分功率殼體臥式雙面鉆孔專用機床設計說明書,功率,殼體,臥式,雙面,鉆孔,專用,機床,設計,說明書,仿單 分功率殼體臥式雙面鉆孔專用機床設計 目 錄 引言…………………………………………………………………………………4 第一章 通用部件簡介 ………………………………………………………6 1.通用部件的分類 …………………………………………………………6 2.動力部件…………………………………………………………………6 3.支承部件…………………………………………………………………7 4.控制部件…………………………………………………………………8 5.輔助部件…………………………………………………………………8 第二章 組合機床的總體設計的步驟……………………………………8 1組合機床工藝方案的制定………………………………………………8 2確定切削用量及選擇刀具………………………………………………9 3組合機床總體設計—三圖一卡…………………………………………10 第三章組合機床多軸箱設計………………………………………………12 1概述………………………………………………………………………12 2設計原則…………………………………………………………………14 第四章夾具的設計 1定位基準的選擇………………………………………………………15 2 夾緊力的計算…………………………………………………………15 第五章液壓原理圖……………………………………………………16 1液壓傳動圖……………………………………………………………16 第六章PLC梯形圖……………………………………………………16 1 工作原理及電氣控制要求…………………………………………16 2 電氣控制系統(tǒng)硬件設計……………………………………………16 3.電氣控制系統(tǒng)軟件設計……………………………………………17 結論……………………………………………………………………17 致謝……………………………………………………………………18 參考文獻………………………………………………………………18 附錄A 綜述 附錄B 調研報告 附錄C 外文翻譯 附錄D 原文 引言 組合機床是一種自動化或半自動化的機床.無論是機械電氣或液壓電氣控制的都能實現(xiàn)自動循環(huán).半自動化的組合機床,工人只要將工件裝夾好,按一下按鈕,機床即可自動進行加工,加工一個循環(huán)停止.自動化的組合機床,工人只要將工件放到料斗或上料架上,機床即可連續(xù)不斷的進行工作.我國傳統(tǒng)的組合機床及組合機床自動線主要采用機、電、氣、液壓控制,它的加工對象主要是生產批量比較大的大中型箱體類和軸類零件(近年研制的組合機床加工連桿、板件等也占一定份額) ,完成鉆孔、擴孔、鉸孔,加工各種螺紋、鏜孔、車端面和凸臺,在孔內鏜各種形狀槽,以及銑削平面和成形面等。組合機床的分類繁多,有大型組合機床和小型組合機床,有單面、雙面、三面、臥式、立式、傾斜式、復合式,還有多工位回轉臺式組合機床等;隨著技術的不斷進步,一種新型的組合機床———柔性組合機床越來越受到人們的青睞,它應用多位主軸箱、可換主軸箱、編碼隨行夾具和刀具的自動更換,配以可編程序控制器( PLC) 、數(shù)字控制(NC) 等,能任意改變工作循環(huán)控制和驅動系統(tǒng),并能靈活適應多品種加工的可調可變的組合機床。另外,近年來組合機床加工中心、數(shù)控組合機床、機床輔機(清洗機、裝配機、綜合測量機、試驗機、輸送線) 等在組合機床行業(yè)中所占份額也越來越大。由于組合機床及其自動線是一種技術綜合性很高的高技術專用產品,是根據用戶特殊要求而設計的,它涉及到加工工藝、刀具、測量、控制、診斷監(jiān)控、清洗、裝配和試漏等技術。我國組合機床組合機床自動線總體技術水平比發(fā)達國家要相對落后,國內所需的一些高水平組合機床及自動線幾乎都從國外進口。工藝裝備的大量進口勢必導致投資規(guī)模的擴大,并使產品生產成本提高。因此,市場要求我們不斷開發(fā)新技術、新工藝,研制新產品,由過去的“剛性”機床結構,向“柔性”化方向發(fā)展,滿足用戶需求,真正成為剛柔兼?zhèn)涞淖詣踊b備。隨著市場競爭的加劇和對產品需求的提高,高精度、高生產率、柔性化、多品種、短周期、數(shù)控組合機床及其自動線正在沖擊著傳統(tǒng)的組合機床行業(yè)企業(yè),因此組合機床裝備的發(fā)展思路必須是以提高組合機床加工精度、組合機床柔性、組合機床工作可靠性和組合機床技術的成套性為主攻方向。一方面,加強數(shù)控技術的應用,提高組合機床產品數(shù)控化率;另一方面,進一步發(fā)展新型部件,尤其是多坐標部件,使其模塊化、柔性化,適應可調可變、多品種加工的市場需求。從2002 年年底第21 屆日本國際機床博覽會上獲悉,在來自世界10 多個國家和地區(qū)的500 多家機床制造商和團體展示的最先進機床設備中,超高速和超高精度加工技術裝備與復合、多功能、多軸化控制設備等深受歡迎。據專家分析,機床裝備的高速和超高速加工技術的關鍵是提高機床的主軸轉速和進給速度。該屆博覽會上展出的加工中心,主軸轉速10 000～20 000 r/ min ,最高進給速度可達20～60 m/ min ;復合、多功能、多軸化控制裝備的前景亦被看好。在零部件一體化程度不斷提高、數(shù)量減少的同時,加工的形狀卻日益復雜。多軸化控制的機床裝備適合加工形狀復雜的工件。另外,產品周期的縮短也要求加工機床能夠隨時調整和適應新的變化,滿足各種各樣產品的加工需求。然而更關鍵的是現(xiàn)代通信技術在機床裝備中的應用,信息通信技術的引進使得現(xiàn)代機床的自動化程度進一步提高,操作者可以通過網絡或手機對機床的程序進行遠程修改,對運轉狀況進行監(jiān)控并積累有關數(shù)據;通過網絡對遠程的設備進行維修和檢查、提供售后服務等。在這些方面我國組合機床裝備還有相當大的差距,因此我國組合機床技術裝備高速度、高精度、柔性化、模塊化、可調可變、任意加工性以及通信技術的應用將是今后的發(fā)展方向。 第一章 通用部件簡介 1.通用部件的分類 1.1. 通用部件已列為國家標準，并等效為國際標準，設計時應貫徹執(zhí)行國家標準。我國有些企業(yè)有內部標準，但其主要技術參數(shù)及部件和聯(lián)系尺寸必須統(tǒng)一執(zhí)行國家標準，以實現(xiàn)部件通用化標準。 2.動力部件 2.1動力滑臺是由滑座、滑鞍和驅動裝置等組成，是實現(xiàn)組合機床直線進給運動的動力部件。 動力滑臺的用途：根據被加工工件的工藝要求，可以在滑臺上安裝動力箱、鉆削頭、銑削頭和鏜孔車端面頭等各種部件，以完成對工件的鉆孔、擴孔、鉸孔、螳孔、倒角、削端面、車端面、銑削及攻絲等工序，有時也作為輸送部件使用，配置多工位組合機床。 2.2TD系列動力箱的用途 動力箱是將電動機的動力傳遞給多軸箱的動力部件。動力箱安裝在滑臺或其它進給部件的結合面上，動力箱前端結合面上安裝多軸箱，動力箱的輸出軸驅動動力箱的每個主軸及傳動軸，使多軸箱完成各種工藝切削運動。1DT系列動力箱分兩種：第一種根據用于配置小型組合機床，其型號為1DT121DT25，本規(guī)格的動力箱輸出軸有兩種傳動形式，I型用輸出軸安裝的平鍵，齒輪輸出轉矩；II型用輸出軸端面鍵輸出轉矩。第二種動力箱用于配置大型組合機床，其規(guī)格為1DT321DT80，其輸出軸只有平鍵，齒輪一種輸出轉矩的形式。液壓滑臺：1HY系列液壓滑臺；1HYA系列長臺面型液壓滑臺；1HYS系列液壓十字滑臺。機械滑臺：1HJ系列機械滑臺；1HJC系列機械滑臺；NC-1HJ系列交流伺服數(shù)機械滑臺。 3.支承部件 組合機床支承部件包括中間底座，側底座，立柱，立柱底座，支架及墊塊等。