氣門搖臂軸支座零件加工工藝規(guī)程及Φ11孔加工專用夾具設(shè)計(jì)

資源目錄里展示的全都有，所見即所得。下載后全都有,請(qǐng)放心下載。原稿可自行編輯修改=【QQ：401339828 或11970985 有疑問可加】 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 遼寧工程 技術(shù)大學(xué) 機(jī)械加工工序卡片 產(chǎn)品型號(hào) 　 零件圖號(hào) 01 　 產(chǎn)品名稱 　 零件名稱 氣門搖臂軸支座 共1頁 第1頁 　 車間 工序號(hào) 工序名 材料牌號(hào) 　 3 鉆孔 HT200 毛坯種類 毛坯外形尺寸 每毛坯可制件數(shù) 每臺(tái)件數(shù) 鑄件 1 1 設(shè)備名稱 設(shè)備型號(hào) 設(shè)備編號(hào) 同時(shí)加工件數(shù) 立式鉆床 Z525 　 1 夾具編號(hào) 夾具名稱 切削液 　 專用夾具 　 工位器具編號(hào) 工位器具名稱 工序工時(shí)/s 準(zhǔn)終 單件 　 　 　0 　 工序號(hào) 工序內(nèi)容 工藝裝備 主軸轉(zhuǎn)速 /r·s-1 切削速度 /m·min-1 進(jìn)給量 fz/(mm/z) 背吃刀 量/㎜ 進(jìn)給 次數(shù) 工序工時(shí)/s 機(jī)動(dòng) 輔助 描圖 3 鉆φ11孔 直柄短麻花鉆、標(biāo)準(zhǔn)粗糙塊、專用夾具 680 23.5 0.10 11 1 　王世達(dá) 底圖號(hào) 　 　 　　 　 　 　 　 　 　 　 　 　 　 　 　 　 裝訂號(hào) 　 　 　 　 　 　 　 　 　 　 設(shè)計(jì) （日期） 審核 （日期） 標(biāo)準(zhǔn)化 （日期） 會(huì)簽日期） 　 　 　 　 　 　 　 　 　 　 　 　 　 標(biāo)記 處數(shù) 更改文件號(hào) 簽字 日期 標(biāo)記 處數(shù) 更改文件號(hào) 簽字 日期 　 　 　 　 　 遼寧工程技術(shù)大學(xué) 機(jī)械加工工藝過程卡片 產(chǎn)品型號(hào) 　 零件圖號(hào) 　 　 　 產(chǎn)品名稱 　 零件名稱 氣門搖臂軸支座 共1頁 第1頁 材料牌號(hào) HT200 毛坯種類 鑄件 毛坯外形尺寸 每壞件數(shù) 1 每臺(tái)件數(shù) 1 備注 　 工序號(hào) 工序名稱 工序內(nèi)容 車間 工段 設(shè)備 工藝裝備 工序時(shí)間 準(zhǔn)終 單件 1 粗銑上端面 粗銑氣門搖臂軸支座的上端面 立式銑床X51 端面銑刀、游標(biāo)卡尺、標(biāo)準(zhǔn)粗糙塊、專用夾具 2 精銑下端面 精銑氣門搖臂軸支座的下端面 　 立式銑床X51 端面銑刀、游標(biāo)卡尺、標(biāo)準(zhǔn)粗糙塊、專用夾具 　 　 3 鉆孔 鉆孔φ11mm孔 立式鉆床 麻花鉆、游標(biāo)卡尺、標(biāo)準(zhǔn)粗糙塊 　 　 4 粗銑 精銑φ26mm圓柱兩端面 臥室鏜床 端面銑刀、專用夾具、標(biāo)準(zhǔn)粗糙塊 5 精銑 精銑φ28mm圓柱兩端面 臥室鏜床 端面銑刀、專用夾具、標(biāo)準(zhǔn)粗糙塊 描圖 6 鉆、擴(kuò)、鉸孔 鉆、擴(kuò)、鉸孔φ18mm孔 　 臥室鏜床 麻花鉆、通孔鏜刀、鉸刀、專用夾具、標(biāo)準(zhǔn)粗糙塊、內(nèi)徑千分尺、游標(biāo)卡尺 　 　 機(jī)電06-3 7 鉆、擴(kuò)、鉸孔 鉆、擴(kuò)、鉸孔φ16mm孔 臥室鏜床 麻花鉆、通孔鏜刀、鉸刀、專用夾具、標(biāo)準(zhǔn)粗糙塊、內(nèi)徑千分尺、游標(biāo)卡尺 王世達(dá) 8 鏜內(nèi)孔 鏜φ18mm、φ16mm孔內(nèi)孔的倒角 　 臥室鏜床 通孔鏜刀、萬能角度卡尺 　 　 描校 9 鉆φ3mm 鉆孔φ3mm孔 　 立式鉆床　 麻花鉆、專用夾具、塞規(guī) 　 　 10 去毛刺 鉗工 平銼 11 清洗 清洗臺(tái) 12 終檢 塞規(guī)、百分表、卡尺等 裝訂號(hào) 　 　 　 　 　 　 　 　 　 　 設(shè)計(jì) 日期 審核 （日期） 標(biāo)準(zhǔn)化 （日期） 會(huì)簽 （日期） 　 　 　 　 　 　 　 　 　 　 　 　 　 標(biāo)記 處數(shù) 更改文件號(hào) 簽字 日期 標(biāo)記 處數(shù) 