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1、天津工程师范学院2007届本科生毕业设计A NOVEL INTEGRATED SYSTEM FOR RAPID PRODUCT DEVELOPMENTThis paper presents a novel integrated system of rapid product development for reducing the time and cost of product development. The system is composed of four building blocks digital prototype, virtual prototype, physical p
2、rototype and rapid tooling manufacturing system. It can aid effectively in product design, analysis, prototype, mould, and manufacturing process development by integrating closely the various advanced manufacturing technologies which involve the 3D CAD, CAE, reverse engineering, rapid prototyping an
3、d rapid tooling. Furthermore, two actual examples are provided to illustrate the application of this integrated system. The results indicate that the system has a high potential to reduce further the cycle and cost of product development.Keywords: Rapid product development; rapid prototyping; integr
4、ated system.1. IntrroducttionDue to the ppressuure off inteernatiional compeetitioon andd markket gllobaliizatioon in the 21st centuury, tthere contiinues to bee stroong drrivingg forcces inn induustry to coompetee effecctivelly by reduccing mmanufaacturiing tiimes aand coosts wwhile assurring hhigh
5、 qqualitty produucts aand seervicees. Cuurrentt induustriees aree faciing thhe neww challlengees: quuick respoonse tto bussinesss oppoortuniity haas beeen connsiderred ass one of thhe mosst impportannt factoors too ensuure coompanyy comppetitiivenesss; maanufaccturinng inddustryy is eevolviing towar
6、rd diggitaliizatioon, neetworkk and globaalizattion. Thereefore, new produucts mmust bbe more quickkly annd cheeaply develloped, manuufactuured aand inntroduuced tto thee markket. In orrder tto meeet thee demaand off rapiid prooduct devellopmennt, thhe varrious new ttechnoologiees such as reeversee
7、engiineeriing (RRE), 33D CADD, rappid prrototyyping (RP), and rapidd toolling (RT) hhave eemergeed andd are regarrded aas keyy enabbling toolss withh the abiliity too shorrten tthe prroductt deveelopmeent annd mannufactturingg timee. Forr exammple, it haas beeen claaimed that RP caan cutt new produu
8、ct deeveloppment costss by uup to 70% and tthe tiime too markket byy 90%.1 In the fform oof a bbetterr desiign, mmore ddesignn posssibiliities, a 3D CAD mmodel can bbe shoown too the custoomer ffor appprovaal andd prevvents misunndersttandinngs. AA virttual pprotottypingg is eemployyed too guidde in
9、 optimmizatiion of thhe prooduct desiggn andd manuufactuuring proceess pllanninng, whhich mmay reesult in the aaccuraate deetermiinatioon of the pprocesss parrameteers, aand reeduce the nnumberr of costlly phyysicall prottotypee iterrationns. Raapid ttoolinng tecchniquue offfers aa fastt and low cos
10、t methood to produuce mooulds, and showss a hiigh pootentiial foor fasster rresponnse too markeet demmands. Whenn propperly integgratedd amonng 3D CAD, CAE, RE, RRP andd RT, tthese technnologiies wiill pllay a much more imporrtant role to reeduce furthher thhe devellopmennt cyccle annd cosst of the
11、pproducct prooductiion. OOn thee basiis of abovee techhnologgies, a novvel inntegraated ssystemm of rrapid produuct deeveloppment is too be ffoundeed so ass to mmeet tthe reequireement of raapid pproducct devvelopmment.2. Archhitectture oof thee Inteegrateed Devvelopmment SSystemmThe devvelopmment p
12、processs froom iniitial conceeptuall desiign too commmerciaal prooduct is ann iteraative proceess whhich iincluddes: pproducct dessign; analyysis oof perrformaance, safetty andd reliaabilitty; prroductt prottotypiing foor expperimeental evaluuationn; andd desiign moodificcationn. Thereefore, any ste
