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學(xué)生畢業(yè)設(shè)計(jì)(論文)中期檢查表
學(xué)生姓名
學(xué) 號
指導(dǎo)教師
選題情況
課題名稱
撥叉零件的工藝規(guī)程編訂及銑夾具設(shè)計(jì)
難易程度
偏難
適中
√
偏易
工作量
較大
合理
√
較小
符合規(guī)范化的要求
任務(wù)書
有
√
無
開題報告
有
√
無
外文翻譯質(zhì)量
優(yōu)
良
√
中
差
學(xué)習(xí)態(tài)度、出勤情況
好
√
一般
差
工作進(jìn)度
快
按計(jì)劃進(jìn)行
√
慢
中期工作匯報及解答問題情況
優(yōu)
良
√
中
差
中期成績評定:良
所在專業(yè)意見:
學(xué)習(xí)較主動、積極,態(tài)度認(rèn)真,階段成果較明顯。
負(fù)責(zé)人:
年 月 日
畢業(yè)設(shè)計(jì)(論文)任務(wù)書
系 部:
機(jī)械工程系
專 業(yè):
機(jī)械工程及自動化
學(xué) 生 姓 名:
學(xué) 號:
設(shè)計(jì)(論文)題目:
撥叉零件的工藝規(guī)程編訂及
銑夾具設(shè)計(jì)
起 迄 日 期:
設(shè)計(jì)(論文)地點(diǎn):
指 導(dǎo) 教 師:
專業(yè)負(fù)責(zé)人:
發(fā)任務(wù)書日期: 年 2 月 26 日
畢 業(yè) 設(shè) 計(jì)(論 文)任 務(wù) 書
1.本畢業(yè)設(shè)計(jì)(論文)課題應(yīng)達(dá)到的目的:
機(jī)械制造加工工藝的編制對機(jī)械產(chǎn)品的制造而言,具有重要的作用,直接影響著機(jī)械產(chǎn)品的加工質(zhì)量和生產(chǎn)效益。通過對撥叉零件的工藝規(guī)程編訂及銑夾具設(shè)計(jì),可以有效培養(yǎng)學(xué)生綜合應(yīng)用機(jī)械設(shè)計(jì)制造知識,并根據(jù)工程實(shí)際要求,進(jìn)行問題的分析解決,從而提高獨(dú)立工作的能力,適應(yīng)社會需求。
2.本畢業(yè)設(shè)計(jì)(論文)課題任務(wù)的內(nèi)容和要求(包括原始數(shù)據(jù)、技術(shù)要求、工作要求等):
本設(shè)計(jì)要求學(xué)生根據(jù)撥叉零件的結(jié)構(gòu)特點(diǎn)、機(jī)械制造加工工藝規(guī)程編制的原則,編制出撥叉零件的加工工藝規(guī)程,并設(shè)計(jì)出特定工序的專用銑夾具,繪出零件圖和裝配圖,學(xué)習(xí)AutoCAD、Pro/Engineer等軟件在機(jī)械設(shè)計(jì)中的應(yīng)用,具體要求如下:
1、查閱相關(guān)資料(不少于15篇),翻譯一定量的外文資料(不少于3000漢字),撰寫開題報告及文獻(xiàn)綜述(不少于2000字);
2、完成撥叉零件加工工藝規(guī)程的編制;
3、選擇合適的工件定位方式;
4、確定恰當(dāng)?shù)膴A緊方案;
5、選擇和設(shè)計(jì)相應(yīng)的定位元件和夾緊裝置;
6、進(jìn)行銑夾具總圖及零件圖的繪制;
7、撰寫設(shè)計(jì)說明書。
相關(guān)的技術(shù)要求:
1、被加工工件為45號鋼;
2、被加工工件為滲碳處理,表面硬度為HV650-800;
3、表面無毛刺、劃痕。
畢 業(yè) 設(shè) 計(jì)(論 文)任 務(wù) 書
3.對本畢業(yè)設(shè)計(jì)(論文)課題成果的要求〔包括畢業(yè)設(shè)計(jì)論文、圖表、實(shí)物樣品等〕:
1、相關(guān)資料的英文翻譯與文獻(xiàn)綜述;
2、撥叉零件的加工工藝規(guī)程;
3、銑夾具的零件圖、裝配圖;
4、畢業(yè)設(shè)計(jì)論文。
畢業(yè)設(shè)計(jì)成果以設(shè)計(jì)圖樣和說明書形式提交。要求圖樣規(guī)范,符合國家標(biāo)準(zhǔn);說明書層次分明、論據(jù)可靠、計(jì)算正確、圖標(biāo)規(guī)范、語句通順。
4.主要參考文獻(xiàn):
[1] 濮良貴,紀(jì)名剛. 機(jī)械設(shè)計(jì)(第八版)[M]. 北京: 高等教育出版社, 2006.
[2] 王先逵. 機(jī)械制造工藝學(xué) [M]. 北京:機(jī)械工業(yè)出版社,2004.
[3] 薛源順. 機(jī)床夾具設(shè)計(jì)(第二版)[M]. 北京:機(jī)械工業(yè)出版社,2003.
[4] 王維模,管琪明. 機(jī)床夾具的誤差及誤差系統(tǒng)圖 [J]. 貴州工業(yè)大學(xué)學(xué)報,1997,26(2): 76~82.
[5] 周海寶. 提高機(jī)床夾具精度的實(shí)用方法 [J]. 機(jī)床與液壓,2000,4: 96~97.
[6] 王黎明. 適應(yīng)現(xiàn)代機(jī)床要求的新型夾具[J]. 產(chǎn)品與技術(shù),1999,11(4): 92~93.