更改文件號(hào) 簽字 日期 　 　 　 　 遼寧工程技術(shù)大學(xué)課程設(shè)計(jì)　　　　　　　　　　　　　　　　　　　　　　　　16 課 程 設(shè) 計(jì) 題 目： 氣門搖臂軸支座零件加工工藝規(guī)程 及Φ11孔加工專用夾具設(shè)計(jì) 班　　級(jí)： 姓　　名： 指導(dǎo)教師： 完成日期： 摘要 現(xiàn)貨機(jī)械加工行業(yè)發(fā)生著黨課的結(jié)構(gòu)性變化，工藝工裝的設(shè)計(jì)與改良已成為企業(yè)生存和發(fā)展的必要條件，工藝工裝的設(shè)計(jì)與改良直接影響著氣門搖臂軸支座的質(zhì)量與性能。柴油機(jī)行業(yè)作為一個(gè)傳統(tǒng)而富有活力的行業(yè)，近十幾年取得了突飛猛進(jìn)的發(fā)展，在新經(jīng)濟(jì)時(shí)代，柴油機(jī)行業(yè)呈現(xiàn)了新的發(fā)展趨勢，由此對(duì)其它的質(zhì)量，性能立生了新的變化。 本文首先介紹了氣門搖臂軸支座的作用和工藝分析，其次確定毛坯尺寸，然后進(jìn)行了工藝規(guī)程設(shè)計(jì)。 關(guān)鍵詞：工藝分析 工藝規(guī)程設(shè)計(jì) 夾具設(shè)計(jì) Abstract lectures on the spot machining industry is undergoing structural changes. The design and improvement of technology and equipment have become a necessary condition for the existence and development of enterprises. Process Equipment Design and direct impact on improving the quality and performance valve rocker arm shaft bearings. Diesel industry as a traditional and highly dynamic industries, over the last 10 years there has a new diesel engine industry, in the new economic era, has a new diesel engine industry trends, which of the other quality properties with a change in health legislation. This paper introduces the valve rocker arm shaft bearing on the role and process analysis, followed by rough determine the size, then the process specification free verse. Key Words: Process Design Technology of fixture design valve rocker arm shaft bearings 目錄 1. 零件的分析 5 1.1零件的作用 5 2. 確定毛坯、畫毛坯零件圖 6 2.1確定毛坯 6 2.2 畫毛坯零件圖 6 3. 零件制造的工藝設(shè)計(jì) 7 3.1表面加工方法的確定 8 3.2定位基準(zhǔn)的選擇 8 3.3 制定工藝路線錯(cuò)誤！未找到索引項(xiàng)。 9 3.4.1加工設(shè)備和工藝設(shè)備 11 4. 夾具設(shè)計(jì) 11 4.1夾具選擇 11 4.2 夾具設(shè)計(jì) 13 4.2.1 定位分析 13 5.2.2切削力及夾緊力的計(jì)算 13 4.3夾具操作說明 14 4.4.確定導(dǎo)向裝置 14 5.機(jī)床夾具設(shè)計(jì)體會(huì)與展望 15 參考文獻(xiàn) 16 氣門搖臂軸支座零件圖 1. 零件的分析 1.1零件的作用 氣門搖臂之座是柴油機(jī)的重要零件之一。該零件是1105柴油機(jī)中氣門搖臂座結(jié)合部的氣門搖臂軸支座，Φ18mm孔裝搖臂軸，軸上兩端各裝一進(jìn)，排氣門搖臂，Φ16mm孔內(nèi)裝一減壓軸，用于降低氣缸內(nèi)壓力，便于起動(dòng)柴油機(jī)，兩孔間距為56mm可保證減壓軸在搖臂上打開氣門，實(shí)現(xiàn)減壓，該零件通過Φ11mm孔用M10螺桿與氣缸蓋相連。 