支承部件主要用來安裝動力部件及其它工作部件是組合機床的基礎部件。支承部件應用于足夠的剛度，以保證各部件之間相對位置精度長期正確，從而保證組合機床的加工精度。組合機床的支承部件采用組合式，例如：臥式組合機床的床身，由中間底座與側底座裝配而成，而立式組合機床的床身由立柱及立柱底座裝配而成。此種裝配結構優(yōu)點是加工和裝配工藝性好，調整和運輸比較方便。但是，組合式結構減弱了床身的整體剛性，這一缺點通常用加強部件之間的連接剛度來補償。 3.1.1CC系列滑臺側底座 1CC系列滑臺側底座用于安裝1HY系列液壓滑臺及各種機械滑臺側底座長度按滑臺行程長度分型并與其配套?；惭b在側底座上，側底座與中間底座用螺釘及銷（或鍵）連接成一體，滑臺與側底座之間裝有5mm厚的調整墊。采用調整墊鐵對機床的制造和維修都方便。因為當滑座導軌磨損后，或重新組裝機床時，只須取下滑臺將導軌面重新修刮或修磨，再重新更換調整墊厚度，可使機床達到應有精度。 側底座的頂面具有與滑座結合的平面外在其周圍有收集冷卻液或潤滑油用的溝槽，用管道將油液引回存儲槽中，側底座的另一側面有電氣壁盒，以供安裝電器元件用。一般電器壁盒與冷卻液存儲箱不應靠近，以防電氣元件潮濕。為了便于支承部件及整臺機床運輸，側底座應用走絲吊孔或吊環(huán)螺釘孔及放入撬杠用的底面凹槽。 4.控制部件 控制部件用來控制組合機床行動循環(huán)。 5.輔助部件 除上述部件外的部件稱輔助部件，主要指用于潤滑、冷卻和排屑等部件。 第二章 組合機床的總體設計的步驟 1組合機床工藝方案的制定 雙面鉆孔組合機床是在工件兩相對表面上鉆孔的一種高效率自動化專用加工設備。機床的兩個液壓動力滑臺對面布置,左、右刀具電動機分別固定在兩邊的滑臺上,中間底座上裝有工件定位夾緊裝置。組合機床的總體設計通常是根據與用戶簽定的和同和協(xié)議書，針對具體加工零件，擬訂工藝和結構方案，并進行方案圖樣和有關技術文件的設計。根據工藝方案確定機床的型式和總體布局。在選擇機床配置型式時，既考慮到實現(xiàn)工藝方案，保證加工精度、技術要求及生產率，又考慮到機床操作、維護、修理和排屑的方便性。在選擇組合鉆床結構方案時，必須保證穩(wěn)定的加工精度。固定式夾具組合鉆床能達到的鉆孔位置精度最高，采用固定導套一般能達± 0.20mm?？紤]到操作的方便性，需要合理確定裝料高度為使鉆床在溫度過高時工作性能穩(wěn)定，而且由于被加工件不需多次進給，故選用機械通用部件配置鉆床。根據被加工零件的特點,為實現(xiàn)加工精度要求,同時考慮到經濟效益和生產率,經過反復論證、分析和計算,我們采用了臥式雙面多軸鉆、組合機床的總體設計方案。本機床采用多工位臥式組合機床,變速箱體裝在工作臺的夾具上,這樣便于上、下料。機床機械部分主要有:底座、側底座、多軸箱、刀具、夾具、冷卻系統(tǒng);控制部分為PLC 控制系統(tǒng)及液壓傳動系統(tǒng)。機床的工作循環(huán)為:人工裝上一工件,定位銷插銷定位→夾緊油缸夾緊→I 滑臺開始工作循環(huán):快進(冷卻供、主軸轉) →工進(死檔鐵停留) →快退至原位(主軸停) 滑臺開始工作循環(huán):快進(冷卻供、主軸轉) →工進(死檔鐵停留) →快退至原位(主軸停、冷卻停) ,定位銷拔出,夾緊油缸松開,防護門自動打開,油缸推出工件,工件到位后油缸退回 ,死檔鐵停留,工作循環(huán)結束 2確定切削用量及選擇刀具 切削用量選擇是否合理，對組合機床的加工精度、生產率、刀具的耐用度、機床的布局及正常工作均有很大的影響。 組合機床切削用量的選擇特點： 2.1.在大多數(shù)情況下，組合機床為多軸，多刀，多面同時加工，因此切削用量，根據經驗應比一般萬能機床單刀加工低30%左右。 2.2.組合機床多軸箱下，所有刀具共用一個進給系統(tǒng)，通常為標準動力滑臺，工作時，要求所以的刀具的每分鐘進給量相同，且等于動力滑臺的分鐘進給量。由于工件材料：HT200 壁厚：2.510 HBS：157236 =220 查《工藝師手冊》鉆孔切削速度查得：鑄鐵：v=16~24m/min.取v=20m/min,f=0.15/0.12mm/r 3.三圖一卡設計 3.1.加工示意圖 加工示意圖的作用和內容 零件的加工工藝方案要通過加工示意圖反映出來，加工示意圖表示被加工零件在機床尚的加工過程，刀具輔具的布置狀況以及工件，夾具，刀具等機床各部件間的相對位置關系，機床的工作行程及工作循環(huán)等。因此，加工示意圖是組合機床設計的主要圖紙之一。在總體設計中占據重要地位。它是刀具，輔具，夾具，多軸箱，液壓電氣裝置設計及通用部件選擇的主要原始資料；也是整臺組合機床布局和性能的原始要求，同時還是調整機床刀具及成車的依據，其內容為： （1）應反映機床的加工方法，加工條件及加工過程。 （2）根據加工部位特點及加工要求，決定刀具類型，數(shù)量，結構，尺寸（直徑 和長度），包括鏜削加工是膛桿直徑和長度。 （3）決定主軸的結構類型，規(guī)格尺寸及外伸長度。 （4）選擇標準或設計專用的接桿，浮動卡頭，導向裝置，攻絲靠模裝置，刀桿 托架等，并決定它們的結構參數(shù)及尺寸。 （5）標明主軸，接桿，夾具（導向）與工件之間的聯(lián)系尺寸，配合及精度。 （6）根據機床要求的生產率及刀具，材料特點等，合理正確定并標注各主軸的 切削用量。 3.2被加工零件工序圖 被加工零件為分功率器殼體，材料為H200，工序為箱體兩端面鉆孔，左端面為12個10加工孔和8個6，右端面為6個10和8個6加工孔。采用一面兩孔定位，一面為箱體底面，兩孔為底面上的長邊上的兩孔。采用箱體頂面夾緊。 3.3加工示意圖 加工10的孔： 錐柄長麻花鉆 硬質合金 d=10mm L=168mm L1=87mm 依據公式 M= ， 選剛性主軸，直徑為30/20mm 外伸長度為115 mm 切削用量 v=20 m/min f=0.15 mm/r 加工6的孔： 錐柄麻花鉆 硬質合金 d=6mm L=138 mm L1=57`mm 依據公式 M= 選剛性主軸，直徑為22/14mm 外伸長度為115 mm 切削用量 v=30m/min f=0.15 mm/r 箱體左端面工進長度35 mm 快進85mm 快退120 mm 箱體右端面工進長度35 mm 快進 85mm 快退120 mm 3.4機床聯(lián)系尺寸圖 左端面：20根主軸 右端面:14根主軸 多軸箱輪廓尺寸 H=336+100+100=536 mm B=400+2100=600 mm 厚度取325 mm長寬取630630 mm 最低孔位置44mm 最低主軸高度100 mm 軸向力==1371.2N 轉矩 ==7282.4Nmm 功率 ==0.274kw 18=4.932kw 18=19745.28N 根據以上計算所得 選取液壓動力滑臺1HY40 動力箱1TD40-IIA （7.5kw）電機 Y132M-4 側底座 1CC401 3.5機床生產率計算卡 機床負荷率等。根據選定得機床工作循環(huán)所需要的工作行程長度，切削用量，動力部件的速度及工進速度等；就可以計算機床的生產率并編制生產率計算卡；用以反映機床的加工過程；完成每一動作所需的時間，切削用量，機床生產率等 (1)機床生產效率計算卡 1. 理想生產率 ==23 件/h 2. 實際生產率 =31件/h 3. 機床負荷率 =0.75 第三章組合機床多軸箱設計 1.概述 組合機床多軸箱的設計計算是組合機床設計工程中的重要環(huán)節(jié)，是主軸箱零部件設計的理論基礎，計算稍有不慎，便會導致后期的設計制造前功盡棄。依據總體設計圖， 對主軸箱進行結構創(chuàng)新設計。由于在本機床上需同時加工12個孔，不僅孔多、間距小，而且孔的排列分散，采用通常方案排箱無法實現(xiàn)12孔的工序集中。