機械制造專業(yè)畢業(yè)設計外文翻譯--制造分析

1、<p>　　MANUFACTURING ANALYSIS:HOW MUCH FLEXIBILITY?</p><p>　　In addition to production systems that fabricate very high quality products,at low cost,and with ultrarapid delivery,many strategic planners a

2、nd economists point to the need for flexibility.</p><p>　　Publications from Japan(Yoshio,1994;Ohsono,1995)express a similar view,and the more recent J.D.Powers comparative surveys on automobiles indicate tha

3、t"now that others are closing the quality gap,the Japanese have to compete in other areas"(see Rechtin,1994;and the annual J.D.Powers report series).Emphasis is thus place on these combined factors of quality,c

4、ost,delivery,and flexibility(QCDF).The ability to react to smaller lot sizes and the quest for ultrarapid delivery are major conconcerns,culm</p><p>　　In an ideal situation,once the various market sectors ha

5、ve been established,production will settle into a groove and be constantly refined and improved but with no major upheavals.Unfortunately,in recent years,manufacturers have not been able to rely on long periods of uninte

6、rrupted production because events in the world economy have forced rapid changes in consumer demand and the range of consumer preferences.</p><p>　　Henry Ford"s favorite aphorism-that his cutomers could

7、 have any color of car they wanted as long as it was black-is in sharp contrast to today's range of consumer preferences.This has led to the proposal by some academics that manufactering can be built for "custom

8、ized mass production."This sounds nice on first hearing.Howerver,for products like automobiles,the degree of customization can go only so far for a given batch size and price point.Only hyperwealthy CEOs and movie s

9、tars can get precise</p><p>　　Nevertheless,an ability to be prepared for any sudden market shifts is becoming more of an issue.As new equipment is purchased,manufacturing companies must decide between harwar

10、e that is dedicate to only a few tasks and is thus relatively inexpensive,and more costly but more versatile equipment that might perform unforeseen tasks in the future.The methodologies for analyzing capital expenditure

11、s,returns=on-investment(ROI),and depreciations are given in many texts (see Parkin,1992).</p><p>　　these can be used to analyze the ROI for new machinery that has been identified as useful and is therefore a

12、bout to be purchased.However,since today's market trends are so uncertain,such analyses do not help to predict the specific systems to install in the firt place.The hope is that some of the engineering solutions will

13、 provide much more flexible machinery for only a modest increase in cost(Greeenfeld et al.,1989).In this way,the investment dilemna might be less critical.</p><p>　　The preceding discussions emphasize that f

14、lexibility is a main challenge for the continued growth of a mew company.The main question is:Can a design and fabrication system that is first set up to respond to one market sector be quickly reconfiqured to respond to

15、 the needs of another market sector,or even another product,and be just as efficient?</p><p>　　Today,the answer to this question is"probably not."For example,if a machine shop is well equipped with

16、 lathes but has no vertical boring machines,there will be a natural limit on achievable tolerances.It is unlikely that it will be able to suddenly jump from truck transmissions to helicopter teansmissions.And even in the

17、 reverse scenario,if a shop has dedicated itself to precision boring.it is unlikely that the equipment and the craftspeople will be able to br quickly redeployed in a cost-effect</p><p>　　This general need f

18、or flexibl,reconfigurable manufacturing systems was of course a key aspect of CIMi its original xonception.Merchant(1980)led a number of industy forecasts between 1969and 1971 that refined the details and needs of the CI

19、M philosophy.However,theseforecasts overestimated the rate at which flexible manufacturing systems ang related technology would be asorbed into factories.During the 1970s and 1980s,machines exchanged”handshakes”when task

20、s were completed.If these tasks were comp</p><p>　　2.6.1Design for Flexibility(Reuse)</p><p>　　Design for flexibility in the automobile industry can pay off in a bigway if there is some reusabil

21、ity of fixture families.The automated assembly lines where the frames, doors, and chassis are asembled with robots and welded together are obviously intensely expensive.These are suall two_story-high lines as big as many

22、 football fields where robots,fixtures,and alignment cradles bring the body components together for welding and assemblu.The intense cost of these lines is hard to picture without a</p><p>　　Some companies,t

23、hose with smaller batch sizes,might use a mixed production line.As one views such a line, several body styles go by:perhaps the mix is as simple as regular sedans and station wagons.but the mix can often be stretched bey

24、ond this to dufferent cars of more or less the same size.With good design for multiple usability,many of the hard fixtures and robots cah be used gor all the differing vehicles in the family.</p><p>　　Also,w

