連桿平行度測量儀設(shè)計含5張CAD圖
連桿平行度測量儀設(shè)計含5張CAD圖,連桿,平行,測量儀,設(shè)計,cad
附錄1 專題論文
連桿加工工藝
摘 要:簡要介紹了連桿的組成、功用、鍛造和主要加工工藝, 并對發(fā)動機連桿不同加工工藝方案進行了對比分析,闡述了撐斷新工藝的機理,探討了應(yīng)用撐斷工藝應(yīng)考慮的幾個問題,并對加工中夾具應(yīng)注意的問題進行說明。
關(guān)鍵詞:連桿大頭 連桿兩端面加工 整體鍛造 光整加工 工藝改進
0 引言
眾所周知,連桿是發(fā)動機的五大主關(guān)件之一,其在發(fā)動機中的地位是顯而易見。它是發(fā)動機傳遞動力的主要運動件,在機體中做復(fù)雜的平面運動,連桿小頭隨活塞作上下往復(fù)運動;連桿大頭隨曲軸作高速回轉(zhuǎn)運動;連桿桿身在大、小頭孔運動的合成下作復(fù)雜的擺動。
圖1 連桿立體圖
連桿在承受往復(fù)的慣性力之外,還要承受高壓氣體的壓力,在氣體的壓力和慣性力合成下形成交變載荷,這就要求連桿具有耐疲勞、抗沖擊,并具備足夠的強度、剛度和較好的韌性。在今天隨著汽車工業(yè)的高速發(fā)展,“小體積、大功率、低油耗”的高性能發(fā)動機對連桿提出更新、更高的要求:1)作為高速運動件重量要輕,減小慣性力,降低能耗和噪聲;2)強度、剛度要高,并具有較高的韌性;3)連桿比要大,連桿要短。這也就意味著對連桿的設(shè)計和加工有更高的要求。
連桿由連桿大頭、桿身和連桿小頭三部分組成。連桿大頭是分開的,一半為連桿蓋,另一半與桿身為一體,通過連桿螺栓連起來。連桿大頭孔內(nèi)分別裝有軸瓦,由于連桿體與連桿蓋的接合面是與大小頭孔的中心聯(lián)線垂直,故稱為直剖式連桿。有些連桿大頭結(jié)構(gòu)粗大,為了使連桿在裝卸時能從氣缸孔內(nèi)通過,采用斜剖式結(jié)構(gòu),即接合面與大、小頭孔軸線形成一定的角度。
連桿是活塞式發(fā)動機的重要零件之一,其大頭孔與曲軸連接,小頭孔通過活塞銷和活塞連接,將作用于活塞的氣體膨脹壓力傳給曲軸,又受曲軸驅(qū)動而帶動活塞壓縮氣缸中的氣體。連桿承受的是高交變載荷,氣體的壓力在桿身內(nèi)產(chǎn)生很大的壓縮應(yīng)力和縱向彎曲應(yīng)力。由活塞和連桿重量引起的慣性力,使連桿承受拉應(yīng)力,所以連桿承受的是沖擊性質(zhì)的動載荷,因此要求連桿重量輕,強度要好。
連桿材料一般采用45鋼或40cr,45Mn2等優(yōu)質(zhì)鋼或合金鋼。鋼制連桿都用模鍛制造毛坯。它的鍛造工藝有兩種方案,將連桿體和蓋分開鍛造,連桿體和蓋整體鍛造。
從鍛造后材料的組織來看,分開鍛造的連桿蓋金屬纖維是連續(xù)的,因此具有較高的強度,而整體鍛造的連桿,銑切后,連桿蓋的金屬纖維是斷裂的,因而削弱了強度。整體鍛造要增加切開連桿的工序,但整體鍛造可以提高材料利用率,減少結(jié)合面的加工余量。加工時裝夾也較方便。工廠中連桿的材料是40cr,調(diào)質(zhì)處理,整體鍛造,只需要一套鍛模,一次便可鍛成,也有利于組織和管理生產(chǎn)。鍛造時表面冷卻速度快,對內(nèi)產(chǎn)生壓應(yīng)力,表面應(yīng)力是平衡的,但銑分開面后應(yīng)力不平衡,易變形,所以要增加校力這一工序。
曲軸連桿廠的連桿加工屬于大批量生產(chǎn),而連桿剛性差,因此工藝路線多為工序分散,大部分工序用高生產(chǎn)率的組合機床和專用機床,并廣泛地使用氣動、液動夾具,以提高生產(chǎn)率。我們在車間首先看到的是連桿毛坯件,它的大頭孔是橢圓的,沿橢圓短軸銑分開面,去掉加工余量,正好是一個圓與曲軸相配合,毛坯鍛造后要進行磁場探傷,檢驗裂紋,并校直保證直線度。在車間,我們看到過程卡把工序排為40多個,主要分為粗加工,半精加工和精加工三個階段。
首先進行兩端面加工。連桿的兩端面是連桿加工過程中最主要的定位基準(zhǔn)面,而且在許多工序中使用,所以應(yīng)先加工它,且隨著工藝過程的進行要逐漸精化其基準(zhǔn),以提高其定位精度。我們在車間看到銑兩端時,為保證兩端面對稱于桿身軸線,以桿身定位,在專用銑床上裝
兩把硬質(zhì)合金端銑刀盤,工件裝夾在回轉(zhuǎn)工作臺上作低速回轉(zhuǎn)進給運動,加工完一個面,轉(zhuǎn)過180°再加工另一端面。然后采用雙端面磨床進行磨削,以保證兩端面的平行度和高的生產(chǎn)率。
連桿大小頭端面對稱分布在桿身的兩側(cè),由于大小頭孔厚度不等,所以大頭端面與同側(cè)小頭端面不在一個平面上,用這樣不等高面作定位基準(zhǔn),必定會產(chǎn)生定位誤差。因大小頭厚度公差要求不高,工廠在制定工藝時采用最經(jīng)濟的方法加工成一樣厚度。這樣,以任一端面、小頭孔及工藝凸臺作為大部分工序的統(tǒng)一定位基準(zhǔn),有利于保證連桿的加工精度,而且端面面積大,定位也比較穩(wěn)定。
連桿大小頭孔的加工是連桿加工中的關(guān)鍵工序,尤其大頭孔的加工是連桿各部位加工中要求最高的部位,直接影響連桿成品的質(zhì)量。
