止轉(zhuǎn)墊板冷沖壓工藝及其連續(xù)模設(shè)計(jì)-沖壓模具【含14張CAD圖紙+PDF圖】

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存檔編碼：無無錫錫太太湖湖學(xué)學(xué)院院 2013 屆屆畢畢業(yè)業(yè)作作業(yè)業(yè)周周次次進(jìn)進(jìn)度度計(jì)計(jì)劃劃、檢檢查查落落實(shí)實(shí)表表 系別：信機(jī)系 班級(jí)：機(jī)械96 學(xué)生姓名：劉奎 課題（設(shè)計(jì)）名稱：止轉(zhuǎn)墊片冷沖壓工藝及連續(xù)模設(shè)計(jì) 開始日期：2012年11月12日周次起止日期工作計(jì)劃、進(jìn)度每周主要完成內(nèi)容存在問題、改進(jìn)方法指導(dǎo)教師意見并簽字備 注1-32012年11月12日-2012年12月2日教師下達(dá)畢業(yè)設(shè)計(jì)任務(wù)，學(xué)生初步閱讀資料，完成畢業(yè)設(shè)計(jì)開題報(bào)告。按照任務(wù)書要求查閱論文相關(guān)參考資料，填寫畢業(yè)設(shè)計(jì)開題報(bào)告書存在問題：不了解課題，資源缺乏，對(duì)設(shè)計(jì)目的及要求不明確，沒有實(shí)際設(shè)計(jì)能力。改進(jìn)方法：尋求導(dǎo)師的指導(dǎo)，自己上網(wǎng)查資料，多讀點(diǎn)沖壓方面的書籍。4-102012年12月3日-2013年1月20日指導(dǎo)專業(yè)實(shí)訓(xùn)機(jī)械制造綜合實(shí)訓(xùn)，機(jī)械零件加工方法和加工工藝編制存在問題：知識(shí)能力欠缺，實(shí)際與理論相差較遠(yuǎn)，動(dòng)手能力不足。改進(jìn)方法：及時(shí)的對(duì)自己的知識(shí)點(diǎn)查漏補(bǔ)缺，了解加工的工序，理解工藝編制。11-122013年1月21日-3月1日指導(dǎo)畢業(yè)實(shí)習(xí)到企業(yè)進(jìn)行崗位實(shí)習(xí)，了解本專業(yè)的實(shí)踐知識(shí)存在問題：缺乏實(shí)際動(dòng)手能力。改進(jìn)方法：向工廠師傅多請(qǐng)教，認(rèn)真學(xué)習(xí)實(shí)際能力132013年3月4日-3月8日查閱參考資料查閱與設(shè)計(jì)有關(guān)的參考資料不少于10篇，其中外文不少于5篇存在問題：身邊資料欠缺，相關(guān)理論知識(shí)不足。改進(jìn)方法：利用周末的時(shí)間去校圖書館、新華書店等地方翻閱書籍，并利用工作之余在網(wǎng)上搜索相關(guān)資料加以整理142013年3月11日-3月15日翻譯外文資料翻譯外文資料（8000-10000字符）存在問題：不了解專業(yè)詞匯，需要慢慢查找。改進(jìn)方法：翻閱字典并結(jié)合翻閱軟件，上網(wǎng)查找，向?qū)熐笾确椒?，不斷提升英語翻譯能力。152013年3月18日-3月22日設(shè)計(jì)模具沖壓工藝方案分析產(chǎn)品圖、分析沖壓工序、排樣方案，優(yōu)選確定模具沖壓工藝方案存在問題：方案不會(huì)確定，排樣不是很明白，存在材料浪費(fèi)，工藝性差。改進(jìn)方法：多查閱資料理解排樣、方案的合理設(shè)計(jì)，建立正確的沖壓工藝方案。162013年3月25日-3月29日模具結(jié)構(gòu)分析確定模具結(jié)構(gòu)存在問題：連續(xù)模結(jié)構(gòu)復(fù)雜，我們見識(shí)不足。改進(jìn)方法：多找點(diǎn)連續(xù)模圖片看看，咨詢導(dǎo)師，改進(jìn)模具結(jié)構(gòu)。172013年4月1日-4月5日模具刃口尺寸計(jì)算計(jì)算模具刃口所需的尺寸存在問題：刃口計(jì)算原則不會(huì)，計(jì)算公式使用混亂，沒有合理的排布尺寸。改進(jìn)方法：查閱相關(guān)資料，翻閱理解別人的設(shè)計(jì)方案，通過分析公式的計(jì)算原則和應(yīng)用條件，合理運(yùn)用各種公式。182013年4月8日-4月12日主要零件結(jié)構(gòu)設(shè)計(jì)和計(jì)算主要零件結(jié)構(gòu)設(shè)計(jì)和尺寸計(jì)算存在問題：不知道怎么設(shè)計(jì)模具零件的結(jié)構(gòu)，甚至計(jì)算值不合理的情況，零件結(jié)構(gòu)尺寸選取困難。改進(jìn)方法：詢問指導(dǎo)老師，多了解實(shí)際情況，重新設(shè)計(jì)零件結(jié)構(gòu)。192013年4月15日-4月19日畫裝配圖初步繪制模具裝配圖存在問題：新的繪圖軟件操作不熟，實(shí)際裝配圖很難做的完美。改進(jìn)方法：加以訓(xùn)練caxa等繪圖軟件，并請(qǐng)教導(dǎo)師合理的裝配關(guān)系。202013年4月22日-4月26日完成裝配圖修改模具裝配圖存在問題：裝配圖中標(biāo)準(zhǔn)件畫法不正確，技術(shù)要求填寫不合理，沒能正確填寫明細(xì)欄。改進(jìn)方法：多看看以前學(xué)的標(biāo)準(zhǔn)，請(qǐng)導(dǎo)師檢閱幫助。212013年4月29日-5月3日繪制零件圖繪制模具主要零件的零件圖，不少于5個(gè)存在問題：零件圖上尺寸公差復(fù)雜混亂，粗糙度選用不規(guī)范。改進(jìn)方法：多查查標(biāo)準(zhǔn)書，修改零件圖以求以求達(dá)到合理要求。222013年5月6日-5月10日填寫沖壓工藝和完善設(shè)計(jì)資料等填寫沖壓工藝卡片等存在問題：沒怎么接觸過，不能正確理解，工藝編排不正確。改進(jìn)方法：多看看模板，再次填寫工藝卡片。232013年5月13日-5月17日設(shè)計(jì)說明書（論文）、摘要和小結(jié)編寫完成設(shè)計(jì)說明書、摘要和小結(jié)存在問題：說明書（論文）的格式不規(guī)范，摘要不合理要求等。改進(jìn)方法：按學(xué)院要求重新修改書面格式，重新并編寫摘要。