25、ith good cooperation between manufacturing and design,the existing robots and fixtures might even be able to “upwardly constrain the vehicle design space”foor future vehickes.Therefore,viewed across several years and mor

26、e than one family of vehickes,automation costs are relatively lower per indevidual vehicle</p><p>　　2.62 Concluding Remarks:design Aesthetics versus Manufacturing</p><p>　　Just to keep a proper

27、 perspective at the close ofthis subsection,it must ve emphasized that design for manufacturability(or flxibility)has to be prudently app;ied with the perceived end user constantly in mind ,The Japanese articles concerne

28、d with TQM(Yoshio,1994;Iwata et al.,1990;see Haiser and Clausing,1988)increasingly emphasize the more qualitative aspectsof aesthetics as one of their next thrusts, even though this is much more defficult to measure as a

29、 design objective.</p><p>　　At one extreme,a component that is destined to be buries deep in a car,a washing machine,or a furnace does not need to look good.DFM and DFA methods can be applied at very step in

30、 Figure2.1.</p><p>　　At one extreme,there will always be a market for high-quality expensive products such as the $300 polo shirt disscussed in Section 2.4.10,a new Jaguar,or an expensive Bang and Olfson mus

31、ic system.In these cases the buyer is actively seeking style and luxury.Therefore,the design-for-manufacturability engineers cannot have it all their own way, or a car might end up ;ooking lke a rectangular box on fourwh

32、eels:cheap,it is true,but hard to sell.</p><p>　　To conclude with personal observations, it is ckear from visits to Tokyo and Kyoto that wealthy Japanese people prefer a Mercdes Benz,.a BM,a Jaguar, or the l

33、arge Tootas and Accuras.Not many American cars are seen on the streets,even in the financial districts and embassy areas of Yokyo.One does see the occasional Cadillac,some fully loaded Jeeps, and some of the newer Ford M

34、ustangs,but not many.</p><p>　　The”Big Three”U.S.companies complain that the reason for this is that Japanimposes trade barriers on U.S.vehicles.However,perhaps the real reason is that a wealthy Japanese bus

35、inessman wants a car with brando.This us a Japanese phrase meaning “brand appeal.”So,perhaps U.S.cars in Japan just do not have enough brando at the present time.After all, Japan is swamped wuth ither U.S.products that d

36、o have brando:Lecu’s 501,McDonald’sHollywood action movies,and CDs by American musicians.And,inevitably,</p><p>　　The moral of the story is that product design and product manufacturing have art and irration

37、al emotions lurking in their corners that design and manufacturing engineers should not ignore.</p><p>　　2.7 MANAGEMENT OF TECHNOLOGY</p><p>　　Chapter 1 reviewed the art,technology,science,and b

38、usiness of manufacturing,.During the last 100 years design and manufacturing have clearly moved from an art/technology endeavor to a business/science endeavor.Empatically,in this new business/science envronment,being gif

39、t in just the science and technology is not enough to win the day.Specifically,U.S.manufacturing in the late 1980s was clearly in a panic.Basicindustries such as semiconductors,automobiles,consumer electronics,and machin

40、e tools w</p><p>　　Today,things do seem a lot better on all fronts.In'How the Words Sees Us"the New YorkTimes boldly stated:"Our technology-computerized weapon systems,medical scanners, the Int

41、ernet-sets the standard to which developing countries aspire."</p><p>　　No single miracle has happened,but steady progress has occurred in:</p><p>　　●Creativity in design and manufacturing&

42、lt;/p><p>　　●Quality assurance and control of bbasic manufacturing methods</p><p>　　●Downsizing companies to be more efficient</p><p>　　●Global commerce</p><p>　　●Internet

43、 commerce</p><p>　　●The fact that some of our international competitors did not fare too well and struggled with unfavorable ccurrency exchange rates in the late-1990s also made it easier for U.S.companies t

44、o compete.</p><p>　　At the time of this writing,the challenge for the future is to kkeep this real growth going .Fpr a few uears. U.S.,manufacturers were chasing their Psvigiv Rim and European competitors an

45、d even enjoying the athketic-event psychology of"coming from behind."Staying up with the front-runners or,better still,being ahead requires an extra degree of crestivity and commitment.</p><p>　　Si

46、milar to the above list,perhps some specific areas for continued creativity include:</p><p>　　●Further exploiting global markets through Internet commerce.</p><p>　　●Focusing on cmplex systems,s