一般先加工小頭孔,因尺寸小,鍛坯上不鍛出預(yù)孔,所以小頭孔首道工序為鉆削加工,加工方案多為:鉆—擴(拉)—鏜(鉸),采用有三個爪的浮動夾板,自動定心夾緊,它的錐度和小頭錐度相同,并用大孔心軸定位,避免轉(zhuǎn)動。然后加工大頭孔,一般都會鍛出預(yù)孔,所以加工方案為粗鏜—半精鏜—精鏜。采用整體鍛造大頭孔在半精鏜之后將連桿身蓋銑開,并以分開面定位鉆螺紋出孔,斜剖式結(jié)構(gòu)連桿剛性不足,設(shè)計時加浮動支撐,然后合鉆擴,攻螺孔保證同軸度,修正螺紋孔時,可用銑刀擴孔,不用鉆頭,以消除向下的力。這一工序主要保證螺紋孔的
垂直度,可將垂直度轉(zhuǎn)化為平行度進行檢驗。
組裝后精鏜大小頭孔,在專用雙軸鏜床上同時進行。大小頭孔的光整加工是保證孔的尺寸,形狀精度和表面粗糙度不可缺少的工序。大孔的衍磨是一種有切屑的加工,去掉波峰,提高孔的圓柱度,小孔的滾壓則是一種無切屑的加工,把波峰壓下去,降低表面粗糙度。
連桿本身剛度比較低,易變形,所以在安排工藝時應(yīng)把各主要面粗、精加工工序分開,這樣,粗加工產(chǎn)生的變形在半精加工中得到修正,半精加工產(chǎn)生的變形在精加工中得到修正,最后達到零件的技術(shù)要求。
連桿是發(fā)動機的關(guān)鍵零件,對強度有較高的要求。其作用是把活塞和曲軸聯(lián)接起來,使活塞的往復(fù)直線運動變?yōu)榍S的回轉(zhuǎn)運動,以輸出動力。就制造工藝而言,連桿屬于較難鍛造與加工的一種零件,為了提高發(fā)動機的效率,延長其使川壽命,有必要對連桿加工工藝進行改進。
1 不同的連桿加工工藝流程對比
原加工工藝流程:毛坯鍛造——銑兩端面——粗磨兩端畫——鉆小頭孔——鉆大頭孔——車大頭外圓——粗鏜小頭孔——粗鏜大頭孔——半精鏜小頭孔——半精鏜大頭孔——銑切連桿大頭分開面——粗銑分離面——精銑分離面——鉆鉸定位銷孔——攻螺紋孔——磨分離面——精磨兩端面——壓銅套——精鏜大頭孔——精鏜銅套孔——珩磨大頭孔
改進后加工工藝流程:毛坯鍛造——粗銑兩端面——鉆大小頭孔——粗磨兩端面——粗鏜大小頭孔——車大頭外圓——鉆、攻螺栓孔——連桿撐斷——精磨兩端面——壓銅套——精鏜大頭孔、銅套孔——滾壓銅套孔——珩磨大頭孔。
2 連桿加工藝改進分析
(1)采用了連桿撐斷新工藝。連桿撐斷工藝的基本原理是:在連桿大頭孔的剖分面上,加一個V型凹槽,在該凹槽處施加一個撐開的力,由于在V形凹槽處形成壓力集中,而將連桿和連桿蓋撐開,斷口沿V形凹槽準(zhǔn)確斷裂,其斷裂面的特性可使連桿體和連桿蓋在裝配時處于最佳吻合狀態(tài)。
采用撐斷工藝將連桿斷開以后,連桿蓋、桿結(jié)合面具有完全嚙合的犬牙交錯結(jié)構(gòu),以保證結(jié)合面精確相接、吻介,結(jié)合面不須再進行任何加工。其優(yōu)點如下:
①減少了加工工序數(shù)(無結(jié)合面的銑削、磨削及拉削),使連桿加工變得更簡單,節(jié)省機床投資25%,減少刀具費用35%,節(jié)省能源40% ,節(jié)省面積20%。
②由于結(jié)合面的特殊開口,使蓋的定位準(zhǔn)確,可保證連桿在使用過程中的精度,而不需要定位螺栓(只需要普通螺栓),省去了螺母。
③由于連桿撐斷接觸面是凸凹不平的,大大提高了接觸面積,從而提高了連桿承載能力、抗剪能力。
④節(jié)省了操作人員。
⑤降低了生產(chǎn)線運行費用,減少了維護保養(yǎng)。
(2)提高了連桿兩孔中心距尺寸精度。一是加工工藝改進前,大頭孔與小頭孔的鉆、粗鏜以及精鏜均分開為兩道工序,兩次裝夾,故兩孔中心距的尺寸公差分布范圍較大;工藝改進后,一次裝夾鉆或鏜兩孔,能夠?qū)⑦B桿兩孔中心距尺寸誤差控制在很小范圍內(nèi)。二是工藝改進后,車大頭外圓在粗鏜大頭孔和小頭孔后,更有利于后續(xù)工序回轉(zhuǎn)自由度限制的一致性與穩(wěn)定性。
(3)保證了兩孔的平行度。一是連桿毛坯為模鍛件,孔加工余量大,內(nèi)應(yīng)力變形大,改進后的工藝,由于先鉆兩孔,再粗磨端面,使連桿在鉆孔工序時,避免了孔端面平面度、平行度被破壞。二是改進后的連桿加工工藝,以連桿整個端面定位,并壓緊整個端面,同時鏜兩孔,保證連桿兩孔的平行度。
(4)提高了連桿大頭孔和小頭銅套孔的光潔度、尺寸精度、形狀精度。改進后的連桿加工工藝,小頭銅套孔在精位后進行滾壓加工,有利于提高光潔度、尺寸精度,并能產(chǎn)生有利的殘余壓應(yīng)力。而大頭孔采用珩磨加工,珩磨頭與機床主軸浮動連接,有利于減少主軸回轉(zhuǎn)中心與被加工孔的同軸度誤差的影響
3 連桿撐斷工藝應(yīng)考慮的問題
連桿撐斷技術(shù)的原理是利用材料斷裂理論,為保證連桿產(chǎn)品的性能和切削性,應(yīng)關(guān)注以下幾個問題:
(1)毛坯材料及毛坯工藝
撐斷連桿要求其材料塑性變形小、強度較好、脆性適中、工藝性好。按撐斷加工技術(shù)要求,主要采用的材料有:高碳鋼(廣泛應(yīng)用,例:一汽的連桿材料C70S6BY)、球墨鑄鐵、可鍛鑄鐵、粉末燒結(jié)材料(粉末成分為Fe一Cu一C一S),這幾種材質(zhì)的毛坯,室溫下可實現(xiàn)脆性斷裂,連桿大頭孔不產(chǎn)生明顯塑性變形,
其變形量≤40微米。例:一汽的連桿材料C7056BY其金相組織為珠光體加斷續(xù)的鐵素體,抗拉強度為900-1050MPa,屈服極限為520MPa,最大延伸率為10%。
撐斷連桿鍛件毛坯形狀、尺寸與普遍連桿毛坯并無多大區(qū)別,但為減少撐斷過程中的撐斷力及大頭孔變形,在不影響斷裂面嚙合的情況下,盡量減少大頭孔中心處撐斷截面積。撐斷連桿鍛件在鍛造過程中不需特殊的防范,一般鍛后在保護坑內(nèi)空冷。