因此，本鉆床的主軸箱傳動系統(tǒng)在對被加工零件進行了深入、細致分析計算的基礎上，通過采用滾針軸承，將常規(guī)狀況下不能完成的排箱得以實現(xiàn)，而且所設計的主軸箱結構緊湊。（該設計只設計左面多軸箱的結構，右面多軸箱類似）依據組合鉆床總體設計繪制主軸箱設計原始依據圖其內容為主軸箱設計的原始要求和已知條件： 1. 主軸箱輪廓尺寸630mm×630mm； 2. 工件輪廓尺寸及各孔位置尺寸 主軸及通用傳動軸結構型式的選擇方案 主軸結構型式由零件的加工工藝決定，并考慮主軸的工作條件和受力情況，采用長主軸。由于采用鉆削加工主軸，需承受較大的單向軸向力，所以優(yōu)選向心球軸承和推力球軸承組合的支承結構，且推力球軸承配置在主軸前端。傳動軸的轉速較低，但載荷較大，因此用圓錐滾子軸承。按上述方案配置的主軸和傳動軸，按所選的軸承類型繪制軸承孔檢查圖，發(fā)現(xiàn)有些部位采用此配置因孔間距較小，箱體上的軸承座孔太大，導致箱體強度不夠。因此，這些部位都將原方案改為推力球軸承與滾針軸承組合的支承結構，以減小徑向尺寸，滿足強度要求，實現(xiàn)合理排箱。 按以上原則設計的傳動系統(tǒng)，保證了主軸箱的質量，提高了主軸箱的通用化程度，使得設計和制造工作量及成本都大大降低。為實現(xiàn)本機床“體積小、質量輕、結構簡單、使用方便、效率高、質量好”的設計目標奠定了基礎。 2.設計原則 1) 從面對主軸的方位看去，所有主軸均采用逆時針方向旋轉。 2) 在保證轉速和轉向的前提下，力求用最少的傳動軸和齒輪（數(shù)量和規(guī)格），以減少各類零件的品種。具體措施：采用一根傳動軸同時帶動多根主軸，并將齒輪布置在同一排位置上，當齒輪嚙合中 心距不符合標準時，采用了變位齒輪。 3) 放棄了用主軸帶主軸的方案，這樣避免了增加主軸負荷，不會影響加工質量。 4) 為使主軸箱結構緊湊，主軸箱內齒輪傳動副的傳動比都在1.0~1.5之間。 5) 為了使主軸上的齒輪不太大，有的在最后一級采用升速傳動。 6) 因鉆削加工切削力大，為了減少主軸的扭曲變形，主軸上的齒輪盡量靠近前支承。 對傳動系統(tǒng)的一般要求 1) 盡量用一根中間軸帶動很多根主軸,當齒輪齒合中心距不符合標準時,可用變位齒輪或略變傳動比的方法解決. 2) 一般情況下,盡量不采用主軸帶動主軸的方案,因為會增加主動軸的負荷,如遇到主軸分布密集而切削負荷又不大時,為了減少中心軸,也可用一根主軸帶1-2根或更多根主軸的傳動方案. 3) 為使結構緊湊多軸箱體的齒輪傳動副的最佳傳動比為1-1.5,在多軸箱后蓋內的第IV排(或第V排)齒輪,根據需要,其傳動比可以取大些,但一般不超過33.5。 4) 根據轉速與轉距成反比的道理，一般情況下如驅動軸轉速較高時，可采用逐步降速傳動，如驅動軸轉速較低時可先使速度升高一點再降速，這樣可使傳動鏈前面幾根軸齒輪上的齒輪應盡量安排靠近前支承，以減少主軸的扭轉變形。 5）粗加工切削力大，主軸上的齒輪應盡量安排靠近前支承，以減少主軸的扭轉變形。 6）齒輪安排數(shù)可按下面方法安排： 不同軸上齒輪不相碰，可放在箱體內同一排上。 不同軸上齒輪與軸或軸套不相碰，可放在箱體內不同排上。 齒輪與軸相碰，可放在后蓋內。 四專用夾具結構設計 機床夾具是在機床上所使用的一種輔助裝置，用它來準確迅速地確定工件與機床刀具間地相對位置，即將工件定位及夾緊，以完成加工所需地相對運動。使用夾具地最終目的是保證產品質量，改善工人勞動條件，提高生產效率，降低產品成本。 1定位基準的選擇 由零件圖可知，采用雙面加工的方法，同時為了縮短輔助時間采用液壓夾緊。 2 夾緊力的計算 查《機床夾具設計手冊》表1－2－11 工件以平面定位，夾緊力與切削力方向垂直。 其中為基本安全系數(shù)1，2 為加工性質系數(shù)1，2 為刀具鈍化系數(shù)1 為斷續(xù)切削系數(shù)1 ＝0.16 ＝0.7 ＝2.5 則＝＝2750N 現(xiàn)選用地腳式的液壓缸，查《機床夾具設計手冊》： 故本夾具可安全工作。 第五章液壓原理圖 第六章PLC控制設計 1 工作原理及電氣控制要求 雙面鉆孔組合機床是在工件兩相對表面上進行鉆孔的一種高效自動化專用加工設備 。2 個動力滑臺對面布置并安裝在標準側底座上,刀具電動機M2 ,M3 分別固定在左、右動力滑臺上,中間底座上裝有工件定位夾緊裝置。該機床采用電動機和液壓系統(tǒng)(未畫出) 相結合的驅動方式,其中電動機M2 ,M3 分別帶動左、右主軸箱的刀具主軸提供切削主運動,而左、右動力滑臺和工件定位夾緊裝置則由液壓系統(tǒng)驅動,M1 為液壓泵的驅動電動機,M4 為冷卻泵電動機。機床的電氣控制要求為M1 先啟動,只有系統(tǒng)正常供油后,其它控制電路才能通電工作; M2 ,M3在滑臺進給循環(huán)開始時啟動,滑臺退回原位后停機;M4 可手動控制啟停,也可在滑臺工作進給時自動提供油液。其控制過程是典型的順序控制,當把工件裝入夾具后,按下啟動按鈕SB3 ,機床便開始自動循環(huán)的工作過程. 2 電氣控制系統(tǒng)硬件設計 雙面鉆孔組合機床的電氣控制屬單機控制, 輸入輸出均為開關量。根據實際控制要求,并考慮系統(tǒng)改造成本,在準確計算I/ O 總點數(shù)的基礎上,采用抗干擾強、穩(wěn)定性和可靠性較高的三菱公司生產的FX1N260MR 可編程控制器。該控制系統(tǒng)中所有輸入觸發(fā)信號采用常開觸點接法,所需的24 V 直流電源由PLC 內部提供;輸出負載中的所有直流電磁換向閥同樣采用由PLC 內部提供的24 V 直流電源,輸出負載中的4 個交流接觸器線圈則需外接220 V 交流電源.由于雙面鉆孔組合機床中轉換開關、按鈕及行開關較多,為了減少輸入點數(shù),降低費用,對輸入信號作了適當處理,如4 臺電動機的過載保護不作為輸入信號,而直接接入輸出線圈回路中。另外,電磁閥為感性負載并且通斷頻繁,為了保護PLC 的輸出觸點,在每個電磁閥兩端各并上1 個續(xù)流二極管,來吸收反向過電壓。 3.電氣控制系統(tǒng)軟件設計 由雙面鉆孔組合機床的控制要求可知,該控制系統(tǒng)需要實現(xiàn)3 個控制功能: ① 動力滑臺的點動、復位控制; ②動力滑臺的單機自動循環(huán)控制; ③整機全自動工作循環(huán)控制。本程序經模擬調試,完全符合雙面鉆孔組合機床的電氣控制要求,使用效果良好。在使用過程中,還可根據不同的控制要求,在不改動接線或改動很少的情況下,通過改變程序來實現(xiàn)不同要求,大大節(jié)省了安裝調試時間,提高了效率。 　 結論 本系統(tǒng)經過PLC 融入后,運行良好,故障率低。而且組合機床控制系統(tǒng)具有很好的柔性,能適應產品的變化,當工藝程序變更時,只需修改程序,就可滿足新的加工要求?？梢妭鹘y(tǒng)的機械設備融入PLC技術 后,既能使之成為機電一體化的新產品,適用生產過程的自動控制,又能發(fā)揮原組合機床的效能,而且投資較小,可見,靈活應用PLC 是實現(xiàn)組合機床電氣自動化的有效途徑。本組合機床較好地解決了大批量鉆變速箱兩端面孔的問題。不但保正加工質量,而且大為提高了工效,具有良好的經濟效益和應用價值。 致謝 這次設計是在范真導師的精心指導下完成的。范老師進場抽出大量寶貴時間來關心我們,并且經常指導我的畢業(yè)設計。每當我們在設計上遇到什么問題或是有什么想不通的，她都會細心的講解，直到我們懂為止，在此，獻上誠摯的謝意。還要謝謝在設計中幫助我的同學，以及幫我答辯的各位老師！ 參考資料 1、《組合機床設計》沈陽工業(yè)大學、吉林工業(yè)大學、大連鐵道學院主編　上海出版社出版　1985年9月 2、《組合機床設計》　大連組合機研究所編　　機械工業(yè)出版社　1975年6月 3、《金屬切削加工工藝人員手冊》上?？