畢 業(yè) 設(shè) 計(jì)(論 文)任 務(wù) 書
5.本畢業(yè)設(shè)計(jì)(論文)課題工作進(jìn)度計(jì)劃:
起 迄 日 期
工 作 內(nèi) 容
2009年
3 月 9 日 ~ 3月 23 日
3 月 24 日 ~ 4月 6 日
4 月 7 日 ~ 5月 11日
5 月 12 日 ~ 5月 31 日
6 月 1 日 ~ 6月 9 日
6月 10日 ~ 6月 14 日
熟悉課題,準(zhǔn)備相關(guān)資料,完成資料翻譯
完成文獻(xiàn)綜述,撰寫開題報告,熟悉AutoCAD、Pro/Engineer等繪圖軟件
掌握機(jī)械制造加工工藝編制的要點(diǎn),分析撥叉零件的特點(diǎn),完成撥叉零件制造加工工藝規(guī)程的編制
掌握機(jī)床夾具設(shè)計(jì)特點(diǎn),完成銑夾具的結(jié)構(gòu)設(shè)計(jì),畫出相關(guān)零件圖和裝配圖
撰寫并打印設(shè)計(jì)說明書,整理相關(guān)資料
準(zhǔn)備論文答辯
所在專業(yè)審查意見:
負(fù)責(zé)人:
2008年 月 日
系部意見:
系部主任:
2008年 月 日
畢業(yè)設(shè)計(jì)(論文)前期工作材料
學(xué)生姓名:
學(xué) 號:
系 部:
機(jī)械系
專 業(yè):
機(jī)械工程及自動化
設(shè)計(jì)(論文)題目:
撥叉零件的工藝規(guī)程編訂及
銑夾具設(shè)計(jì)
指導(dǎo)教師:
材 料 目 錄
序號
名 稱
數(shù)量
備 注
1
畢業(yè)設(shè)計(jì)(論文)選題、審題表
1
2
畢業(yè)設(shè)計(jì)(論文)任務(wù)書
1
3
畢業(yè)設(shè)計(jì)(論文)開題報告〔含文獻(xiàn)綜述〕
1
4
畢業(yè)設(shè)計(jì)(論文)外文資料翻譯〔含原文〕
1
5
畢業(yè)設(shè)計(jì)(論文)中期檢查表
1
年5月
畢業(yè)設(shè)計(jì)(論文)外文資料翻譯
系 部: 機(jī)械工程系
專 業(yè): 機(jī)械工程及自動化
姓 名:
學(xué) 號:
(用外文寫)
外文出處: CNC Machine Tool Geometric Error and its Compensation Method
附 件: 1.外文資料翻譯譯文;2.外文原文。
指導(dǎo)教師評語:此翻譯文章詳細(xì)描述了數(shù)控技術(shù)的發(fā)展,翻譯用詞基本準(zhǔn)確,文筆也較為通順,具備一定的英語基礎(chǔ),為在以后工作中接觸英文資料打下了基礎(chǔ)。
簽名:
年 月 日
注:請將該封面與附件裝訂成冊。
附件1:外文資料翻譯譯文
數(shù)控技術(shù)的發(fā)展
1、數(shù)控系統(tǒng)發(fā)展簡史及趨勢
1946年誕生了世界上第一臺電子計(jì)算機(jī),這表明人類創(chuàng)造了可增強(qiáng)和部分代替腦力勞動的工具。它與人類在農(nóng)業(yè)、工業(yè)社會中創(chuàng)造的那些只是增強(qiáng)體力勞動的工具相比,起了質(zhì)的飛躍,為人類進(jìn)入信息社會奠定了基礎(chǔ)。
1.1、數(shù)控(NC)階段 早期計(jì)算機(jī)的運(yùn)算速度低,對當(dāng)時的科學(xué)計(jì)算和數(shù)據(jù)處理影響還不大,但不能適應(yīng)機(jī)床實(shí)時控制的要求。人們不得不采用數(shù)字邏輯電路“搭”成一臺機(jī)床專用計(jì)算機(jī)作一、數(shù)控系統(tǒng)發(fā)展簡史及趨勢
1946年誕生了世界上第一臺電子計(jì)算機(jī),這表明人類創(chuàng)造了可增強(qiáng)和部分代替腦力勞動的工具。它與人類在農(nóng)業(yè)、工業(yè)社會中創(chuàng)造的那些只是增強(qiáng)體力勞動的工具相比,起了質(zhì)的飛躍,為人類進(jìn)入信息社會奠定了基礎(chǔ)1.1、數(shù)控(NC)階段(1952~1970年)早期計(jì)算機(jī)的運(yùn)算速度低,對當(dāng)時的科學(xué)計(jì)算和數(shù)據(jù)處理影響還不大,但不能適應(yīng)機(jī)床實(shí)時控制的要求。人們不得不采為數(shù)控系統(tǒng),被稱為硬件連接數(shù)控(HARD-WIRED NC),簡稱為數(shù)控(NC)。隨著元器件的發(fā)展,這個階段歷經(jīng)1952年的第一代--電子管;1959年的第二代--晶體管;1965年的第三代--小規(guī)模集成電路。
1.2、計(jì)算機(jī)數(shù)控(CNC)階段(1970年~現(xiàn)在)
到1970年,通用小型計(jì)算機(jī)業(yè)已出現(xiàn)并成批生產(chǎn)。于是將它移植過來作為數(shù)控系統(tǒng)的核心部件,從此進(jìn)入了計(jì)算機(jī)數(shù)控(CNC)階段(把計(jì)算機(jī)前面應(yīng)有的“通用”兩個字省略了)。到1971年,美國INTEL公司在世界上第一次將計(jì)算機(jī)的兩個最核心的部件--運(yùn)算器和控制器,采用大規(guī)模集成電路技術(shù)集成在一塊芯片上,稱之為微處理器(MICROPROCESSOR),又可稱為中央處理單元(簡稱CPU)。
到1974年微處理器被應(yīng)用于數(shù)控系統(tǒng)。這是因?yàn)樾⌒陀?jì)算機(jī)功能太強(qiáng),控制一臺機(jī)床能力有富裕(故當(dāng)時曾用于控制多臺機(jī)床,稱之為群控),不如采用微處理器經(jīng)濟(jì)合理。而且當(dāng)時的小型機(jī)可靠性也不理想。早期的微處理器速度和功能雖還不夠高,但可以通過多處理器結(jié)構(gòu)來解決。由于微處理器是通用計(jì)算機(jī)的核心部件,故仍稱為計(jì)算機(jī)數(shù)控。
到了1990年,PC機(jī)(個人計(jì)算機(jī),國內(nèi)習(xí)慣稱微機(jī))的性能已發(fā)展到很高的階段,可以滿足作為數(shù)控系統(tǒng)核心部件的要求。數(shù)控系統(tǒng)從此進(jìn)入了基于PC的階段。
