystemcanbespecializedtohandleasinglegeometry.Partsarelocatedpreciselyonthefixtureandmovedfromonestationtoanotheronthefixture.Fixturesofthistypeareusuallycalledpalletfixtures,orpallets.Manyofthepalletfixturesemployedtodayhavestandard“T-slots”cutinthem,andusestandardfixturekitstocreatethepart-locatingand-holdingenvironmentneedformachining.3.COMPUTERCONTROLOFFLEXIBLEMANUFACTURINGSYSTEMS3.1FMSArchitectureAnFMSisacomplexnetworkofequipmentandprocessesthatmustbecontrolledviaacomputerornetworkofcomputers.InordertomakethetaskofcontrollinganFMSmoretractable,thesystemisusuallydividedintoatask-basedhierarchy.OneofthestandardhierarchiesthathaveevolvedistheNationalInstituteofStandardsandTechnology(NIST)factory-controlhierarchy.(NISTwasformerlytheNationalBureauofstandards.NBS.)ThishierarchyconsistsoffivelevelsandisillustratedinFigures2andFigures3Thesystemconsistsofphysicalmachiningequipmentatthelowestlevelofthesystem.Workstationequipmentresidesjustabovetheprocesslevelandprovidesintegrationandinterfacefunctionsfortheequipment.Forinstancepalletfixturesandprogrammingelementsarepartoftheworkstation.Theworkstationtypicallyprovidesbothman-machineinterfaceaswellasmachine-partinterface.Off-lineprogrammingsuchasAPTforNCorAMLforrobotresidesattheworkstationlevel.Thecellistheunitinthehierarchywhereinteractionbetweenmachinesbecomespartofthesystem.Thecellcontrollerprovidestheinterfacebetweenthemachinesandmaterial-handlingsystem.Assuch,thecellcontrollerisresponsibleforsequencingandschedulingpartsthroughthesystem.Attheshoplevelintegrationofmultiplecellsoccursaswellastheplanningandmanagementofinventory.TheFigure3Therelationshipbetweenthedata-administration(DAS)intheNISTarchitecture:(1)thetopologiesoftheIntegratedManufacturingDataAdministrationSystem(IMDAS)data-administrationsystem;(2)thenetworkdata-communicationnetwork;(3)thehierarchicalsystemofdata-drivencontrol:datapreparationisimpliedin(4)thefacilitylevelofcontrolfacilitylevelistheplaceinthehierarchywherethemasterproductionscheduleisconstructedandmanufacturingresourceplanningisconducted.Orderingmaterialsplanninginventoriesandanalyzingbusinessplansarepartoftheactivitiesthataffecttheproductionsystem.Poorbusinessandmanufacturingplanswillincapacitatethemanufacturingsystemjustassurlytheunavailabilityofamachine.3.2FMSSchedulingandcontrolFlexiblemanufacturingsystems,likeothermanufacturingsystemcandiffersignificantlycomplexity.Thiscomplexityisnotonlydeterminedbythenumberofmachinesandthenumberofpartsresidentinthesystem,butalsobythecomplexityofpartsandcontrolrequirementsofthespecificequipment.SomeFMSsrequireonlyasimpleprogrammablecontrollertoregulatetheflowofpartsthoughthesystem,whereasothersrequiresophisticatedcomputercontrolsystems.Inthefollowingsections,exampleofFMSsandtheircontrolarepresented.ThemostsimpleFMSconsistsofaprocessingmachine,aload/unloadarea,andamaterialhandler(aone-machinesystemisthemostsimpleFMSthatcanbeconstructed).Operationofthissystemconsistsofloadingthepart(s)thatmovedownaconveyorthemachine.Oncethepartisloadedontothemachine,therobotisretractedtoa“safeposition”andthemachiningbegins.Althoughthisisaverysimplesystem,itillustratesseveralinterestingdesignandcontroldecisionsthatmustbeconsidered.Ifonlyasinglepartistobeprocessedinthesystem,aminimumnumberofswitchesandsensorsnecessaryforthesystem.Onerequirementofthesystemisthatthepartsontheconveyorallhavetobeorientedinthesameway.ThisisrequiredsothattherobotcanpickupthepartanddeliverittotheNCmachineinthesameorientationeverytime.Aproximityswitchormicro-switchisrequiredattheendoftheconveyortodetectwhenapartisresident,andonthemachineforthesamepurpose.计算机辅助制造1.绪论当今的工业的竞争已经是真正意义上的国际市场竞争。高效的运输网络建立了一个我们每天都要参与的“世界市场”。对于任何工业化国家要参与这个市场竞争，就必须采用一种适时的方式为其客户提供经济、优质的产品。将产品设计和过程设计进行集成的重要性，在产品系统被怎么强调都不为过。但是，即使一种设计最终被落实，制造业者一定愿意通过允许最后的工程设计变化，而没有通过影响装运进度表，或者改变产品质量来适应他们的用户。大多数美国的生产公司基于趋向计算机辅助设计（CAD）/计算机辅助制（CAM）和CIM为他们的制造系统提供灵活性。今天，计算机用于制造已经很平常。现在不仅为零件生产设计制造系统，而且为零件从一台机器运送到另一台机器的命令顺序设计了制造系统，如图（1），它还包含一个经济区域的制造经济计划在美国和其他国家，手工产品总是还有一些市场的，此外真正的工业产品对于特殊的“one-of-a-kind”技术项目还是需要的。“one-of-a-kind”通过大量的货物来表明、各种各样的工业需要各种各样的加工方法。有些系统将看起来像我们的祖父母曾经工作过的工厂，而其它则呈现出一种未来派的情景。在后文中，我们将展开讨论柔性制造系统。图（1）2.柔性制造系统柔性制造系统（FMS）像人们通常知道的那样的，能使用一个可编程的制造系统自动地生产各种各样的产品。自从亨利·福特率先提出并且使流水生产线实现现代化，我们就已经能自动执行多种生产的生产。不过，改变这些系统甚至只作较小的变动，这些产品的生产都会变得相当繁重。当其他机器或者零部件要经过修理或者废弃，以适应这种萧萧的变化，整个机器才可能被引进到系统。在今天的竞争性市场里，能适应客户的各种变化是很必要的。传统的制造系统以特征可划分为以下两种：