茖W技術出版社 4、《金屬切削機床設計參考圖冊》　機械工業(yè)出版社 5、《金屬切削機床設計》　大連工學院　戴曙主編　機械工業(yè)出版　　1985年12月 6、《組合機床液壓滑臺圖冊》　機械工業(yè)出版社 7、《機械設計手冊》　　遼寧科學技術出版社 8、《機床設計手冊》　機械工業(yè)出版社　1978年12月 9、《組合機床設計參考圖冊》　大連組合機床研究所編　機械工業(yè)出版社 19 The Development and Application of a Planar Encoder Measuring System for Performance Tests of CNC Machine Tools W. Jywe Department of Automation Engineering, National Huwei Institute of Technology, Huwei, Yunlin, Taiwan In this paper, a measuring device with a planar encoder is developed to test the performance of a CNC machine tool. With the assistance of a PC, this system can be employed for both 2D contouring tests and 3D positioning tests for a CNC machine tool. The structure and the principle of the system, the applications for the general 2D contouring test, the drift test, and the specified geometric part path tests. An actual case study on improving the accuracy of machining a cam are described. Finally, a new 3D positioning method using the optic encoder is demonstrated. Keywords: Ball bar system; CNC machine tool; Geometric part path; Planar encoder; Thermal drift test; Three-dimensional positioning; Two-dimensional contouring 1. Introduction Machine tool performance and consistency is the main determinant of the quality of parts machined by it. It is of importance to check the performance of the machine tool systematically for direct quality control purposes or to compensate for this uncertainty. Schlesinger, in 1932 [1], first provided a systematic testing method for machine tools. This method was developed as the basis of the ISO standard. Tlusty, in 1959 [2], employed an electric level and sensor to test the spindle accuracy. Tlusty and Koenigsberger [3] and Burdekin [4] indicated new testing rules for machine tools. Burdekin [5] checked the relation between the motion accuracy of machine tools and the machined part. Tlusty [6] proposed a non-cutting testing method. The tests for machine tool performance were then classified into a direct cutting test and an indirect cutting test. Ericson [7] first described the work zone of machine tools. Bryan and Pearson [8] explained the definition and the way to measure the pitch, roll and yaw motion and straightness error. After the commercial laser interferometer [9] was available, the analysis of volumetric errors [10–13] was described. Voutsudopoulos and Burdekin [14] indicated a calibrating model for a coordinate measuring machine. Fan [15] used a laser interferometer and a related device with the assistance of a PC to calibrate different types of NC machine tools. Zhang and Hockey [16] obtained the 21 error components by measuring the position errors. Zhang and Zang [17] designed a 1-D ball array to find the 21 error components, then Zhang [18] described a rapid method to obtain the straightness error. In 2000, Jywe [19] described a method of employing a ball bar system for the verification of the volumetric error of CNC machine tools. Circular tests were developed to check both geometric errors and contouring errors. Burdekin [20] described cutting tests using circular paths for accuracy assessment. Bryan [21] developed the first ball bar system for the contouring test. However, in this system, the uncertainty is high due to the friction between the master balls and the magnetic sockets and no accurate contouring radius was given. Knapp’s