總之,計(jì)算機(jī)數(shù)控階段也經(jīng)歷了三代。即1970年的第四代--小型計(jì)算機(jī);1974年的第五代--微處理器和1990年的第六代--基于PC(國外稱為PC-BASED)。
還要指出的是,雖然國外早已改稱為計(jì)算機(jī)數(shù)控(即CNC)了,而我國仍習(xí)慣稱數(shù)控(NC)。所以我們?nèi)粘Vv的“數(shù)控”,實(shí)質(zhì)上已是指“計(jì)算機(jī)數(shù)控”了。
1.3、數(shù)控未來發(fā)展的趨勢
1.3.1 繼續(xù)向開放式、基于PC的第六代方向發(fā)展
基于PC所具有的開放性、低成本、高可靠性、軟硬件資源豐富等特點(diǎn),更多的數(shù)控系統(tǒng)生產(chǎn)廠家會走上這條道路。至少采用PC機(jī)作為它的前端機(jī),來處理人機(jī)界面、編程、聯(lián)網(wǎng)通信等問題,由原有的系統(tǒng)承擔(dān)數(shù)控的任務(wù)。PC機(jī)所具有的友好的人機(jī)界面,將普及到所有的數(shù)控系統(tǒng)。遠(yuǎn)程通訊,遠(yuǎn)程診斷和維修將更加普遍。
1.3.2 向高速化和高精度化發(fā)展
這是適應(yīng)機(jī)床向高速和高精度方向發(fā)展的需要。
1.3.3 向智能化方向發(fā)展
隨著人工智能在計(jì)算機(jī)領(lǐng)域的不斷滲透和發(fā)展,數(shù)控系統(tǒng)的智能化程度將不斷提高。
(1)應(yīng)用自適應(yīng)控制技術(shù)
數(shù)控系統(tǒng)能檢測過程中一些重要信息,并自動調(diào)整系統(tǒng)的有關(guān)參數(shù),達(dá)到改進(jìn)系統(tǒng)運(yùn)行狀態(tài)的目的。
(2)引入專家系統(tǒng)指導(dǎo)加工
將熟練工人和專家的經(jīng)驗(yàn),加工的一般規(guī)律和特殊規(guī)律存入系統(tǒng)中,以工藝參數(shù)數(shù)據(jù)庫為支撐,建立具有人工智能的專家系統(tǒng)。
(3)引入故障診斷專家系統(tǒng)
(4)智能化數(shù)字伺服驅(qū)動裝置
可以通過自動識別負(fù)載,而自動調(diào)整參數(shù),使驅(qū)動系統(tǒng)獲得最佳的運(yùn)行。
2、機(jī)床數(shù)控化改造的必要性
2.1、微觀看改造的必要性
從微觀上看,數(shù)控機(jī)床比傳統(tǒng)機(jī)床有以下突出的優(yōu)越性,而且這些優(yōu)越性均來自數(shù)控系統(tǒng)所包含的計(jì)算機(jī)的威力。
2.1.1 可以加工出傳統(tǒng)機(jī)床加工不出來的曲線、曲面等復(fù)雜的零件。
由于計(jì)算機(jī)有高超的運(yùn)算能力,可以瞬時準(zhǔn)確地計(jì)算出每個坐標(biāo)軸瞬時應(yīng)該運(yùn)動的運(yùn)動量,因此可以復(fù)合成復(fù)雜的曲線或曲面。
2.1.2 可以實(shí)現(xiàn)加工的自動化,而且是柔性自動化,從而效率可比傳統(tǒng)機(jī)床提高3~7倍。
由于計(jì)算機(jī)有記憶和存儲能力,可以將輸入的程序記住和存儲下來,然后按程序規(guī)定的順序自動去執(zhí)行,從而實(shí)現(xiàn)自動化。數(shù)控機(jī)床只要更換一個程序,就可實(shí)現(xiàn)另一工件加工的自動化,從而使單件和小批生產(chǎn)得以自動化,故被稱為實(shí)現(xiàn)了“柔性自動化”。
2.1.3 加工零件的精度高,尺寸分散度小,使裝配容易,不再需要“修配”。
2.1.4 可實(shí)現(xiàn)多工序的集中,減少零件 在機(jī)床間的頻繁搬運(yùn)。
2.1.5 擁有自動報警、自動監(jiān)控、自動補(bǔ)償?shù)榷喾N自律功能,因而可實(shí)現(xiàn)長時間無人看管加工。
2.1.6 由以上五條派生的好處。
如:降低了工人的勞動強(qiáng)度,節(jié)省了勞動力(一個人可以看管多臺機(jī)床),減少了工裝,縮短了新產(chǎn)品試制周期和生產(chǎn)周期,可對市場需求作出快速反應(yīng)等等。
以上這些優(yōu)越性是前人想象不到的,是一個極為重大的突破。此外,機(jī)床數(shù)控化還是推行FMC(柔性制造單元)、FMS(柔性制造系統(tǒng))以及CIMS(計(jì)算機(jī)集成制造系統(tǒng))等企業(yè)信息化改造的基礎(chǔ)。數(shù)控技術(shù)已經(jīng)成為制造業(yè)自動化的核心技術(shù)和基礎(chǔ)技術(shù)。
2.2、宏觀看改造的必要性
從宏觀上看,工業(yè)發(fā)達(dá)國家的軍、民機(jī)械工業(yè),在70年代末、80年代初已開始大規(guī)模應(yīng)用數(shù)控機(jī)床。其本質(zhì)是,采用信息技術(shù)對傳統(tǒng)產(chǎn)業(yè)(包括軍、民機(jī)械工業(yè))進(jìn)行技術(shù)改造。除在制造過程中采用數(shù)控機(jī)床、FMC、FMS外,還包括在產(chǎn)品開發(fā)中推行CAD、CAE、CAM、虛擬制造以及在生產(chǎn)管理中推行MIS(管理信息系統(tǒng))、CIMS等等。以及在其生產(chǎn)的產(chǎn)品中增加信息技術(shù),包括人工智能等的含量。由于采用信息技術(shù)對國外軍、民機(jī)械工業(yè)進(jìn)行深入改造(稱之為信息化),最終使得他們的產(chǎn)品在國際軍品和民品的市場上競爭力大為增強(qiáng)。而我們在信息技術(shù)改造傳統(tǒng)產(chǎn)業(yè)方面比發(fā)達(dá)國家約落后20年。如我國機(jī)床擁有量中,數(shù)控機(jī)床的比重(數(shù)控化率)到1995年只有1.9%,而日本在1994年已達(dá)20.8%,因此每年都有大量機(jī)電產(chǎn)品進(jìn)口。這也就從宏觀上說明了機(jī)床數(shù)控化改造的必要性。
3、機(jī)床與生產(chǎn)線數(shù)控化改造的市場
3.1、機(jī)床數(shù)控化改造的市場
