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密 級 分類號 編 號 成 績 本科生畢業(yè)設計 (論文) 外 文 翻 譯 原 文 標 題 Mechanical Design and Manufacturing Processes 譯 文 標 題 機械設計及加工工藝 作者所在系別 機電工程學院 作者所在專業(yè) 作者所在班級 作 者 姓 名 作 者 學 號 指導教師姓名 指導教師職稱 完 成 時 間 2017 年 2 月 譯文標題 機械設計及加工工藝 原文標題 Mechanical Design and Manufacturing Processes 作 者 Alex Elias 譯 名 艾力克斯 國 籍 美國 原文出處 Journal of Composite Materials 摘要：機械設計是一門通過改進老產(chǎn)品或設計新產(chǎn)品，為了滿足人類需求而有的應用學科。它涉及到了工程技術的許多領域，主要研究產(chǎn)品的尺寸和形狀以及具體結構的詳細構思，同時還要研究產(chǎn)品在制造、銷售及使用中面臨的各種問題。 關鍵詞：機械；設計；加工工藝 進行各種機械設計的工作人員一般被稱為設計工程師或者設計人員。機械設計一個具有創(chuàng)造性的工作。設計工程師要求在工作上具有創(chuàng)新思維，還得在工程材料、機械制圖、動力學、運動學和機械制造工藝學等學科具有強大的知識儲備。 像之前所說，機械設計的目的是生產(chǎn)人類所需要的產(chǎn)品。發(fā)現(xiàn)、發(fā)明和科學知識并不一定能給人類帶來好處，只有當它們被使用在產(chǎn)品上它們才能產(chǎn)生效益。所以，我們應該在對一個產(chǎn)品進行設計之前，了解人們是否需要這種產(chǎn)品。 我們應該把機械設計看成是設計人員運用創(chuàng)造性的思維進行產(chǎn)品的設計、系統(tǒng)的分析以及制訂產(chǎn)品的加工工藝的一個機會。掌握機械設計的基礎知識比熟記一些公式和數(shù)據(jù)更重要。只用數(shù)據(jù)和公式并不能完整的做出一個好的設計。同時，設計者應該精確定的進行運算。比如，即使將一個小數(shù)點的位置弄錯，正確的設計也會變成錯誤的。 一個好的設計工程師應當敢于提出新的想法，并且敢于承擔一定的風險，當方法不適合時，就立即采用以前的方法。所以，設計工程師必須要有耐心，因為花費許多時間努力可能并不會成功。一個創(chuàng)新的設計，要求設計者拋棄許多舊的、人們都知道的方法。因為許多人都容易墨守成規(guī)，所以這樣做不是一件簡單的事情。一個設計者應當不斷地努力探索改良舊產(chǎn)品的方法，在這個過程中，應該選擇原有的設計原理，并把它同新觀念相結合起來。 新設計的本身可能會有很多的缺陷和問題，只有在這些問題和缺陷解決之后，新產(chǎn)品的優(yōu)越性才能體現(xiàn)出來。所以，一個好的產(chǎn)品產(chǎn)生的同時，也有著巨大的風險。應當強調(diào)的是，如果設計不要求采用完全新的方法，那就沒有必要為了改變而采用全新的辦法。 在設計的開始階段，應當讓設計工程師充分發(fā)揮自己的創(chuàng)造性，擺脫各種約束?；蛟S在這之中可能會產(chǎn)生許多不適用的想法，但是這可以在設計的開始階段，在生產(chǎn)圖紙繪制之前進行改正。只有這樣，才不會阻擋創(chuàng)新的思維。一般需要提出幾種設計方案，并進行比較?？赡茉谧詈筮x擇的方案中，采用了一些未被接受的方案中的一些想法。 心理學家經(jīng)常探討怎樣讓人們適應所操作的機器。設計工程師的基本職責是讓機器來適應人們。這并不是一個簡單的工作，因為一個對所有人都做好的操作范圍和操作過程是并不存在的。 另外一個應當被知道的重要問題，設計者必須能夠和其他相關人員進行溝通和交流。與別人進行設計方案的交流和溝通是設計的關鍵階段也是最后階段。有很多偉大的發(fā)明設計和創(chuàng)造并沒有被人們所利用，因為創(chuàng)造者不愿意或者不善于向他人介紹自己的成果。提出方案是一個說服別人的事情。當一個設計工程師向經(jīng)營、管理部門或者領導提出自己的新方案時，就是希望說明或證明自己的方案很好。只有很好的完成這個工作，為了這個方案耗費的大量時間和精力才會有意義。 人們只有三種表達自己思想的方式，分別是文字說明、口頭闡述和繪圖說明。所以，一個優(yōu)秀的設計師不到要掌握大量的技術，還應該掌握這幾種表達方式。如果一個技術很強的人，但是表達能力較差，他就會面臨巨大的困難。如果以上三種表達能力都很差，那么永遠都沒有人知道他的才能。 一個真正有能力的設計工程師不該漢派自己提出的方案可能不可行。實際上，失敗是肯定會發(fā)生的，因為每個每個真正有創(chuàng)造性的想法總是有批評或者失敗伴隨著它。從一次失敗中可以學到很多的東西，只有不怕失敗的人才能取到巨大的收獲。 總之，決定不把方案提交出來，才是真正的失敗。? 為了進行有效的交流，需要解決下列問題： (1)所要設計的這個產(chǎn)品是否真正為人們所需要?? ?(2)此產(chǎn)品與其他公司的現(xiàn)有同類產(chǎn)品相比有無競爭能力?? ?(3)生產(chǎn)這種產(chǎn)品是否經(jīng)濟?? ?(4)產(chǎn)品的維修是否方便?? ?(5)產(chǎn)品有無銷路?是否可以盈利?? 只有時間才能對上述問題給出正確的答案。但是，產(chǎn)品的設計、制造和銷售只能在對上述問題的初步肯定答案的基礎上進行。設計工程師還應該通過零件圖和裝配圖，與制造部門一起對最終設計方案進行溝通。通常，在制造過程中會出現(xiàn)某個問題?？赡芤髮δ硞€零件尺寸或公差做一些更改，使零件的生產(chǎn)變得容易。但是，工程上的更改必須經(jīng)過設計人員批準，以保證不會損傷產(chǎn)品的功能。 有時，在產(chǎn)品的裝配時或者裝箱外運前的試驗中才發(fā)現(xiàn)設計中的某種缺陷。這些事例恰好說明了設計是一個動態(tài)過程?？偸谴嬖谥玫姆椒▉硗瓿稍O計工作，設計人員應該不斷努力，尋找這些更好的方法。 