47、pecifically developing CAD/CAM techniques for the electro/mechanical/biological products that are on the horizon.</p><p>　　●Continuing with the time-ti-market awareness,balanced by aesthetic creativity.</

48、p><p>　　●Continually striving for the 6-sigma quality goal.</p><p>　　●Creating an organization that can cope and even thrive on change.For example,all industries-from semiconductors,to machine shop

49、s, to steel mills-are being told to bemore environmentally conscious.Being so,and yet still being competitive with other countries that might care much less about issues such as pollution or industrial safety,challaenges

50、 manufacturers to be especially creative and efficient.</p><p>　　.Responding proactively to government funding opportunities,public policy,and federal regulationd that impact all industries at some level. Fo

51、r example,a project such as the original Internet was launched more than 25years ago by the Defense Advanced Research Project Agecy(DARPA),and it has continued to be nurtured by the National Seience Foundation(NSF).The M

52、OSIS(2000)story is similar.It can thus be reasonably argued that much of the wealth of Silicon Valley in nouthern California and Route 128</p><p>　　. The initial time-to-market of a new product and the ongoi

53、ng delivery time of an established product are ongoing themes of this book.The integration issues that will be discussed around design,planing,and fabrication are obvious areas to focus on technically.In particular,new h

54、ardware and doftware environments allow the connections between design,planning,and fabrication to be simplified. Particular benefits include the reduction of the time taken to obtain the first prototype of a designed ob

55、j</p><p>　　Although there will be many new trends and unexpected disturbances, one basic business goal will remain constant:the winners will be those who desogn,plan and manufacture a high-quality product at

56、 the right price and get it to market first.To address this need,Chapter 2 has considered some general principles of manufacturing analysis in the context of four parameters;quality,cost,delivery,and flexibility(QCDF).Ge

57、neric approaches for quality assurance methods were also reviewed. The chapter also </p><p><b>　　制造分析</b></p><p>　　靈活性程度制造系統(tǒng)除了有生產產品的高質量,低成本,超快的流通速度外,許多學者和經濟學家指出了靈活性的需要.</p>&l

58、t;p>　　美國和歐州的文章特別談到柔性制造系統(tǒng)的需要,這些揉性制造系統(tǒng)涉及在生產流程的各個環(huán)節(jié)提高其靈活性和流動性.通過一個固件或在幾個固件中整合組成產品的零部件,以及軟件和信息流系統(tǒng)的整合.</p><p>　　日本出版的文章表達了相似的觀點,最近,杰.帝力量對汽車的比較性調查表明:既然他們追求質量,那日本就因該在別的領域和他們競爭,分析強調在質量,價格,流動,靈活性這些綜合性要素.</p>

59、<p>　　在理想的情形中,各種市場一旦建立,生產就會馬上上軌,并無波動地進行調整和改進.不幸的是,在最近幾年,生產已經不可能長時期無間斷進行,因為再經濟領域的事情已經使消費者的需求和選擇范圍快速變化.</p><p>　　亨利.福德的格言:他的客戶可以擁有他們想要的任何顏色的汽車,只要是黑色.是和現在消費者選擇范圍多樣的強烈對比.這導致了一些學者建議制造業(yè)可以建立在大批量定單式生產基礎上.這最初聽

60、起來不錯.但是,象汽車這樣的產品,客戶的需求滿足度只能是在給定的批料尺寸和價格基點上.只有總裁和電影明星才能在汽車這樣的產品上隨便選擇.</p><p>　　然而,市場波動的適應能力正越來越被重視.對于購購買的機器,制造公司應該權衡利弊,是選擇那些功能比較少,但價格相對較低的,還是選擇價格貴,功能多,能執(zhí)行未來沒預測的任務的.對資金消耗,投資回報,價格下跌的分析在很多事例中都有體現.</p><

61、;p>　　這些可以用來分析那些被認為有用并因此即將購買的新機器的投資回報.然而,因為今天的市場動向是那么不確定,這樣的分析不能幫助預測首要的具體系統(tǒng).希望其它的工程問題的解決方法可以提供更多的柔性制造,價格上相應少許提高,這樣投資困境就不會那么嚴重.</p><p>　　前面的論述強調靈活性對新公司的持續(xù)性發(fā)展是一個主要的挑戰(zhàn).主要問題是,一個主要建立在對市場靈活反應的基礎上的設計與制造系統(tǒng)能否迅速對另外一