我國目前機(jī)床總量380余萬臺,而其中數(shù)控機(jī)床總數(shù)只有11.34萬臺,即我國機(jī)床數(shù)控化率不到3%。近10年來,我國數(shù)控機(jī)床年產(chǎn)量約為0.6~0.8萬臺,年產(chǎn)值約為18億元。機(jī)床的年產(chǎn)量數(shù)控化率為6%。我國機(jī)床役齡10年以上的占60%以上;10年以下的機(jī)床中,自動/半自動機(jī)床不到20%,F(xiàn)MC/FMS等自動化生產(chǎn)線更屈指可數(shù)(美國和日本自動和半自動機(jī)床占60%以上)。可見我們的大多數(shù)制造行業(yè)和企業(yè)的生產(chǎn)、加工裝備絕大數(shù)是傳統(tǒng)的機(jī)床,而且半數(shù)以上是役齡在10年以上的舊機(jī)床。用這種裝備加工出來的產(chǎn)品普遍存在質(zhì)量差、品種少、檔次低、成本高、供貨期長,從而在國際、國內(nèi)市場上缺乏競爭力,直接影響一個企業(yè)的產(chǎn)品、市場、效益,影響企業(yè)的生存和發(fā)展。所以必須大力提高機(jī)床的數(shù)控化率。
3.2、進(jìn)口設(shè)備和生產(chǎn)線的數(shù)控化改造市場
我國自改革開放以來,很多企業(yè)從國外引進(jìn)技術(shù)、設(shè)備和生產(chǎn)線進(jìn)行技術(shù)改造。據(jù)不完全統(tǒng)計(jì),從1979~1988年10年間,全國引進(jìn)技術(shù)改造項(xiàng)目就有18446項(xiàng),大約165.8億美元。
這些項(xiàng)目中,大部分項(xiàng)目為我國的經(jīng)濟(jì)建設(shè)發(fā)揮了應(yīng)有的作用。但是有的引進(jìn)項(xiàng)目由于種種原因,設(shè)備或生產(chǎn)線不能正常運(yùn)轉(zhuǎn),甚至癱瘓,使企業(yè)的效益受到影響,嚴(yán)重的使企業(yè)陷入困境。一些設(shè)備、生產(chǎn)線從國外引進(jìn)以后,有的消化吸收不好,備件不全,維護(hù)不當(dāng),結(jié)果運(yùn)轉(zhuǎn)不良;有的引進(jìn)時只注意引進(jìn)設(shè)備、儀器、生產(chǎn)線,忽視軟件、工藝、管理等,造成項(xiàng)目不完整,設(shè)備潛力不能發(fā)揮;有的甚至不能啟動運(yùn)行,沒有發(fā)揮應(yīng)有的作用;有的生產(chǎn)線的產(chǎn)品銷路很好,但是因?yàn)樵O(shè)備故障不能達(dá)產(chǎn)達(dá)標(biāo);有的因?yàn)槟芎母摺a(chǎn)品合格率低而造成虧損;有的已引進(jìn)較長時間,需要進(jìn)行技術(shù)更新。種種原因使有的設(shè)備不僅沒有創(chuàng)造財富,反而消耗著財富。
這些不能使用的設(shè)備、生產(chǎn)線是個包袱,也是一批很大的存量資產(chǎn),修好了就是財富。只要找出主要的技術(shù)難點(diǎn),解決關(guān)鍵技術(shù)問題,就可以最小的投資盤活最大的存量資產(chǎn),爭取到最大的經(jīng)濟(jì)效益和社會效益。這也是一個極大的改造市場。
4、數(shù)控化改造的內(nèi)容及優(yōu)缺
4.1、國外改造業(yè)的興起
在美國、日本和德國等發(fā)達(dá)國家,它們的機(jī)床改造作為新的經(jīng)濟(jì)增長行業(yè),生意盎然,正處在黃金時代。由于機(jī)床以及技術(shù)的不斷進(jìn)步,機(jī)床改造是個"永恒"的課題。我國的機(jī)床改造業(yè),也從老的行業(yè)進(jìn)入到以數(shù)控技術(shù)為主的新的行業(yè)。在美國、日本、德國,用數(shù)控技術(shù)改造機(jī)床和生產(chǎn)線具有廣闊的市場,已形成了機(jī)床和生產(chǎn)線數(shù)控改造的新的行業(yè)。在美國,機(jī)床改造業(yè)稱為機(jī)床再生(Remanufacturing)業(yè)。從事再生業(yè)的著名公司有:Bertsche工程。美國得寶公司已在中國開辦公司。在日本,機(jī)床改造業(yè)稱為機(jī)床改裝(Retrofitting)業(yè)。從事改裝業(yè)的著名公司有:大隈工程集團(tuán)、崗三機(jī)械公司、千代田工機(jī)公司、野崎工程公司、濱田工程公司、山本工程公司等。
4.2、數(shù)控化改造的內(nèi)容
機(jī)床與生產(chǎn)線的數(shù)控化改造主要內(nèi)容有以下幾點(diǎn):
其一是恢復(fù)原功能,對機(jī)床、生產(chǎn)線存在的故障部分進(jìn)行診斷并恢復(fù);
其二是NC化,在普通機(jī)床上加數(shù)顯裝置,或加數(shù)控系統(tǒng),改造成NC機(jī)床、CNC機(jī)床;
其三是翻新,為提高精度、效率和自動化程度,對機(jī)械、電氣部分進(jìn)行翻新,對機(jī)械部分重新裝配加工,恢復(fù)原精度;對其不滿足生產(chǎn)要求的CNC系統(tǒng)以最新CNC進(jìn)行更新;
其四是技術(shù)更新或技術(shù)創(chuàng)新,為提高性能或檔次,或?yàn)榱耸褂眯鹿に?、新技術(shù),在原有基礎(chǔ)上進(jìn)行較大規(guī)模的技術(shù)更新或技術(shù)創(chuàng)新,較大幅度地提高水平和檔次的更新改造。
4.3.1 減少投資額、交貨期短
同購置新機(jī)床相比,一般可以節(jié)省60%~80%的費(fèi)用,改造費(fèi)用低。特別是大型、特殊機(jī)床尤其明顯。一般大型機(jī)床改造,只花新機(jī)床購置費(fèi)用的1/3,交貨期短。但有些特殊情況,如高速主軸、托盤自動交換裝置的制作與安裝過于費(fèi)工、費(fèi)錢,往往改造成本提高2~3倍,與購置新機(jī)床相比,只能節(jié)省投資50%左右。
4.3.2 機(jī)械性能穩(wěn)定可靠,結(jié)構(gòu)受限
所利用的床身、立柱等基礎(chǔ)件都是重而堅(jiān)固的鑄造構(gòu)件,而不是那種焊接構(gòu)件,改造后的機(jī)床性能高、質(zhì)量好,可以作為新設(shè)備繼續(xù)使用多年。但是受到原來機(jī)械結(jié)構(gòu)的限制,不宜做突破性的改造。
4.3.3 熟悉了解設(shè)備、便于操作維修
購買新設(shè)備時,不了解新設(shè)備是否能滿足其加工要求。改造則不然,可以精確地計(jì)算出機(jī)床的加工能力;另外,由于多年使用,操作者對機(jī)床的特性早已了解,在操作使用和維修方面培訓(xùn)時間短,見效快。改造的機(jī)床一安裝好,就可以實(shí)現(xiàn)全負(fù)荷運(yùn)轉(zhuǎn)。