242013年5月20日-5月25日上交資料、準(zhǔn)備答辯整理所有資料，打印后上交指導(dǎo)教師，準(zhǔn)備答辯按指導(dǎo)老師要求結(jié)合學(xué)院要求整理書籍及資料 說明：1、“工作計(jì)劃、進(jìn)度”、“指導(dǎo)教師意見并簽字”由指導(dǎo)教師填寫，“每周主要完成內(nèi)容”，“存在問題、改進(jìn)方法”由學(xué)生填寫。2、本表由各系妥善歸檔，保存?zhèn)洳椤Ｖ艽纹鹬谷掌诠ぷ饔?jì)劃、進(jìn)度每周主要完成內(nèi)容存在問題、改進(jìn)方法指導(dǎo)教師意見并簽字備 注 無錫太湖學(xué)院 冷沖壓工藝卡片 零件名稱 止轉(zhuǎn)墊板 零件圖號(hào) 115010 材料牌號(hào)及規(guī)格 10鋼 0.7×25.4×L 毛坯種類 帶料 毛坯尺寸 25.4×L 每毛坯可制件數(shù) 1件/每22.52 工序號(hào) 工序名稱 工序內(nèi)容 沖壓設(shè)備 工藝裝備 一次加工數(shù) 工 序 附 圖 10 沖裁 沖2個(gè)孔、側(cè)刃 J23-10 模具和自動(dòng)送料機(jī)構(gòu) 1 20 沖裁 沖內(nèi)孔 J23-10 模具和自動(dòng)送料機(jī)構(gòu) 1 30 沖裁 落料 J23-10 模具和自動(dòng)送料機(jī)構(gòu) 1 40 沖裁 側(cè)刃 J23-10 模具和自動(dòng)送料機(jī)構(gòu) 1 50 檢驗(yàn) 檢驗(yàn) 班級(jí) 機(jī)械96 姓名 劉奎 學(xué)號(hào) 0923278 日期 2013.5.16 批改 日期 編號(hào) 無錫太湖學(xué)院 畢業(yè)設(shè)計(jì)（論文） 相關(guān)資料 題目： 止轉(zhuǎn)墊板冷沖壓工藝及連續(xù)模設(shè)計(jì) 信機(jī) 系 機(jī)械工程及自動(dòng)化專業(yè) 學(xué) 號(hào)： 　　　0923278　　　　 學(xué)生姓名： 劉 奎 指導(dǎo)教師： 鐘建剛 （職稱：副教授 ） （職稱： ） 2013年5月25日 目 錄 一、畢業(yè)設(shè)計(jì)（論文）開題報(bào)告 二、畢業(yè)設(shè)計(jì)（論文）外文資料翻譯及原文 三、學(xué)生“畢業(yè)論文（論文）計(jì)劃、進(jìn)度、檢查及落實(shí)表” 四、實(shí)習(xí)鑒定表  無錫太湖學(xué)院 畢業(yè)設(shè)計(jì)（論文） 開題報(bào)告 題目：止轉(zhuǎn)墊板冷沖壓工藝及連續(xù)模設(shè)計(jì) 信機(jī) 系 機(jī)械工程及自動(dòng)化 專業(yè) 學(xué) 號(hào)： 0923278 學(xué)生姓名： 劉奎 指導(dǎo)教師： 鐘建剛 （職稱：副教授） （職稱： ） 2012年11月20日 課題來源 來源于無錫海諾有限公司，是電器產(chǎn)品上的一個(gè)零件。 科學(xué)依據(jù) （1）課題科學(xué)意義 隨著當(dāng)今科技的發(fā)展，?工業(yè)生產(chǎn)中模具的使用已經(jīng)越來越引起人們的重視，而被大量應(yīng)用到工業(yè)生產(chǎn)中來。沖壓模具的自動(dòng)送料技術(shù)也投入到實(shí)際的生產(chǎn)中，沖壓模具可以大大的提高勞動(dòng)生產(chǎn)效率，減輕工人負(fù)擔(dān)，具有重要的技術(shù)進(jìn)步意義和經(jīng)濟(jì)價(jià)值。 現(xiàn)在模具生產(chǎn)采用了一系列高新技術(shù)，如CAD/CAE/CAM/CAPP等技術(shù)、計(jì)算機(jī)網(wǎng)絡(luò)技術(shù)、激光技術(shù)、逆向工程和并行工程、快速成形技術(shù)及敏捷制造技術(shù)、高速加工及超精加工、微細(xì)加工、復(fù)合加工、表面處理技術(shù)等等。因此，模具工業(yè)已成為高新技術(shù)產(chǎn)業(yè)的一個(gè)重要組成部分。模具技術(shù)水平在很大程度上決定于人才的整體水平，而模具技術(shù)水平的高低，又決定著產(chǎn)品的質(zhì)量、效益和新產(chǎn)品的開發(fā)能力，因此模具技術(shù)已成為衡量一個(gè)國家產(chǎn)品制造水平高低的重要標(biāo)志！ 如今汽車、電子、電器、航空、儀表、輕工、塑料、日用品等工業(yè)部門極其依賴模具。沒有模具，就沒有高質(zhì)量的產(chǎn)品。模具不是一般的工藝裝備，而是技術(shù)密集型的產(chǎn)品，工業(yè)發(fā)達(dá)國家把模具作為機(jī)械制造方面的高科技產(chǎn)品來對(duì)待他們認(rèn)為：“模具是發(fā)展工業(yè)的一把鑰匙”；“模具是一個(gè)企業(yè)的心臟”；“模具是富裕社會(huì)的一種動(dòng)力”。 工業(yè)發(fā)展水平的不斷提高，工業(yè)產(chǎn)品更新速度加快，對(duì)模具的要求越來越高，盡管改革開放以來，模具工業(yè)有了較大發(fā)展，但無論是數(shù)量還是質(zhì)量仍滿足不了國內(nèi)市場(chǎng)的需要，因此，要使國民經(jīng)濟(jì)各個(gè)部門獲得高速發(fā)展，加速實(shí)現(xiàn)社會(huì)主義四個(gè)現(xiàn)代化，就必須盡快將模具工業(yè)搞上去，從而充分發(fā)揮模具工業(yè)在國民經(jīng)濟(jì)中的關(guān)鍵作用。 （2）研究狀況及其發(fā)展前景 我國沖壓模具無論在數(shù)量上，還是在質(zhì)量、技術(shù)和能力等方面都已有了很大發(fā)展，但與國外經(jīng)濟(jì)需求和世界先進(jìn)水平相比，差距仍很大，一些大型、精度、復(fù)雜、長(zhǎng)壽命的高檔模具每年仍大量進(jìn)口。近年許多模具企業(yè)加大了用于技術(shù)進(jìn)步的投資力度，將技術(shù)進(jìn)步視為企業(yè)發(fā)展的重要?jiǎng)恿?。一些國?nèi)模具企業(yè)已普及了二維CAD，并陸續(xù)開始使用UG、Pro/Engineer、I-DEAS、Euclid-IS等國際通用軟件，個(gè)別廠家還引進(jìn)了Moldflow、C-Flow、DYNAFORM、Optris和MAGMASOFT等CAE軟件，并成功應(yīng)用于沖壓模的設(shè)計(jì)中。