銷軸軸端的槽、面銑成組夾具設(shè)計(jì)【三維UG】【含cad圖紙+文檔全套資料】

喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請放心下載，，有疑問咨詢QQ:414951605或者1304139763 ======================== 喜歡就充值下載吧。。資源目錄里展示的文件全都有，，請放心下載，，有疑問咨詢QQ:414951605或者1304139763 ======================== 浙江工業(yè)大學(xué)之江學(xué)院畢業(yè)設(shè)計(jì)（論文）任務(wù)書 學(xué)生姓名 樓挺 學(xué)號 201120070312 專業(yè)班級 機(jī)自1102 題　　目 銷軸軸端的槽、面銑成組夾具設(shè)計(jì) 指導(dǎo)教師 舒欣 職 稱 講師 課題類型 √設(shè)計(jì) □論文 課題來源 □教師科研課題 √ 教師生產(chǎn)實(shí)際課題 □學(xué)生自立課題 畢業(yè)設(shè)計(jì)（論文）起止時(shí)間 2014年11月1日至 2015年6月15日 一、畢業(yè)設(shè)計(jì)（論文）的主要內(nèi)容及要求 1、開題報(bào)告和文獻(xiàn)閱讀 （1）文獻(xiàn)閱讀：查閱文獻(xiàn)應(yīng)不少于15篇，其中外文文獻(xiàn)不少于2篇，近5年內(nèi)的文獻(xiàn)數(shù)應(yīng)不少于文獻(xiàn)總數(shù)的1/3，并應(yīng)有近2年內(nèi)的文獻(xiàn)。 （2）文獻(xiàn)綜述：3000字以上，包括國內(nèi)外現(xiàn)狀、研究方向、進(jìn)展情況、存在問題、參考依據(jù)等。 （3）開題報(bào)告：2000字以上，包括選題的意義、可行性分析、研究的內(nèi)容、研究方法、擬解決的關(guān)鍵問題、預(yù)期結(jié)果、研究進(jìn)度計(jì)劃等。 （4）外文翻譯：3000字以上（翻譯成中文后的漢字字?jǐn)?shù)）。 2、課題要解決的主要問題和具體要求 本課題通過分析一組小軸類零件上銑削槽的特點(diǎn)，找出共性，確定銑削夾具形式，進(jìn)行結(jié)構(gòu)設(shè)計(jì)，確保定位精度滿足加工要求，工件夾緊牢固可靠；要求機(jī)構(gòu)合理、加工方便等，并繪制二維、三維裝配圖和部分零件的工程圖。 3、論文：10000字以上（部分特殊專業(yè)根據(jù)實(shí)際情況，經(jīng)教務(wù)辦確認(rèn)，可適當(dāng)調(diào)整有關(guān)字?jǐn)?shù)方面的要求），包括緒論、正文、結(jié)論、參考文獻(xiàn)等。 二、主要參考文獻(xiàn) [1] 徐愛玲．機(jī)床夾具設(shè)計(jì)方法探討[J]．裝備制造技術(shù)，2008（8）：60-64． [2] 隋聚艷．夾具的發(fā)展及其趨勢分析[J]．現(xiàn)代商貿(mào)工業(yè)，2009，32（19）：323-324 [3] 李定志，龔書強(qiáng)，王永國．成組夾具技術(shù)在小批量銑加工生產(chǎn)中的應(yīng)用[J]．機(jī)械工人冷加工，2007 (1)：43-44． [4] 張亞明，機(jī)床夾具的分類與構(gòu)成[J]．煤炭技術(shù)，2008，27（4）：12-13 [5] 王守忠，陳愛榮．成組夾具技術(shù)在機(jī)械加工中的應(yīng)用探析[J]．商丘職業(yè)技術(shù)學(xué)院學(xué)報(bào)，2006(2)：62-64． 　　　　　　　　　　　　　　　　　　　　指導(dǎo)教師簽名： 年 月 日 專業(yè)教研室意見： □同意下達(dá)任務(wù)書 □不同意下達(dá)任務(wù)書 教研室主任簽章： 年 月 日 1.外文翻譯 機(jī)械加工零件的工藝及夾具設(shè)計(jì) 摘 要：本文對機(jī)械加工零件的結(jié)構(gòu)和工藝進(jìn)行了分析，確定了機(jī)械加工工藝路線，夾具在機(jī)械加工中所占的地位和重要性，以及夾具設(shè)計(jì)。隨著科學(xué)的日益發(fā)展進(jìn)步和國家產(chǎn)業(yè)政策的調(diào)整,工程機(jī)械行業(yè)已成為沒有政策壁壘的完全競爭行業(yè) 關(guān)鍵詞：技術(shù)背景/發(fā)展趨勢/工序/定位方案 1 機(jī)械加工歷史背景及其意義 機(jī)械制造業(yè)是一個(gè)古老而永遠(yuǎn)充滿生命力的行業(yè)。隨著現(xiàn)代工業(yè)的發(fā)展，對機(jī)械產(chǎn)品的要求越來越高，機(jī)械制造工藝也在日新月異地發(fā)展。自新中國成立以來，我國的制造技術(shù)與制造業(yè)得到了長足發(fā)展，一個(gè)具有相當(dāng)規(guī)模和一定技術(shù)基礎(chǔ)的機(jī)械工業(yè)體系基本形成。改革開放二十多年來，我國制造業(yè)充分利用國內(nèi)國外兩方面的技術(shù)資源，有計(jì)劃地推進(jìn)企業(yè)的技術(shù)改造，引導(dǎo)企業(yè)走依靠科技進(jìn)步的道路，使制造技術(shù)、產(chǎn)品質(zhì)量和水平及經(jīng)濟(jì)效益發(fā)生了顯著變化，為推動國民經(jīng)濟(jì)的發(fā)展做出了很大的貢獻(xiàn)。盡管我國制造業(yè)的綜合技術(shù)水平有了大幅度提高，但與工業(yè)發(fā)達(dá)國家相比，仍存在階段性差距。進(jìn)入二十一世紀(jì)，我國發(fā)展經(jīng)濟(jì)的主導(dǎo)產(chǎn)業(yè)仍然是制造業(yè)，特別是在我國加入世貿(mào)組織后，世界的制造中心就從發(fā)達(dá)國家遷移到了亞洲，我國有廉價(jià)的勞動力和廣大的消費(fèi)市場，因此，我國工業(yè)要想發(fā)展，就需要有相應(yīng)的技術(shù)和設(shè)備來支持。 機(jī)械工業(yè)是國民經(jīng)濟(jì)的裝備工業(yè)；是科學(xué)技術(shù)物化的基礎(chǔ)；是高新技術(shù)產(chǎn)業(yè)化的載體；是國防建設(shè)的基礎(chǔ)；是實(shí)現(xiàn)經(jīng)濟(jì)快速增長的重要支柱；也是為提高人民生活質(zhì)量、提供消費(fèi)類機(jī)電產(chǎn)品的供應(yīng)工業(yè)。它對國民經(jīng)濟(jì)運(yùn)行的質(zhì)量和效益、產(chǎn)業(yè)結(jié)構(gòu)的調(diào)整和優(yōu)化具有極其重要的作用。 2 機(jī)械行業(yè)的現(xiàn)狀及發(fā)展趨勢 隨著社會的發(fā)展，各種機(jī)械逐漸運(yùn)用到各個(gè)行業(yè)中，不管是在農(nóng)用、軍用、工用等方面，離開了機(jī)械的操作就談不上效率，因此，從某中角度上來說，一個(gè)國家的經(jīng)濟(jì)實(shí)力、社會地位，和機(jī)械行業(yè)的發(fā)展是密不可分的。各工業(yè)化國家經(jīng)濟(jì)發(fā)展的歷程表明，沒有強(qiáng)大的裝備制造業(yè)，就不可能實(shí)現(xiàn)國民經(jīng)濟(jì)的工業(yè)化、現(xiàn)代化和信息化[3]。目前裝備制造業(yè)發(fā)展滯后是制約我國經(jīng)濟(jì)發(fā)展和產(chǎn)業(yè)升級的重要因素，加大結(jié)構(gòu)調(diào)整力度，推進(jìn)機(jī)械工業(yè)持續(xù)、健康、穩(wěn)定發(fā)展，對于轉(zhuǎn)變經(jīng)濟(jì)增長方式，提高國民經(jīng)濟(jì)整體素質(zhì)，增強(qiáng)我國經(jīng)濟(jì)的國際競爭力，保障國防安全等都具有重要而深遠(yuǎn)的意義。 3 機(jī)械加工工藝規(guī)程制訂 3.1 機(jī)械加工工藝過程的定義 機(jī)械加工工藝過程是指用機(jī)械加工方法改變毛坯的形狀，尺寸，相對位置和性質(zhì)等，使其成為成品或半成品的全過程。機(jī)械加工工藝過程直接決定零件及產(chǎn)品的質(zhì)量和性能，對產(chǎn)品的成本、生產(chǎn)周期都有較大的影響，是整個(gè)工藝過程的重要組成部分。 3.2 機(jī)械加工工藝過程的組成 組成機(jī)械加工工藝過程的基本單元是工序。工序又是由安裝、工位、工步及走刀組成的。 ⑴ 工序是指一個(gè)或一組工人，在一個(gè)工作地對同一個(gè)或同時(shí)對幾個(gè)工件所連續(xù)完成的那一部分工藝過程。工序是制定勞動定額、配備工人及機(jī)床設(shè)備、安排作業(yè)計(jì)劃和進(jìn)行質(zhì)量檢驗(yàn)的基本單元。 ⑵ 安裝是工件經(jīng)一次裝夾后所完成的那一部分工序。 ⑶ 當(dāng)應(yīng)用轉(zhuǎn)位（或移位）加工的機(jī)床（或夾具）進(jìn)行加工時(shí)，在一次裝夾中，工件（或刀具）相對于機(jī)床要經(jīng)過幾個(gè)位置依次進(jìn)行加工，在每一個(gè)工作位置上所完成的那一部分工序，稱為工位。采用多工位加工可以減少裝夾的次數(shù)，減少裝夾誤差，提高生產(chǎn)率。 ⑷ 工步是加工表面在切削刀具和切削用量（僅指主軸轉(zhuǎn)速和進(jìn)給量）都不變的情況下所完成的那一部分工藝過程。 ⑸ 在一個(gè)工步中，如果要切掉的金屬層很厚，可分幾次切削，每切削一次就稱為一次走刀。 3.3 機(jī)械加工工藝規(guī)程的定義 規(guī)定產(chǎn)品或零部件制造過程和操作方法等的工藝文件，稱為工藝規(guī)程，它是企業(yè)生產(chǎn)中的指導(dǎo)性技術(shù)文件。 3.4 機(jī)械加工工藝規(guī)程的作用及內(nèi)容 機(jī)械加工工藝規(guī)程是生產(chǎn)準(zhǔn)備工作的主要依據(jù)。根據(jù)它來組織原材料和毛坯的供應(yīng)，進(jìn)行機(jī)床調(diào)整，專用工藝裝備的設(shè)計(jì)與制造，編制生產(chǎn)作業(yè)計(jì)劃，調(diào)配勞動力，以及進(jìn)行生產(chǎn)成本核算等。 機(jī)械加工工藝規(guī)程也是組織生產(chǎn)、進(jìn)行計(jì)劃調(diào)度的依據(jù)。有了它就可以制定生產(chǎn)產(chǎn)品的進(jìn)度計(jì)劃和相應(yīng)的調(diào)度計(jì)劃，并能做到各工序科學(xué)地銜接，使生產(chǎn)均衡、順利，實(shí)現(xiàn)優(yōu)質(zhì)、高產(chǎn)和低消耗。 機(jī)械加工工藝過程卡片和機(jī)械加工工序卡片，是兩個(gè)主要的工藝文件。機(jī)械加工工藝過程卡片，是說明零件加工工藝過程的工藝文件。在單件、小批量生產(chǎn)中，以機(jī)械加工工藝過程卡片指導(dǎo)生產(chǎn)，過程卡的各個(gè)項(xiàng)目編制較為詳細(xì)。機(jī)械加工工序卡片是為每個(gè)工序詳細(xì)制定的，用于直接指導(dǎo)工人進(jìn)行生產(chǎn)，多用于大批量生產(chǎn)的零件和成批生產(chǎn)中的重要零件。 3.5 制訂機(jī)械加工工藝規(guī)程的原則及步驟 在一定的生產(chǎn)條件下，以最少的勞動消耗和最低的費(fèi)用，按計(jì)劃加工出符合圖紙要求的零件，是制訂機(jī)械加工工藝規(guī)程的基本原則。 制訂機(jī)械加工工藝規(guī)程的步驟如下： ①根據(jù)零件的生產(chǎn)綱領(lǐng)決定生產(chǎn)類型； ②分析零件加工的工藝性； ③選擇毛坯的種類和制造方法； ④擬訂工藝過程； ⑤工序設(shè)計(jì)； ⑥編制工藝文件。 4 夾具設(shè)計(jì) 4.1 夾具設(shè)計(jì)的意義 在機(jī)械行業(yè)中，如何去保證工件的高精度、加工的成本等實(shí)質(zhì)性問題，一直是從事于機(jī)械行業(yè)人員研究的問題，其中在設(shè)計(jì)夾具的時(shí)候就要考慮以上問題，高效的夾具是工件高精度的保證，如何讓夾具更高效、更經(jīng)濟(jì)，這是行業(yè)人急需要解決的。 隨著社會的發(fā)展，科技的不斷提高，各種高科技技術(shù)逐漸滲透到各個(gè)行業(yè)，如何利用這些高科技為人類服務(wù)，如何充分利用這些高科技在機(jī)械行業(yè)中，這還需要機(jī)械行業(yè)人員不斷的努力，開拓創(chuàng)新。 隨著科學(xué)技術(shù)的發(fā)展，和社會市場需要，夾具的設(shè)計(jì)在逐步的超向柔性制造系統(tǒng)方向發(fā)展。迄今為止,夾具仍是機(jī)電產(chǎn)品制造中必不可缺的四大工具之一,刀具本身已高度標(biāo)準(zhǔn)化,用戶只需要按品種、規(guī)格選用采購。而模具和夾具則和產(chǎn)品息息相關(guān),產(chǎn)品一有變化就需重新制作,通常是屬于專用性質(zhì)的工具,模具已發(fā)展成為獨(dú)立的行業(yè);夾具在國內(nèi)外也正在逐漸形成一個(gè)依附于機(jī)床業(yè)或獨(dú)立的小行業(yè)。 組合夾具不僅具有標(biāo)準(zhǔn)化、模塊化、組合化等當(dāng)代先進(jìn)設(shè)計(jì)思想,又符合節(jié)約資源的原則,更適合綠色制造的環(huán)境保護(hù)原理。所以是今后夾具技術(shù)的一個(gè)重要發(fā)展方向單位 。 機(jī)床夾具通常是指裝夾工件用的裝置:至于裝夾各種刀具用的裝置,則一般稱為“輔助工具”。輔助工具有時(shí)也廣義地包括在機(jī)床夾具的范圍內(nèi)。按照機(jī)床夾具的應(yīng)用范圍,一般可分為通用夾具,專用夾具和可調(diào)整式夾具等。 通用夾具是在普通機(jī)床上一般都附有通用夾具,如車床上的卡盤,銑床上的回轉(zhuǎn)工作臺,分度頭,頂尖座等。它們都一標(biāo)準(zhǔn)化了,具有一定的通用性,可以用來安裝一定形狀尺寸范圍內(nèi)的各種工件而不需要進(jìn)行特殊的調(diào)整。但是,在實(shí)際生產(chǎn)中,通用夾具常常不能夠滿足各種零件加工的需要;或者因?yàn)樯a(chǎn)率低而必須把通用夾具進(jìn)行適當(dāng)?shù)母倪M(jìn);或者由于工件的形狀,加工的要求等的不同須專門設(shè)計(jì)制造一種專用夾具,以解決生產(chǎn)實(shí)際的需要。 用夾具是為了適應(yīng)某一工件的某一工序加工的要求而專門設(shè)計(jì)制造的,其功用主要有下列幾個(gè)方面:1.保證工件被加工表面主要包括加工工件所需要的機(jī)動時(shí)間和裝卸工件等所需要的輔助時(shí)間兩部分。2.采用專用夾具后,安裝工件和轉(zhuǎn)換工位的工作都可以大為簡化,不再需要畫線和找正,縮短了工序的輔助時(shí)間并且節(jié)省了畫線這個(gè)工序,從而提高了勞動生產(chǎn)率.在生產(chǎn)中由于采用了多工件平行加工的夾具,使同時(shí)加工的幾個(gè)工件的機(jī)動時(shí)間將與加工一個(gè)工件的機(jī)動時(shí)間相同。采用回轉(zhuǎn)式多工位連續(xù)加工夾具,可以在進(jìn)行切削加工某個(gè)工件的同時(shí),進(jìn)行其它工件的裝卸工作,從而使輔助時(shí)間與機(jī)動時(shí)間相重合?？傊?隨著專用夾具的采用和進(jìn)一步改善,可以有效地縮短工序時(shí)間,滿足生產(chǎn)不斷發(fā)展的需要。3.采用專用夾具還能擴(kuò)大機(jī)床的工藝范圍。例如在普通車床上附加鏜模夾具后,便可以代替鏜床工作;裝上專用夾具后可以車削成型表面等,以充分發(fā)揮通用機(jī)床的作用。4.減輕勞動強(qiáng)度,保障安全生產(chǎn)。根據(jù)生產(chǎn)需要,采用一些氣動,液壓或其它機(jī)械化,自動化程度較高的專用夾具,對于減輕工人的勞動強(qiáng)度,保障生產(chǎn)安全和產(chǎn)品的穩(wěn)質(zhì)高產(chǎn)都有很大作用。加工大型工件時(shí),例如加工車床床身上,下兩面上的螺孔,需要把床身工件翻轉(zhuǎn)幾次進(jìn)行加工,勞動強(qiáng)度大而且不安全。采用電動回轉(zhuǎn)式鉆床家具后,就能夠達(dá)到提高生產(chǎn)效率,減輕勞動強(qiáng)度,保障生產(chǎn)安全的目的。 4.2 夾具的發(fā)展趨勢 工業(yè)設(shè)計(jì)是人類社會發(fā)展和科學(xué)技術(shù)進(jìn)步的產(chǎn)物，從英國莫里斯的“工藝美術(shù)運(yùn)動”，到德國的包豪斯設(shè)計(jì)革命以及美國的廣泛傳播與推廣，工業(yè)設(shè)計(jì)經(jīng)過了醞釀，探索，形成，發(fā)展百余年的歷史滄桑。時(shí)至今日，工業(yè)設(shè)計(jì)已成為一門獨(dú)立的專業(yè)學(xué)科，并且有一套完整的研究體系。 1980年國際工業(yè)設(shè)計(jì)協(xié)會理事會（ICSID）給工業(yè)作了明確定義：“就批量生產(chǎn)的工業(yè)產(chǎn)品而言，憑借訓(xùn)練，技術(shù)知識，經(jīng)驗(yàn)及視覺感受，而預(yù)示材料、結(jié)構(gòu)、構(gòu)造、形態(tài)、色彩、表面加工，裝飾以新的品質(zhì)和規(guī)格，叫做工業(yè)設(shè)計(jì)。