C6143型臥式車床的數(shù)控化改造及四方刀架設(shè)計【普通C6143車床的經(jīng)濟型數(shù)控改造及四方刀架設(shè)計】
C6143型臥式車床的數(shù)控化改造及四方刀架設(shè)計【普通C6143車床的經(jīng)濟型數(shù)控改造及四方刀架設(shè)計】,普通C6143車床的經(jīng)濟型數(shù)控改造及四方刀架設(shè)計,C6143型臥式車床的數(shù)控化改造及四方刀架設(shè)計【普通C6143車床的經(jīng)濟型數(shù)控改造及四方刀架設(shè)計】,c6143,臥式,車床,數(shù)控,改造,四方,刀架,設(shè)計
設(shè) 計題 目:C6143型臥式車床的數(shù)控化改造及四方刀架設(shè)計院 (系): 專 業(yè): 班 級: 學(xué)生姓名: 導(dǎo)師姓名: 職稱: 起止時間: 摘要 針對現(xiàn)有常規(guī)C6143普遍車床的缺點提出數(shù)控改裝方案和單片機系統(tǒng)設(shè)計,提高加工精度和擴大機床使用范圍,并提高生產(chǎn)率。本論文說明了普通車床的數(shù)控化改造的設(shè)計過程,較詳盡地介紹了C6143機械改造部分的設(shè)計及數(shù)控系統(tǒng)部分的設(shè)計。采用以8031為CPU的控制系統(tǒng)對信號進行處理,由I/O接口輸出步進脈沖,經(jīng)一級齒輪傳動減速后,帶動滾動絲杠轉(zhuǎn)動,從而實現(xiàn)縱向、橫向的進給運動。 結(jié)合我國實際國情,經(jīng)濟型數(shù)控車床是我國從普通車床向數(shù)控車床發(fā)展的及其重要的臺階。利用現(xiàn)有的普通車床,對其進行數(shù)控化改造是一條低成本,高效益的途徑。數(shù)控車床作為機電一體化的典型產(chǎn)品,在機械制造業(yè)中發(fā)揮著巨大的作用,很好地解決了現(xiàn)代機械制造中結(jié)構(gòu)復(fù)雜、精密、批量小、多變零件的加工問題,且能穩(wěn)定產(chǎn)品的加工質(zhì)量,大幅度地提高生產(chǎn)效率。我國作為機床大國,數(shù)控機床的占有率還不足百分之三,但是在歐美等發(fā)達國家數(shù)控機床的占有率達到了百分之三十六以上,單從數(shù)字上來看我過和歐美等發(fā)達國家還有相當大的距離。其主要原因為數(shù)控車床價格較貴,一次性投資較大使企業(yè)心有余而力不足。對普通機床數(shù)控化改造不失為一種較好的良策。在金屬加工行業(yè)中車床在所有加工設(shè)備中占有最大比重,例如最常見的軸類零件,就是由車床加工而成本論文針對目前國內(nèi)企業(yè)現(xiàn)狀,以C6143普通車床為例提出簡易型經(jīng)濟數(shù)控改造思路和設(shè)計方法。關(guān)鍵詞:數(shù)控機床, 單片機數(shù)控系統(tǒng),改裝設(shè)計, 伺服電機 傳動系統(tǒng) 控制系統(tǒng) 數(shù)控改造, Abstract To remedy the defects of ordinary lathe C6143, a design of data processing system and its single chip microcomputer system program is put forward to raise the processing precision and extend the machines usage, and to improve production rate。This paper presents the process of designing numerical control reform,and explicitly introduces the design of mechanical and numerical control system reforms。We adopt control system which has 8031 as cpu to cope with the signal,and output the step pulse through the I/O interface。After transmitting and slowing down by force 1 gear, the step pulses drive the leading screw to roll。Thus achieve the vertical movement and the crosswise movement。 Chinas actual conditions and economic CNC lathe is from the ordinary to the lathe and NC lathe important development stage.Use of existing ordinary lathe, NC transformation is its low cost and highly efficient way.CNC lathe as a typical electromechanical integration products, machinery manufacturing plays an enormous role,good solution to the structural complexity of modern machinery, precision, small batches, changeable parts processing,able to stabilize the quality of the processing products, a significant increase in production efficiency.As the big machine, CNC machine tools was less than 3.0% share.However, in Europe and the United States and other developed countries to achieve the 36% share of the CNC machine moreI can see from the figures over Europe and the United States and other developed countries there is still a considerable distance.The main reason for the higher prices of CNC lathe, a one-time investment to fill larger enterprises.CNC transformation of the ordinary would be a better process.Lathe in the metal processing industry accounts for the largest proportion of all processing equipment, for example, the most common shaft.Papers from the machining cost is the present status of domestic enterprises.Simple C6143 made to the general economic NC lathe ideas and design methods.KEY WORDS: numerical control machine tool, single chip microcomputer system,reform design,The C6143 servo electrical machinery transmission system control system electricity control line economical numerical control changes 目錄摘要2Abstract3第1章 緒論5 1.1 數(shù)控技術(shù)的產(chǎn)生和發(fā)展5 1.2 數(shù)控機床的發(fā)展趨勢6 1.3 車床數(shù)控改造的必要性與可行性8第2章 設(shè)計任務(wù)9第3章 總體方案的確定9第4章.四方回轉(zhuǎn)刀架部分設(shè)計與計算10第5章. 步進電動機的計算與選型 204.1步進電動機選用的基本原則 204.2步進電動機的選折 21第6章.主軸交流伺服電機 225.1主軸的變速變速范圍 225.2初選主軸電機的型號 225.3主軸電機的校核 22 結(jié)論 29參考文獻 301緒論普通車床是金屬切削加工最常用的一類機床。普通機床刀架的縱向和橫向進給運動是由主軸回轉(zhuǎn)運動經(jīng)掛輪傳遞而來,通過進給箱變速后,由光杠或絲杠帶動溜板箱、縱溜箱、橫溜板移動。進給參數(shù)要靠手工預(yù)先調(diào)整好,改變參數(shù)時要停車進行操作。刀架的縱向進給運動和橫向進給運動不能聯(lián)動,切削次序也由人工控制。一、數(shù)控機床的產(chǎn)生數(shù)控機床最早是從美國開始研制的。1948年,美國帕森斯公司在研制加工直升機槳葉輪廓用檢查樣板的加工機床任務(wù)時,提出了研制數(shù)控機床的初始設(shè)想。1949年,帕森斯公司與麻省理工學(xué)院伺服機構(gòu)實驗室合作,開始從事數(shù)控機床的研制工作。并于1952年試制成功世界上第一臺數(shù)控機床實驗性樣機。這是一臺采用脈沖乘法器原理的直線插補三坐標連續(xù)控制銑床。經(jīng)過三年改進和自動編程研究,于1955年進入實用階段。一直到20世紀50年代末,由于價格和技術(shù)原因,品種多為連續(xù)控制系統(tǒng)。到了60年代,由于晶體管的應(yīng)用,數(shù)控系統(tǒng)提高了可靠性且價格開始下降,一些民用工業(yè)開始發(fā)展數(shù)控機床,其中多數(shù)是鉆床、沖床等點位控制的機床。數(shù)控技術(shù)不僅在機床上得到實際應(yīng)用,而且逐步推廣到焊接機、火焰切割機等,使數(shù)控技術(shù)不斷的擴展應(yīng)用范圍。