1.2 零件的工藝分析 由附圖1得知，其材料為HT200，該材料具有較高的強(qiáng)度，耐磨性，耐熱性及減振性，適用于承受較大應(yīng)力，要求耐磨的零件。 該零件主要加工面為Φ18mm，Φ16mm兩圓柱孔，Φ18mm孔的平等度為0.05直接影響搖臂軸的接觸精度及密封，Φ16mm孔的平行度為0.05，粗糙度都為1.6，所以對(duì)軸與孔的接觸精度及密封還是比較高的。 有關(guān)面和孔加工的經(jīng)濟(jì)精度用機(jī)床能達(dá)到的位置精度可知，上述技術(shù)要求是可達(dá)到的，零件的結(jié)構(gòu)工藝性也是可行的。 2. 確定毛坯、畫毛坯零件圖 2.1確定毛坯 根據(jù)零件材料確定毛坯為鑄件，毛坯的鑄造方法選用砂型機(jī)器造型。由參考文獻(xiàn)知，用查表法確定各表面的總余量如表所示。此外，為消除殘余應(yīng)力，鑄造后應(yīng)安排人工時(shí)效。 2.2 畫毛坯零件圖 3. 零件制造的工藝設(shè)計(jì) 生產(chǎn)過程是指將原材料轉(zhuǎn)變?yōu)槌善返娜^程。它包括原材料的準(zhǔn)備、運(yùn)輸和保存，生產(chǎn)的準(zhǔn)備，毛坯的制造，毛坯經(jīng)過加工、熱處理而成為零件，零件、部件經(jīng)裝配成為產(chǎn)品，機(jī)械的質(zhì)量檢查及其運(yùn)行試驗(yàn)、調(diào)試，機(jī)械的油漆與包裝等。 工藝過程是指在生產(chǎn)過程中，通過改變生產(chǎn)對(duì)象的形狀、相互位置和性質(zhì)等，使其成為成品或半成品的過程。機(jī)械產(chǎn)品的工藝過程又可分為鑄造、鍛造、沖壓、焊接、機(jī)械加工、熱處理、裝配、涂裝等工藝過程。其中與原材料變?yōu)槌善分苯佑嘘P(guān)的過程，稱為直接生產(chǎn)過程，是生產(chǎn)過程的主要部分。而與原材料變?yōu)楫a(chǎn)品間接有關(guān)的過程，如生產(chǎn)準(zhǔn)備、運(yùn)輸、保管、機(jī)床與工藝裝備的維修等，稱為輔助生 ????由于零件加工表面的多樣性、生產(chǎn)設(shè)備和加工手段的加工范圍的局限性、零件精度要求及產(chǎn)量的不同，通常零件的加工過程是由若干個(gè)順次排列的工序組成的。工序是加工過程的基本組成單元。每一個(gè)工序又可分為一個(gè)或若干個(gè)安裝、工位、工步或走刀。毛坯依次通過這些工序而變成零件。 工序是一個(gè)或一組工人，在相同的工作地對(duì)同一個(gè)或同時(shí)對(duì)幾個(gè)工件連續(xù)完成的那一部分工藝過程。 工序是組成工藝過程的基本單元，也是生產(chǎn)計(jì)劃、成本核算的基本單元。一個(gè)零件的加工過程需要包括哪些工序，由被加工零件的復(fù)雜程度、加工精度要求及其產(chǎn)量等因素決定 3.1表面加工方法的確定 根據(jù)零件的幾何形狀、尺寸精度及位置精度等技術(shù)要求，以及加工方法所能達(dá)到的經(jīng)濟(jì)精度，在生產(chǎn)綱領(lǐng)已確定的情況下,可以考慮采用萬能性機(jī)床配以專用工卡具,并盡量使工序集中來提高生產(chǎn)率。除此之外，還應(yīng)當(dāng)考慮經(jīng)濟(jì)效果，以便使生產(chǎn)成本盡量下降。查《機(jī)械制造課程設(shè)計(jì)指導(dǎo)書》10頁表1-7、1-8、1-9，選擇零件的加工方法及工藝路線方案如下： 氣門搖臂軸支座各表面加工方案 加工項(xiàng)目 尺寸公差等級(jí) 粗糙度 加工方案 備注 軸支座上端面 GB1804-C 12.5 粗銑 表1-8 軸支座下端面 GB1804-C 6.3 粗銑 表1-8 Φ11孔 IT11 12.5 鉆 表1-7 φ18孔兩端面 IT7 3.2 粗銑—半精銑 表1-8 φ16孔兩端面 IT11 12.5 粗銑 表1-8 φ18孔 IT7 1.6 鉆—擴(kuò)—鉸 表1-7 φ16孔 IT7 1.6 鉆—擴(kuò)—鉸 表1-7 Φ3孔 IT11 12.5 鉆 表1-8 3.2定位基準(zhǔn)的選擇 毛坯選擇：根據(jù)零件材料、形狀、尺寸、批量大小等因素，選擇砂型鑄造。 基準(zhǔn)分析：底面A是零件的主要設(shè)計(jì)基準(zhǔn)，也比較適合作零件上眾多表面加工的定位基準(zhǔn)。 零件安裝方案：加工底面A、頂面B時(shí)，均可采用虎鉗安裝（互為基準(zhǔn)）；Φ11、Φ16、Φ18內(nèi)孔表面加工均采用專用夾具安裝且主要定位基面均為A；加工斜孔仍采用專用夾具安裝，主要加工基準(zhǔn)為Φ18孔兩端面。 