4.3.4 可充分利用現(xiàn)有的條件
可以充分利用現(xiàn)有地基,不必像購入新設(shè)備時那樣需重新構(gòu)筑地基。
4.3.5 可以采用最新的控制技術(shù)
可根據(jù)技術(shù)革新的發(fā)展速度,及時地提高生產(chǎn)設(shè)備的自動化水平和效率,提高設(shè)備質(zhì)量和檔次,將舊機(jī)床改成當(dāng)今水平的機(jī)床。
5、數(shù)控系統(tǒng)的選擇
數(shù)控系統(tǒng)主要有三種類型,改造時,應(yīng)根據(jù)具體情況進(jìn)行選擇。
5.1 步進(jìn)電機(jī)拖動的開環(huán)系統(tǒng)
該系統(tǒng)的伺服驅(qū)動裝置主要是步進(jìn)電機(jī)、功率步進(jìn)電機(jī)、電液脈沖馬達(dá)等。由數(shù)控系統(tǒng)送出的進(jìn)給指令脈沖,經(jīng)驅(qū)動電路控制和功率放大后,使步進(jìn)電機(jī)轉(zhuǎn)動,通過齒輪副與滾珠絲杠副驅(qū)動執(zhí)行部件。只要控制指令脈沖的數(shù)量、頻率以及通電順序,便可控制執(zhí)行部件運(yùn)動的位移量、速度和運(yùn)動方向。這種系統(tǒng)不需要將所測得的實(shí)際位置和速度反饋到輸入端,故稱之為開環(huán)系統(tǒng),該系統(tǒng)的位移精度主要決定于步進(jìn)電機(jī)的角位移精度,齒輪絲杠等傳動元件的節(jié)距精度,所以系統(tǒng)的位移精度較低。
該系統(tǒng)結(jié)構(gòu)簡單,調(diào)試維修方便,工作可靠,成本低,易改裝成功。
5.2、異步電動機(jī)或直流電機(jī)拖動,光柵測量反饋的閉環(huán)數(shù)控系統(tǒng)
該系統(tǒng)與開環(huán)系統(tǒng)的區(qū)別是:由光柵、感應(yīng)同步器等位置檢測裝置測得的實(shí)際位置反饋信號,隨時與給定值進(jìn)行比較,將兩者的差值放大和變換,驅(qū)動執(zhí)行機(jī)構(gòu),以給定的速度向著消除偏差的方向運(yùn)動,直到給定位置與反饋的實(shí)際位置的差值等于零為止。閉環(huán)進(jìn)給系統(tǒng)在結(jié)構(gòu)上比開環(huán)進(jìn)給系統(tǒng)復(fù)雜,成本也高,對環(huán)境室溫要求嚴(yán)。設(shè)計(jì)和調(diào)試都比開環(huán)系統(tǒng)難。但是可以獲得比開環(huán)進(jìn)給系統(tǒng)更高的精度,更快的速度,驅(qū)動功率更大的特性指標(biāo)??筛鶕?jù)產(chǎn)品技術(shù)要求,決定是否采用這種系統(tǒng)。
5.3、交/直流伺服電機(jī)拖動,編碼器反饋的半閉環(huán)數(shù)控系統(tǒng)
半閉環(huán)系統(tǒng)檢測元件安裝在中間傳動件上,間接測量執(zhí)行部件的位置。它只能補(bǔ)償系統(tǒng)環(huán)路內(nèi)部部分元件的誤差,因此,它的精度比閉環(huán)系統(tǒng)的精度低,但是它的結(jié)構(gòu)與調(diào)試都較閉環(huán)系統(tǒng)簡單。在將角位移檢測元件與速度檢測元件和伺服電機(jī)作成一個整體時則無需考慮位置檢測裝置的安裝問題。
當(dāng)前生產(chǎn)數(shù)控系統(tǒng)的公司廠家比較多,國外著名公司的如德國SIEMENS公司、日本FANUC公司;國內(nèi)公司如中國珠峰公司、北京航天機(jī)床數(shù)控系統(tǒng)集團(tuán)公司、華中數(shù)控公司和沈陽高檔數(shù)控國家工程研究中心。
選擇數(shù)控系統(tǒng)時主要是根據(jù)數(shù)控改造后機(jī)床要達(dá)到的各種精度、驅(qū)動電機(jī)的功率和用戶的要求。
6、數(shù)控改造中主要機(jī)械部件改裝探討
一臺新的數(shù)控機(jī)床,在設(shè)計(jì)上要達(dá)到:有高的靜動態(tài)剛度;運(yùn)動副之間的摩擦系數(shù)小,傳動無間隙;功率大;便于操作和維修。機(jī)床數(shù)控改造時應(yīng)盡量達(dá)到上述要求。不能認(rèn)為將數(shù)控裝置與普通機(jī)床連接在一起就達(dá)到了數(shù)控機(jī)床的要求,還應(yīng)對主要部件進(jìn)行相應(yīng)的改造使其達(dá)到一定的設(shè)計(jì)要求,才能獲得預(yù)期的改造目的。
6.1、滑動導(dǎo)軌副
對數(shù)控車床來說,導(dǎo)軌除應(yīng)具有普通車床導(dǎo)向精度和工藝性外,還要有良好的耐摩擦、磨損特性,并減少因摩擦阻力而致死區(qū)。同時要有足夠的剛度,以減少導(dǎo)軌變形對加工精度的影響,要有合理的導(dǎo)軌防護(hù)和潤滑。
6.2、齒輪副
一般機(jī)床的齒輪主要集中在主軸箱和變速箱中。為了保證傳動精度,數(shù)控機(jī)床上使用的齒輪精度等級都比普通機(jī)床高。在結(jié)構(gòu)上要能達(dá)到無間隙傳動,因而改造時,機(jī)床主要齒輪必須滿足數(shù)控機(jī)床的要求,以保證機(jī)床加工精度。
6.3、滑動絲杠與滾珠絲杠
絲杠傳動直接關(guān)系到傳動鏈精度。絲杠的選用主要取決于加工件的精度要求和拖動扭矩要求。被加工件精度要求不高時可采用滑動絲杠,但應(yīng)檢查原絲杠磨損情況,如螺距誤差及螺距累計(jì)誤差以及相配螺母間隙。一般情況滑動絲杠應(yīng)不低于6級,螺母間隙過大則更換螺母。采用滑動絲杠相對滾珠絲杠價格較低,但難以滿足精度較高的零件加工。
滾珠絲杠摩擦損失小,效率高,其傳動效率可在90%以上;精度高,壽命長;啟動力矩和運(yùn)動時力矩相接近,可以降低電機(jī)啟動力矩。因此可滿足較高精度零件加工要求。
6.4、安全防護(hù)
必須以安全為前提。在機(jī)床改造中要根據(jù)實(shí)際情況采取相應(yīng)的措施,切不可忽視。滾珠絲杠副是精密元件,工作時要嚴(yán)防灰塵特別是切屑及硬砂粒進(jìn)入滾道。在縱向絲杠上也可加整體鐵板防護(hù)罩。大拖板與滑動導(dǎo)軌接觸的兩端面要密封好,絕對防止硬質(zhì)顆粒狀的異物進(jìn)入滑動面損傷導(dǎo)軌。