我國的模具正向著高新產(chǎn)業(yè)逐步邁進(jìn)。 今后模具技術(shù)的發(fā)展應(yīng)該為適應(yīng)模具產(chǎn)品“交貨期短”、“精度高”、“質(zhì)量好”、“價(jià)格低”的要求服務(wù)。 一方面是制品使用周期短，品種更新快，另一方面制品的花樣變化頻繁，均要求模具的生產(chǎn)周期越快越好。因此，開發(fā)快速經(jīng)濟(jì)具越來越引起人們的重視，另外，采用計(jì)算機(jī)控制和機(jī)械手操作的快速換模裝置、快速試模技術(shù)也要得到發(fā)展和提高。在未來的模具設(shè)計(jì)制造中更要全面推廣CAD/CAM/CAE技術(shù)并將CAD/CAM/CAE向集成化、智能化和網(wǎng)絡(luò)化發(fā)展。隨著微機(jī)軟件的發(fā)展和進(jìn)步，技術(shù)培訓(xùn)工作也日趨簡(jiǎn)化，在普及推廣模具CAD/CAM技術(shù)的過程中，應(yīng)抓住機(jī)遇，重點(diǎn)扶持國產(chǎn)模具軟件的開發(fā)和應(yīng)用。在競(jìng)爭(zhēng)如此激勵(lì)的今天，抓住模具市場(chǎng)日益全球化的機(jī)遇將模具產(chǎn)品向大型化、精密化、多功能復(fù)合模具進(jìn)一步發(fā)展。 研究?jī)?nèi)容 本課題要求對(duì)給定零件止板墊片進(jìn)行落料、沖孔、成形連續(xù)模設(shè)計(jì)，通過對(duì)零件進(jìn)行詳細(xì)的沖壓工藝、排樣方案、模具結(jié)構(gòu)分析確定零件的沖壓工藝方案并制定部分零件的制造工藝，如：凸模、凹模、凸凹模、凸模固定板、墊板、凹模固定板、卸料板、導(dǎo)尺、擋料銷、導(dǎo)正銷等。通過該課題能夠讓學(xué)生掌握中等復(fù)雜程度零件沖壓連續(xù)模設(shè)計(jì)與制造的一般方法，對(duì)零件沖壓連續(xù)模工藝方案的制定、工藝計(jì)算及連續(xù)模具設(shè)計(jì)有了更深層次的認(rèn)識(shí)。 擬采取的研究方法、技術(shù)路線、實(shí)驗(yàn)方案及可行性分析 1、到圖書館或網(wǎng)上查閱相關(guān)資料，查找相關(guān)書籍。對(duì)連續(xù)模深入了解 2、工藝性分析，包括結(jié)構(gòu)、尺寸、基準(zhǔn)的分析計(jì)算 3、工藝方案的確定，包括工序的性質(zhì)、順序及其種類組合，確定沖壓設(shè)備編寫沖壓工藝過程卡片。 4、通過對(duì)零件、排樣圖等具體的計(jì)算分析，檢查設(shè)計(jì)是否合理。 5、總裝圖的繪制，編制技術(shù)文件。 課題完全由計(jì)算數(shù)據(jù)決定整套模具裝配圖及其零件圖，通過對(duì)實(shí)際情況的了解，以數(shù)據(jù)為依據(jù)進(jìn)行設(shè)計(jì)分析，具體的設(shè)計(jì)計(jì)算也完全可以通過查表或者書籍獲得，加上對(duì)于整套設(shè)計(jì)有完整的設(shè)計(jì)思路，完全有可行性。 研究計(jì)劃及預(yù)期成果 研究計(jì)劃： 2012年11月12日-2012年12月2日：按照任務(wù)書要求查閱論文相關(guān)參考資料，填寫畢業(yè)設(shè)計(jì)開題報(bào)告書。 2012年12月3日-2013年1月20日：機(jī)械制造實(shí)訓(xùn) 2013年1月21日-2013年3月1日：到企業(yè)實(shí)習(xí)，了解本專業(yè)實(shí)踐知識(shí) 2013年3月4日-2013年3月8日：查閱與設(shè)計(jì)相關(guān)的資料不少于10篇，其中外文不少于5篇。 2013年3月11日-2013年3月15日：翻譯外文資料（8000-10000字符）。 2013年3月18日-2013年3月22日：分析產(chǎn)品圖、分析沖壓工序、排樣方案，優(yōu)選確定模具沖壓方案。 2013年3月25日-3月29日： 確定模具結(jié)構(gòu) 2013年4月1日-4月5日：計(jì)算模具刃口所需的尺寸 2013年4月8日-4月12日：主要零件結(jié)構(gòu)設(shè)計(jì)和尺寸計(jì)算 2013年4月15日-4月19日：初步繪制模具裝配圖 2013年4月22日-4月26日：修改模具裝配圖 2013年4月29日-5月3日：繪制模具主要零件的零件圖，不少于5個(gè) 2013年5月6日-5月10日：填寫沖壓工藝卡片等 2013年5月13日-5月17日：完成設(shè)計(jì)說明書（論文）、摘要和小結(jié) 2013年5月20日-5月25日：整理所有資料，打印后上交指導(dǎo)教師，準(zhǔn)備答辯 預(yù)期成果： 1．完成模具裝配圖：1張（A0或A1）； 2．零件圖：主要非標(biāo)準(zhǔn)件零件圖（不少于5張）； 3．冷沖壓工藝卡片：1張； 4．設(shè)計(jì)說明書：1份； 5．翻譯8000以上外文印刷字符或譯出約5000左右漢字的有關(guān)技術(shù)資料或?qū)I(yè)文獻(xiàn)，內(nèi)容要盡量結(jié)合課題。 特色或創(chuàng)新之處 1、 使用caxa，繪圖方便快捷，方便改變參量，能夠直接觀察成形的凸凹模。 2、在設(shè)計(jì)時(shí)通過三維軟件進(jìn)行模擬，真實(shí)的知道設(shè)計(jì)里存在的不足 3、連續(xù)模相對(duì)復(fù)合模具有效率高、壽命高等優(yōu)點(diǎn) 已具備的條件和尚需解決的問題 已具備的條件： ① 設(shè)計(jì)方案思路已經(jīng)非常明確，已初步具備設(shè)計(jì)基礎(chǔ)，工程制圖與AutoCAD，機(jī)械制造工藝學(xué)，工程材料及熱處理等知識(shí)，完全含蓋了設(shè)計(jì)所涉及的各個(gè)方面。 ② 能夠使用相關(guān)三維軟件繪制裝配圖及其零件圖。 尚需解決的問題： 初次涉及連續(xù)模，所以對(duì)設(shè)計(jì)的每個(gè)環(huán)節(jié)考慮不是很周全。在設(shè)計(jì)連續(xù)模時(shí)，要準(zhǔn)確掌握加工速度、沖材材質(zhì)、沖壓力、工位數(shù)、模具間隙等各種因素。