system [22,23] used a circular comparison standard disc mounted on the test table of the machine tool and a 2D-probe. The problems for this system are the existence of friction between the 2D probe and the disc, its small bandwidth, which causes the system to be unusable for high-speed contouring tests, and the high cost of the 2D probe. Kakinov [24–27] provided a series of methods using a ball bar system to calibrate a coordinate measuring machine and CNC machine tools. Knapp [28,29] described a rule to reduce the errors due to stick–slip etc. Burdekin and Park [30] modified the original ball bar system by employing a four-rod linkage. Burdekin and Jywe [31] provided a method to diagnose the contouring error and to adjust the parameters of the CNC controller to optimise the performance of the tested CNC machine tool. Ziegert and Mize [32] described a laser ball bar system. All these ball bar systems, including the lateral Renishaw system [33] provide only the radius error during the contouring test. This limits the analysis of contouring error since no individual error in each axis is available. Jywe [34] used two position silicon detectors (PSD) for a contouring test to obtain the contouring error in each axis. One laser source emits a laser beam and the laser beam is split into two vertical lines and projected onto two positioning silicon detectors, which are set vertically to each other on the test machine table. The Heidenhein [35] grid encoder also provides a 2D contouring test, but at very high cost. A planar encoder system was developed [36] for applications such as semiconductor and electronics manufacturing equipment. The system, which has a good dynamic response, can provide up to a 0.1
m resolution in positioning, and it is of importance that it is of low cost. However, the original planar encoder was designed for manual operation. It is not suitable for the contouring test of CNC machine tools due to the following considerations: 1. The original system only included an encoder and a reading head. No related interface and driver are available. 2. Thus there were no related contouring software and testing methods. Thus, in this paper a new computer-aided planar encoder system has been employed and integrated, with the related software, for checking the both the dynamic performance and the geometric error of a CNC machine tool. It is of importance that 90% of the cost of the contouring testing device can be reduced compared to the equivalent Heidenhein grid encoder system. From the previous research, it has been found that the device for the circular test is not always suitable for a 3D geometric error test. Furthermore, these devices are not suitable for a free-form 2D contouring test. In this paper a simple measuring device is designed and developed to check contouring performance with a single axis output. The application for a 3D positioning test is also developed. 