13、p of thhe neww prodduct ddeveloopmentt proccess hhas a direcct andd stronng inffluencce on time-to-maarket in shhort oorder. A goood prroductt deveelopmeent systeem musst enaable ddesignners oor dessign tteams to coonsideer alll aspeects oof prooduct desiggn, maanufaccturinng, seellingg and recyccli
14、ng at thhe earrly sttage oof thee desiign cyycle. So thhat deesign iteraation and cchangees cann be mmade eeasilyy and effecctivelly. Thhe morre fluennt thee feeddback is thhe higgher ppossibbilityy of ssuccesss thee systtem haas. Deesign for manuffacturring (DFM) and cconcurrrent enginneerinng (CEE
15、) neccessittate tthat pproducct and pprocesss dessign bbe devvelopeed simmultanneouslly ratther tthan ssequenntiallly. The inntegraated ssystemm of rrapid produuct deeveloppment is coomposeed of four modulles: digittal prrototyype, vvirtuaal proototyppe, phhysicaal proototyppe andd rapiid toooling.T
16、he pproducct devvelopmment sstartss fromm the creattion oof a 33D CADD modeel usiing a CAD ssoftwaare paackagee. At that stagee, thee prodduct ggeomettry iss defiined aand itts aesthhetic and ddimenssionall charracterristiccs aree veriified. The main functtion oof diggital protootype is too perfform
17、 33D CADD modeellingg. Thee CAD modell is rregardded ass a centrral coomponeent off the wholee systtem orr projject iinformmationn basee whicch meaans that in alll dessign, analyysis aand maanufaccturinng acttivitiies thhe samme datta is utiliized. The pproducct andd its compoonentss are direcctly d
18、designned onn a 3DD CAD systeem (e.g.Proo/Engiineer, Uniggraphiics, CCATIA, IDEAAS, ettc.) dduringg the creattive ddesignn. If a physiical ppart iis reaady, tthe moodel ccan bee consstructted byy the reverrse enngineeering technnique. RE iis a mmethoddologyy for consttructiing CAAD moddels oof phyys
19、icall partts by digittizingg an eexistiing paart, ccreatiing a digittal moodel aand thhen ussing iit to manuffacturre compoonentss. RE can rreducee the devellopmennt cyccle whhen reedesiggns beecome necesssary for iimprovved prroductt quallity. Preexxistinng parrts wiith feeaturees forr imprroved pe
20、rfoormancce cann be rreadilly inccorporrated into the ddesireed parrt dessign. Thereefore, it is veery usseful in crreatinng thee CAD modell of aan exiistingg partt whenn the enginneerinng desiggn is lost or haas gonne thrrough many desiggn chaanges. Whenn a deesigneer creeates a neww desiign ussing
21、 mmock-uup, itt is aalso nnecesssary tto connstrucct thee CAD modell of thhe mocck-up for ffurtheer usee of tthe deesign data in annalysiis andd manuufactuuring. The tthree primaary stteps iin RE proceess arre parrt diggitizaation, feattures extraactionn, and CCAD moodelliing. PPart ddigitiizatioon
22、is accommplishhed byy a vaarietyy of ccontacct or non-ccontacct diggitizeers. TThere are vvariouus commmerciial syystemss avaiilablee for part digittizatiion. Thesee systtems rrange from coorddinatee meassuringg machhine (CMM), laseer scannners tto ulttrasonnic diigitizzers. They can bbe claassifiie
23、d innto twwo brooad caategorries: contaact annd nonn-conttact. Laserr triaangulaation scannner (LLTS), magneetic rresonaance imagees (MRRI), aand coomputeer tommograpphy (CCT) arre commmonlyy usedd as nnon-coontactt devicces. CContacct diggitizeers maainly have CMM aand crross-ssectioonal iimaginng
24、meaasuremment (CIM). Feaature extraactionn is nnormallly acchieveed by segmeentingg the digittized data and ccapturring ssurfacce feaaturess suchh as eedges. Partt modeellingg is ffulfilled thhroughh fittiing a varieety off surffaces to thhe seggmenteed datta poiints.In ordeer to reducce thee iterra