(2)溫度影響
撐斷面分為三區(qū),由斷裂源向外依次可分為纖維區(qū)、放射區(qū)、剪切唇。當(dāng)斷面的放射區(qū)較寬時,表示材料的塑性差,脆性較大。反之,纖維區(qū)較大,表明材料就塑性及韌性較好,如何加大放射區(qū)寬度,縮小纖維區(qū)寬度,是實現(xiàn)脆性斷裂的條件。
圖1所示為溫度對斷口三要素各區(qū)大小的影響,材料為40Cr。從圖中可見,當(dāng)溫度低于室溫時,放射區(qū)顯著增大,為室溫下實施連桿的撐斷工藝提供了保障。
圖2 溫度對脆性斷裂的影響 圖3 溝槽深度與斷裂強度的關(guān)系
(3)初始溝槽的加工
初始溝槽深度與斷裂強度成反比(如圖2所示),即對于一定的應(yīng)力值,存在著一個臨界的溝槽裂紋深度。
因此,初始溝槽加工工藝、方法直接影響撐斷加工質(zhì)量。目前常規(guī)的機加工方法是用拉削工藝加工“V型”槽,但為減少撐斷變形及撐斷力,提高撐斷效率和質(zhì)量,激光加工初始溝槽方法正逐步得以運用。
4 連桿加工夾具的幾點說明
(1)自為基準(zhǔn)
為適應(yīng)“一面一孔一凸臺”(即大小頭端面、小頭孔、大頭孔一側(cè)外圓面)的統(tǒng)一精基準(zhǔn),而大、小頭孔是一次裝夾中鏜出,故須考慮“自為基準(zhǔn)”情況,這時小頭定位銷應(yīng)做成活動的,當(dāng)連桿定位夾緊后,再抽出定位銷,進行加工。
(2)車大頭外圓夾具
傳統(tǒng)的車大頭外圓的定位方式為以連桿端面、連桿小頭孔、連桿大頭孔內(nèi)側(cè)定位(即一面兩銷定位方式)。此種定位方式的問題是:因前道工序租鏜大頭孔是以毛坯外側(cè)定位來加工內(nèi)孔,由此而產(chǎn)生毛坯的較大鍛造尺寸公差帶來了加工后內(nèi)孔兩側(cè)壁厚超差,致使車大頭外圓時單邊現(xiàn)象嚴(yán)重,甚至車不出來而報廢。
根據(jù)連桿毛坯外側(cè)對稱的特征,可設(shè)計一種自定心車夾具,以實現(xiàn)毛坯的對中定位。如圖3所示,將連桿裝在夾具體上,移動定位套與工件接觸,利用定位套前端的錐面對連桿大頭兩側(cè)實現(xiàn)對中頂定位。然后裝上開口壓板,擰緊六角螺釘使工件夾緊后,再將定位套退回規(guī)定位置進行車削,阻尼鋼球主要起定位套在加工狀態(tài)下的限位作用。
圖4 車連桿大頭夾具示意圖
(3)自動定心夾緊機構(gòu)與聯(lián)動夾緊機構(gòu)的運用
自動定心夾緊機構(gòu)是一種同時實現(xiàn)對工件定心定位和夾緊的夾緊機構(gòu),即在夾緊過程中,能使工件相對于某一對稱面保持對稱性。連桿銑兩端面工序是以連桿桿身對稱面定位,其夾具可采用螺旋定心夾緊機構(gòu)(如圖4所示),利用左右反螺紋的螺桿帶動壓塊夾緊工件,并采用雙面銑,來實現(xiàn)連桿對稱度要求及減少工件變形。
連桿加工中,聯(lián)動夾緊機構(gòu)也得到廣泛采用,例同時幢大小頭孔夾具,一個夾緊力源對工件大小頭孔處同時實施夾緊。聯(lián)動夾緊機構(gòu)設(shè)計的關(guān)鍵是必須要有中間浮動環(huán)節(jié),才能保證夾緊力能同時均勻地傳遞作用于各個施力點。
圖5 螺旋定心夾緊機構(gòu)示意圖
5結(jié)束語
雖然連桿加工本身所包括的工藝內(nèi)容并不復(fù)雜,但由于材質(zhì)、外形尺寸以及要求的加工精度,經(jīng)常給加工帶來困難。隨著高效加工工藝的出現(xiàn),更合理、更經(jīng)濟地安排零件的加工工藝及生產(chǎn)流程便成為可能。因撐斷工藝具有傳統(tǒng)工藝無可比擬的優(yōu)點,因而迅速獲得了應(yīng)用。
參考文獻
1、上海交通大學(xué).金屬斷口分析.國防出版社,1979
2、劉寶深.實驗斷裂和損傷力學(xué)測試技術(shù).機械工業(yè)出版社,1994
3、劉鴻文.材料力學(xué).高等教育出版社,1990
4、 宋正元.康明斯B系列連桿工藝設(shè)計的研究與實踐.組合機床與自動化加工技術(shù),1999 (7)
5、王先透.機械制造工藝學(xué).機械工業(yè)出版社,1999.10
6、貴州工學(xué)院.機床夾具結(jié)構(gòu)圖冊.貴州人民出版社,1983
XX設(shè)計(XXX)任務(wù)書
姓名:
任務(wù)下達日期: 20XX 年 3 月 13 日
設(shè)計(論文)開始日期: 20XX 年 3 月 14 日
設(shè)計(論文)完成日期: 20XX 年 6 月 20 日
一、設(shè)計(論文)題目: 連桿平行度測量儀
二、專題題目:
三、設(shè)計的目的和意義: 我國汽車及相關(guān)零部件行業(yè)發(fā)展迅速,而連桿又是連桿是發(fā)動機的五大主關(guān)件之一,是發(fā)動機傳遞動力的主要運動件。因而連桿檢測成了生產(chǎn)中頻繁而又不可缺少的環(huán)節(jié)。連桿平行度測量儀是專門為檢測汽車連桿而設(shè)計的專用測量工具,其結(jié)構(gòu)簡單、測量精度高。它極大地提高了檢測效率,同時也提高了檢測的精度,具有很好的市場前景。
四、設(shè)計(論文)主要內(nèi)容: 本設(shè)計的主要內(nèi)容是設(shè)計連桿平行度測量儀的機械系統(tǒng)和控制系統(tǒng),我設(shè)計的主要工作是機械系統(tǒng)的設(shè)計。