2. The 2D Planar Encoder Contouring Measuring System for CNC Machine Tools 2.1 Principle of the Planar Encoder A planar encoder system, such as the Renishaw RGX grid plate, has been developed for applications such as semiconductor and electronics manufacturing equipment. The system uses a reading head with two orthogonal sensors that read a checkered grid in both the X and Y directions simultaneously. The system has a good dynamic response and can provide up to 0.1 m resolution in positioning. The software in V-Basic is edited to carry out the measuring procedure. Figure 1 shows the arrangement of the contouring test using the simple planar encoder. This planar encoder provides positioning information in each axis for 2D contouring. During the test, the planar encoder is set on the CNC machine tool, and the reading head is fixed in the spindle. The computer software can read the sampling data via a counter card. 3. Uncertainty of the Measuring System 3.1 Uncertainty Due to Sampling Procedure The developed software incorporated the following factors: 1. Sampling must be uniform around the profile and reasonably independent of the type and speed of the computer. A Planar Encoder Measuring System for CNC Machine Tools 21 2. Sufficient sampling data is required to display and analyse the error at high resolution. 3. Sampling data should be independent of contouring speed, computer speed and contouring radius. 3.2 Uncertainty Due to Thermal Effect Considering the thermal effect of the system for the tests, if the temperature in the planar encoder is different from that of the machine tool table, the radius error will be affected. If the temperature of the planar encoder itself is not uniform, the out of roundness error will be affected. Although the thermal expansion coefficient of the planar encoder is rather small, to minimise the effects, the encoder should be put on the test machine table for some time to reduce the difference in the temperatures and to let the temperatures of the encoder stabilise. 4. Test Results of a Circular Contouring Path A simple contouring test is carried out on the XY-plane of a vertical CNC machine tool with a 0M Fanuc controller. The contouring result is shown in Fig. 2. The anticlockwise and clockwise contouring tests at 20 mm radius can meet ISO 230-1 and 230-2 requirements. From the results, the absolute radius error can be found easily. For general contouring systems, only the out of roundness is given. Furthermore, the error for each axis can also be found individually if necessary. This is useful for analytical purposes. 5. Thermal Drift This contouring system provides a non-contacting contouring test. For general contouring systems such as a ball bar system, only a limited number of runs are executed, due to the problem of winding of the signal cable. In this application, the test run is unlimited. Thus, a thermal drift test can be carried out easily without additional fixtures. For eight-hour continuous clockwise contouring runs, contouring results are shown in Fig. 3 for each two-hour period. The contouring centre for each 30 minutes, is plotted in Fig. 4. The contouring centre drift is significant in the 8 hours. It is important that not only the contouring centre drift is given but also the contouring error form in each run can be obtained. From this test, the performance of continuous runs can be monitored easily by this system. Fig. 1. The optical measuring system for contouring performance test on a CNC machine tool. Fig. 2. The clockwise and anticlockwise contouring test results with Fig. 3. The thermo drift test results during 8 hours continuous the planar encoder measuring system. Fig4.The thermal drift test results presented by the drift of the contouring centres. Fig. 5. The squareness test result on a CNC machine tool with theplanar encoder measuring system. 