62、個市場甚至另外一個產品作出快速有效的調整.</p><p>　　今天,這個問題的答案是:可能還不能.例如,一個用車床很好地裝配了的車間,沒有垂直鏜鉆床.要達到所要求的公差,就有天然的不便.它不象有可能由汽車傳輸突然跳到直升飛機傳輸那樣,即使在相反的境況下,車間裝配了鏜床,設備和操作人員也不可能很快地在有資金下重新配置,去改變生產工序和減少需求公差,他們的競爭優(yōu)勢就會喪失.這種同樣的比較也可以在半導體制造上作出.現

63、時正密切關注大容量芯片的制造商不會馬上去辦理申請和配置機器.可以得出的大致結論是:今天的制造機器,包括具體的機床,工業(yè)機器人,和制造系統(tǒng)仍然與具體的銷路密切相關,還不夠靈活.</p><p>　　靈活性的需求,重新配制制造系統(tǒng)也是計算機集程制造系統(tǒng)在它最初意義上的主要方面.商人在1969到1971作出的預測,提煉計算機集成制造系統(tǒng)科學的細節(jié)和需求.然而,這種預測過高估計了被制造廠運用的柔性制造系統(tǒng)和相關技術水平.

64、在十九世紀七十年代和十九世紀八十年代,任務完成以后機器更新換代.假如任務正確準時完成,柔性制造系統(tǒng)繼續(xù)滿意地運作. 然而,如果機器跳動嚴重,聯系中斷,為了使系統(tǒng)有效進行,頻繁的人為界入就變的需要.在這段時期,幾個研究與發(fā)展組織經驗表明聯系軟件細胞的不精確可能是計算機集成制在工業(yè)中運用的主要障礙.有意思的是,到了九十年代末,回顧計算機集成制造的文章比柔性制造系統(tǒng)少得多,只有三種或四種機器被認為有此種性能.所有這些趨勢需求熟練的電腦技術和制

65、造層面感應技術.</p><p>　　2.6.1靈活性設計(再利用)</p><p>　　在氣車工業(yè)靈活性設計可以在一定程度上得到補償,假如一些裝置有再利用性.那些用工業(yè)機器人把門,框架,機架裝配和焊接在一起的自動裝配線明顯昂貴.通常有像足球場大的裝配線,在那里,工業(yè)機器人,固定裝置,較正裝置,把主要部件裝配焊接在一起.沒有親自去標準自動工廠,你是無法知道其切確的耗資.主要的是盡可能地擴大

66、這些生產線的利用和再利用價值.假如設計者給予完全的自由,加工組的所有裝置都需要經過特別加工.將不允許價格昂貴的裝置存在.就像前面提到的,這個因素在設計中有很大的依賴性.在理想的情形下,新的被設計部件是在現有的車間裝置下,在脫離板的自動解決方法下設計而成的.理想的情形是現有的裝置和一些無使用的裝置可以被重新利用.</p><p>　　一些小批量生產的公司,可能使用混合生產線.可能和一般的轎車和公車一樣,簡單.但在尺

67、寸基本相同的不同轎車制造上,其更具靈活性.在優(yōu)秀的多性能設計上,很多裝置和自動機器人有多種使用性.</p><p>　　當然,隨著在設計與制造越來越多的合作,現有的機器有可能對未來裝置變得更是一個制約.因此再過幾年,隨著更多加工中心的出現,其耗價有可能變得比單一裝置更便宜.</p><p>　　結論:設計美學與制造</p><p>　　接下來為了作一個準確的預測,必

68、須強調在消費者心里出存在的已經被運用的設計制造.日本的文章逐步強調產品的美學質量作為他們的下一個目標.雖然它很難作為一個具體的設計客體作衡量.</p><p>　　極端情況,深藏在車里,洗衣機里,或爐里的零件就沒有必要做得很好看.</p><p>　　另外一種極端情況下,一些高質量高價格商品也有市場,比如三百美元的運動衫,一只美洲豹,昂貴的毒品.在這種情況下購買者尋找的是時髦與奢侈.因此,

69、設計制造工程師不能按照他們自己的方式辦,轎車就像在輪子上的矩型框,便宜,沒錯,但很難賣.</p><p>　　通過個別的調查,得出結論,沖從東京到京都,富裕的日本人選擇奔馳等.大街上美國轎車不是很多,即使在繁華街,和東京的使館區(qū).有時可以看到卡迪拉克,一些滿載的吉普.和一些最新的馬字達.但不是很多.</p><p>　　美國三大公司抱怨說這是日本對美國商品制造關稅壁壘.雖然,真正的原因是有