根據(jù)當(dāng)時(shí)的具體情況，工業(yè)設(shè)計(jì)師應(yīng)在上述工業(yè)產(chǎn)品全部側(cè)面或其中幾個(gè)方面進(jìn)行工作，而且需要工業(yè)設(shè)計(jì)師對包裝、宣傳、展示，市場開發(fā)等問題的解決付出自己的技術(shù)知識和經(jīng)驗(yàn)以及視覺評價(jià)能力時(shí)，這也屬于工業(yè)設(shè)計(jì)的范疇”。 材料、結(jié)構(gòu)、工藝是產(chǎn)品設(shè)計(jì)的物質(zhì)技術(shù)基礎(chǔ)，一方面，技術(shù)制約著設(shè)計(jì)；另一方面，技術(shù)也推動著設(shè)計(jì)。從設(shè)計(jì)美學(xué)的觀點(diǎn)看，技術(shù)不僅僅是物質(zhì)基礎(chǔ)還具有其本身的“功能”作用，只要善于應(yīng)用材料的特性，予以相應(yīng)的結(jié)構(gòu)形式和適當(dāng)?shù)募庸すに?，就能夠?chuàng)造出實(shí)用，美觀，經(jīng)濟(jì)的產(chǎn)品，即在產(chǎn)品中發(fā)揮技術(shù)潛在的“功能”。 任何設(shè)計(jì)都是時(shí)代的產(chǎn)物，它的不同的面貌，不同的特征反映著不同歷史時(shí)期的科學(xué)技術(shù)水平。技術(shù)是產(chǎn)品形態(tài)發(fā)展的先導(dǎo)，新材料，新工藝的出現(xiàn)，必然給產(chǎn)品帶來新的結(jié)構(gòu)，新的形態(tài)和新的造型風(fēng)格。材料，加工工藝，結(jié)構(gòu)，產(chǎn)品形象有機(jī)地聯(lián)系在一起的，某個(gè)環(huán)節(jié)的變革，便會引起整個(gè)機(jī)體的變化。 現(xiàn)在，機(jī)械加工工藝及夾具隨著制造技術(shù)的發(fā)展也突飛猛進(jìn)。機(jī)械加工工藝以各個(gè)工廠的具體情況不同，其加工的規(guī)程也有很大的不同。突破已往的死模式。使其隨著情況的不同具有更加合理的工藝過程。也使產(chǎn)品的質(zhì)量大大提高。制定加工工藝雖可按情況合理制定，但也要滿足其基本要求：在保證產(chǎn)品質(zhì)量的前提下，盡可能提高勞動生產(chǎn)率和降低加工成本。并在充分利用本工廠現(xiàn)有生產(chǎn)條件的基礎(chǔ)上，盡可能采用國內(nèi)、外先進(jìn)工藝技術(shù)和經(jīng)驗(yàn)。還應(yīng)保證操作者良好的勞動條件。但我國現(xiàn)階段還是主要依賴工藝人員的經(jīng)驗(yàn)來編制工藝，多半不規(guī)定工步和切削用量，工時(shí)定額也憑經(jīng)驗(yàn)來確定，十分粗略，缺乏科學(xué)依據(jù)，難以進(jìn)行合理的經(jīng)濟(jì)核算 國際生產(chǎn)研究協(xié)會的統(tǒng)計(jì)表明，目前中、小批多品種生產(chǎn)的工件品種已占工件種類總數(shù)的85％左右?，F(xiàn)代生產(chǎn)要求企業(yè)所制造的產(chǎn)品品種經(jīng)常更新?lián)Q代，以適應(yīng)市場的需求與競爭。然而，一般企業(yè)都仍習(xí)慣于大量采用傳統(tǒng)的專用夾具，一般在具有中等生產(chǎn)能力的工廠里，約擁有數(shù)千甚至近萬套專用夾具；另一方面，在多品種生產(chǎn)的企業(yè)中，每隔3～4年就要更新50～80％左右專用夾具，而夾具的實(shí)際磨損量僅為10～20％左右。特別是近年來，數(shù)控機(jī)床、加工中心、成組技術(shù)、柔性制造系統(tǒng)（FMS）等新加工技術(shù)的應(yīng)用，對機(jī)床夾具提出了如下新的要求： 1）能迅速而方便地裝備新產(chǎn)品的投產(chǎn)，以縮短生產(chǎn)準(zhǔn)備周期，降低生產(chǎn)成本； 2）能裝夾一組具有相似性特征的工件； 3）能適用于精密加工的高精度機(jī)床夾具； 4）能適用于各種現(xiàn)代化制造技術(shù)的新型機(jī)床夾具； 5）采用以液壓站等為動力源的高效夾緊裝置，以進(jìn)一步減輕勞動強(qiáng)度和提高勞動生產(chǎn)率； 6）提高機(jī)床夾具的標(biāo)準(zhǔn)化程度。 現(xiàn)代機(jī)床夾具的發(fā)展趨勢主要表現(xiàn)為標(biāo)準(zhǔn)化、高效化、精密化和柔性化等四個(gè)方面。 利用更好的夾具，可以提高勞動生產(chǎn)率，提高加工精度，減少廢品，可以擴(kuò)大機(jī)床的工藝范圍，改善操作的勞動條件。因此，夾具是機(jī)械制造中的一項(xiàng)重要的工藝裝備。一個(gè)好的夾具是加工出合格產(chǎn)品的首要條件，為了讓夾具有更好的發(fā)展，夾具行業(yè)應(yīng)加強(qiáng)產(chǎn)、學(xué)、研協(xié)作的力度，加快用高新技術(shù)改造和提升夾具技術(shù)水平的步伐，創(chuàng)建夾具專業(yè)技術(shù)網(wǎng)站，充分利用現(xiàn)代信息和網(wǎng)絡(luò)技術(shù)，與時(shí)俱進(jìn)地創(chuàng)新和發(fā)展夾具技術(shù)。主動與國外夾具廠商聯(lián)系，爭取合資與合作，引進(jìn)技術(shù)，這是改造和發(fā)展我國夾具行業(yè)較為行之有效的途徑。 參考文獻(xiàn) 1：裘愉，組合機(jī)床，北京：機(jī)械工業(yè)出版社，1995. 2：金振華.組合機(jī)床及其調(diào)整與使用.北京：機(jī)械工業(yè)出版社，1990. 3：沈延山.生產(chǎn)實(shí)習(xí)與組合機(jī)床設(shè)計(jì).大連：大連理工大學(xué)出版社，1989. 4：上海市大專院校機(jī)械制造工藝學(xué)協(xié)作組編著.機(jī)械制造工藝學(xué).福建科學(xué)技術(shù)出版社，1996. 5：王華坤，范元勛.機(jī)械設(shè)計(jì)基礎(chǔ).北京：兵器工業(yè)出版社，2000. 6：馮辛安.機(jī)械制造裝備設(shè)計(jì).北京：機(jī)械工業(yè)出版社，1998. 7：陳日曜.機(jī)械原理.北京：機(jī)械工業(yè)出版社，1992. 8：方子良.機(jī)械制造技術(shù)基礎(chǔ).上海：上海交通大學(xué)出版社，2004. 9：劉秋生，李忠文.液壓傳動與控制.北京：宇航出版社，1994. 10：陳于萍，周兆元.互換性與測量技術(shù)基礎(chǔ).北京：機(jī)械工業(yè)出版社，2005. 11：東北重型機(jī)械學(xué)院等.機(jī)床夾具設(shè)計(jì)手冊.上海：上海科技技術(shù)出版社，1979. 12：《機(jī)械設(shè)計(jì)手冊》聯(lián)合編寫組.機(jī)械設(shè)計(jì)手冊.北京：機(jī)械工業(yè)出版社，1987. 13：王先逵.機(jī)械制造工藝學(xué)（上下冊）.北京：清華大學(xué)出版社，1989. 14：崇凱.機(jī)械制造技術(shù)基礎(chǔ)課程設(shè)計(jì)指南. 15：黃如林，汪群.金屬加工工藝及工裝設(shè)計(jì). 16：魯屏宇.工程圖學(xué). 17：馮辛安.機(jī)械制造裝備設(shè)計(jì). 18：Gell Maurice Materials Science and Engineering，1995，A204：246—251 19：X. Chen, J.W. Hutchinson, M.Y. He, A.G. Evans, Acta Mater. 