1.加工车间类型系统能生产多种产品，但是费用高。

2.流水线能以合理费用生产能大量产品，但是仅局限于几种不同零件的生产。

数控(NC)和机器人技术的时代已经来临，这为我们提供了在最小准备时间里，使机器的程序重新调定。NC机床和机器人是重新可编程序的制造系统的基本物理组成部分。2.1.柔性制造系统的设备2.1.1机床为了满足柔性制造系统定义的要求，该系统的基本工艺应实现自动化。因为自动化必须是可编程的，以适应不同的产品要求，而易于改变，以及通用机床必须执行这些工艺。计算机数控（CNC）车削中心、计算机数控（CNC）加工中心、及机器人工作站构成了这些设备。这些机器不仅仅是易于重新编程，同时也适应置于刀具存储系统及刀具更换器中的不同刀具。通常CNC加工中心备有60多把或更多刀具（铣刀、钻头、镗刀等）。对于CNC车削中心，备有12把或更多的刀具（右车刀、左车刀、镗杆、钻头等）。书动机床的自动换刀器及刀库使它们对材料的工艺装备作出自然的选择。零件必须在加工站点之间自动化的移动，采用了数种不同的物料输送系统，把这些零件从一个站点输送到另一个站点。物料输送系统的选择是数种系统特征函数。首先，物料输送系统的选择必须适应零件（或许是零件的夹具）的负荷及批量。大型的、重型的零件需要大型的、强力的输送系统，如滚子输送、导向小车、轨道驱动车辆系统。构成的机床数量及机床布置也提供了另一种设计上的考虑。如果用单一的物料输送机来运送零件到系统内的所有机床，则运输机的工作覆盖面至少必须是和整个系统一样大。通常一台机器人定位于一两台机床或一个装卸站。一台输送机或自动导向车可以扩大到数英里的工厂区域。物料输送也可以以即时的方式将零件从一台机床输送到另一台机床。如果系统内的机床耗费大量的时间在等待输送零件的到来，则其生产率是不会高地。如果有许多种零件包括在系统内，而且这些零件要经常输送到机床上，物料系统要能够支持这些活动。通常由采用极快的输送装置