二、數(shù)控機床的發(fā)展自1952年,美國研制成功第一臺數(shù)控機床以來,隨著電子技術(shù)、計算機技術(shù)、自動控制和精密測量等相關(guān)技術(shù)的發(fā)展,數(shù)控機床也在迅速地發(fā)展和不斷地更新?lián)Q代,先后經(jīng)歷了五個發(fā)展階段。第一代數(shù)控:1952-1959年采用電子管元件構(gòu)成的專用數(shù)控裝置。第二代數(shù)控:從1959年開始采用晶體管電路的NC系統(tǒng)。第三代數(shù)控:從1965年開始采用小、中規(guī)模集成電路的NC系統(tǒng)。第四代數(shù)控:從1970年開始采用大規(guī)模集成電路的小型通用電子計算機控制的系統(tǒng)。第五代數(shù)控:從1974年開始采用微型電子計算機控制的系統(tǒng)。目前,第五代微機數(shù)控系統(tǒng)基本上取代了以往的普通數(shù)控系統(tǒng),形成了現(xiàn)代數(shù)控系統(tǒng)。它采用微型處理器及大規(guī)?;虺笠?guī)模集成電路,具有很強的程序存儲能力和控制功能。這些控制功能是由一系列控制程序來實現(xiàn)的。這些數(shù)控系統(tǒng)的通用性很強,幾乎只需改變軟件,就可以適應(yīng)不同類型機床的控制要求,具有很大的柔性。隨著集成電路規(guī)模的日益擴大,光纜通信技術(shù)應(yīng)用于數(shù)控裝置中,使其體積日益縮小,價格逐年下降,可靠性顯著提高,功能也更加完善。近年來,微電子和計算機技術(shù)的日益成熟,它的成果正在不斷滲透到機械制造的各個領(lǐng)域中,先后出現(xiàn)了計算機直接數(shù)控系統(tǒng),柔性制造系統(tǒng)和計算機集成制造系統(tǒng)。所有這些高級的自動化生產(chǎn)系統(tǒng)均是以數(shù)控機床為基礎(chǔ),它們代表著數(shù)控機床今后的發(fā)展趨勢。三、我國數(shù)控機床的發(fā)展概況我國從1958年由北京機床研究所和清華大學(xué)等首先研制數(shù)控機床,并試制成功第一臺電子管數(shù)控機床。從1965年開始,研制晶體管數(shù)控系統(tǒng),直到60年代末和70年代初,研制的劈錐數(shù)控銑床、非圓錐插齒機等獲得成功。與此同時,還開展了數(shù)控加工平面零件自動編程的研究。1972-1979年是數(shù)控機床的生產(chǎn)和使用階段。例如:清華大學(xué)研制成功集成電路數(shù)控系統(tǒng);數(shù)控技術(shù)在車、銑、鏜、磨、齒輪加工、電加工等領(lǐng)域開始研究與應(yīng)用;數(shù)控加工中心機床研制成功;數(shù)控升降臺銑床和數(shù)控齒輪加工機床開始小批生產(chǎn)供應(yīng)市場。從80年代初開始,隨著我國開放政策的實施,先后從日本、美國、德國等國家引進先進的數(shù)控技術(shù)。上海機床研究所引進美國GE公司的MTC-1數(shù)控系統(tǒng)等。在引進、消化、吸收國外先進技術(shù)基礎(chǔ)上,北京機床研究所又開發(fā)出BSO3經(jīng)濟型數(shù)控系統(tǒng)和BSO4全功能數(shù)控系統(tǒng),航空航天部706所研制出MNC864數(shù)控系統(tǒng)等。進而推動了我國數(shù)控技術(shù)的發(fā)展,使我國數(shù)控機床在品種上、性能上以及水平上均有了新的飛躍。我國的數(shù)控機床已跨入一個新的發(fā)展階段。四、數(shù)控機床的發(fā)展趨勢從數(shù)控機床技術(shù)水平看,高精度、高速度、高柔性、多功能和高自動化是數(shù)控機床的重要發(fā)展趨勢。對單臺主機不僅要求提高其柔性和自動化程度,還要求具有進入更高層次的柔性制造系統(tǒng)和計算機集成制造系統(tǒng)的適應(yīng)能力。在數(shù)控系統(tǒng)方面,目前世界上幾個著名的數(shù)控裝置生產(chǎn)廠家,諸如日本的FANCU,德國的SIEMENS和美國的A-B公司,產(chǎn)品都向系列化、模塊化、高性能和成套性方向發(fā)展。它們的數(shù)控系統(tǒng)都采用了16位和32位微機處理機、標準總線及軟件模塊和硬件模塊結(jié)構(gòu),內(nèi)存容量擴大到1MB以上,機床分辨率可達0.1微米,高速進給可達100m/min,控制軸數(shù)可達16個,并采用先進的電裝工藝。在驅(qū)動系統(tǒng)方面,交流驅(qū)動系統(tǒng)發(fā)展迅速。交流傳動已由模擬式向數(shù)字式方向發(fā)展,以運算放大器等模擬器件為主的控制器正在被以微處理器為主的數(shù)字集成元件所取代,從而克服了零點漂移、溫度漂移等弱點。五、數(shù)控機床改造的意義數(shù)控機床改造在國外已發(fā)展成一個新興的工業(yè)部門,早在60年代已經(jīng)開始迅速發(fā)展,其發(fā)展的原因是多方面的,主要有技術(shù)、經(jīng)濟、市場和生產(chǎn)上的原因。我國是擁有300多萬臺機床的國家。而這些機床又大多是多年累積生產(chǎn)的通用機床,不論資金和我國機床制造廠的能力都是辦不到的。因此,盡快將我國現(xiàn)有一部分普通機床實現(xiàn)自動化和精密化改裝,是我國現(xiàn)有設(shè)備技術(shù)改造迫切要求解決的課題。用數(shù)控技術(shù)改造機床,正是適應(yīng)了這一要求。它是建立在微電子現(xiàn)代技術(shù)與傳統(tǒng)技術(shù)相結(jié)合的基礎(chǔ)上。在機床改造中引入微機的應(yīng)用,不但技術(shù)上具有先進性,同時,在應(yīng)用上比其它傳統(tǒng)的自動化改裝方案,有較大的通用性與可調(diào)性。而且所投入的改造費用低,一套經(jīng)濟型數(shù)控裝置的價格僅為全功能數(shù)控裝置的1/3至1/5,用戶承擔的起。從若干單位成功應(yīng)用的實例可以證明,投入使用后,確實成倍地提高了生產(chǎn)效率,減少了廢品率,取得了顯著的技術(shù)經(jīng)濟效益。因此,我國提出從大力推廣經(jīng)濟型數(shù)控這一中間技術(shù)的基礎(chǔ)上,再逐步推廣全功能數(shù)控這條道路,適合我國的經(jīng)濟水平、教育水平和生產(chǎn)水平,已成為我國設(shè)備技術(shù)改造主要方向之一。同時,它還可以作為全功能數(shù)控機床應(yīng)用的準備階段,為今后使用全功能數(shù)控機床,培養(yǎng)人才,積累維護、使用經(jīng)驗,而且也是實現(xiàn)我國傳統(tǒng)的機械制造技術(shù)朝機電一體化的方向過渡的主要內(nèi)容之一。對普通車床進行數(shù)控化改造,主要是將縱向和橫向進給系統(tǒng)改為用微機控制的、能獨立運動的進給伺服系統(tǒng);刀架改造成為能自動換刀的回轉(zhuǎn)刀架。這樣,利用數(shù)控裝置,車床就可以按預(yù)先輸入的加工指令進行切削加工。由于加工過程中的切削參數(shù),切削次序和刀具都會按程序自動調(diào)節(jié)和更換,再加上縱向和橫向進給聯(lián)動的功能,數(shù)控改裝后的車床就可以加工出各種形狀復(fù)雜的回轉(zhuǎn)零件,并能實現(xiàn)多工序自動車削,從而提高了生產(chǎn)效率和加工精度,也能適應(yīng)小批量多品種復(fù)雜零件的加工。2設(shè)計要求2.1總體方案設(shè)計要求總體方案設(shè)計應(yīng)考慮機床數(shù)控系統(tǒng)的類型,計算機的選擇,以及傳動方式和執(zhí)行機構(gòu)的選擇等。(1)普通車床數(shù)控化改造后應(yīng)具有定位、縱向和橫向的直線插補、圓弧插補功能,還要求能暫停,進行循環(huán)加工和螺紋加工等,因此,數(shù)控系統(tǒng)選連續(xù)控制系統(tǒng)。(2)車床數(shù)控化改裝后屬于經(jīng)濟型數(shù)控機床,在保證一定加工精度的前提下應(yīng)簡化結(jié)構(gòu)、降低成本,因此,進給伺服系統(tǒng)采用步進電機開環(huán)控制系統(tǒng)。(3)根據(jù)普通車床最大的加工尺寸、加工精度、控制速度以及經(jīng)濟性要求,經(jīng)濟型數(shù)控機床一般采用8位微機。在8位微機中,MCS51系列單片機具有集成度高、可靠性好、功能強、速度快、抗干擾能力強、具有很高的性價比,因此,可選 MCS51系列單片機擴展系統(tǒng)。(4)根據(jù)系統(tǒng)的功能要求,微機數(shù)控系統(tǒng)中除了CPU外,還包括擴展程序存儲器,擴展數(shù)據(jù)存儲器、I/O接口電路;包括能輸入加工程序和控制命令的鍵盤,能顯示加工數(shù)據(jù)和機床狀態(tài)信息的顯示器,包括光電隔離電路和步進電機驅(qū)動電路,此外,系統(tǒng)中還應(yīng)包括螺紋加工中用的光電脈沖發(fā)生器和其他輔助電路。(5)設(shè)計自動回轉(zhuǎn)刀架及其控制電路。(6)縱向和橫向進給是兩套獨立的傳動鏈,它們由步進電機、齒輪副、絲杠螺母副組成,其傳動比應(yīng)滿足機床所要求的分辨率。(7)為了保證進給伺服系統(tǒng)的傳動精度和平穩(wěn)性,選用摩擦 小、傳動效率高的滾珠絲杠螺母副,并應(yīng)有預(yù)緊機構(gòu),以提高傳動剛度和消除間隙,齒輪副也應(yīng)有消除齒側(cè)間隙的機構(gòu)。(8)采用貼塑導(dǎo)軌,以減小導(dǎo)軌的摩擦力。