70、錢的日本商人喜歡有品牌的商品,這在日本稱做品牌效應,所以美國轎車現時在日本沒有足夠的品牌度.畢竟,日本市場被其他有品牌的美國商品占領. 如麥當勞,好來塢電影,美國音樂光盤.不可避免地,還有咖啡店.</p><p>　　那文章的主旨在于設計與制造工程師不能忽視在設計與制造過程中的藝術和非理性的東西.</p><p><b>　　2.7 技術管理</b></p>

71、;<p>　　過去一百年,設計與制造已經從純技術領域的怒力向商品化方向努力轉變.特別地,在這種商業(yè)化環(huán)境中,</p><p>　　需要強調的是，再這種新的商業(yè)環(huán)境中要取得成功只靠科學技術是不行的，特別地，二十世紀八十年代末的美國制造業(yè)處于一種恐慌中基礎工業(yè)如半導體，汽車，電子產品，機床都失去了國際競爭力。</p><p>　　今天，情況看起來確是比前面好多了，在世界如何看美國

72、的評論中紐約時報刊登：我們的技術－電腦系統(tǒng)，醫(yī)學掃描，因特網。建立了發(fā)展中國家羨慕的標準。</p><p>　　●設計與制造中的創(chuàng)造力。</p><p>　　●基礎制造方法中的質量保證與控制，</p><p>　　●更加有效率的公司。</p><p><b>　　●全球性商務。</b></p><p&

73、gt;<b>　　●因特網商務。</b></p><p>　　事實是，一些國際竟爭者在與不樂觀的二十世紀八十年代末的匯率使得美國公司更有競爭力的斗爭中進展不順利。</p><p>　　在寫這文章的時代，對未來的挑戰(zhàn)就是保持持續(xù)性增長，在幾年里，美國制造業(yè)趕上太平洋沿岸的國家何歐洲競爭者。甚至提倡“后來居上”的體育精神。趕上【跑在前面的。更好點，跑在最前頭需要有超呼尋常

74、的創(chuàng)造力和承諾。和上面的相似，有可能在一些特別領域的持續(xù)性創(chuàng)造力包括：</p><p>　　●通過因特網進一步開拓全球市場。</p><p>　　●聚焦與復雜系統(tǒng)，在機電產品，生物工程層面上，特別發(fā)展CAD/CAM技術。</p><p>　　●繼續(xù)把握好占領市場的時間意識，用創(chuàng)造美學去平衡。</p><p>　　●繼續(xù)為六大質量目標奮斗。&l

75、t;/p><p>　　●產生一個可以應付甚至可以在變化中求生存的組織。比如，所有工業(yè)，從半導體產業(yè)到機器，再到鋼鐵磨床，被認為跟環(huán)境有更大關系。這樣，雖然依然和對環(huán)境污染或工業(yè)安全注意較少的其他國家。存在競爭。創(chuàng)造競爭就變得特別有創(chuàng)造力和效率。</p><p>　　●對政府的投資機會，公共政策，在一定程度上對所有工業(yè)都有引響的聯邦法規(guī)靈活反應。例如，一個像二十五年前，預防與發(fā)展委員會發(fā)起的最初

76、的因特網。他被美國國家科學院持續(xù)服持。因此基本上可以推出在加利福尼亞北部，波思頓128路附近的硅谷的很大一部分財富是通過在像這樣的工程中發(fā)展的。公司很希望知道那些限制，然后沿著其發(fā)展可以獲得最大利益。然而，達到的同一性可以被經?；煜?，浪費時間。就像最近在對圍繞電子通訊業(yè)的調節(jié)中看到的那樣。（另外一個對生物技術的限制事例，FDA藥物監(jiān)督局確實在很長一段時間內對首期研究與發(fā)展投資和市場份額上施加影響?？赡芫褪且驗檫@個原因，許多生物技術被那些

77、資深的藥物公司開發(fā)。</p><p>　　●圍繞設計，構思，制造主要設計領域展開討論，特別地，新的硬件和軟件環(huán)境允許在設計構思和制造中地聯系簡單化。包括節(jié)省時間以達到設計目標樣品的特別利益。不管它是削片或電腦箱，新技術和新軟件系統(tǒng)的標準同樣提供了盡可能多的涉及設計理念和制造機能上的充足信息的文章。那種快速地掌握搜首要的標本的能力允許設計者評估設計的美學價值。它同樣允許對一個簡單的待裝配客體如何與粗糙部件的連接作預