零件表面加工：底面A、頂面B采用銑削加工。 3.3 制定工藝路線錯(cuò)誤！未找到索引項(xiàng)。 機(jī)械加工工序的安排 在安排加工工序時(shí)，應(yīng)根據(jù)加工階段的劃分、基準(zhǔn)的選擇和被加工表面的主次來決定，一般應(yīng)該遵循以下幾個(gè)原則： （1）先基準(zhǔn)后其他：即首先應(yīng)加工用作精基準(zhǔn)的表面，再以加工出的精基準(zhǔn)為定位基準(zhǔn)加工其他表面 （2）先粗后精：各表面的加工順序，按加工階段，從粗到精進(jìn)行安排 （3）先主后次：先加工主要平面，在加工次要平面 （4）先面后孔：先加工平面，后加工孔。因?yàn)槠矫娑ㄎ槐容^穩(wěn)定、可靠，所以像箱體、支架、連桿等平面輪廓尺寸較大的零件，常先加工平面，，然后在加工該平面上的孔，以保證加工質(zhì)量。 按照以上原則制定工藝卡片如下： 3.4.1加工設(shè)備和工藝設(shè)備 1 機(jī)床的選擇：采用Z525立式鉆床、立式銑床、臥室鏜床。 2 選擇夾具：該氣門搖臂軸支座的生產(chǎn)綱領(lǐng)為小批生產(chǎn)，所以采用專用夾具。 3 選擇刀具：在銑床上加工的各工序，采用高速鉆刀即可保證加工質(zhì)量；在鉆床上加工的工序采用麻花鉆；在鏜床上加工的工序采用通用鏜刀。 4選擇量具：采用游標(biāo)卡尺、塞規(guī)、內(nèi)徑千分尺萬能角度卡尺。 4. 夾具設(shè)計(jì) 4.1夾具選擇 夾具是一種能夠使工件按一定的技術(shù)要求準(zhǔn)確定位和牢固夾緊的工藝裝備，它廣泛地運(yùn)用于機(jī)械加工，檢測和裝配等整個(gè)工藝過程中。在現(xiàn)代化的機(jī)械和儀器的制造業(yè)中，提高加工精度和生產(chǎn)率，降低制造成本，一直都是生產(chǎn)廠家所追求的目標(biāo)。正確地設(shè)計(jì)并合理的使用夾具，是保證加工質(zhì)量和提高生產(chǎn)率，從而降低生產(chǎn)成本的重要技術(shù)環(huán)節(jié)之一。同時(shí)也擴(kuò)大各種機(jī)床使用范圍必不可少重要手段。 （夾具裝配圖4—1） （一）提出問題 （1）怎樣限制零件的自由度：一個(gè)面限制3個(gè)自由度，3個(gè)螺栓限制3個(gè)自由度。 （2）怎樣夾緊：設(shè)計(jì)夾具由銷釘配合專用壓緊塊夾緊工件，定位塊起支撐工件的作用。 （3）設(shè)計(jì)的夾具怎樣排削：此次加工利用麻花鉆，排削通過鉆模板與工件之間的間隙排削。 （4）怎樣使夾具使用合理，便于裝卸。 （二）設(shè)計(jì)思想 設(shè)計(jì)必須保證零件的加工精度，保證夾具的操作方便，夾緊可靠，使用安全，有合理的裝卸空間，還要注意機(jī)構(gòu)密封和防塵作用，使設(shè)計(jì)的夾具完全符合要求。 本夾具主要用來對(duì)φ11圓柱孔進(jìn)行加工，表面粗糙度Ra12.5，鉆孔即可滿足其精度。所以設(shè)計(jì)時(shí)要在滿足精度的前提下提高勞動(dòng)生產(chǎn)效率，降低勞動(dòng)強(qiáng)度。 4.2 夾具設(shè)計(jì) 4.2.1 定位分析 （1）定位基準(zhǔn)的選擇 據(jù)《夾具手冊(cè)》知定位基準(zhǔn)應(yīng)盡可能與工序基準(zhǔn)重合，在同一工件的各道工序中，應(yīng)盡量采用同一定位基準(zhǔn)進(jìn)行加工。故加工φ11圓柱孔時(shí)，采用曲柄右端面和φ12孔內(nèi)圓柱面作為定位基準(zhǔn)。 （2）定位誤差的分析 定位元件尺寸及公差的確定。夾具的主要定位元件為一個(gè)面與兩個(gè)孔定位，因?yàn)樵摱ㄎ辉亩ㄎ换鶞?zhǔn)為孔的軸線，所以基準(zhǔn)重合△b=0，由于加工向下孔即不存在基準(zhǔn)位移誤差△j=0。 5.2.2切削力及夾緊力的計(jì)算 2、切削力及夾緊力的計(jì)算 刀具：Φ11的麻花鉆。 鉆孔切削力：查《機(jī)床夾具設(shè)計(jì)手冊(cè)》P70表3-6，得鉆削力計(jì)算公式： 式中 P───鉆削力 t───鉆削深度, 39mm S───每轉(zhuǎn)進(jìn)給量, 0.1mm D───麻花鉆直徑, Φ11mm HB───布氏硬度，140HBS 所以 =1185（N） ③鉆孔夾緊力：查《機(jī)床夾具設(shè)計(jì)手冊(cè)》P70表3-6，查得工件以一個(gè)面和兩個(gè)孔定位時(shí)所需夾緊力計(jì)算公式： 式中 p───鉆削力 ───工件與夾緊元件之間的摩擦系數(shù),0.12 ───工件與夾緊元件之間的距離 ───孔到定位面距離 則所需夾緊力 =866N 4.3夾具操作說明 此次設(shè)計(jì)的夾具夾緊原理為：通過φ22孔的下端面為定位基準(zhǔn)，在螺栓、平面實(shí)現(xiàn)完全定位，以鉆模板引導(dǎo)刀具進(jìn)行加工。