51 (2003) 2017. Procedia CIRP 21 ( 2014 ) 189 194 Available online at 2212-8271 2014 Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:/creativecommons.org/licenses/by-nc-nd/3.0/).Selection and peer-review under responsibility of the International Scientific Committee of “24th CIRP Design Conference” in the person of the Conference Chairs Giovanni Moroni and Tullio Toliodoi: 10.1016/j.procir.2014.03.120 ScienceDirect24th CIRP Design ConferenceRobust design of fixture configurationGiovanni Moronia, Stefano Petr oa,*, Wilma PolinibaMechanical Engineering Department, Politecnico di Milano, Via La Masa 1, 20156, Milano, ItalybCivil and Mechanical Engineering Department, Cassino University, Via di Biasio 43, 03043, Cassino, ItalyCorresponding author. Tel.: +39-02-2399-8530; fax: +39-02-2399-8585. E-mail address: stefano.petropolimi.itAbstractThe paper deals with robust design of fixture configuration. It aims to investigate how fixture element deviations and machine tool volumetricerrors affect machining operations quality. The locator position configuration is then designed to minimize the deviation of machined featureswith respect to the applied geometric tolerances.The proposed approach represents a design step that goes further the deterministic positioning of the part based on the screw theory, and may beused to look for simple and general rules easily applicable in an industrial context.The methodology is illustrated and validated using simulation and simple industrial case studies.c ? 2014 The Authors. Published by Elsevier B.V.Selection and peer-review under responsibility of the International Scientific Committee of “24th CIRP Design Conference” in the person of theConference Chairs Giovanni Moroni and Tullio Tolio.Keywords:Tolerancing; Error; Modular Fixture.1. IntroductionWhen a workpiece is fixtured for a machining or inspectionoperation, the accuracy of an operation is mainly determined bythe efficiency of the fixturing method. In general, the machinedfeature may have geometric errors in terms of its form and posi-tion in relation to the workpiece datum reference frame. If thereexists a misalignment error between the workpiece datum ref-erence frame and machine tool reference frame, this is knownas localization error 1 or datum establishment error 2. Alocalization error is essentially caused by a deviation in the po-sition of the contact point between a locator and the workpiecesurface from its nominal specification. In this paper, such a the-oretical point of contact is referred to as a fixel point or fixel,and its positioning deviation from its nominal position is calledfixel error. Within the framework of rigid body analysis, fixelerrors have a direct effect on the localization error as defined bythe kinematics between the workpiece feature surfaces and thefixels through their contact constraint relationships 3.The localization error is highly dependent on the configu-ration of the locators in terms of their positions relative to theworkpiece. A proper design of the locator configuration (orlocator layout) may have a significant impact on reducing thelocalization error. This is often referred to as fixture layout op-timization 4.A main purpose of this work is to investigate how geomet-ric errors of a machined surface (or manufacturing errors) arerelated to main sources of fixel errors. A mathematic frame-work is presented for an analysis of the relationships among themanufacturing errors, the machine tool volumetric error, andthe fixel errors. Further, optimal fixture layout design is speci-fied as a process of minimizing the manufacturing errors. Thispaper goes beyond the state of the art, because it considers thevolumetric error in tolerancing. Although the literature demon-strates that the simple static volumetric error considered hereis only a small portion of the total volumetric error, a generalframework for the inclusion of volumetric error in tolerancingis established.There are several formal methods for fixture analysis basedon classical screw theory 5,6 or geometric perturbation tech-niques 3. In nineties many studies have been devoted to modelthe part deviation due to fixture 7. Sodenberg calculated a sta-bility index to evaluate the goodness of the locating scheme 8.The small displacement torsor concept is used to model the partdeviationduetogeometricvariationofthepart-holder9. Con-ventional