25、tionns of desiggn-proototyppe-tesst cyccles, increease tthe produuct prrocesss and manuffacturring rreliabbilityy, it is neecessaary too guidde in optimmizingg the pproducct dessign aand maanufaccturinng proocess throuugh viirtuall prottotypee (VP). VP iss a prrocesss of uusing 3D CAAD moddel, iin l
26、ieeu of a phyysicall prottotypee, forr testting and eevaluaation of sppecifiic chaaracteeristiics off a prroductt or aa manuufactuuring proceess. It iss ofteen carrried out bby CAEE and virtuual maanufaccturinng sysstem. Compuuter aaided enginneerinng (CAAE) annalysiis is an inntegraal parrt of time
27、-comprressioon tecchnoloogies. Varioous sooftwarre toools avvailabble (ii.e. AANSYS, MARCC, I-DDEAS, AUTOFFORM, DYNAFFORM, etc.) can speedd up tthe deeveloppment of neew prooductss by iinitiaating desiggn opttimizaation beforre phyysicall prottotypees aree buillt. Thhe CADD modeels caan be transsfer
28、reed to a CAEE enviironmeent foor an analyysis oof thee prodduct ffunctiional perfoormancce and oof thee manuufactuuring proceesses for pproduccing tthe prroductts coomponeents. It haas alsso prooven tto be of grreat vvalue in thhe dessign ooptimiizatioon of part geomeetry, to deetermiine itts dimme
29、nsioons annd to contrrol waarpagee and shrinnkage whilee miniimizinng proceess-innducedd resiidual stressses aand deeformaationss. Virrtual manuffacturring ssystemm (VM) is thhe nattural extennsion of CAAE. Itt simuulatess the produuct fuunctioonalitty andd the pprocessses ffor prroduciing itt prioo
30、r to the ddeveloopmentt of pphysiccal prrototyypes. VM ennabless a deesigneer to visuaalize and ooptimiize a produuct prrocesss withh a seet of proceess paarametters. The vvisuallizatiion off a viirtuallly siimulatted paart prrior tto phyysicall fabriicatioon hellps too reduuce unnwanteed proototypp
31、e iteeratioons. TThereffore, a prooduct virtuual maanufaccturinng sysstem mmay reesult in acccuratte detterminnationn of tthe prrocesss parammeterss, andd reduuce thhe nummber oof cosstly pphysiccal prrototyype itteratiions. 3D CAAD modell and VP alllow mmost pprobleems wiith unnfittiing too becoome
32、 obbviouss earlly in the produuct deeveloppment proceess. AAssembblies can bbe verrifiedd for interrferennce ass VP can bbe exeerciseed thrrough a rannge off taskks. Sttructuure annd theermal analyysis ccan bee perfoormed on thhe samme moddel emmployiing CAAE appplicattions as weell ass simuulatinng
33、 down-streaam mannufactturingg proccessess. It is cllear tthat VVP inccreasees proocess and produuct reeliabiility. Althhough VP iss inteended to ennsure that unsuiitablee desiigns aare rejeccted oor moddifiedd, in many casess, a vvisuall and physiical eevaluaation of thhe reaal commponennt is neeed
34、ed. Thiss ofteen reqquiress physsical protootype to bee prodduced. Hencce, once the VVP is finisshed, the mmodel may ooften be seent diirectlly to physiical ffabriccationn. The CADD modeel cann be ddirecttly coonvertted too the physiical pprotottype uusing a RP teechniqque orr highh-speeed macchinin
35、ng (HSSM) prrocesss. Thee 3D CCAD moodel iis to be exxporteed nott onlyy in tthe STTL forrmat wwhich is coonsideered tthe dee factto staandardd for iinterffacingg CAD and RRP sysstems, but also in thhe NC codinng whiich caan be used by HSSM. HSSM hass a pootentiial foor rappid prroduciing pllasterr
36、or wwoodenn patttern ffor RT. RRP is a neww formming pprocesss whiich faabricaates pphysiccal paarts llayer by laayer uunder compuuter ccontrool dirrectlyy fromm 3D CCAD moodels in a very shortt timee. In contrrast tto tradiitionaal macchininng metthods, the majorrity oof rappid prrototyyping systee