總體方案設(shè)計圖如下圖(2)所示:進給伺服系統(tǒng)總體方案方框圖如圖(3)所示:2.2設(shè)計參數(shù)設(shè)計參數(shù)包括車床的部分技術(shù)參數(shù)和設(shè)計數(shù)控進給伺服系統(tǒng)所需要的參數(shù)?,F(xiàn)列出C6143臥式車床的技術(shù)數(shù)據(jù):名稱 技術(shù)參數(shù) 在床身上 430mm工件最大直徑在刀架上 210mm頂尖間最大距離 650;900;1400;1900mm 公制螺紋 mm 1-12(20種)加工螺紋范圍 英制螺紋 t/m 2-24(20種) 模數(shù)螺紋 mm0.25-3(11種) 徑節(jié)螺紋 t/m7-96(24種) 最大通過直徑 48mm 孔錐度莫氏6# 主軸 正轉(zhuǎn)轉(zhuǎn)速級數(shù) 24 正轉(zhuǎn)轉(zhuǎn)速范圍101400r/min 反轉(zhuǎn)轉(zhuǎn)速級數(shù)12 反轉(zhuǎn)轉(zhuǎn)速范圍14-1580r/min縱向級數(shù)64進給量縱向范圍0.028-6.33mm/r橫向級數(shù)64橫向范圍0.014-3.16mm/r 滑板行程 橫向320mm縱向650;900;1400;1900mm 最大行程140mm 刀架最大回轉(zhuǎn)角 90刀杠支承面至中心的距離26mm刀杠截面BH2525mm 頂尖套莫氏錐度5#尾座橫向最大移動量10mm外形尺寸 長寬高241810001267mm 圓度 0.01mm工作精度圓柱度200:0.02 平面度0.02/300mm表面粗糙度Ra1.6-3.2m 主電動機7.5kw電動機功率總功率7.84kw改造設(shè)計參數(shù)如下:最大加工直徑 在床面上 400mm 在床鞍上210mm最大加工長度 1000mm快進速度 縱向2.4m/min 橫向1.2m/min最大切削進給速度 縱向0.5m/min 橫向0.25m/min溜板及刀架重力 縱向800N 橫向600N 代碼制ISO脈沖分配方式 逐點比較法輸入方式 增量值、絕對值通用控制坐標數(shù) 2脈沖當量 縱向0.01mm/脈沖 橫向0.005mm/脈沖機床定位精度0.015mm刀具補償量 0mm-99.99mm進給傳動鏈間隙補償量 縱向0.15mm橫向 0.075mm自動升降速性能 有2.3.其它要求(1) 原機床的主要結(jié)構(gòu)布局基本不變,盡量減少改動量 ,以降低成本縮短改造周期。(2)機械結(jié)構(gòu)改裝部分應(yīng)注意裝配的工藝性,考慮正確的裝配順序,保正安裝、調(diào)試、拆卸方便,需經(jīng)常調(diào)整的部位調(diào)整應(yīng)方便。第四章 C6143型臥式車床數(shù)控化改造的四方刀架設(shè)計自動回轉(zhuǎn)刀架總體結(jié)構(gòu)設(shè)計1、 減速傳動機構(gòu)的設(shè)計普通的三項異步電動機因轉(zhuǎn)速太快,不能直接驅(qū)動刀架進行換刀,必須經(jīng)過適當?shù)臏p速。根據(jù)立式轉(zhuǎn)位刀架的結(jié)構(gòu)特點,采用蝸桿副減速時最佳選擇。蝸桿副傳動可以改變運動的方向,獲得較大的傳動比,保證傳動精度和平穩(wěn)性,并且具有自鎖功能,還可以實現(xiàn)整個裝置的小型化。2、 上刀體鎖緊與精定位機構(gòu)的設(shè)計由于刀具直接安裝在上刀體上,所以上刀體要承受全部的切削力,其鎖緊與定位的精度將直接影響工件的加工精度。本設(shè)計上刀體的鎖進玉定位機構(gòu)選用端面齒盤,將上刀體和下刀體的配合面加工成梯形端面齒。當?shù)都芴幱阪i緊狀態(tài)時,上下端面齒相互嚙合,這時上刀體不能繞刀架的中心軸旋轉(zhuǎn);換刀時電動機正轉(zhuǎn),抬起機構(gòu)使上刀體抬起,等上下端面齒脫開后,上刀體才可以繞刀架中心軸轉(zhuǎn)動,完成轉(zhuǎn)位動作。3、 刀架抬起機構(gòu)的設(shè)計要想使上、下刀體的兩個端面齒脫離,就必須設(shè)計適合的機構(gòu)使上刀體抬起。本設(shè)計選用螺桿-螺母副,在上刀體內(nèi)部加工出內(nèi)螺紋,當電動機通過蝸桿-蝸輪帶動蝸桿繞中心軸轉(zhuǎn)動時,作為螺母的上刀體要么轉(zhuǎn)動,要么上下移動。當?shù)都芴幱阪i緊狀態(tài)時,上刀體與下刀體的端面齒相互嚙合,因為這時上刀體不能與螺桿一起轉(zhuǎn)動,所以螺桿的轉(zhuǎn)動會使上刀體向上移動。當端面齒脫離嚙合時,上刀體就與螺桿一起轉(zhuǎn)動。設(shè)計螺桿時要求選擇適當?shù)穆菥?,以便當螺桿轉(zhuǎn)動一定的角度時,使得上刀梯與下刀體的端面齒能夠完全脫離嚙合狀態(tài)。下圖為自動回轉(zhuǎn)刀架的傳動機構(gòu)示意圖,詳細的裝配圖在一號圖紙上。三、自動回轉(zhuǎn)刀架的工作原理自動回轉(zhuǎn)刀架的換刀流程如下圖。圖上表示自動回轉(zhuǎn)刀架在換刀過程中有關(guān)銷的位置。其中上部的圓柱銷2和下部的反靠銷6起著重要作用。當?shù)都芴幱阪i緊狀態(tài)時,兩銷的情況如圖A所示,此時反靠銷6落在圓盤7的十字槽內(nèi),上刀體4的端面齒和下刀體的端面齒處于嚙合狀態(tài)(上下端面齒在圖中未畫出)。需要換刀時,控制系統(tǒng)發(fā)出刀架轉(zhuǎn)位信號,三項異步電動機正向旋轉(zhuǎn),通過蝸桿副帶動蝸桿正向轉(zhuǎn)動,與螺桿配合的上刀體4逐漸抬起,上刀體4與下刀體之間的端面齒慢慢脫開;與此同時,上蓋圓盤1也隨著螺桿正向轉(zhuǎn)動(上蓋圓盤1通過圓柱銷與螺桿聯(lián)接),當轉(zhuǎn)過約時,上蓋圓盤1直槽的另一端轉(zhuǎn)到圓柱銷2的正上方,由于彈簧3的作用,圓柱銷2落入直槽內(nèi),于是上蓋圓盤1就通過圓柱銷2使得上刀體4轉(zhuǎn)動起來(此時端面齒已完全脫開)。上蓋圓盤1、圓柱銷2以及上刀體4在正轉(zhuǎn)的過程中,反靠銷6能夠從反靠圓盤7中十字槽的左側(cè)斜坡滑出,而不影響上刀體4尋找刀位時的正向轉(zhuǎn)動。上刀體4帶動磁鐵轉(zhuǎn)到需要的刀位時,發(fā)信盤上對應(yīng)的霍爾元件輸出低電平信號,控制系統(tǒng)收到后,立即控制刀架電動機反轉(zhuǎn),上蓋圓盤1通過圓柱銷2帶動上刀體4開始反轉(zhuǎn),反靠銷6馬上就會落入反靠圓盤7的十字槽內(nèi),至此,完成粗定位。此時,反靠銷6從反靠圓盤7的十字槽內(nèi)爬不上來,于是上刀體4停止轉(zhuǎn)動,開始下降,而上蓋圓盤1繼續(xù)反轉(zhuǎn),其直槽的左側(cè)斜坡將圓柱銷2的頭部壓入上刀體4的銷空內(nèi),之后,上蓋圓盤1是下表面開始與圓柱銷2的頭部滑動。再次期間,上、下刀體的端面齒逐漸嚙合,實現(xiàn)精定位,經(jīng)過設(shè)定的延時時間后,刀架電動機停轉(zhuǎn),整個換刀過程結(jié)束。由于蝸桿副具有自鎖功能,所以刀架可以穩(wěn)定地工作。 蝸桿-蝸輪減速 銷連接上蓋圓盤旋轉(zhuǎn)螺桿正轉(zhuǎn)刀架電動機正轉(zhuǎn) 上刀體抬起 螺桿-螺母 端面齒錯開 霍爾元件觸發(fā) 上刀體旋轉(zhuǎn)到位回答圓柱銷落入上蓋圓盤 蝸桿-蝸輪減速 反靠銷反靠端面齒嚙合螺桿反轉(zhuǎn)刀架電動機旋轉(zhuǎn)上刀體下降,粗定位 精定位延時鎖緊電動機停轉(zhuǎn) 圖:自動回轉(zhuǎn)刀架的換刀流程主要傳動部件的設(shè)計1. 蝸桿副的設(shè)計計算自動回轉(zhuǎn)刀架的動力源是三相異步電動機。其中蝸桿與電動機直聯(lián),刀架轉(zhuǎn)位時蝸輪與上刀體直聯(lián)。已知電動機額定功率=90W。,額定轉(zhuǎn)速=1480r/min,上刀體設(shè)計轉(zhuǎn)速=40r/min,蝸桿副的傳動比i=/=37。刀架從轉(zhuǎn)位到鎖緊時,需要蝸桿反向,工作載荷不均勻,啟動時沖擊較大,今要求蝸桿副的使用壽命=10000h。(1) 蝸桿的選型 GB/T10085-1988推薦采用漸開線蝸桿和錐面包絡(luò)蝸桿。本設(shè)計采用結(jié)構(gòu)簡單,制造方便的漸開線型圓柱蝸桿。(2) 蝸桿副的材料 刀架中的蝸桿副傳動的功率不大,但蝸桿轉(zhuǎn)速干,一次,蝸桿的材料選用45鋼,其螺旋齒面要淬火,硬度為4555HRC,以提高其表面耐磨行;蝸輪的轉(zhuǎn)速較低,其材料主要考慮耐磨性,選用鑄錫磷青銅ZCuSn10P1,采用金屬模制造。(3) 按齒面接觸疲勞強度進行設(shè)計 刀架中的蝸桿副采用閉式傳動,多因齒面膠合或點蝕而失效。因此,進行載荷計算時,先按齒面接觸疲勞強度進行設(shè)計,再按齒根彎曲疲勞強度進行校核。按蝸輪接觸疲勞強度條件設(shè)計計算的公式 a (4-1)式中 a蝸桿副的傳動中心距,單位mm; K載荷系數(shù); 作用在蝸輪上的轉(zhuǎn)矩,單位N.mm; 彈性影響系數(shù)ZE; 許用接觸應(yīng)力,單位為MPa。從式4-1算出蝸桿副的中心距a之后,根據(jù)已知的傳動比i=35,查表選擇一個合適的中心距a值,以及相應(yīng)的蝸桿,蝸輪參數(shù)。1) 確定作用在蝸輪上的轉(zhuǎn)矩,設(shè)蝸桿頭數(shù)=1,蝸桿副的傳動效率=0.8,由電動機的額定功率=90W,可以算出蝸輪傳動的功率=,再由蝸輪的轉(zhuǎn)速=40r/min求得作用在蝸輪上的轉(zhuǎn)矩=9.55=9.55=25.47Nm=22923Nmm2) 確定載荷系數(shù)K 載荷系數(shù)K= KA KB K。其中KA為使用系數(shù),有表6-3查得, 由于工作載荷不均勻,啟動時沖擊較大,因此取KA=1.15; 為齒向分布系數(shù),因工作載荷在啟動和停止時有變化,故取KB=1.15; 為動載系數(shù),由于轉(zhuǎn)數(shù)不高。沖擊不大,可取K=1.05。則載荷系數(shù)K=KA KB K 1.39使用系數(shù)工作類型IIIIII載荷性質(zhì)均勻,無沖擊不均勻,小沖擊不均勻,大沖擊每小時起動次數(shù)50起動載荷小較大大KA11.151.23) 確定彈性影響系數(shù)ZE,鑄錫磷青銅蝸輪與鋼蝸桿相配時,從有關(guān)手冊查的彈性影響系數(shù) ZE=160Mpa 1/2;4) 確定接觸系數(shù) 先假設(shè)蝸桿分度圓直徑d1 和傳動中心距a的比值d1/a=0.35。查表的Zp=2.9鑄錫青銅蝸輪的基本許用接觸應(yīng)力H(MPa)蝸輪材料鑄造方法蝸桿螺旋面的硬度45HRC45HRC鑄錫磷青銅ZCuSn10P1砂模鑄造150180金屬模鑄造220268鑄錫鋅鉛青銅ZCuSn5Pb5Zn5砂模鑄造113135金屬模鑄造1281405)確定許用接觸應(yīng)力 根據(jù)蝸輪材料為鑄錫磷青銅ZCuSn10P1金屬模制造蝸桿螺旋齒面硬度大于45HRC可查表的蝸輪的基本許用應(yīng)力=268MPa已知蝸桿為單頭,蝸輪每轉(zhuǎn)一轉(zhuǎn)時每個輪齒嚙合的次數(shù)j=1;蝸輪轉(zhuǎn)數(shù)=40r/min;蝸桿副的使用壽命=10000h。