and computer-aided fixture design procedures havebeen described in traditional design manuals 10 and recent lit-erature 11,12, especially for designing modular fixtures 13.A number of methods for localization error analysis and reduc-tion have been reported. A mathematical representation of thelocalization error was given in 14 using the concept of a dis-placements screw vector. Optimization techniques were sug- 2014 Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:/creativecommons.org/licenses/by-nc-nd/3.0/).Selection and peer-review under responsibility of the International Scientifi c Committee of “24th CIRP Design Conference” in the person of the Conference Chairs Giovanni Moroni and Tullio Tolio190 Giovanni Moroni et al. / Procedia CIRP 21 ( 2014 ) 189 194 gested to minimize the magnitude of the localization error vec-tor or the geometric variation of a critical feature 14,15. Ananalysis is described by Chouduri and De Meter 2 to relatethe locator shape errors to the worst case geometric errors inmachined features. Geometric deviations of the workpiece da-tum surfaces were also analyzed by Chouduri and De Meter2 for positional, profile, and angular manufacturing tolerancecases. Their effects on machined features, such as by drillingand milling, were illustrated. A second order analysis of thelocalization error is presented by Carlson 16. The computa-tionaldifficultiesoffixturelayoutdesignhavebeenstudiedwithan objective to reduce an overall measure of the localization er-ror for general three dimensional (3D) workpieces such as tur-bine air foils 1,4. A more recent paper shows a robust fixturelayout approach as a multi-objective problem that is solved bymeans of Genetic Algorithms 17. It considers a prismatic andrigid workpiece, the contact between fixture and workpiece iswithout friction, and the machine tool volumetric error is notconsidered.About the modeling of the volumetric error, several modelshave been proposed in literature. Ferreira et al. 18,19 haveproposed quadratic model to model the volumetric error of ma-chines, in which each axis is considered separately, thoghetherwith a methodology for the evaluation of the model parame-ters. Kiridena and Ferreira in a series of three papers 2022discuss how to compensate the volumetric error can be mod-eled, the parameters of the model evaluated, and then the er-ror compensated based on the model and its parameters, for athree-axis machine. Dorndorf et al. 23 describe how volu-metric error models can help in the error budgeting of machinetools. Finally, Smith et al. 24 describe the application of vol-umetric error compensation in the case of large monolithic partmanufacture, which poses serious difficulties to traditional vol-umetric error compensation. Anyway, it is worth noting that allthese approaches are aimed at volumetric error compensation:generally volumetric error is not considered for simulation intolerancing.In previous papers a statistical method to estimate the po-sition deviation of a hole due to the inaccuracy of all the sixlocators of the 3-2-1 locating scheme was developed for 2Dplates and 3D parts 25,26. In the following, a methodologyfor robust design of fixture configuration is presented. It aimsto investigate how fixel errors and machine tool volumetric er-ror affect machining operations quality. In 2 the theoreticalapproach is introduced, in 3 a simple industrial case study ispresented, and in 4 some simple and general rules easily ap-plicable in an industrial contest are discussed.2. Methodology for the simulation of the drilling accuracyTo illustrate the proposed methodology, the case study ofa drilled hole will be considered. The case study is shown inFig. 