對(duì)于模具里的標(biāo)準(zhǔn)件使用需也要相當(dāng)注意。 指導(dǎo)教師意見 指導(dǎo)教師簽名： 年 月 日 教研室（學(xué)科組、研究所）意見 教研室主任簽名： 年 月 日 系意見 主管領(lǐng)導(dǎo)簽名： 年 月 日 英文原文 Cutting Technology and Machining Operations Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile workpiece in the form of a severely deformed chip. The chip is a waste product that is considerably shorter than the workpiece from which it came but with a corresponding increase in thickness of the uncut chip. The geometrical shape of workpiece depends on the shape of the tool and its path during the machining operation. Most machining operations produce parts of differing geometry. If a rough cylindrical workpiece revolves about a central axis and the tool penetrates beneath its surface and travels parallel to the center of rotation, a surface of revolution is produced, and the operation is called turning. If a hollow tube is machined on the inside in a similar manner, the operation is called boring. Producing an external conical surface uniformly varying diameter is called taper turning, if the tool point travels in a path of varying radius, a contoured surface like that of a bowling pin can be produced; or, if the piece is short enough and the support is sufficiently rigid, a contoured surface could be produced by feeding a shaped tool normal to the axis of rotation. Short tapered or cylindrical surfaces could also be contour formed. Multiple-edged tools can also be used. Drilling uses a twin-edged fluted tool for holes with depths up to 5 to 10 times the drill diameter. Whether the drill turns or the workpiece rotates, relative motion between the cutting edge and the workpiece is the important factor. In milling operations a rotary cutter with a number of cutting edges engages the workpiece. Which moves slowly with respect to the cutter. Plane or contoured surfaces may be produced, depending on the geometry of the cutter and the type of feed. Horizontal or vertical axes of rotation may be used, and the feed of the workpiece may be in any of the three coordinate directions. Speeds, feeds, and depth of cut are the three major variables for economical machining. Other variables are the work and tool materials, coolant and geometry of the cutting tool. The rate of metal removal and power required for machining depend upon these variables. The depth of cut, feed, and cutting speed are machine settings that must be established in any metal-cutting operation. They all affect the forces, the power, and the rate of metal removal. They can be defined by comparing them to the needle and record of a phonograph. The cutting speed (V) is represented by the velocity of- the record surface relative to the needle in the tone arm at any instant. Feed is represented by the advance