五、設(shè)計目標(biāo): 本設(shè)計的設(shè)計目標(biāo)是將連桿平行度測量儀的機械系統(tǒng)的每一個零件進行三維造型,并進行裝配和運動仿真。
六、進度計劃: 2006年3月13日至3月31日進行為期3周的生產(chǎn)實習(xí);4月1日至4月10日完成對設(shè)計題目的資料收集與查詢;4月11日至5月20日完成各零件及圖紙的繪制;5月11日至6月10日完成運動仿真和畢業(yè)設(shè)計說明書的編寫;6月11日至6月20日最后的審稿及說明書和圖紙的打印。
七、參考文獻資料: 趙松主編.機電一體化技術(shù)基礎(chǔ)及應(yīng)用.機械工業(yè)出版社.1996;王錫良主編.機械計量測試技術(shù).東北工業(yè)出版社.1995;李信主編.微型計算機原理與接口.南開大學(xué)出版社.2002等參考資料近20本。
指 導(dǎo) 教 師:
院(系)主管領(lǐng)導(dǎo):
年 月 日
附錄2 外文譯文
虛擬制造技術(shù)及其應(yīng)用
摘要:闡述了虛擬制造的基本概念,虛擬制造的核心技術(shù),以及虛擬制造技術(shù)應(yīng)用。
關(guān)鍵詞:制造業(yè) 虛擬制造 虛擬現(xiàn)實
0 引言
當(dāng)今的制造業(yè)基本技術(shù)日臻成熟,其市場處于以消費者為導(dǎo)向的市場環(huán)境下,產(chǎn)品品種、上市時間和用戶滿意度成為企業(yè)取得競爭優(yōu)勢的主要因素。制造業(yè)這種全球化的激烈競爭不斷催生了各種先進制造技術(shù)和新的制造哲理,虛擬制造技術(shù)將會在本世紀(jì)涌向潮頭,其樸素的思想和高新的技術(shù)手段都為研究領(lǐng)域和業(yè)界所推崇。
虛擬制造就是根據(jù)企業(yè)市場競爭的需求,在強調(diào)柔性和快速的前提下,美國80年代提出的,隨著計算機技術(shù)和信息網(wǎng)絡(luò)技術(shù)的發(fā)展,在90年代得到人們的重視,并獲得迅速的發(fā)展。
1 虛擬制造
虛擬制造的基本思想是在產(chǎn)品制造過程的上游——設(shè)計階段就進行對產(chǎn)品制造全過程的虛擬集成,將全階段可能出現(xiàn)的問題解決在這一階段,通過設(shè)計的最優(yōu)化達到產(chǎn)品的一次性制造成功。
虛擬現(xiàn)實技術(shù)是使用感官組織仿真設(shè)備的真實或虛幻環(huán)境的動態(tài)模型生成或創(chuàng)造出人能夠感知的環(huán)境或現(xiàn)實,使人能夠憑借直覺作用于計算機產(chǎn)生的三維仿真模型的虛擬環(huán)境?;谔摂M現(xiàn)實技術(shù)的虛擬制造技術(shù)在一個統(tǒng)一模型之下對設(shè)計和制造等過程集成,它將與產(chǎn)品制造相關(guān)的各種過程與技術(shù)集成在三維的、動態(tài)的仿真真實過程的實體數(shù)字模型之上。其目的是在產(chǎn)品設(shè)計階段,借助建模與仿真技術(shù)及時地、并行地、模擬出產(chǎn)品未來制造過程乃至產(chǎn)品全生命周期的各種活動對產(chǎn)品設(shè)計的影響,預(yù)測、檢測、評價產(chǎn)品性能和產(chǎn)品的可制造性等等。從而更加有效的、經(jīng)濟的、柔性的組織生產(chǎn),增強決策與控制水平,有力地降低由于前期設(shè)計給后期制造帶來的回溯更改,達到產(chǎn)品的開發(fā)周期和成本最小化、產(chǎn)品設(shè)計質(zhì)量的最優(yōu)化、生產(chǎn)效率的最大化。
虛擬制造系統(tǒng)是各制造功能的虛擬集成,它的可視化集成范圍包括與設(shè)計相關(guān)的各項子系統(tǒng)的功能,如用戶支持、工程分析、材料選用、工藝計劃、工裝分析、快速原型,甚至包括制造企業(yè)全部功能(如計劃、操作、控制)的集成。
虛擬制造系統(tǒng)擁有產(chǎn)品和相關(guān)制造過程的全部信息,包括虛擬設(shè)計、制造和控制產(chǎn)生的數(shù)據(jù)、知識和模型信息。虛擬控制制造系統(tǒng)按照功能歸集為三種不同類型的子環(huán)境,共同構(gòu)成中心三元耦合的系統(tǒng)模式:
(1)虛擬制造設(shè)計中心:給設(shè)計者提供各種工具以便虛擬設(shè)計、虛擬制造,設(shè)計出符合設(shè)計準(zhǔn)則(如DFX)的產(chǎn)品模型;
(2)虛擬制造加工中心:研究開發(fā)產(chǎn)品制造過程模型和環(huán)境模型及其分析各種可行的生產(chǎn)計劃和工藝規(guī)劃;
(3)虛擬制造控制中心:評價產(chǎn)品設(shè)計、產(chǎn)品原型、生產(chǎn)計劃、制造模擬和控制策略等等。
2 虛擬制造技術(shù)支持
虛擬制造技術(shù)是多學(xué)科綜合的系統(tǒng)技術(shù),需要研究開發(fā)相應(yīng)的硬件集成系統(tǒng)與軟件,就軟件技術(shù)而言,相關(guān)的研究支持如下:
可視化:真實、直觀地再現(xiàn)主觀產(chǎn)品與客觀制造過程;
基本環(huán)境:增強可視化和其它虛擬制造功能的集成系統(tǒng)平臺;
信息描述:表達各種信息,包括數(shù)據(jù)、知識和模型的統(tǒng)一的方法、語義、語法;