采用壓緊塊夾緊工件。 定位元件： 定位元件是用以確定正確位置的元件。用工件定位基準(zhǔn)或定位基面與夾具定位元件接觸或配合來實(shí)現(xiàn)工件定位。 4.4.確定導(dǎo)向裝置 本工序要求對(duì)被加工的孔依次進(jìn)行鉆的加工，最終達(dá)到工序簡圖上規(guī)定的加工要求，故選用可換鉆套作為刀具的導(dǎo)向元件，查表9-13，確定鉆套高度H=d=1.4×11=15.4mm，排泄空間h=0.7d=7.7mm。d：基本偏差F7(0.010—0.022);D=10mm，偏差m6（0.001—0.010）。 5.機(jī)床夾具設(shè)計(jì)體會(huì)與展望? 通過此次課程設(shè)計(jì)，能運(yùn)用所學(xué)基本理論知識(shí)，正確解決工件在加工時(shí)的定位和夾緊問題，選擇合理的方案，進(jìn)行必要的計(jì)算，根據(jù)題意設(shè)計(jì)出符合優(yōu)質(zhì)、高效、低成本的夾具。學(xué)習(xí)正確的調(diào)查研究方法，收集國內(nèi)外有關(guān)資料，掌握正確的夾具設(shè)計(jì)思想、方法和手段，學(xué)會(huì)正確使用有關(guān)手冊(cè)及其它技術(shù)資料。分析研究結(jié)構(gòu)工藝性問題，提高結(jié)構(gòu)設(shè)計(jì)能力。進(jìn)一步了解有關(guān)機(jī)床、刀具和量具等工裝知識(shí)。 夾具是機(jī)械加工不可缺少的部件，在機(jī)床技術(shù)向高速、高效、精密、復(fù)合、智能、環(huán)保方向發(fā)展的帶動(dòng)下，夾具技術(shù)正朝著高精、高效、模塊、組合、通用、經(jīng)濟(jì)方向發(fā)展。 一、高精，隨著機(jī)床加工精度的提高，為了降低定位誤差，提高加工精度，對(duì)夾具的制造精度要求更高。世界知名的夾具制造公司都是精密機(jī)械制造企業(yè)。為了適應(yīng)不同行業(yè)的需求和經(jīng)濟(jì)性，夾具有不同的型號(hào)，以及不同檔次的精度標(biāo)準(zhǔn)供選擇。 二、高效，為了提高機(jī)床的生產(chǎn)效率，雙面、四面和多件裝夾的夾具產(chǎn)品越來越多。為了減少工件的安裝時(shí)間，各種自動(dòng)定心夾緊、精密平口鉗、杠桿夾緊、凸輪夾緊、氣動(dòng)和液壓夾緊等，快速夾緊功能部件不斷地推陳出新。 三、模塊、組合，夾具元件模塊化是實(shí)現(xiàn)組合化的基礎(chǔ)。利用模塊化設(shè)計(jì)的系列化、標(biāo)準(zhǔn)化夾具元件，快速組裝成各種夾具，已成為夾具技術(shù)開發(fā)的基點(diǎn)。省工、省時(shí)，節(jié)材、節(jié)能，體現(xiàn)在各種先進(jìn)夾具系統(tǒng)的創(chuàng)新之中。模塊化設(shè)計(jì)為夾具的計(jì)算機(jī)輔助設(shè)計(jì)與組裝打下基礎(chǔ)，應(yīng)用CAD技術(shù)，可建立元件庫、典型夾具庫、標(biāo)準(zhǔn)和用戶使用檔案庫，進(jìn)行夾具優(yōu)化設(shè)計(jì)，為用戶三維實(shí)體組裝夾具。模擬仿真刀具的切削過程，既能為用戶提供正確、合理的夾具與元件配套方案，又能積累使用經(jīng)驗(yàn)，了解市場需求，不斷地改進(jìn)和完善夾具系統(tǒng)。組合夾具分會(huì)與華中科技大學(xué)合作，正在著手創(chuàng)建夾具專業(yè)技術(shù)網(wǎng)站，為夾具行業(yè)提供信息交流、夾具產(chǎn)品咨詢與開發(fā)的公共平臺(tái)，爭取實(shí)現(xiàn)夾具設(shè)計(jì)與服務(wù)的通用化、遠(yuǎn)程信息化和經(jīng)營電子商務(wù)化。 四、通用、經(jīng)濟(jì)，夾具的通用性直接影響其經(jīng)濟(jì)性。采用模塊、組合式的夾具系統(tǒng)，一次性投資比較大，只有夾具系統(tǒng)的可重組性、可重構(gòu)性及可擴(kuò)展性功能強(qiáng)，應(yīng)用范圍廣，通用性好，夾具利用率高，收回投資快，才能體現(xiàn)出經(jīng)濟(jì)性好。