毕业设计外文翻译模块化设计产品设计的分解与整合Word文件下载.docx
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ABSTRACT
Inthelastfewyears,corporationhasengagedinstudiestoimprovetheirdesignprocesses,rangingfrommarketingtosupport.Recentgovernment,academicandindustrialsectorinitiativeshavesoughtadvancetechnologiesfordevelopingandmanagingproductdevelopmentenvironment.Manycompanieshaveestablishedaconcurrentdesignprocessfortheirproductdevelopmentandhaverecognizedaneedfortoolsinevaluatingthelevelofdecompositionandintegration,whileanalyzingtheimpactonthefinaldesign.Thisarticlewillproposeathree-phasemethodologyfordesignofproductswhileconsideringmodularity,assemblyandmanufacture.
KEYWORDS
Modularity,Grouptechnology,Optimization,Decomposition,Classification
1.Introduction
Modulardesignisadesigntechniquethatcanbeusedtodevelopcomplexproductsusingsimilarcomponents.Componentsusedinamodularproductmusthavefeaturesthatenablethemtobecoupledtogethertoformacomplexproduct.Modulardesigncanbealsoviewedastheprocessofproducingunitsthatperformdiscretefunctions,andthentheunitsareconnectedtogethertoprovideavarietyoffunctions.Modulardesignemphasizestheminimizationofinteractionsbetweencomponents,whichwillenablecomponentstobedesignedandproducedindependentlyfromeachother.Eachcomponent,designedformodularity,issupposedtosupportoneormorefunction.Whencomponentsarestructuredtogether,toformaproduct,theywillsupportalargerorgeneralfunction.Thisshowstheimportanceofanalyzingtheproductfunctionanddecomposingitintosub-functionsthatcanbesatisfiedbydifferentfunctionalmodules.Modularitycanbeappliedintheproductdesign,designproblems,productionsystems,orallthree.Itispreferabletousethemodulardesigninallthreetypesatthesametime.
Modularproductsrefertoproductsthatfulfillvariousoverallfunctionsthroughthecombinationofdistinctbuildingblocksormodules.Inthesensethattheoverallfunction,performedbytheproduct,canbedividedintosubfunctionsthatcanbeimplementedbydifferentmodulesorcomponents.Animportantaspectofmodularproductsisthecreationofabasiccoreunittowhichdifferentelements(modules)canbefitted,thusenablingavarietyofversionsofthesamemoduletobeproduced.Thecoreshouldhavesufficientcapacitytocopewithallexpectedvariationsinperformanceandusage.
Mostdesignproblemscanbebrokendownintoasetofeasytomanagesimplersub-problems.Sometimescomplexproblemsarereducedintoeasiersub-problems,whereasmallchangeinthesolutionofonesub-problemcanleadtoachangeinothersub-problems’solutions.Thismeansthatthedecompositionhasresultedinfunctionallydependentsub-problems.Modularityfocusesondecomposingtheoverallproblemintofunctionallyindependentsub-problems,inwhichinteractionorinterdependencebetweensub-problemsisminimized.Thus,achangeinthesolutionofoneproblemmayleadtoaminormodificationinotherproblems,oritmayhavenoeffectonothersub-problems.
Modularityinproductionsystemsaimsatbuildingproductionsystemsfromstandardizedmodularmachines.Thefactthatawidediversityofproductionrequirementsexistshasledtotheintroductionofavarietyofproductionmachinery,andalackofagreementonwhatthebuildingblocksshouldbe.Thismeansthattherearenostandardsformodularmachinery.Inordertobuildamodularproductionsystem,productionmachinerymustbeclassifiedintofunctionalgroupsfromwhichaselectionofamodularproductionsystemcanbemadetorespondtodifferentproductionrequirements.Rogersclassifiedproductionmachineryintofourbasicgroupsof“primitive”productionelements.Theseareprocessmachineprimitives,motionunits,modularfixtures,andconfigurablecontrolunits.Itisarguedthatifaselectionismadefromthesefourcategories,itwillbepossibletobuildadiverserangeofefficient,automatedandintegratedproductionsystem.
2.OverviewofProductDevelopment
Productdevelopmentisanecessaryandimportantpartoftheactivitiesperformedbyamanufacturingfirm.Duetochangesinmanufacturingtechnology,consumerpreferences,andgovernmentregulations(tonameafewinfluences),existingproductswillbecomelessprofitableovertime.Thesalesvolumeofatypicalproductstartsslowly,accelerates,becomesflat,andthensteadilydeclines.Althoughtheremaybeafewproductsthatremainprofitableformanyyears,firmscontinuallydevelopnewproductsthatwillgeneratemoreprofits.Productdevelopmentdetermineswhatthefirmwillmanufactureandsell.Thatis,itattemptstodesignproductsthatcustomerswillbuyandtodesignmanufacturingprocessesthatmeetcustomerdemandprofitably.Poordecisionsduringproductdevelopmentleadtoproductsthatnoonewantstobuyandproductsthatareexpensivetomanufactureinsufficientquantity.