中介模型:構(gòu)造、定義、開發(fā)對過程易于中斷介入的模型;
基層集成組織結(jié)構(gòu):硬件與軟件的基層組織結(jié)構(gòu);
仿真模型:在計算機系統(tǒng)中設(shè)計的真實系統(tǒng)模型;
應(yīng)用方法:產(chǎn)品多樣性與過程動態(tài)性的共同特征的抽象提??;
制造特征:各種材料在虛擬制造環(huán)境中的變化過程;
虛擬制造系統(tǒng)評價:可制造性、工藝性、可靠性、經(jīng)濟性、質(zhì)量、工期等等。
2.1建模技術(shù)
虛擬制造系統(tǒng)是現(xiàn)實制造系統(tǒng)在虛擬環(huán)境下的映射,是RMS的模型化、形式化和計算機化的抽象描述和表示。VMS的建模應(yīng)包括:生產(chǎn)模型、產(chǎn)品模型和工藝模型的信息體系結(jié)構(gòu)。
(1)生產(chǎn)模型歸納為靜態(tài)描述和動態(tài)描述兩個方面。靜態(tài)描述是指系統(tǒng)生產(chǎn)能力和生產(chǎn)特性的描述。動態(tài)描述是指在已知系統(tǒng)狀態(tài)和需求特性的基礎(chǔ)上預(yù)測產(chǎn)品生產(chǎn)的全過程。
(2)產(chǎn)品模型是制造過程中,各類實體對象模型的集合。對VMS來說,要使產(chǎn)品實施過程中的全部活動集成,就必須具有完備的產(chǎn)品模型,所以虛擬制造下的產(chǎn)品模型不再是單一的靜態(tài)特征模型,它能通過映射、抽象等方法提取產(chǎn)品實施中各活動所需的模型。
(3)工藝模型將工藝參數(shù)與影響制造功能的產(chǎn)品設(shè)計屬性聯(lián)系起來,反應(yīng)生產(chǎn)模型與產(chǎn)品模型之間的交互作用。工藝模型必須具備以下功能:計算機工藝仿真、制造
數(shù)據(jù)表、制造規(guī)劃、統(tǒng)計模型以及物理和數(shù)學(xué)模型。
2.2仿真技術(shù)
仿真就是應(yīng)用計算機對復(fù)雜的現(xiàn)實系統(tǒng)經(jīng)過抽象和簡化形成系統(tǒng)模型,然后在分析的基礎(chǔ)上運行此模型,從而得到系統(tǒng)一系列的統(tǒng)計性能。
仿真的基本步驟為:研究系統(tǒng)——收集數(shù)據(jù)——建立系統(tǒng)模型——確定仿真算法——建立仿真模型——運行仿真模型——輸出結(jié)果并分析。
產(chǎn)品制造過程仿真,可歸納為制造系統(tǒng)仿真和加工過程仿真。虛擬制造系統(tǒng)中的產(chǎn)品開發(fā)涉及到產(chǎn)品建模仿真、設(shè)計過程規(guī)劃仿真、設(shè)計思維過程和設(shè)計交互行為仿真等,以便對設(shè)計結(jié)果進行評價,實現(xiàn)設(shè)計過程早期反饋,減少或避免產(chǎn)品設(shè)計錯誤。加工過程仿真,包括切削過程仿真、裝配過程仿真,檢驗過程仿真以及焊接、壓力加工、鑄造仿真等。目前上述兩類仿真過程是獨立發(fā)展起來的,尚不能集成,而VM中應(yīng)建立面向制造全過程的統(tǒng)一仿真。
2.3虛擬現(xiàn)實技術(shù)
虛擬現(xiàn)實技術(shù)是在為改善人與計算機的交互方式,提高計算機可操作性中產(chǎn)生的,它是綜合利用計算機圖形系統(tǒng)、各種顯示和控制等接口設(shè)備,在計算機上生成可交互的三維環(huán)境(稱為虛擬環(huán)境)中提供沉浸感覺的技術(shù)。
由圖形系統(tǒng)及各種接口設(shè)備組成,用來產(chǎn)生虛擬環(huán)境并提供沉浸感覺,以及交互操作的計算機系統(tǒng)稱為虛擬現(xiàn)實系統(tǒng)。虛擬現(xiàn)實系統(tǒng)包括操作者、機器和人機接口3個基本要素。利用VRS可以對真實世界進行動態(tài)模似,通過用戶的交互輸入,并及時按輸出修改虛擬環(huán)境,使人產(chǎn)生身臨其境的沉浸感覺。虛擬現(xiàn)實技術(shù)是VM的關(guān)鍵技術(shù)之一。
3 VM在制造業(yè)中應(yīng)用
雖然在產(chǎn)品開發(fā)過程中應(yīng)用建模和仿真可以大大縮短開發(fā)周期,改進產(chǎn)品的性能和可靠性,但在工業(yè)界的設(shè)計過程中實際應(yīng)用并不多。目前的仿真系統(tǒng)還不能適應(yīng)工業(yè)界在設(shè)計過程中進行分析和驗證等的要求。
高級工程仿真系統(tǒng)應(yīng)具有下列特點:
三維的復(fù)雜零件”零件接口;本質(zhì)上不同響應(yīng)特性的多元材料;材料重要的非線性性質(zhì),諸如:非牛頓行為、塑料變形、斷裂;多相現(xiàn)象;帶有化學(xué)反應(yīng)的多相能量轉(zhuǎn)移;移動或自由邊界;非線性動力學(xué)。
在以模型為基礎(chǔ)的設(shè)計中,實現(xiàn)高級工程仿真的關(guān)鍵技術(shù)可歸納如下:
用戶接口;分析式立體造型;對殼體和實體的先進網(wǎng)格生成算法(有限元分析用);解的誤差分析和改進;材料模型;優(yōu)化目標(biāo)函數(shù)的設(shè)計;面向?qū)ο蟮能浖こ?;海量并行計算;可視化?