制定符合中國國情的總體發(fā)展戰(zhàn)略,確立與國際接軌的發(fā)展道路,對21世紀(jì)我國數(shù)控技術(shù)與產(chǎn)業(yè)的發(fā)展至關(guān)重要。本文在對數(shù)控技術(shù)和產(chǎn)業(yè)發(fā)展趨勢的分析,對我國數(shù)控領(lǐng)域存在的問題進(jìn)行研究的基礎(chǔ)上,對21世紀(jì)我國數(shù)控技術(shù)和產(chǎn)業(yè)的發(fā)展途徑進(jìn)行了探討,提出了以科技創(chuàng)新為先導(dǎo),以商品化為主干,以管理和營銷為重點(diǎn),以技術(shù)支持和服務(wù)為后盾,堅(jiān)持可持續(xù)發(fā)展道路的總體發(fā)展戰(zhàn)略。在此基礎(chǔ)上,研究了發(fā)展新型數(shù)控系統(tǒng)、數(shù)控功能部件、數(shù)控機(jī)床整機(jī)等的具體技術(shù)途徑。
我們衷心希望,我國科技界、產(chǎn)業(yè)界和教育界通力合作,把握好知識經(jīng)濟(jì)給我們帶來的難得機(jī)遇,迎接競爭全球化帶來的嚴(yán)峻挑戰(zhàn)。
附件2:外文原文(復(fù)印件)
Numerical control technology development
Numerical control system develop biref history and trend the first electronic computer in the world borned in 1946, this indicates the mankind has created the tool that can strengthen and replace the mental labour partly . It, and mankind those that create to strengthen tool of manual labor compare among agriculture, industrial society, the qualitative leap has arisen , has established the foundation that the mankind enters the information-intensive society .
6 years later, namely in 1952, the technology of the computer was applied to the lathe , the first numerical control lathe has emerged in U.S.A.. From then on, the traditional lathe had produced the change of the quality. In nearly half a century, numerical control system go through two stage and six development of generation.
The stage of numerical control (NC ) (1952-1970 years) The operation of the early computer is low in speed, influence not also big scientific caculation and data processing at that time, but can't meet the needs of real-time control of the lathe . People have to adopt the digital logical circuit to " put up " and become the special-purpose computer of a lathe as the numerical control system, known as the hardware and connect numerical control (HARD-WIRED NC ) , abbreviate as the numerical control (NC ). With the development of components and parts, does this stage go through you of the sixth of the twelve Earthly Branches? First generation in 952 --Electron tube ; Second generation in 1959 --Transistor; The third generation in 1965 --Small-scale integrated circuit. The stage of numerical control of the computer (CNC ) (1970 - now) By 1970, the small-scale computer industry in common use has already appeared and produced by batch. Then transplant it over as the key part of system of numerical control, enter computer numerical control stage from now on (whether due " in common use two words " omit computer). By 1971, in the world for the first time two central part most of computer Company , INTEL of U.S.A. , --arithmetic unit and controller , adopt the technology intergration of the large scale integrated circuit on a chip, call it microprocessor (MICROPROCESSOR ) , can call central authorities punish Entrance (abbreviate as CPU).