37、ms teend too fabriicate partss baseed on addittive mmanufaacturiing prrocesss, ratther tthan ssubtraactionn or removval off mateerial. Therreforee, thiis typpe of fabriicatioon is unconnstraiined bby thee limiitatioons attriibutedd to cconvenntionaal macchininng appproachhes. TThe appplicaation of R
38、PP technnique as a usefuul toool cann provvide bbenefiits thhroughhout tthe prrocesss of ddevelooping new pproduccts. SSpecifficallly, thhere aare seeriouss beneefits that RP caan briing inn the areass of maarket reseaarch, saless suppport, promootionaal matteriall, andd the ever-imporrtant produuct
39、 laaunch. Physsical RP caan alsso beccome aa poweerful commuunicattions tool to ensurre thaat eveeryonee invoolved in thhe devvelopmment pprocesss fullly unndersttands and appreeciatees thee prodduct bbeing develloped. Hencce, itt can help to reeduce substtantiaally the iinevittable riskss in tthe r
40、ooute ffrom pproducct conncept to coommerccial ssuccesss, and hhelp sshorteen timme-to-markeet, immprovee quallity aand reeduce cost. Overr the last 20 yeears, RP maachinees havve beeen widdely uused iin inddustryy. Thee RP mmethodds commeerciallly avvailabble inncludee Sterreolitthgrapphy (SSLA), S
41、elecctive Laserr Sintteringg (SLS), Fussed Deeposittion MManufaacturiing (FFDM), Laminnated Objecct Mannufactturingg (LOM), Balllistiic Parrticlee Manuufactuuring (BMP), andd Threee-Dimmensioonal PPrintiing (3D pprintiing), etc.Once thhe dessign hhas beeen acccepteed, thhe reaalizattion oof thee pro
42、dductioon linne reppresennts a majjor taask wiith a long lead time beforre anyy prodduct ccan bee put to thhe markeet. Inn partticulaar, thhe preeparattion oof commplex tooliing iss usuaally iin thee crittical path of a projeect annd hass therreforee a diirect and sstrongg inflluencee on ttime-tto-m
43、arrket. In orrder tto redduce tthe prroductt deveelopmeent tiime annd cosst, thhe neww techhniquee of RT haas beeen devvelopeed. RTT is aa techhniquee thatt can transsform the RRP pattternss intoo functtionall partts, esspeciaally mmetal partss. It offerrs a ffast aand loow cosst metthod tto prooduc
44、e mouldds andd funcctionaal parrts. FFurtheermoree, thee inteegratiion off bothh RP aand RTT in deeveloppment strattegy ppromottes thhe impplemenntatioon of concuurrentt engiineeriing inn compaanies. Numeerous proceesses have been develloped for pproduccing ddies ffrom RRP systeem. Thhe RT methoods
45、caan gennerallly be dividded innto diirect and iindireect tooolingg categgoriess, andd alsoo softt (firrm) annd harrd toooling subgrroups. Indiirect RT reequirees some kindss of mmasterr pattterns, whicch cann be mmade bby connventiional methoods (ee.g. HSM), or mmore ccommonnly byy an RRP proocess
46、such as SLLA or SLS. Direcct RT, as tthe name suggeests, invollves tthe maanufaccturinng of a toool cavvity ddirecttly onn a RPP systtem, hencee elimminatiing thhe inttermeddiate step of geeneratting aa patttern. Soft tooliing can bbe obttainedd via repliicatioon froom a ppositiive paatternn or mmas
47、terr. Sofft toooling is assocciatedd withh low costss; useed forr low volumme prooductiion annd usees matterialls thaat have low hhardneess leevels such as siiliconnes, eepoxiees, loow mellting pointt allooys, eetc. RTV ssilicoone ruubber mouldds, eppoxy mmouldss, mettal spprayinng mouulds, etc. are
48、 ssome of thhese ttypicaal sofft molldingss. Harrd toooling is asssociaated wwith hhigherr voluume off prodductioon, and tthe usse of materrials of grreaterr harddness. Kelttool pprocesss, Quuickcaast proceess, aand thhe ExppressTTool pprocesss aree somee of tthese hard tooliings. Electtricall dischharge machiining (EDM) seemms to be ann inteerestiing arrea inn whicch rappid tooolingg findss a pootentiial appplicaation. Somee methhods oof makking EEDM ell