of the needle radially inward per revolution, or is the difference in position between two adjacent grooves. The depth of cut is the penetration of the needle into the record or the depth of the grooves. The basic operations performed on an engine lathe are illustrated. Those operations performed on external surfaces with a single point cutting tool are called turning. Except for drilling, reaming, and lapping, the operations on internal surfaces are also performed by a single point cutting tool. All machining operations, including turning and boring, can be classified as roughing, finishing, or semi-finishing. The objective of a roughing operation is to remove the bulk of the material as rapidly and as efficiently as possible, while leaving a small amount of material on the work-piece for the finishing operation. Finishing operations are performed to obtain the final size, shape, and surface finish on the workpiece. Sometimes a semi-finishing operation will precede the finishing operation to leave a small predetermined and uniform amount of stock on the work-piece to be removed by the finishing operation. Generally, longer workpieces are turned while supported on one or two lathe centers. Cone shaped holes, called center holes, which fit the lathe centers are drilled in the ends of the workpiece-usually along the axis of the cylindrical part. The end of the workpiece adjacent to the tailstock is always supported by a tailstock center, while the end near the headstock may be supported by a headstock center or held in a chuck. The headstock end of the workpiece may be held in a four-jaw chuck, or in a type chuck. This method holds the workpiece firmly and transfers the power to the workpiece smoothly; the additional support to the workpiece provided by the chuck lessens the tendency for chatter to occur when cutting. Precise results can be obtained with this method if care is taken to hold the workpiece accurately in the chuck. Very precise results can be obtained by supporting the workpiece between two centers. A lathe dog is clamped to the workpiece; together they are driven by a driver plate mounted on the spindle nose. One end of the Workpiece is mecained;then the workpiece can be turned around in the lathe to machine the other end. The center holes in the workpiece serve as precise locating surfaces as well as bearing surfaces to carry the weight of the workpiece ?and to resist the cutting forces. After the workpiece has been removed from the lathe for any reason, the center holes will accurately align the workpiece back in the lathe or in another lathe, or in a cylindrical grinding machine. The workpiece must never be held at the headstock end by both a chuck and a lathe center. While at first thought this seems like a quick