The microprocessor is applied the numerical control system by 1974. This because being function too strong, minicom control one lathe ability have rich (use for controlling many lathes at that time, call it team control ), have more rational economy than the adoption microprocessor. And the minicomputer dependability at that time was unsatisfactory. Early microprocessor speed and function although enough high, can solve through many processor structure. Because the microprocessor is a key part of the all-purpose computer , so still called the numerical control of the computer.
By 1990, the performance of the PC (personal computer , is used to calling the computer at home ) has already developed into very high stage, can meet the demand which is regarded as the key part of the numerical control system . The numerical control system entered the stage based on PC from then on. In a word, the computer went through three generations too at numerical control stage. Namely the fourth generation in 1970 --Minicom ; The fifth generation in 1974 --The microprocessor and the sixth generation of 1990 --Because of PC (call PC-BASED abroad).
The ones that were also wanted and is pointed out are, though has already renamed as the numerical control of the computer (namely CNC ) abroad, and our country is still used to being called the numerical control (NC ). So our daily " numerical control " that speak, has already referred to " the numerical control of the computer " in fact.
Future development trend of numerical control 1. 3. 1 continue to open , based on PC six generation cubic meter to develop Characteristic of enriching on the basis of opening , low cost , high dependability , software and hardware resource that PC has etc., more systematic manufacturers of numerical control will go on this road . Adopt PC as front machine of it , is it deal with man-machine interface , programming , network communication ,etc. problem to come at least, undertaken the task of numerical control by the already existing system. The friendly man-machine interface that the PC has, will run through all numerical control systems. Telecommunication , will diagnose long-rangly and maintain more general.
Develop to high speed and high accuracy This is meeting the need that the lathe is developed in the high-speed and high-accuracy direction.
Develop toward intellectuality With the constant infiltration and development in the field of computer of artificial intelligence, the intelligent degree of the numerical control system will be improved constantly.
1)Use the adaptive control technology Numerical control system can of the detection procedure some important information, and adjust the relevant parameters of the system automatically, achieve the goal of improving systematic operation state.