1. A location tolerance specifies the hole position. Threelocators on the primary datum, two on the secondary datum,and one on the tertiary determine the position of the workpiece.Each locator has coordinates related to the machine tool refer-ence frame, represented by the following six terns of values:p1(x1,y1,z1)p2(x2,y2,z2)p3(x3,y3,z3)p4(x4,y4,z4)p5(x5,y5,z5)p6(x6,y6,z6)(1)Fig. 1. Locator configuration schema.The proposed approach considers the uncertainty source inthe positioning error of the machined hole due to the error inthe positioning of the locators, and the volumetric error of themachine tool. The final aim of the model is to define the ac-tual coordinates of the hole in the workpiece reference system.The model input includes the nominal locator configuration, thenominal hole location (supposed coincident with the drill tip)and direction (supposed coincident with the drill direction), andthe characteristics of typical errors which can affect this nomi-nal parameters.2.1. Effect of locator errorsThe positions of the six locators are completely defined bytheireighteencoordinates. Itisassumed thateachof thesecoor-dinates is affected by an error behaving independently, accord-ing to a Gaussian N?0,2?distribution.The actual locator coordinates will then identify the work-piece reference frame. In particular, the z?axis is constitutedby the straight line perpendicular to the plane passing throughthe actual positions of locators p1, p2and p2, the x?axis is thestraight line perpendicular to the z?axis and to the straight linepassing through the actual position of locators p4and p5, andfinally the y?axis is straightforward computed as perpendicularto both z?and x?axes. The origin of the reference frame can beobtained as intersection of the three planes having as normalsthe x?, y?, and z?axes and passing through locators p4, p6andp1respectively. The formulas for computing the axis-directionvectors and origin coordinates from the actual locators coordi-nates are omitted here, for reference see the work by Armillottaet al. 26.The axis-direction vectors and origin coordinates define anhomogeneous transformation matrix0Rp27, which allows toconvert the drill tip coordinate expressed in the machine toolreference frame P0to the same coordinates expressed in theworkpiece reference frame P?0, through the formula:P?0=0R1pP0(2)191 Giovanni Moroni et al. / Procedia CIRP 21 ( 2014 ) 189 194 2.2. Effect of machine tool volumetric errorTo simulate the hole location deviation due to the drillingoperation, i.e. to the volumetric error of the machine tool, theclassical model of three-axis machine tool has been considered27. It will be assumed the drilling tool axis is coincident withthe machine tool z axis, so that, in nominal conditions and at thebeginning of the drilling operation, its tip position can be de-fined by the nominal hole location and the homogeneous vectork = 0010T. The aim is to identify the position errorpof the drill tip in the machine tool reference system, and thedirection error dof the tool axis. According to the three-axismachine tool model it is possible to state that:p=0R11R22R3P3 P0(3)where P0=?xyz l1?Tis the nominal drill tip locationin the machine tool reference system (x, y, and z beingthe trans-lations alongthe machinetool axes, and l being thedrill length),P3= 00 l1Tis the drill tip position in the third (zaxis) reference system, and0R1,1R2,2R3are respectively theperturbed transformation matrices due to the perturbed transla-tion along the x, y, and z axes. These matrices share a similarform, for example:0R1=1z(x)y(x)x + x(x)z(x)1x(x)y(x)y(x)x(x)1z(x)0001(4)where the and terms are the translation and rotation errorsalong and around the x, y, and z axes (e.g. z(x) is the rotationerror around the z axis due to a translation along the x axis).Considering three transformation matrices, there are eighteenerror terms. These errors are usually a function of the volu-metric position (i.e. the translations along the three axes), butif the volumetric error is compensated, their systematic