則應(yīng)力循環(huán)次數(shù):N=60j n2 =2.4 10 7壽命系數(shù): KHN =0.693許用接觸應(yīng)力: =KHN=186MPa6)計算中心距 將以上各參數(shù)帶入4-1,求得中心距: a = 47.1 mm查表取a=63,已知蝸桿頭數(shù)=1,設(shè)模數(shù)m=1.6mm,得蝸桿分度圓直徑d1=28mm。這時d1/a=0.59,查表得接觸系數(shù)=2.35。因為較大,所以上述計算結(jié)果可用。(4)蝸桿和蝸輪的主要參數(shù)與幾何尺寸 由蝸桿和蝸輪的基本尺寸和主要參數(shù),算的蝸桿和蝸輪的主要幾何尺寸后,即可繪制蝸桿副的工作圖。 1)蝸桿的參數(shù)與尺寸 頭數(shù)=1,模數(shù)m=1.6mm,軸向齒距=m=5.027mm軸向齒厚=0.5m=2.514mm,分度圓直徑=28,直徑系數(shù)q=17.5,分度圓導(dǎo)程角=。 取齒頂高系數(shù)=1,徑向間隙系數(shù)=0.2,則齒頂圓直徑=+2m=31.2mm,齒根圓直徑=-2m(+)=24.314mm。 2)蝸輪參數(shù)與尺寸 齒數(shù)=60,模數(shù)m=1.6mm,分度圓直徑為=m=96mm,變位系數(shù)=a-()/2/m=0.6,蝸輪喉圓直徑為=+2m()=101.12mm,蝸輪齒根圓直徑=-2m(-+)=94.08mm,蝸輪咽喉母圓半徑=a-/2=12.44mm。(5)校核蝸輪齒根彎曲疲勞強度 即檢驗下式是否成立: = 由蝸桿頭數(shù)=1,傳動比i=35,可以計算出蝸輪齒數(shù)=i=35則蝸輪的當量齒數(shù): =35.17根據(jù)蝸輪變位系數(shù)=0.6和當量齒數(shù)=35.17,查表的齒形系數(shù)=2.08螺旋角影響系數(shù) =1-=0.977 根據(jù)蝸輪的材料和制造方法,查表得蝸輪基本許用彎曲應(yīng)力: =56MPa 蝸輪的壽命系數(shù): =0.702 蝸輪的許用彎曲應(yīng)力: = =39.3MPa 將數(shù)據(jù)帶入得: 可見, ,蝸輪齒根的彎曲強度滿足要求。蝸輪的基本許用彎曲應(yīng)力(MPa)蝸輪材料鑄造方法單側(cè)工作雙側(cè)工作鑄錫青銅ZCuSn10P1砂模鑄造4029金屬模鑄造5640鑄錫鋅鉛青銅ZCuSn5Pb5Zn5砂模鑄造2622金屬模鑄造3226鑄鋁鐵青銅ZCuAl10Fe3砂模鑄造8057金屬模鑄造9064灰鑄鐵HT150砂模鑄造4028HT200砂模鑄造48342.螺桿的設(shè)計計算(1) 螺距的確定 刀架轉(zhuǎn)位時,要求螺桿在轉(zhuǎn)動約 的情況下,上刀體的端面齒與下刀體的端面齒完全脫離;在鎖緊的時候,要求上下端面的嚙合深度達2mm。因此,螺桿的螺距P應(yīng)滿足P2.4mm,今取螺桿的螺距P=6mm。(2) 確定其他參數(shù) 采用單頭梯形螺桿,頭數(shù)n=1,牙側(cè)角= 150,外螺紋大徑=50mm,牙頂間隙=0.5mm,基本牙型高度=0.5P=3mm,外螺紋牙高=3.5mm,外螺紋中徑=47mm,外螺紋小徑=43mm,螺桿螺紋部分長度H=50mm。(3) 自鎖性能校核 螺桿-螺母材料均用45鋼,查表取摩擦系數(shù)f=0.11;再求得梯形螺旋副的當量摩擦角: 6.50而螺紋升角: = 2.33 小于當量摩擦角。因此滿足自鎖條件。結(jié)論這次課題設(shè)計總計費時一個多月,剛開始時不知從何下手,在老師的指導(dǎo)下到圖書館查閱相關(guān)資料。有關(guān)數(shù)控上的資料翻了數(shù)次,有參考了相關(guān)設(shè)計資料,終于知道了該怎么做。接下來塞選出一系列有價值的資料,與同組同學(xué)不斷的討論、向老師請教,終于完成了設(shè)計。在做設(shè)計的過程中,不但復(fù)習了所學(xué)過的知識點,還學(xué)到了新的知識,同時將所學(xué)到的知識充分的運用起來,做到了學(xué)以致用,還學(xué)會了查資料,除此之外,我還懂得了團結(jié)合作的重要性,知道了集體的力量!當然,在此過程中也有許多不足之處,例如:知識的不全面,所學(xué)的還沒有全部掌握,思維的狹隘等,讓我在畢業(yè)前上了生動形象的一課。同時,做設(shè)計也是磨練決心與毅力的過程,面對復(fù)雜冗長的數(shù)據(jù),打印長篇的論文,我也想過放棄,但想到它的意義我就又堅持了下來。做完了后,有一種豁然開朗的感覺,內(nèi)心激動無比,經(jīng)過了這次設(shè)計以后,我有信心,我也堅信只要努力、堅持,我們就能走好人生的每一步。 參考文獻1.吳振彪主編.機電綜合設(shè)計指導(dǎo).中國人民大學(xué)社.2000.2.余英良主編.機床數(shù)控改造設(shè)計與實例.機械工業(yè)出版社.19973.機床設(shè)計手冊編寫組編. 機床設(shè)計手冊第一,三,四冊. 械工業(yè)出版社.1998.4.明興祖主編.數(shù)控加工技術(shù).化學(xué)工業(yè)出版社.2001.5.胡占齊,楊莉主編.機床數(shù)控技術(shù). 機械工業(yè)出版社.1999.6.王先逵主編.機械制造工藝學(xué). 機械工業(yè)出版社.2002.7.邱宣懷主編.機械設(shè)計.高等教育出版社.20028.黃調(diào),趙松年主編.機電一體化技術(shù)基礎(chǔ)及應(yīng)用. 機械工業(yè)出版社.1999.第 21 頁 共 21 頁附錄譯文:The open system merit of Computer Numerical Control and Numerical control of production equipmentsAbstractThe open system merit is the system simple, the cost low, but the shortcoming is the precision is low. The reverse gap, the guide screw pitch error, stop inferiorly can affect the pointing accuracy by mistake. Following several kind of improvements measure may cause the pointing accuracy distinct improvement.The key word:numerical control 、NC 、the open systerm 1)reverse gap error compensates The numerical control engine bed processing cutting tool and the work piece relative motion is depends upon the drive impetus gear,the guide screw rotation, thus the impetus work floor and so on moves the part to produce moves realizes. As traditional part gear, guide screw although the manufacture precision is very high, but always unavoidably has the gap. As a result of this kind of gap existence, when movement direction change, starts the section time to be able tocause inevitably actuates the part wasting time, appears the instruction pulse to push the motionless functional element the aspect. This has affected the engine bed processing precision, namely the instruction pulse and actual enters for the step does not tally,has the processing error therefore, the split-ring numerical control system all establishes generally has the reverse gap errorcompensatory function, with by makes up which wastes time the step reverse gap difference compensates is first actual reverse enters for the error, converts the pulse equivalent number it, compensates the subroutine as the gap the output, when the computer judgment appearswhen instruction for counter motion, transfers the gap to compensate the subroutine immediately, compensates the pulse after the output to eliminate the reverse gap to carry on again normally inserts makes up the movement. 