2)Introduced to the expert system and guided and processedExperienced operator and experience of expert, universal law and special law of processing deposit system, regard parameter database of the craft as support, set up the expert system with artificial intelligence.
3)Introduce the trouble and diagnose the expert system (4)Intelligent digital servo drive Can through discern load automatically , adjust parameter automatically, is it urge system win the best operation to make. Second, necessity 2 of lathe numerical control transformation. 1, Watch the necessity transformed a little Looking from microcosmic, the numerical control lathe has the following and outstanding superiority more than the traditional lathe , and superiority the come from numerical control might of computer system include.
2. 1. 1 can process such complicated parts as the curve coming out in traditional machine tooling , curved surface ,etc. Because computer have superb operation ability, can instantaneous to calculate out each coordinate axis instantaneous amount of exercise that should move accurate, so can compound into the complicated curve or curved surface .
2. 1. 2 can realize automation that process, and flexible automation, thus efficiency raise than the traditional lathe by 3-7 times. Because the computer has memory and stores ability, can remember and store the procedure input , then carry out automatically according to the order that the procedure stipulates , thus realize automation. So long as numerical control lathe changes a procedure , can realize the automation that another work piece is processed , thus make single piece and produce automation of must using in small batches, so known as realizing " flexible automation ".
2. 1. 3 The precision of 3 processing parts is high, the size is dispersed degree small, it is easy to enable assembling, no longer need to " repair the damaged parts of a machine and supply replacements ".
2. 1. 4 concentration that can realize many processes , reduce the frequently carrying among the lathes of part.
2. 1. 5 has such many kinds of self-containment functions as autoalarm , controlling , automatic compensation automatically ,etc., therefore can realize nobody guards and processes for a long time
2. 1. 6 is by the above five spin-off advantages. For instance: Have reduce workers' labour intensity, has saved the workforce (a person can guard many lathes ), reduce frocks, shorten trial production of new products cycle and production cycle , can make fast reaction ,etc. to market demand . The above superiority could not be imagined by forefathers , was an extremely great break-through. In addition, the numerical control of the lathe pursues FMC Foundation in such enterprise's information-based transformations as (flexible manufacturing unit ) , FMS (flexible manufacturing system ) and CIMS (CIMS ) ,etc.. Numerical control technology has already become key technology of automation of manufacturing industry and basic technology.
2. 2, See the necessity transformed in macroscopic Look from macroscopic, the army of the industrially developed country, the people's mechanical industry, by the end of the 70 s, already begin to use the numerical control lathe on a large scale at the beginning of the eighties. Its essence is, adopt the information technology to carry on technological transformation to the traditional industry (including the army , the people's mechanical industry ). Except that adopt the numerical control lathe in the course of making, FMC, outside the FMS , pursue CAD , CAE , CAM , fictitious to make and pursue MIS (the management information system ) , CIMS ,etc. in production management in product development also. And increase the information technology , including the content in artificial intelligence ,etc. in the products that its produce. Adopt information technology carry on the deep transformation to foreign countries army , the people mechanical industry (call it the informationization), make products of them competitiveness strengthen very at international military products and market of civilian goods finally. And we are 20 years for about backwardness than developed country in traditional industry of technological transformation of information. In the owning amount of lathe of our country, there is only 1 by 1995 in the proportion (numerical control rate ) of the numerical control lathe . 9%, and Japan had already been up to 20 in 1994. 8%, so a large number of electronic products are imported every year. This states the necessity of numerical control transformation of the lathe from macroscopic too. Third, the markets of the lathe and production line numerical control transformation 3. 1, Market of numerical control transformation of the lathe The total amount of the lathe at present of our country is more than 3,800,000, and the total amount of numerical control lathes is 11 among them. 340,000, namely the numerical control rate of lathe of our country is less than 3%. In the past 10 years, the annual production of numerical control lathe of our country is about 0. 6-0. 80,000, annual output is about 1,800 million yuan. The annual production numerical control of the lathe turns rate into 6%. To account for more than 60% of our country more than 10 years such as enlistment age such as lathe; In the lathe under 10 years, automatic / semi-automatic lathe is less than 20%, there are very fewer such automatic production lines as FMC/FMS ,etc. (the automatic and semi-automatic lathe of U.S.A. and Japan accounts for more than 60%). It is obvious most manufacturing and production of enterprise of us , is it equip hopeless great number traditional lathe to process, and more than half is the old lathe in above 10 years of enlistment age. Have quality to be poor with the equipment products come out to process variety little of low grade with high costs, thus uncompetitive on world, domestic market, influence products , market , benefit of an enterprise directly, influence the existence and development of enterprises. So must improve the numerical control rate of the lathe in a more cost-effective manner .
3. 2, The numerical control of import equipment and production line transforms the market Our country has introduced the technology , equipment and production line to carry on technological transformation from foreign countries in a lot of enterprises since reform and opening-up. According to incomplete statistics, from 10 year past 1979-1988, the whole country introduce technological transformation project have 18446 items, about 165. 800 million dollars.
In these projects, most projects have played a due role for the economic construction of our country. But some introduce projects for various reasons, equipment or the production line can't run well , even paralysed, make the benefits of enterprises influenced , the serious one makes enterprises get into a difficult position . After some equipment , production line introduce from foreign countries, it is kind for some to digest and assimilate, the spare part is not complete, it is improper to safeguard, the result operates badly ; Some only pay attention to introducing the equipment , instrument , production line while introducing , ignoring software , craft , management ,etc., causing the project to be incomplete, the potentiality of the equipment can't be given play to;
Some can't even start and run , have not given play to the role of should have ing ; Some products of production line sell quickly, but because equipmen