com-ponent can be neglected and they can be assumed to be purelyrandom with mean equal to zero. Developing Eq. (3) leads tovery complex equations; for example,dx=x(x) + x(y) z(x)(y(y) + y) y(z) (z(x) + z(y) x(y)y(x) + z(y)y(x) x(z)(y(x)y(y) + z(x)z(y) 1) l(y(x) + y(y) + x(z)(z(x) + z(y) x(y)y(x) + x(y)z(x) y(z)(y(x)y(y)+ z(x)z(y) 1) + (z(z) + z)(y(x) + y(y)+ x(y)z(x)(5)However, volumetric errors in general should be far smallerthan translations along the axes, so only the first order com-ponents of Eq. (3) are usually significant. Finally, Assumingthe drilling tool axis coincide with the z axis, Eq. (3) can alsocalculate the direction error dby substituting P0= P3= k.If only the first order components are considered, it is possi-ble to demonstrate that pand dare linear combination of the and terms. In particular, lets define as =?pd?(6)the six-elements vector containing pand dstaked. ApplyingEq. (3), neglecting terms above the second order, it is possibleto demonstrate that (please note that, due format constraints, inEq. (7) the dots . indicate that a row of the matrix is bro-ken over more lines, so the overall linear combination matrixappearing here is a 6 X 18 matrix) =111000.000000.z lz lly00000111.000l zl zl.000000000000.111000.000000000000.000100.111000000000.000111.010000000000.000000.000001x(x)x(y)x(z)y(x)y(y)y(z)z(x)z(y)z(z)x(x)x(y)x(z)y(x)y(y)y(z)z(x)z(y)z(z)= Cd(7)Now, lets assume that each term is independently dis-tributed according to a Gaussian N?0,2p?distribution, andthat each term is independently distributed according to aN?0,2d?distribution. It is then possible to demonstrate 28that follows a multivariate Gaussian distribution, with nullexpected value and covariance matrix which can be calculatedby the formula CCT, where is the covariance matrix of d,which happens to be a diagonal 18 X 18 matrix with the firstnine diagonal elements equal to 2p, an the remaining diagonal192 Giovanni Moroni et al. / Procedia CIRP 21 ( 2014 ) 189 194 elements equal to 2d. The final covariance matrix of is:2dy2+22d(l z)2+32p+l22d002d(3l2z)2d(l z)0022d(l z)2+32p+l22d02d(l z)2d(3l2z)00032p0002d(3l2z)2d(l z)042d002d(l z)2d(3l2z)0042d0000002d(8)This model can be adopted to simulate the error in the loca-tionanddirectionoftheholeduetothemachinetoolvolumetricerror.2.3. Actual location of the manufactured holeNow, it is possible to simulate the tip location and directionaccording to the model described in 2.2, and to transform itinto the workpiece reference frame as described in 2.1:P0?=0R1p?P0+ p?k?=0R1p(k + d)(9)With this information it is possible to determine the entranceand exit location of the hole in the workpiece reference system.Point P?0and vector k?define a straight line, which is nothingelse than the hole axis, as:p?= P0?+ sk?px?py?pz?=P0 x?P0y?P0z?+ skx?ky?kz?(10)where p is a generic point belonging to the line and s R isa parameter. Defining T as the plate thickness, it is possible tocalculate the values of s for which p?zis equal respectively to 0and T:sexit= P0z?/kz?sentrance= (P0z? T)/kz?(11)These values of s substituted in Eq. (10) yield respectivelythe coordinates of the exit and entrance point of the hole.Finally, it is possible to calculate the distances between thetwo exit and entrance points of the drilled and nominal holes:d1=?P0?+ sentrancek? P0?d2=?P0?+ sexitk? P0,exit?