不能采用解析法計算的情況下，可以在基本公式內(nèi)引入系數(shù)。例如，對于薄壁鋼管，考慮到腐蝕性，可將根據(jù)壓力求得的厚度增加一些。當必須應用一個基本公式來確定形狀、材料和使用條件，而這些被確定的量僅僅與在公式推導中的假設比較接近時，要采取措施使結果“偏于安全”。當數(shù)據(jù)不完全時，可以應用理論公式作為尺寸的指南，在擴展后的范圍內(nèi)獲得令人滿意的設計結果。 4．根據(jù)性能組合選擇材料。選擇材料時需要考慮有關的性能組合，不僅考慮強度，硬度和重量，而且有時還要考慮抗沖擊性，抗腐蝕性和耐高溫或低溫的能力。成本和制造性能都是應該考慮的因素，這些因素包括可焊接性，機械加工性能，對熱處理溫度變化的敏感性和所需要的涂層等。 5．在現(xiàn)有零件和整體零件之間進行認真的選擇。若一個以前研制的零件能夠滿足性能要求和可靠性要求，并適用于所設計的那臺機器而無須附加的研制費用，那么設計人員及其公司通常會從零件制造廠的現(xiàn)貨中選取該零件。但是，只有充分了解其性能，才能進行認真的選擇工作，因為任何一個機器零件的失效都會影響公司的信譽，并使公司承擔相應的責任。在其他情況下，若機器設計人員自己來設計零件，則零件的強度，可靠性和成本等方面的要求就可以更好地得到滿足?？蓪⒛硞€零件與其他零件設計成一個整體零件，例如將幾個齒輪設計為一個鍛件或者將齒輪與軸設計為一體，這種方法的主要優(yōu)點是緊湊。 6．保證零件在裝配中準確定位和不發(fā)生干涉。一個良好的設計能夠保證零件定位準確，裝配和修理方便容易。軸肩和導向表面在裝配過程中不需要測量就能提供準確定位。零件的形狀應該被設計得保證這個零件不會被裝反或裝錯位置。必須能夠預見和防止諸如不同的螺紋孔中的螺釘之間的干涉和不同的連桿機構之間的干涉。必須避免部件之間的找正對中誤差和定位誤差，或者必須采用措施，減小任何由此引起的不利的位移和應力。人類通過使用工具和智能，制造使其生活變得更容易和更舒適的物品這種方法，把他們自己與其他種類的生命區(qū)別開來。許多世紀以來，工具和為工具提供動力能源的種類都在不斷地發(fā)展，以滿足人類日益完善和越來越復雜的想法。 在最早的時期，工具主要是由石器構成的?？紤]到所制造的物品相對簡單的形狀和被加工的材料，石頭作為工具是適用的。當鐵制工具被發(fā)明出來以后，耐 用的金屬和更精致的物品能夠被制造出來。在20世紀中，已經(jīng)有了一些由有史以來最耐用，同時也是最難加工的材料制造的產(chǎn)品。為了迎接這些材料給制造業(yè)帶來的挑戰(zhàn)，工具材料已經(jīng)發(fā)展到包括合金鋼、硬質(zhì)合金、金剛石和陶瓷。給我們的工具提供動力的方法也發(fā)生了類似的進步。最初，是由人或動物的肌肉為工具提供動力；隨后，水力、風力、蒸汽和電力得到了利用，人類通過采用新型機器、更高的精度和更快的加工速度來進一步提高制造能力。 附錄： Mechanical Design and Manufacturing Processes Abstract: Mechanical?design?is?the?application?of?science?and?technology?to devise?new? or?improved?products?for?the?purpose of?satisfying?human?needs.It?is?a?vast?field?of?engine technology?which?not?only?concerns?itself?with?the?original?conception?of?the?product?in ?terms?of its?size,?shape?and?construction?details but?also?considers?the?various?factors?involved?in?the?manufacture,?marketing?and?use?of?the?product. Keywords: Mechanical，design，manufacturing process People?who?perform?the?various?functions?of?mechanical?design?are?typically?called?desi-gners,?or?design?engineers.?Mechanical?design?is?basically?a?creative?activity.?However,?in?addition?to?being?innovative,?a?design?engineer?must?also?have?a?solid?background?in?the? a-reas?of?mechanical?drawing,?kinematics,?dynamics,?materials?engineering,?strength?of materials?and?manufacturing?processes. As?stated?previously,?the?purpose?of?mechanical?design?is?to?produce?a?product?which will?serve?a?need?for?man.?Inventions,?discoveries?and?scientific?knowledge?by?themselve-s?do?not?necessarily?benefit?people;?only? if ?they? are ?incorporated? into? a?designed? product? will? a? benefit?be? derived.?It?should?be?recognized,?therefore,?that?a?human?nee-d?must?be?identified?before?a?particular?product?is?designed. Mechanical?design?should?be?considered?to?be?an?opportunity?to?use?innovative?talents?t-o?envision?a?design?of?a?product,?to?analyze?the?system?and?then?make?sound?judgments?o-n?how?the?product?is?to?be?manufactured.?It?is?important?to?understand?the?fundamentals?o-f?engineering?rather? than?memorize?mere?facts? and?equations.?There?are?no? facts?or?equ-ations?which?alone?can?be?used?to?provide?all?the?correct?decisions?required?to?produce?a?go-od?design.? On?the?other?hand,?any?calculations?made?must?be?done?with?the?utmost?care?and?precisi-on.?For?example,?if?a?decimal?point?is?misplaced,?an?otherwise?acceptable?design?may?not?f-unction. Good?designs?require?trying?new?ideas?and?being?willing?to?take?a certain?amount?of?ris-k,?knowing?that?if?the?new?idea?does?not?work?the?existing?method?can?be?reinstated.?Thu-s?a?designer?must?have?patience,?since?there?is?no?assurance?of?success?for?the?time?and?effo-rt?expended.?Creating?a?completely?new?design?generally?requires?that?many?old?and?well-established?methods?be?thrust?aside.?This?is?not?easy?since?many?people?cling?to?familiar?id-eas,?techniques?and?attitudes.?A?design?engineer?should?constantly?search?for?ways?to?impr-ove?an?existing?product?and?must?decide?what?old,?proven?concepts?should?be?used?and?what?new,?untried?ideas?should?be?incorporated.? New?designs?generally?have?"bugs"?or?unforeseen?problems?which?must?be?worked?out?b-efore?the?superior?characteristics?of?the?new?designs?can?be?enjoyed.?Thus?there?is?a?chanc-e?for?a?superior?product,?but?only?at?higher?risk.It?should?be?emphasized?that,if?a?design?do-es?not?warrant?radical?new?methods,?such?methods?should?not?be?applied?merely?for?the?sa-ke?of?change.? During?the?beginning?stages?of?design,?creativity?should?be?allowed?to?flourish?withou-t?a?great?number?of?constraints.Even?though?many?impractical?ideas?may?arise,?it?is?usuall-y?easy?to?eliminate?them?in?the?early?stages?of?design?before?firm?details?are?required?by?ma-nufacturing.?In?this?way,?innovative ideas?are?not?inhibited.?Quite?often,?more?than?one?de-sign?is?developed,?up?to?the?point?where?they?can?be?compared?against?each?other.It?is?entir-ely?possible?that?the?design?which?is?ultimately?accepted?will?use?ideas?existing?in?one?of?t-he?rejected?designs?that?did?not?show?as?much?overall?promise.? Psychologists?frequently?talk?about?trying?to?fit?people?to?the?machines?they?operate.?It?i-s?essentially?the?responsibility?of?the?design?engineer?to?strive?to?fit?machines?to?people.?Th-is?is?not?an?easy?task,?since?there?is?really?no?average?person?for?which?certain?operating??d-imensions?and?procedures?are?optimum.? ? Another?important?point?which