德國demmeler（戴美樂）公司的孔系列組合焊接夾具，僅用品種、規(guī)格很少的配套元件，即能組裝成多種多樣的焊接夾具。元件的功能強(qiáng)，使得夾具的通用性好，元件少而精，配套的費(fèi)用低，經(jīng)濟(jì)實(shí)用才有推廣應(yīng)用的價(jià)值。 專家們建議組合夾具行業(yè)加強(qiáng)產(chǎn)、學(xué)、研協(xié)作的力度，加快用高新技術(shù)改造和提升夾具技術(shù)水平的步伐，創(chuàng)建夾具專業(yè)技術(shù)網(wǎng)站，充分利用現(xiàn)代信息和網(wǎng)絡(luò)技術(shù)，與時(shí)俱進(jìn)地創(chuàng)新和發(fā)展夾具技術(shù)。主動(dòng)與國外夾具廠商聯(lián)系，爭取合資與合作，引進(jìn)技術(shù)，這是改造和發(fā)展我國組合夾具行業(yè)較為行之有效的途徑。 參考文獻(xiàn) 1、機(jī)床夾具設(shè)計(jì)（第二版） 肖繼德、陳寧平主編 機(jī)械工業(yè)出版社 2000.5 2、機(jī)床夾具的現(xiàn)代設(shè)計(jì)方法 秦國華、張衛(wèi)紅主編 航空工業(yè)出版社 2006.11 3、機(jī)械制造技術(shù)基礎(chǔ) 黃健求主編 機(jī)械工業(yè)出版社 2005.11 4、機(jī)床夾具設(shè)計(jì) 秦寶榮主編 中國建材工業(yè)出版社 1998.2 5、機(jī)械制造技術(shù)基礎(chǔ)課程設(shè)計(jì)指南 崇凱主編 化學(xué)工業(yè)出版社 2007.2 6、機(jī)械制造與模具制造工藝學(xué) 陳國香主編 情話大學(xué)出版社 2006.5 7、機(jī)械精度設(shè)計(jì)與檢測技術(shù) 李彩霞主編 上海交通大學(xué)出版社 2006.1 8、機(jī)械制造技術(shù)基礎(chǔ) 方子良主編 上海交通大學(xué)出版社 2005.1 9、敏捷夾具設(shè)計(jì)理論及應(yīng)用 武良臣、郭培紅等主編 煤炭工業(yè)出版社 2003.9 10、機(jī)械制造工藝及專用夾具設(shè)計(jì)指導(dǎo) 孫麗媛 冶金工業(yè)出版社 2002.12 11、機(jī)械制造技術(shù)基礎(chǔ)課程設(shè)計(jì)指導(dǎo)教程 鄒青主編 機(jī)械工業(yè)出版社 2004.8 Robotics and Computer-Integrated Manufacturing 21 (2005) 368378Locating completeness evaluation and revision in fixture planH. Song?, Y. RongCAM Lab, Department of Mechanical Engineering, Worcester Polytechnic Institute, 100 Institute Rd, Worcester, MA 01609, USAReceived 14 September 2004; received in revised form 9 November 2004; accepted 10 November 2004AbstractGeometry constraint is one of the most important considerations in fixture design. Analytical formulation of deterministiclocation has been well developed. However, how to analyze and revise a non-deterministic locating scheme during the process ofactual fixture design practice has not been thoroughly studied. In this paper, a methodology to characterize fixturing systemsgeometry constraint status with focus on under-constraint is proposed. An under-constraint status, if it exists, can