把這些技術(shù)集成起來,可以幫助設(shè)計者進行設(shè)計,了解設(shè)計出來的產(chǎn)品的性能。應(yīng)用上述先進的網(wǎng)格生成算法、誤差分析及計算,可組成自適應(yīng)算法,使僅懂得機構(gòu)、不懂得分析的設(shè)計者也能設(shè)計產(chǎn)品及設(shè)計這一產(chǎn)品的制造過程。自適應(yīng)能力可以保證分析的精度。由于重要的幾何性質(zhì)可以參數(shù)化,因此可以進行形狀的優(yōu)化等。
虛擬制造技術(shù)首先在飛機、汽車等領(lǐng)域獲得成功的應(yīng)用。目前VMT應(yīng)用在以下幾個方面:
3.1虛擬企業(yè)
虛擬企業(yè)建立,其中有一條最重要的原因是因為各企業(yè)本身無法單獨滿足市場需求,迎接市場挑戰(zhàn)。因此,為了快速響應(yīng)市場的需求,圍繞新產(chǎn)品開發(fā),利用不同地域的現(xiàn)有資源、不同的企業(yè)或不同地點的工廠,重新組織一個新公司。該公司在運行之前,必須分析組合是否最優(yōu),能否協(xié)調(diào)運行,并對投產(chǎn)后的風(fēng)險、利益分配等進行評估。這種聯(lián)作公司稱為虛擬公司,或者叫作動態(tài)聯(lián)盟,是一種虛擬企業(yè),它具有集成性和實效性兩大特點的經(jīng)濟實體。
3.2虛擬產(chǎn)品設(shè)計
例如飛機、汽車的外形設(shè)計,其形狀是否符合空氣動力學(xué)原理,運動過程中的阻力,其內(nèi)部結(jié)構(gòu)布局的合理性等。在復(fù)雜管道系統(tǒng)設(shè)計中,采用虛擬技術(shù),設(shè)計者可以”進入其中0進行管道布置,并可檢查能否發(fā)生干涉。在計算機上的虛擬產(chǎn)品設(shè)計,不但能提高設(shè)計效率,而且能盡早發(fā)現(xiàn)設(shè)計中的問題,從而優(yōu)化產(chǎn)品的設(shè)計。例如美國波音公司投資40億美元研制波音777噴氣式客機,從1990年10月開始到1994年6月僅用了3年零8個月時間就完成了研制,一次試飛成功,投入運營。波音公司分散在世界各地的技術(shù)人員可以從777客機數(shù)以萬計的零部件中調(diào)出任何一種在計算機上觀察、研究、討論,所有零部件均是三維實體模型。可見虛擬產(chǎn)品設(shè)計給企業(yè)帶來的效益。
3.3虛擬產(chǎn)品制造
應(yīng)用計算機仿真技術(shù),對零件的加工方法、工序順序、工裝的選用、工藝參數(shù)的選用,加工工藝性、裝配工藝性、配合件之間的配合性、連接件之間的連接性、運動構(gòu)件的運動性等均可建模仿真,可以提前發(fā)現(xiàn)加工缺陷,提前發(fā)現(xiàn)裝配時出現(xiàn)的問題,從而能夠優(yōu)化制造過程,提高加工效率。
3.4虛擬生產(chǎn)過程
產(chǎn)品生產(chǎn)過程的合理制定、人力資源、制造資源、物料庫存、生產(chǎn)調(diào)度、生產(chǎn)系統(tǒng)的規(guī)劃設(shè)計等,均可通過計算機仿真進行優(yōu)化,同時還可對生產(chǎn)系統(tǒng)進行可靠性分析,對生產(chǎn)過程的資金進行分析預(yù)測,對產(chǎn)品市場進行分析預(yù)測等,從而對人力資源、制造資源的合理配置,對縮短產(chǎn)品生產(chǎn)周期,降低成本意義重大。
4 虛擬制造系統(tǒng)體系結(jié)構(gòu)
CIM集成是通過物理的、邏輯的聯(lián)系以便在制造設(shè)備之間傳遞信號,以龐大的信息流為“網(wǎng)線”粘連起企業(yè)活動的全部活動“節(jié)點”,共同澆結(jié)成一整塊“企業(yè)機器”,實際上從各個方面降低了企業(yè)的柔性。而虛擬制造則完全是數(shù)字模型的集成,提供了有別于CIMS“物理集成”的虛擬集成方案,將相互孤立的制造技術(shù)如CAD、CAM、CAPP等等集成在一個虛擬產(chǎn)品制造環(huán)境下,以現(xiàn)實對制造過程的一一對應(yīng)的模型化映射關(guān)系,它相對于物理世界有功能一致性、結(jié)構(gòu)相似性的特點,是對實體制造企業(yè)的產(chǎn)品、作業(yè)、環(huán)境及其評價行為等等四個特征的虛擬實現(xiàn)。虛擬現(xiàn)實技術(shù)應(yīng)用于現(xiàn)在的制造系統(tǒng)如CAD、CAPP、CAM,能夠大大增強各個子系統(tǒng)之間的協(xié)調(diào)與并行。面向模型集成各個子系統(tǒng)功能是虛擬制造技術(shù)的關(guān)鍵之一,由于產(chǎn)品的多樣性與制造過程的動態(tài)性,虛擬制造環(huán)境是一個動態(tài)多變的集成環(huán)境,其過程會產(chǎn)生大量的各種數(shù)據(jù),虛擬過程的數(shù)據(jù)管理變得非常復(fù)雜。面向產(chǎn)品與過程的虛擬制造系統(tǒng)需要對產(chǎn)品、作業(yè)、環(huán)境和評價的數(shù)據(jù)、知識、模型進行共同特征抽取與異型制造過程創(chuàng)建。
擬實制造的基礎(chǔ)是對制造過程(即把各種材料變成產(chǎn)品的過程)的理論和方法進行深入的了解。有了這些了解,才有可能在計算機上進行擬實制造,從而揭示一個產(chǎn)品制造全過程的種種復(fù)雜問題。隨著擬實制造的發(fā)展,它將為工程師們提供一個從產(chǎn)品的概念形成、設(shè)計、制造到實現(xiàn)的全過程三維可視及交互的環(huán)境;它將促使實現(xiàn)制造驅(qū)動設(shè)計,要求設(shè)計者在設(shè)計階段把一個產(chǎn)品的構(gòu)思、設(shè)計、制造統(tǒng)統(tǒng)考慮好。目前,電子類產(chǎn)品,特別是大規(guī)模集成電路,相對地比機械類產(chǎn)品簡單,制造過程具有通用性,發(fā)展得較成熟;機械類產(chǎn)品相對較復(fù)雜,進展得較慢。另外,擬實制造的實現(xiàn)是建筑在一個企業(yè)內(nèi)外實行計算機集成基礎(chǔ)上的,只有在大范圍采用計算機集成后,才能有效地實行擬實制造,并在這基礎(chǔ)上過渡到敏捷制造時代。因此,今天我們在大范圍內(nèi)推廣CIMS的應(yīng)用,是有很深遠的歷史意義的。它將為我國實現(xiàn)跳躍式發(fā)展,打下堅實的基礎(chǔ)。
附錄3 外文原文
Virtual Manufacturing Technology and Its Application
Abstract:This paper describes the fundamental conception,the key virtual technology of virtual manufacturing and its application.
Keywords:Manufacturing industry Virtual manufacturing Virtual reality
0 preface
Nowadays the manufacturing industry basic technique is attain mature, its market be placed in with consumer for direction of market environment descend, product species, the time appear on market and the customer satisfaction to become main factor that the business enterprise obtains the competitive advantage. The manufacturing industry fierce competition of this kind of globalization urges to born various of the manufacturing technique and new manufacturing philosophies forerunners continuously, Virtual manufacturing technique will flow out toward the tide head in this century, it’s simple thought and high and new technique means are all worshiped by studying realm and industries .
Virtual manufacturing just according to the need of the business enterprise market competition, while emphasize the gentle and fast premise, in the 80's the United States put forward of, along with the development of the computer technique and the information networks technical, get the people's value in 90's, and acquire the quick development.
1 virtual manufacturing
The basic thought of the virtual manufacturing is in the upper stream of the product process- the design stage carry on the conjecture to the product making of the whole process gather, resolving the problem that may appear in the whole stage in this stage, passing to design superior to turn once manufacturing success of attain the product.