2)often the value systematic characteristic position error compensatesA kind of storehouse by transfers for the designer. Like this in the components design stage, the designer only must input the characteristic the parameter, the system direct productioncharacteristic example model: We must save the related characteristic class in the database the structure information, the database table collection are use in saving this part of related information. According to the characteristic type definition need, we defined the characteristic class code table, the characteristic class edition information have outstanding shown the characteristic type; Defined the characteristic class structure outstanding to reach the characteristic class the structure; And relates through the components characteristic disposition table and the components characteristic level information. The characteristic level data sheet collection isthis components model database design core, has recorded characteristic example information and so on model design, craft. The characteristic structure table has recorded the characteristicgeometry structure; The characteristic size table, the characteristic shape position table of limits, the characteristic surface roughness table has recorded the characteristic project semantics quotation; The size table, the shape position table of limits, the surface roughnesstable saved all components characteristic data message. In the characteristic level, using characteristic ID, geometry principal linkage and so on essential factor ID, size ID, common difference ID, roughness ID carries on the data retrieval. We apply this components information model database under the factory environment some module CAD in the AM integrative system, has realized CAD and the CAPP characteristic information sharing well. Main use ready-made CAD/the CAM software (Unigra phics 1I) carries on the product design and the NC programming in this system, and through carries on two times of developments gains components to this software the size information; At the same time uses the dialogue window which develops voluntarily, lets design the personnel to input other characteristic information alternately, realizes this software and the system sharing database connection. When assistance technological design, the technological design personnel through the procedure inquiry function, inquires the components information from the sharing database which needs, carries on the interactive technological design. Thus has facilitated the CAPP components information acquisition, enhanced the technological design efficiency. When carries on the NC programming using UG, may from the sharing database gain the craft and the manufacture information which needs, carries on various working procedures the knife axle design and the processing simulation establishes an absolute zero spot on the numerical control engine bed, the actual various coordinate axes syzygy completely position error, makes the curve in order to determined compensates the spot. Attempts l to show is an actual position error curve, (error) carries on this curve y-coordinate take the pulse equivalent as the unit the division, makes the horizontal line, each horizontal line and the curve point of intersection namely compensates the spot for the goal. Chart 1 the center 1 to 6 oclock place position errors for, needs to do reduces the pulse to compensate; But needs to carry on 6 to 9 adds the pulse to compensate in the chart the shadow partially for to compensate the area. Compensates the range of points these to become the error The calibration corrections stores the computer, when work table by zero displacement in position, installs sends out the absolute zero point localization signal in the absolute zero point micros witch, later computer as necessary will send out the goal to compensate to compensate the signal, will carry on the position error to the engine bed to compensate. The cosine generator assigns slide guage initiation signal a electricity and by step of transmission.3) feedbacks compensates the open-loop control Chart 2 has produced this kind of system schematic diagram. This system surveys two parts by the open-loop control and the induction synchromesh direct position to be composed. Here position examination does not serve as the position the feedback, but is compensates the feedback as the position error. Its cardinal principle is: Installs the instruction pulse by the engine bed numerical control which CNC sends out, on the one hand the supplies open system, thecontrol step-by-steps the electrical machinery according to the instruction revolution, and the direct drive platen moves, constitutes the open-loop