Aproductdevelopmentprocessisthesetofactivitiesneededtobringanewproducttomarket.Aproductdevelopmentorganizationincludestheengineers,managers,andotherpersonnelwhomakeprocessandproductengineeringdecisionsandperformtheseactivities.(Notethat,inthispaper,thetermnewproductcoverstheredesignofanexistingproductaswell.)
Becausemakinggooddecisionsrequiresexpertiseandanorganizationofpeoplecanbeexpertsinonlyafewthings,amanufacturingfirmspecializesinacertainclassofproducts.Itfocusesitsattentiononthemarketforthatclassofproducts,thetechnologiesavailabletoproducethatclass,andtheregulationsrelevanttothatclass.
Likeotherpartsofthebusiness,aproductdevelopmentorganizationseekstomaximizetheprofitofthemanufacturingfirmsubjecttotherelevantregulatoryandethicalconstraintsandotherconditionsthatthefirm’sownersimposebasedontheirvalues.Aproductdevelopmentorganizationdoesthisbyregularlyintroducingnewproductsthatthefirmcanmanufacture,market,andsell.Fundamentally,then,aproductdevelopmentorganizationtransformsinformationabouttheworld(e.g.,technology,preferences,andregulations)intoinformationaboutproductsandprocessesthatwillgenerateprofitsforthefirm.Itperformsthistransformationthroughdecision-making(HerrmannandSchmidt,2002).Becausethedesignproblemishighlycomplex,productdevelopmentteamsdecomposetheproblemintoaproductdevelopmentprocess,whichprovidesthemechanismsforlinkingaseriesofdesigndecisionsthatdonotexplicitlyconsiderprofit.
Thefollowingninestepsaretheprimaryactivitiesthatmanyproductdevelopmentprocessesaccomplish(Schmidtetal.,2002):
Step1.Identifythecustomerneeds.
Step2.Establishtheproductspecification.
Step3.Definealternativeconceptsforadesignthatmeetsthespecification.
Step4.Selectthemostsuitableconcept.
Step5.Designthesubsystemsandintegratethem.
Step6.Buildandtestaprototype;
modifythedesignasrequired.
Step7.Designandbuildthetoolingforproduction.
Step8.Produceanddistributetheproduct.
Step9.Tracktheproductduringitslifecycletodetermineitsstrengthsandweaknesses.
Thislist(oranyotherdescriptionthatusesadifferentnumberofsteps)isanextremelysimpledepictionthatnotonlyconveysthescopeoftheprocessbutalsohighlightstheinherent(butunquestioned)decomposition.Therearemanyotherwaystorepresentproductdevelopmentprocessesandthecomponenttasks,includingtheuseofschedulesoradesignstructurematrix(SmithandEppinger,2001).
Manufacturingfirmsunderstandthatdesigndecisions(thoughmadeearlyintheproductlifecycle)haveanexcessiveimpactontheprofitabilityofaproductoveritsentirelifecycle.Consequently,productdevelopmentorganizationshavecreatedandusedconcurrentengineeringpracticesformanyyears(Smith,1997,providesahistoricalview).Manytypesoftoolsandmethods(suchascross-functionalproductdevelopmentteamsanddesignformanufacturingguidelines)havebeencreated,adopted,andimplementedtoimprovedecision-making.Cooper(1994)identifiesthreegenerationsofformalapproachestoproductdevelopment,allofwhichinvolvedecomposition.
Itshouldbenoted,however,thatdecompositionisnottheonlywaytodescribeproductdevelopment.Asanalternativetodecomposingasystemdesignproblemintosubproblems,Hazelrigg(1996)proposescreatingandrefiningsystemdesignmodelstoexpresshowdetaileddesignvariablesaffecttheoverallsystemperformance.Thisapproachsuggeststhataproductdevelopmentprocesswouldendwithusingthemodeltofindtheoptimaldesign.Hazelrigg(1998)encouragesthistypeofoptimizationbutdoesnotdiscusstheprocessofgeneratingtheprofitmaximizationmodel.
3.AMethodologyforDesignforModularity
Athree-phasemethodologyisproposedforthedevelopmentofcomplexproductsusingthemodularityconcept[1,2].Theproposedmethodologymatchesthecriteriasetbythedesignforfunctionality,assemblyandmanufacture.Someofthemajorbenefitsassociatedwiththismethodologyinclude:
·
Increaseddesignaccuracy,efficiency,andthereuseofexistingdesignfornewprograms.
Potentialforintegrationofthedevelopedmethodologyandtechnologyintotheengineeringdesignactivities.
Modularproductdesignandtheprocessofplanningtheproductionareintegratedinoneoverallengineeringprocessinwhichproductfeaturesaremappedintotheirfeasibleprocess(es)inaonetoonecorrespondence.
Inordertoimplementthisconceptsuccessfully,themannerinwhichthemodulesareselectediscritical.Byestablishingsimplein