method of aligning the workpiece in the chuck, this must not be done because it is not possible to press evenly with the jaws against the workpiece while it is also supported by the center. The alignment provided by the center will not be maintained and the pressure of the jaws may damage the center hole, the lathe center, and perhaps even the lathe spindle. Compensating or floating jaw chucks used almost exclusively on high production work provide an exception to the statements made above. These chucks are really work drivers and cannot be used for the same purpose as ordinary three or four-jaw chucks. While very large diameter workpieces are sometimes mounted on two centers, they are preferably held at the headstock end by faceplate jaws to obtain the smooth power transmission; moreover, large lathe dogs that are adequate to transmit the power not generally available, although they can be made as a special. Faceplate jaws are like chuck jaws except that they are mounted on a faceplate, which has less overhang from the spindle bearings than a large chuck would have. Machining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported workpiece. Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced in high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in press worked parts may be machined following the press working operations. The basic tool-work relationship in cutting is adequately described by means of four factors: tool geometry, cutting speed, feed, and depth of cut. The cutting tool must be made of an appropriate material; it must be strong, tough, hard, and wear resistant. The tool s geometry characterized by planes and angles, must be correct for each cutting operation. Cutting speed is the rate at which the work surface passes by the cutting edge. It may be expressed in feet per minute. For efficient machining the cutting speed must be of a magnitude appropriate to the particular work-tool combination. In general, the harder the work material, the slower the speed. Feed is the rate at which the cutting tool advances into the workpiece. "Where the workpiece or the tool rotates, feed is measured in inches per revolution. When the tool or the work reciprocates, feed is measured in inches per stroke, Generally, feed varies inversely with cutting speed for otherwise similar conditions. The depth of cut, measured inches is the distance the tool is set into the work. It is the width of the chip in turning or the thickness of the chip in a rectilinear cut. In roughing operations, the depth of cut can be larger than for finishing operations. In metal cutting operations heat is generated in the primary and secondary deformation zones and these results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip. Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and the cutting temperatures will reduce. When considering increase in unreformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thickness tends to be a scale effect where the amounts of heat which pass to the workpiece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed; however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip m primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate it is appropriate to indicate how cutting temperatures can be assessed from cutting data. The most direct and accurate method for measuring temperatures in high -speed-steel cutting tools is that of Wright &. Trent which also yields detailed information on temperature distributions in high-speed-steel cutting tools. The technique is based on the metallographic examination of sectioned high-speed-steel tools which relates microstructure changes to thermal history. Trent has described measurements of cutting temperatures and temperature ?distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron ?microscopy to study fine-scale microstructure changes arising from over tempering of the tempered martens tic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed -steel single point turning tools and twist drills. Discounting brittle fracture and edge chipping, which have already been dealt with, tool wear is basically of three types. Flank wear, crater wear, and notch wear. Flank wear occurs on both the major and the minor cutting edges. On the major cutting edge, which is responsible for bulk metal removal, these results in increased cutting forces and higher temperatures which if left unchecked can lead to vibration of the tool and workpiece and a condition where efficient cutting can no longer take place. On the minor cutting edge, which determines workpiece size and surface finish, flank wear can result in an oversized product which has poor surface finish. Under most practical cutting conditions, the tool will fail due to major flank wear before the minor flank wear is sufficiently large to result in the manufacture of an unacceptable component. Because of the stress distribution on the tool face, the frictional stress in the region of sliding contact between the chip and the face is at a maximum at the start of the sliding contact region and is zero at the end. Thus abrasive wear takes place in this region with more wear taking place adjacent to the seizure region than adjacent to the point at which the chip loses contact with the face. This result in localized pitting of the tool face some distance up the face which is usually referred to as catering and which normally has a section in the form of a circular arc. In many respects and for practical cutting conditions, crater wear is a less severe