control; On the other hand this instruction pulse supplies the induction synchromesh the measurement system (namely digitally, cosine generator), as position demand signal a by. The work in the warning way induction synchromesh this time not only is the position sensor, also is the comparator, it by, The cosine generator assigns slide guage initiation signal a electricity and by step of transmission.4) conclusions Under the CIMS environment the technology which develops unceasingly based on characteristic components information modeling, how enhances the components order of complexity which the characteristic design can complete; How causes question and so on request which the characteristic design adoption trick recognition, the characteristic semantics transforms also to wait for the people to solve. This article introduced the characteristic technology in the components information modeling application, describes this components data model database realization with emphasis; Establishes the components information database system may satisfy the CIMS system well to the letter. Numerical control (NC) is a form of programmable automation in which the processing equipment is controlled by means of numbers, letters, and other symbols. The numbers, letters, and symbols are coded in an appropriate format to define a program of instructions for a particular workpart or job. When the job changes, the program of instructions is changed. The capability to change the program is what makes NC suitable for low-and medium-volume production. It is much easier to write new programs than to make major alterations of the processing equipment.Basic components of NC A numerical control system consists of the following three basic components:Program of instructionsMachine control unitProcessing equipmentThe general relationship among the three components is illustrated in Fig.2.1. The program is fed into the control unit, which directs the processing equipment accordingly.The program of instructions is the detailed step-by-step commands that direct the processing equipment. In its most common form, the commands refer to positions of a machine tool spindle with respect to the worktable on which the part is fixtured. More advanced instructions include selection of spindle speeds, cutting tool, and other function. The most common medium in use over the last several decades has been 1-in. -wide punched tape. Because of the widespread use of the punched tape, NC is sometimes called “tape control”. However, this is a misnomer in modern usage of numerical control. Coming into use more recently have been magnetic tape cassettes and floppy diskettes.The machine control unit (MCU) consists of the electronics and control hardware that read and interpret the program of instruction and convert it into mechanical actions of the machine tool or other processing equipment.The processing equipment is the third basic component of an NC system. It is the component that performs useful work. In the most common example of numerical control, one that performs machining operations, the processing equipment consists of the worktable and spindle as well as the motors and controls needed to drive them.TYPES OF CONTROL SYSTEMSThere are two basic types of control systems in numerical control: point-to-point and contouring. In the point-to-point system, also called positioning, each axis of the machine is driven separately by leadscrews and, depending on the type of operation, at different velocities. The machine moves initially at maximum velocity in order to reduce nonproductive time but decelerates as the tool reaches its numerically defined position. Thus in an potation such as drilling or punching, the positioning and cutting take place sequentially. After the hole is drilled or punched, the tool retracts, moves rapidly to another position, and repeats the operation. The path followed from one position to another is important in only one respect: The time required should be minimized for efficiency. Point-to-point systems are used mainly in drilling, punching, and straight milling operations.In the contouring system, also known as the continuous path system, positioning and cutting operations are both along controlled paths but at different velocities. Because the tool cuts as it travels along a prescribed path, accurate control and synchronization of velocities and movements are important. The contouring system is used on lathes, milling machines, grinders, welding machinery, and