?should?be?recognized?is?that?a?design?engineer?must?be?a-ble?to?communicate?ideas?to?other?people?if?they?are?to?be?incorporated.?Communicating?th-e?design?to?others?is?the?final,?vital?step?in?the?design?process.?Undoubtedly?many?great?desi-gns,?inventions,?and?creative?works?have?been?lost?to?mankind?simply?because?the?originat-ors?were?unable?or?unwilling?to?explain?their?accomplishments?to?others.?Presentation?i-s?a?selling?job.?The?engineer,?when?presenting?a?new?solution?to?administrative,?manageme-nt,?or?supervisory?persons,?is?attempting?to?sell?or?to?prove?to?them?that?this?solution?is?a?be-tter?one.?Unless?this?can?be?done?successfully,?the?time?and?effort?spent?on?obtaining?the?so-lution?have?been?largely?wasted.? ? Basically,?there?are?only?three?means?of?communication?available?to?us.?These?are?the?w-ritten,?the?oral,?and?the?graphical?forms.?Therefore?the?successful?engineer?will?be?technica-lly?competent?and?versatile?in?all?three?forms?of?communication.?A?technically?competen-t?person?who?lacks?ability?in?any?one?of?these?forms?is?severely?handicapped.If?ability?in?al-l?three?forms?is?lacking,?no?one?will?ever?know?how?competent?that?person?is! The?competent?engineer?should?not?be?afraid?of?the?possibility?of?not?succeeding?in?a?pre-sentation.?In?fact,?occasional?failure?should?be?expected?because?failure?or?criticism?seem-s?to?accompany?every?really?creative?idea.?There?is?a?great?deal?to?be?learned?from?a?failure,and?the?greatest?gains?are?obtained?by?those?willing?to?risk?defeat.?In?the?final?analysis,?th-e?real?failure?would?lie?in?deciding?not?to?make?the?presentation?at?all.? ?To?communicate?effectively,?the?following?questions?must?be?answered:? ?(1)?Does?the?design?really?serve?a?human?need?? ?(2)?Will?it?be?competitive?with?existing?products?of?rival?companies?? ?(3)?Is?it?economical?to?produce?? ?(4)?Can?it?be?readily?maintained?? ?(5)?Will?it?sell?and?make?a?profit? Only?time?will?provide?the?true?answers?to?the?preceding?questions,?but?the?product?shou-ld?be?designed,?manufactured?and?marketed?only?with?initial?affirmative?answers.?The?desi-gn?engineer?also?must?communicate?the?finalized?design?to?manufacturing?through?the?us-e?of?detail?and?assembly?drawings.? ? Quite?often,?a?problem?will?occur?during?the?manufacturing?cycle[3].?It?may?be?that?a?ch-ange?is?required?in?the?dimensioning?or?tolerancing?of?a?part?so?that?it?can?be?more?readil-y?produced.?This?fails?in?the?category?of?engineering?changes?which?must?be?approved?by?t-he?design?engineer?so?that?the?product?function?will?not?be?adversely?affected.? In?other?cases,?a?deficiency?in?the?design?may