(12)where P0,exitis the nominal location of the hole exit point. Theaxis of the drilled hole will be inside location tolerance zoneof the hole if both the distances calculated by Eq. (12) will belower than the half of the location tolerance value t:d1 t/2d2 t/2(13)3. Case study resultsThe model proposed so far has been considered to identifythe expected quality due to locator configuration, given a ma-chine tool volumetric error. To identify which is the optimalone an experiment has been designed and results have been an-alyzed by means of analysis of variance (ANOVA) 29.Because the aim of the research regards only the choice oflocators positions, most of the model parameters can be keptconstant. The constant parameters include: the nominal sizeof the plate (100 x 120 x 60 mm); the standard deviation ofthe random errors in locator positioning ( = 0.01 mm); thenominal location of the entrance (P0= 407060T) andexit (P0= 40700T) points of the hole; the length of thedrill (l = 60 mm); the standard deviation of the machine toolaxes positioning errors (p= 0.01 mm) and of their rotationalerrors (d= 0.01); the location tolerance value (t = 0.1 mm);the plate thickness (T = 60 mm). Each locator has insteadbeen left free to change in order to evaluate its influence on thedrilling accuracy; candidate configurations will be introducedin the next paragraphs, together with their impact discussion.By substituting the simulation parameters indicated so far inEq. (8) the following covariance matrix is yielded (all valuesare in mm2):68000.180.18006300.180.18000300000.180.1800.01000.180.18000.010000000.003 105(14)The considered performance indicator is the fraction of con-forming parts generated by a specific locator configuration, i.e.the fraction of parts for which both of the inequalities in Eq.(13) hold.The conforming fraction has been evaluated tentimes for each experimental condition, for each evaluation tenthousand workpieces have been simulated. Of course, highervalues of this performance indicator are preferable.The ANOVA analysis has worked efficiently, with its hy-potheses correctly verified. The main effect plot in Fig. 2 sum-193 Giovanni Moroni et al. / Procedia CIRP 21 ( 2014 ) 189 194 Fig. 2. Main effect plot for the fraction of conforming workpieces.marizes the results, which are described in depth in the follow-ing paragraphs.3.1. Impact of p1, p2and p3locator configurationThe p1, p2and p3locators define the part z?axis, so theyhave been indicated in Fig. 2 as “z locator configuration”. Toevaluate their impact on the hole accuracy three candidate con-figurations have been considered. The first one (“max area”)tries to cover as much as possible the surface of the workpiecetouched by the locators themselves. The second one (“barycen-tric”) has the barycenter of the locators coincident with the holeposition, but with an area coverage smaller than the max areaconfiguration. The last one (“non barycentric”) has the samearea coverage of the barycentric one, but is far from the hole.Please note that the plate equilibrium has been neglected in thisfirst analysis.The ANOVA suggests that the best condition is the onein which the area coverage is maximum, and that given thesame area coverage, having a barycentric distribution is prefer-able. The impact of the z locator configuration is very relevant,changing the conforming fraction of about 10%.3.2. Impact of p4and p5locator configurationThe p4and p5locators define the part x?axis. Two factorshave been considered for them: their height with the hypothesisthat they have the same one (“x locator height” in Fig. 2), andtheir positions in the y direction (“x locator configuration”).Three candidate heights have been considered, 5, 30 and 55mm. It seems that it is slightly better to have the locators placedat the lower height, but the impact is quite small (about 1%).The impact of the x locator configuration, accounting forabout the 20% of the conforming fraction, is far more relevant.Similarly to the z locator configuration, three configurationshave been considered. The first one (“max distance”) maxi-mizes the distance between the two locators. The second one(“barycentric”) has the barycenter of the two locators in corre-spondence of the hole axis, but with a distance smaller than the“max distance” one. The last one (“non barycentric”) has thesame distance of the barycentric, but it has the barycenter ofthe two locators fa