6. Squareness Error Test by Planar Encoder The squareness error can be tested easily with the planar encoder. Let the encoder be set on the tested plane. The reading head goes along the square of the encoder. A CNC machine tool was tested and the result is shown in Fig. 5. contouring test. 7. Laser Diode and Quadrant Sensor Contouring System [37]* Using a laser diode and a quadrant sensor contouring system, the planar encoder contouring system can be verified. Using a 2 mm clockwise contouring radius, Fig. 6 shows the contouring result using the quadrant sensor, while Fig. 7 gives similar results. Fig. 6. The contouring test results for square path with the laser diode and quadrant sensor contouring system [37].* Fig. 7. The contouring results for a square path with the planar encoder. Fig. 8. The test result for a combination of various geometric shapes provided by the planar encoder measuring system. Fig. 9. The geometric shape of a specified 2D cam. Fig. 10. The test results of the path of the CNC machine tool with/without cutter radius compensation. Fig. 11. The test results with self-calculated cutter radius compensation under different feed rates. Fig. 12. The structure of a 3D positioning measuring device. without sensors, is connected to the spindle of the tested CNC machine tool and to the reading head by two individual balls and magnetic sockets. The centre of the ball on the ball bar on the side of the spindle is the 3D measuring target to be analysed. When the target is reached, the first sample from the planar encoder is then taken at its first position. Without moving the target, the planar encoder is moved to a neighbouring point and a second sample is taken. Finally, the other neighbouring point is sampled as the third sample. Each of the three samples includes 2D coordinates, the 3D coordinates of the target which can be analysed. Thus each 3D movement will be obtained by this 1-point and 3-step (1P3S) method. This method can be described as follows. To obtain the 3D positioning coordinates X, Y and Z, a simple model is developed in Fig. 13, where: Fig. 13. The model for analysing coordinates of x, y, z. x, y, z are the coordinates to be analysed. x1, y1, z1, x2, y2, z2, x3, y3, z3 are the coordinates provided by the 2D optical scale in the first, second and third step samples. L1, L2, L3 are the lengths provided by the ball bar. Then, Solving the equation, where Here, two possible solutions can be found. One is on the top of the planar encoder, while the other is below it. Thus, in this application only the coordinates on the top of the ball plate are used. After the coordinate z is found, x and y can also be found. In this application, the ball bar length is fixed, thus L1  L2  L3. To extend the working range a standard or laser ball bar system with a long working range displacement sensor can be employed. In that case, L1, L2, L3 can be obtained by that sensor. To minimise the cost, in this application only one set of planar encoders and a simple ball bar are considered. Thus, A Planar Encoder Measuring System for CNC Machine Tools 27 the coordinates x1, y1, z1, x2, y2, z2, x3, y3, z3 have to be obtained by the planar encoder in three individual samples. The sampling procedure (1P3S) is: 1. Let the machine tool move to the tested position (one point). 