form of wear than flank wear and consequently flank wear is a more common tool failure criterion. However, since various authors have shown that the temperature on the face increases more rapidly with increasing cutting speed than the temperature on the flank, and since the rate of wear of any type is significantly affected by changes in temperature, crater wear usually occurs at high cutting speeds. At the end of the major flank wear land where the tool is in contact with the uncut workpiece surface it is common for the flank wear to be more pronounced than along the rest of the wear land. This is because of localised effects such as a hardened layer on the uncut surface caused by work hardening introduced by a previous cut, an oxide scale, and localised high temperatures resulting from the edge effect. This localised wear is usually referred to as notch wear and occasionally is very severe. Although the presence of the notch will not significantly affect the cutting properties of the tool, the notch is often relatively deep and if cutting were to continue there would be a good chance that the tool would fracture. If any form of progressive wear allowed to continue, dramatically and the tool would fail catastrophically, i. e. the tool would be no longer capable of cutting and, at best, the workpiece would be scrapped whilst, at worst, damage could be caused to the machine tool. For carbide cutting tools and for all types of wear, the tool is said to have reached the end of its useful life long before the onset of catastrophic failure. For high-speed-steel cutting tools, however, where the wear tends to be non-uniform it has been found that the most meaningful and reproducible results can be obtained when the wear is allowed to continue to the onset of catastrophic failure even though, of course, in practice a cutting time far less than that to failure would be used. The onset of catastrophic failure is characterized by one of several phenomena, the most common being a sudden increase in cutting force, the presence of burnished rings on the workpiece, and a significant increase in the noise level. There are basically five mechanisms which contribute to the production of a surface which have been machined. These are: (l) The basic geometry of the cutting process. (2) The efficiency of the cutting operation. (3) The stability of the machine tool. (4)The effectiveness of removing swarf. (5)The effective clearance angle on the cutting tool. Machine parts are manufactured so they are interchangeable. In other words, each part of a machine or mechanism is made to a certain size and shape so will fit into any other machine or mechanism of the same type. To make the part interchangeable, each individual part must be made to a size that wi