machining centers.Movement along the path, or interpolation, occurs incrementally, by one of several basic methods. In all interpolations, the path controlled is that of the center of rotation of the tool. Compensation for different tools, different diameter tools, or tool wear during machining, can be made in the NC program.There are a number of interpolation schemes that have been developed to deal with the various problems that are encountered in generating a smooth continuous path with a contouring-type NC system. They include:Linear interpolationCircular interpolationHelical interpolationParabolic interpolationCubic interpolationEach of these interpolation procedures permits the programmer (or operator) to generate machine instructions for linear or curvilinear paths, using a relatively few input parameters. The interpolation module in the MCU performs the calculations and directs the tool along the path.Linear interpolation is the most basic and is used when a straight-line path is to be generated in continuous-path NC. Two-axis and three-axis linear interpolation routines are sometimes distinguished in practice, but conceptually they are the same. The program is required to specify the beginning point and end point of the straight line, and the feed rate that is to be followed along the straight line. The interpolator computes the feed rates for each of the two (or three) axes in order to achieve the specified feed rate.Linear interpolation for creating a circular path would be quite inappropriate because the programmer would be required to specify the line segments and their respective end points that are to be used to approximate the circle. Circular interpolation schemes have been developed that permit the programming of a path consisting of a circular arc by specifying the following parameters of the arc: the coordinates of its end points, the coordinates of its center, its radius, and the direction of the cutter along the arc. The tool path that is created consists of a series of straight-line segments, but the segments are calculated by the interpolation module rather than the programmer. The cutter is directed to move along each line segment one by one in order to generate the smooth circular path. A limitation of circular interpolation is that the plane in which the circular arc exists must be a plane defined by two axes of the NC system.Helical interpolation combines the circular interpolation scheme for two axes described above with linear movement of a third axis. This permits the definition of a helical path in three-dimensional space.Parabolic and cubic interpolation routines are used to provide approximations of free-form curves using higher-order equations. They generally require considerable computational power and are not as common as linear and circular interpolation. Their applications are concentrated in the automobile industry for fabricating dies for car body panels styled with free-form designs that cannot accurately and conveniently be approximated by combining linear and circular interpolations.PROGRAMMING FOR NCA program for numerical control consists of a sequence of directions that causes an NC machine to carry out a certain operation, machining being the most commonly used process. Programming for NC may be done by an internal programming department, on the shop floor, or purchased from an outside source. Also, programming may be done manually or with computer assistance.The program contains instructions and commands. Geometric instructions pertain to relative movements between the tool and the workpiece. Processing instructions pertain to spindle speeds, feeds, tools, and so on. Travel instructions pertain to the type of interpolation and slow or rapid movements of the tool or worktable. Switching commands pertain to on/off position for coolant supplies, spindle rotation, direction of spindle rotation, tool changes, workpiece feeding, clamping, and so on. Manual Programming Manual part programming consists of first calculating dimensional relationships of the tool, workpiece, and work table, based on the engineering drawings of the part, and manufacturing operations to be performed and their sequence. A program sheet is then prepared, which consists of the necessary information to carry out the operation, such as cutting tools, spindle speeds, feeds, depth of cut, cutting fluids, power, and tool or workpiece ally a paper tape is first prepared for trying out and debugging the program. Depending on how often it