2. Take the sample by the planar encoder (step 1). 3. Move the reading head to a neighbouring position related to the planar encoder; the tested machine is not moved. Take the sample by the planar encoder (step 2). 4. Move the reading head to the next neighbouring position, the tested machine is not moved. Take the sample by the planar encoder (step 3). z1, z2, z3 are affected by the flatness (?Zij) of the linear XY stage. The flatness of the linear XY stage ?Zij is equal to the ith grid on the X-axis and the jth grid on the Y-axis. 11. Discussion and Conclusions In this paper, a planar encoder system was employed for a contouring test of a CNC machine tool. It was proved that this system could be employed successfully for the contouring test. The advantages of this application can be summarised as follows: 1. During the contouring test, the contouring error for each individual axis can be obtained. This is not possible using a general ball bar system. This function provides more useful information for analysing the contouring error. 2. The system can be employed for a long-period thermal drift test, but the traditional ball bar systems cannot, because in this there is no cable which can be wound up. 2. For contouring a combination of complicated curves such as a cam, the system can be employed while a general ball bar system cannot. Table 1. The verification result of the planar encoder for 3D positioning With this 2D optical measuring system, the 3D positioning error test can also be performed successfully. Thus this optical encoder can be employed for both dynamic performance and geometric error tests on CNC machine tools. Acknowledgements The work was supported by National Science Council, Taiwan, Republic of China, Grant Number NSC-88-2212-E-150-006. References 1. G. Schlesinger, Inspection Test on Machine Tools, Machinery Publishing Co. Ltd, London, 1932. 2. J. Tlusty, System and methods for testing machine tools, Microtechnic, 13, p.162, 1959. 3. J. Tlusty and F. Koenigsberger, Specifications and Tests of Metal Cutting Machine Tools, UMIST, Manchester, 1970. 4. G. Schlesinger, F. Koenigsberger and M. Burdekin, Testing Machine Tools, 8th edn, Machinery Publishing Co. Ltd, London, 1978. 5. M. Burdekin, “Cutting tests for accuracy assessment”, Technology of machine tools, 5, pp. 9–11, 1980. 6. J. Tlusty, “Testing of accuracy of NC machine tools”, Technology of Machine Tools, Supplement 1, 1980. 7. C. Ericson, “Machine alignment – the first step towards product accuracy”, Tech. Paper MM66-171, ASTME, 1966. 8. J. B. Bryan and J. W. Pearson, “Machine tool metrology”, Lawrence Livermore National Laboratory, Livermore, CA, UCRL71164, 1968. 9. Hewlett-Packard Co, CA, “Calibration of a machine tool”, Laser Measurement System Application Note 1156–4. 10. W. J. Loves and A. J. Scarr, “The determination of the volumetric accuracy of multi-axis machines”, Proceedings of the 14th MTDR Conference, pp. 307–315, 1973. 11. R. Schaltshik, “The components of the volumetric accuracy”, Annals of the CIRP, 25, pp. 223–228, 1977. 12. R. Schaltshik, “The accuracy of machine tools under load conditions”, Annals of the CIRP, 28, pp. 339–342, 1979.