The virtual realistic technique is a dynamic state model that uses the sense organs organization to imitate the true or vain environment of true equipments born or create a person can the feeling know of environment or actuality, make person can with borrow the intuition function in three D that calculator produce imitates the true model of virtual environment. According to realistic technical virtual manufacturing technique of conjecture at an unifies the model under gather to the processes such as design and manufacturing etc., it will make with product related various process and techniques gather in three D of, imitate the true true process dynamic state of numerical model of entity on. Its purpose designs the stage in the product, asking for help to set up the mold with imitate the true technique in time, abreast, imitate to produce the article to make in the future the process is to go to various activity of the product whole life cycle to the influence that product design, estimate, examination, evaluate the product function and products can make the sex etc.. Thus and more valid of, economy of, the gentle organization produce, strengthenning decision and controling the level, lowering emolliently because of expecting to design before to behind expected to make to bring of returned to change, attain the development period and cost minimums, products of the product design quantity superior to turn and produced the efficiency to maximize.
The conjecture manufacturing system is the conjecture of each manufacturing function to gather, it can see to turn to gather the scope includes and designs various functions of related sub- system, if customer support, engineering analysis, the material chooses to use, the craft plan, work pack analysis, fast prototype, even include to make all functions( such as plan, operation, control) of business enterprise to gather.
The conjecture manufacturing system owns all informations of the product and related manufacturing process, including the conjecture design and making and controling the output data, knowledge and model informations.The virtual control manufacturing system returns to gather to three kinds of sub- environments of different type according to the function, the system mode that the common composing center three dollar match:
(1)Conjecture manufacturing design center: the one who give design provides various tool for the purpose of conjecture design, the conjecture manufacturing, design to match the product model of design the standard( such as DFX);
(2)Conjecture the manufacturing processes the center: Study to develop the product manufacturing process model and the environment models and its nalytical various viable production plan and craft programmingses;
(3)Conjecture manufacturing control centre:Evaluate the product design, product prototype, produce the plan and make to imitate and control the strategy etc..
2 conjecture manufacturing technique support
The conjecture manufacturing technique is the system technique that many course synthesize, the hardware that needs to study the development to correspond gather system and software, in regard to the software technique, the related research support is as follows:
Can see to turn: True, keep the view ground to reappear the subjective product and objective manufacturing processes;
Basic environment: The to build up can see to turn to gather with other conjecture manufacturing function system terrace;
Information description: Express various information, include data, knowledge and the united method, language righteousness, phrasing of the models;
Win to lie the model: Structure, definition, the model that develop to be easy to to the process break off to get involved;
The basic level gather the organization structure: Grass-roots organization structure of the hardware and software;
Imitate the true model: True system model of the design in the calculator system;
Applied method: The product abstraction of diverse sex and process dynamic state and common characteristic withdraw;
Make the characteristic: Various material makes the variety process in the environment in the conjecture;
Conjecture manufacturing system evaluation: Can make sex, craft, credibility, economy, quantity, the work period...etc..
2.1 set up the mold technique
The conjecture manufacturing system is an actuality manufacturing system under the virtual environment of reflect to shoot, is a RMS model to turn, the formalization and calculators turn abstract description and mean. The VMS set up the mold and should include: Produce the information system structure of the model, the product model and the craft model.