be recognizedwith given locating scheme. All un-constrained motions of a workpiece in an under-constraint status can be automatically identified.This assists the designer to improve deficit locating scheme and provides guidelines for revision to eventually achieve deterministiclocating.r 2005 Elsevier Ltd. All rights reserved.Keywords: Fixture design; Geometry constraint; Deterministic locating; Under-constrained; Over-constrained1. IntroductionA fixture is a mechanism used in manufacturing operations to hold a workpiece firmly in position. Being a crucialstep in process planning for machining parts, fixture design needs to ensure the positional accuracy and dimensionalaccuracy of a workpiece. In general, 3-2-1 principle is the most widely used guiding principle for developing a locationscheme. V-block and pin-hole locating principles are also commonly used.A location scheme for a machining fixture must satisfy a number of requirements. The most basic requirement is thatit must provide deterministic location for the workpiece 1. This notion states that a locator scheme producesdeterministic location when the workpiece cannot move without losing contact with at least one locator. This has beenone of the most fundamental guidelines for fixture design and studied by many researchers. Concerning geometryconstraint status, a workpiece under any locating scheme falls into one of the following three categories:1. Well-constrained (deterministic): The workpiece is mated at a unique position when six locators are made to contactthe workpiece surface.2. Under-constrained: The six degrees of freedom of workpiece are not fully constrained.3. Over-constrained: The six degrees of freedom of workpiece are constrained by more than six locators.In 1985, Asada and By 1 proposed full rank Jacobian matrix of constraint equations as a criterion and formed thebasis of analytical investigations for deterministic locating that followed. Chou et al. 2 formulated the deterministiclocating problem using