is to be used, the tape may be made of more durable Mylar.Manual programming can be done by someone knowledgeable about the particular process and able to understand, read, and change part programs. Because they are familiar with machine tools and process capabilities, skilled machinists can do manual programming with some training in programming. However, the work is tedious, time consuming, and uneconomical-and is used mostly in simple point-to-point applications. Computer-Aided Programming Computer-aided part programming involves special symbolic programming languages that determine the coordinate points of corners, edges, and surfaces of the part. Programming language is the means of communicating with the computer and involves the use of symbolic characters. The programmer describes the component to be processed in this language, and the computer converts it to commands for the NC machine. Several languages having various features and applications are commercially available. The first language that used English-like statements was developed in the late 1950s and is called APT (for Automatically Programmed Tools). This language, in its various expanded forms, is still the most widely used for both point-to-point and continuous-path programming.Computer-aided part programming has the following significant advantages over manual methods: Use of relatively easy to use symbolic languageReduced programming time. Programming is capable of accommodating a large amount of data concerning machine characteristics and process variables, such as power, speeds, feed, tool shape, compensation for tool shape changes, tool wear, deflections, and coolant use. Reduced possibility of human error, which can occur in manual programming Capability of simple changeover of machining sequence or from machine to machine. Lower cost because less time is required for programming.Selection of a particular NC programming language depends on the following factors: Level of expertise of the personnel in the manufacturing facility. Complexity of the part. Type of equipment and computers available. Time and costs involved in programming.Because numerical control involves the insertion of data concerning workpiece materials and processing parameters, programming must be done by operators or programmers who are knowledgeable about the relevant aspects of the manufacturing processes being used. Before production begins, programs should be verified, either by viewing a simulation of the process on a CRT screen or by making the part from an inexpensive material, such as aluminum, wood, or plastic, rather than the material specified for the finished part.Reference:1 Zhang Huashu under. parallel environment based on characteristic components definition model J. mechanical science with technology, 1,999, 18 (1): 14l 144.2 forest morning star, Du full text, Xu Jianxin. characteristic and (,M)/CAPP/CAM integrative system J. the computer-aided design and makes, 1998, 28 (5): 5155.3 Zeng Hui E, Zhou Qingzhong. studied J based on the characteristic mechanical product modelling . the machinery to suppose Counts with the manufacture the regulation, 1,999, 28 (2): 12 l4.譯文:數(shù)控機床開環(huán)控制伺服系統(tǒng)與數(shù)控生產(chǎn)設(shè)備摘要開環(huán)系統(tǒng)的優(yōu)點是系統(tǒng)簡單、成本低,但缺點是精度低。反向間隙、絲杠螺距誤差、起停誤差等都會影響定位精度。下面幾種改進措施可以使定位精度明顯改善。關(guān)鍵字:數(shù)控系統(tǒng)、開環(huán)系統(tǒng)1) 反向間隙誤差補償數(shù)控機床加工刀具與工件的相對運動是依靠驅(qū)動裝置帶動齒輪、絲杠轉(zhuǎn)動,從而推動工作臺面等移動部件產(chǎn)生位移來實現(xiàn)的。作為傳統(tǒng)元件的齒輪、絲杠盡管制造精度很高,但總免不了存在間隙。由于這種間隙存在,當運動的方向改變時,開始段時間必然會引起驅(qū)動元件的空走,出現(xiàn)指令脈沖推不動執(zhí)行元件的局面。這就影響了機床的加工精度,即指令脈沖與實際進給步數(shù)不相符合,產(chǎn)生加工誤差 因此,開環(huán)數(shù)控系統(tǒng)一般都設(shè)置有反向間隙誤差補償功能,用以補足空走的步數(shù)反向間隙差補償就是首先實測反向進給的誤差,把它折算成脈沖當量數(shù),作為間隙補償子程序的輸出量,當計算機判斷出現(xiàn)的指令為反向運動時,隨即調(diào)用間隙補償子程序,通過輸出補償脈沖消除反向間隙后再進行正常的插補運行。2) 常值系統(tǒng)性定位誤差補償類庫以供設(shè)計者調(diào)用。這樣在零件的設(shè)計階段,設(shè)計者只需輸入特征的參數(shù),系統(tǒng)直接生成特征的實例模型:在數(shù)據(jù)庫中我們必須存儲相關(guān)的特征類的結(jié)構(gòu)信息,數(shù)據(jù)庫表集就是用于存儲這一部分的相關(guān)信息。根據(jù)特征類型定義的需要,我們定義了特征類編碼表、特征類版本信息表表示特征類型;定義了特征類構(gòu)造表表達特征類的結(jié)構(gòu);并通過零件特征配置表與零件的特征層信息聯(lián)系起來。特征層數(shù)據(jù)表集是本零件模型數(shù)據(jù)庫設(shè)計的核心,記錄了特征實例模型的設(shè)計、工藝等信息。特征構(gòu)造表記錄了特征的幾何結(jié)構(gòu);特征尺寸表、特征形位公差表、特征表面粗糙度表記錄了特征的工程語義引用;尺寸表、形位公差表、表面粗糙度表存儲了所有零件特征的數(shù)據(jù)信息。在特征層,利用特征ID、幾何要素ID、尺寸ID、公差I(lǐng)D、粗糙度ID等主鍵進行數(shù)據(jù)檢索。我們將該零件信息模型的數(shù)據(jù)庫應(yīng)用于工廠環(huán)境下某型組件的CAD AM 集成系統(tǒng)中,較好地實現(xiàn)了CAD與CAPP的特征信息共享。在該系統(tǒng)中主要使用現(xiàn)成的CADCAM 軟件(Unigraphics 1I)進
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