(1)Produce the model induces to describe to describe two aspects with dynamic state for the static state. The static state description mean the system production ability and produce the description of the characteristic .The dynamic state description mean on the foundation that have already known the system appearance and the need characteristic the whole process that the estimate product produce.
(2)The product model is to make in the process, each kind of entity object model gather. To VMS, to make all activities within the product implement processes gather, must have the complete product model, so virtual manufacturing under of product model is not the single static state characteristic model any more, it can pass to reflect to shoot, abstract etc. the method withdraw the product implement in the model that each activity need.
(3)The craft model hand over the product design that the craft parameter and influences make the function belongs to sex to contact, respond the of produce the model and the product model with each other function.The craft model must have the following function:The calculator craft imitate true, manufacturing
Data form, manufacturing programming, the covariance model and physicses and mathematics models.
2.2 imitate the true technique
Imitate is really applied calculator to complicated of realistic system becomes the system model through abstraction and simplifications, then circulate this model on the analytical foundation, thus getting the covariance function of the system a series.
Imitate the really basic step is: Study the system- collections data- establishment the system model- the assurance imitates the true calculate way- build up imitating the true model- circulate imitate the true model- output the result is also analytical.
The product manufacturing process really imitate, can induce for make the system to imitate true and really process the process to imitate. Conjecture manufacturing product within system development involve the product to set up the mimicry true, design process programming imitate true, design the thinking process and designs hand over with each other the behavior imitates true etc., in order to as a result carry on the evaluation to the design, realization design process earlier period feedback, reduce or avoid the product design mistake. Process the process really imitate, including to slice to pare the process to imitate true, really assemble the process to imitate, examine the process to imitate true and weld, the pressure process, casts to imitate true etc..Above-mentioned currently two the types imitate the true process to develop independently of, can't gather still, but VM in really should build up face to make the whole process to unify to imitate.
2.3 virtual realistic technique
Virtual realistic technique is at for improve the person to hand over with calculator with each other way, output in the exaltation calculator maneuverability, it is to synthesize to make use of the calculator sketch system, various manifestation and control etc. to connect a people's equipments, providing to sink the technique of immerse the felling in compute on board born lternant three D environment ( be called the virtual environment)
From the sketch system and various connect a people's equipments to constitute, use to produce the virtual environment and provide to sink to immerse the felling, and the calculator department that hand over to operate with each other knows together as the virtual realistic system.The virtual realistic system includes the operation the , machine and person's machine connects 3 essential elements of.Make use of the VRS can carry on the dynamic state mold to the real world, hand over through a customer to input with each other, and modify the virtual environment according to the exportation in time, make person the creation body faces its band to sink to immerse the felling.The virtual realistic technique is one of the VM key techniques.
3 the VM is applied in the manufacturing industry
Although in product develop process the application set up the mold and imitate and really can shorten to develop the period consumedly, the function and credibilities of the improvement product, in the design process of the industry field the actual application combine not much.Imitate the request that the true system can't still adapt the industry field to carry on the analysis and verification etc. in design process currently.
The deluxe engineering imitate the true system and should have the following characteristics:
Three complicated spare parts of the D the spare parts connects; Essentially different respond to diverse material of the characteristic; The material is important not the line property, such as: Not Newton's behavior, plastics transform, splits; Have another mutually phenomenon; Take to have the chemical reaction much and mutually the energy transfer; Move or free boundary; Not line dynamics.
In taking model as basal design, carry out the deluxe engineering to imitate the true key technique and can induce as follows:
The customer connects; Stereoscopic shape of analytical type; To the born calculate way of the hull body and the advanced mesh of the entities;( an analysis use)The error margin of the solution analysis and improvement; Material model; Excellent turn the design of the target function; Face to the software engineering of the object; The sea quantity proceeds together the calculation; Can see to turn.
These techniques the one who gather get up, can in aid of design carries on the design, the function of the product that the understanding design come out. Apply the mesh born calculate way, the error margin analysis and calculations of the above-mentioned forerunner, can compose of to adapt the calculate way, making know only the organization and don't know the analytical design also can design the product and design the manufacturing process of this product. Can guarantee the analytical accuracy from the orientation ability. Important several properties can turn with the parameter, so can carry on the shape excellent to turn etc..
The application that the conjecture manufacturing technique achieve success in the realms, such as airplane and automobile...etc. first. Currently the VMT application at following few aspects:
3.1 virtual business enterprise
Virtual business enterprise establishment, among them have the most important reason is because each business enterprise can't satisfy the market need alone, greeting the market challenge.Therefore, for responding to the need of the market quickly, surround the new product development, make use of the existing resources, different business enterprise of the different region or the factory of different locations, re- organize a new company.That company must analyze whether combination is superior or not before movement, can moderate the movement, and to hurl the risk, the benefits allotment...etc. of the postnatal period carry on the valuation.This kind of the parter company to be called the virtual company, or be called the dynamic state alliance, is a kind of virtual business enterprise, it has to gather economic entity of sex and real results two greatest characteristicses.
3.2 virtual product design
For example the shape design of the airplane, automobile, whether its shape match the aerodynamicist principle or not, the sport resistance within process, rationality etc. that its internal structure layout.In the complicated piping system design, the one who adopt virtual technique, design can" enter among them 0 carry on piping's arrange, and can check and can take place the interference. At compute the on board virtual product design, not only can raise to design the efficiency, but also can discover the problem in the design as early as possible, thus excellent turn the design of the product. For example the American company of Boeing invests USD 4,000,000,000 to research to manufacture 777 blow out gas type aerobuses of Boeing, using zero 8 month times of 3 years to complete to research to manufacture only from since October of 1990 to June of 1994, trying to fly the success once, devotion luck camp.The Boeing company dispersion adjusts to serve as HE2 YI to sow in to compute the on board observation, research, discussion in the technical personnel of the world-wide locations can from millions zero parts of 777 aerobuses, all zero partses are three D entity models all. It is thus clear that the virtual product designs the performance that brings for business enterprise.
3.3 virtual product manufacturing
The applied calculator imitates the true technique, processing the method, the work preface to the spare parts in proper order, the work pack of choose to use, the craft parameter chooses to use, processing the craft, assembling the craft, matching with the match between piece, linking the conjunction between piece and exercising a piece of sport etc. really all can s
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