?appear?during?assembly?or?testing?just?prio-r?to?shipping.?These?realities?simply?bear?out?the?fact?that?design?is?a?living?process.?Ther-e?is?always?a?better?way?to?do?it?and?the?designer?should?constantly?strive?towards?finding?t-hat?better?way.? Designing?starts?with?a?need,real?or?imagined.Existing?apparatus?may?need?improvement-s?in?durability,?efficiently,?weight,?speed,?or?cost.?New?apparatus?may?be?needed?to?perfor-m?a?function?previously?done?by?men,?such?as?computation,?assembly,?or?servicing.?With?th-e?objective?wholly?or?partly?defined,?the?next?step?in?design?is?the?conception?of?mechanis-ms?and?their?arrangements?that?will?perform?the?needed?functions.?For?this,?freehand?sketch-ing?is?of?great?value,?not?only?as?a?record?of?one's?thoughts?and?as?an?aid?in?discussion?wit-h?others,?but?particularly?for?communication?with?one's?own?mind,?as?a?stimulant?for?creati-ve?ideas.When?the?general?shape?and?a?few?dimensions?of?the?several?components?becom-e?apparent, analysis?can?begin?in?earnest.The?analysis?will?have?as?its?objective?satisfactor-y?or?superior?performance,?plus?safety?and?durability?with?minimum?weight,and?a?competit-ive?east.? Optimum?proportions?and?dimensions?will?be?sought?for?each?critically?loaded?section,to-gether?with?a?balance?between?the?strength?of?the?several?components.?Materials?and?thei-r?treatment?will?be?chosen.?These?important?objectives?can?be?attained?only?by?analysis?bas-ed?upon?the?principles?of?mechanics,?such?as?those?of?statics?for?reaction?forces?and?for?th-e?optimum?utilization?of?friction;?of?dynamics?for?inertia,?acceleration,?and?energy;of?elasticity?and?strength?of?materials?for?stress?and?deflection;?and?of?fluid?mechanics?for?lubrication?and?hydrodynamic?drives.? Finally,?a?design?based?upon?function?and?reliability?will?be?completed,?and?a?proto typ-e?may?be?built.?If?its?tests?are?satisfactory,?and?if?the?device?is?to?be?produced?in?quantity,?th-e?initial?design?will?undergo?certain?modifications?that?enable?it?to?be?manufactured?in?qua-ntity?at?a?lower?cost.?During?subsequent?years?of?manufacture?and?service,?the?design?is?lik-ely?to?undergo?changes?as?new?ideas?are?conceived?or?as?further?analysis?based?upon?test-s?and?experience?indicate?alterations.?Sales?appeal,?customer?satisfaction,?and?manufactur-e?cost?are?all?related?to?design,?and?ability?in?design?is?intimately?involved?in?the?success?o-f?an?engineering?venture. 8 指 導 教 師 評 語 外文翻譯成績： 指導教師簽字： 年 月 日 注：1. 指導教師對譯文進行評閱時應注意以下幾個方面：①翻譯的外文文獻與畢業(yè)設計（論文）的主題是否高度相關，并作為外文參考文獻列入畢業(yè)設計（論文）的參考文獻；②翻譯的外文文獻字數(shù)是否達到規(guī)定數(shù)量（3 000字以上）；③譯文語言是否準確、通順、具有參考價值。 2. 外文原文應以附件的方式置于譯文之后。