screw theory in 1989. It is concluded that the locating wrenches matrix needs to be full rank toachieve deterministic location. This method has been adopted by numerous studies as well. Wang et al. 3 consideredARTICLE IN PRESS front matter r 2005 Elsevier Ltd. All rights reserved.doi:10.1016/j.rcim.2004.11.012?Corresponding author. Tel.: +15088316092; fax: +15088316412.E-mail address: hsongwpi.edu (H. Song).locatorworkpiece contact area effects instead of applying point contact. They introduced a contact matrix andpointed out that two contact bodies should not have equal but opposite curvature at contacting point. Carlson 4suggested that a linear approximation may not be sufficient for some applications such as non-prismatic surfaces ornon-small relative errors. He proposed a second-order Taylor expansion which also takes locator error interaction intoaccount. Marin and Ferreira 5 applied Chous formulation on 3-2-1 location and formulated several easy-to-followplanning rules. Despite the numerous analytical studies on deterministic location, less attention was paid to analyzenon-deterministic location.In the Asada and Bys formulation, they assumed frictionless and point contact between fixturing elements andworkpiece. The desired location is q*, at which a workpiece is to be positioned and piecewisely differentiable surfacefunction is gi(as shown in Fig. 1).The surface function is defined as giq? 0: To be deterministic, there should be a unique solution for the followingequation set for all locators.giq 0;i 1;2;.;n,(1)where n is the number of locators and q x0;y0;z0;y0;f0;c0? represents the position and orientation of theworkpiece.Only considering the vicinity of desired location q?; where q q? Dq; Asada and By showed thatgiq giq? hiDq,(2)where hiis the Jacobian matrix of geometry functions, as shown by the matrix in Eq. (3). The deterministic locatingrequirement can be satisfied if the Jacobian matrix has full rank, which makes the Eq. (2) to have only one solutionq q?:rankqg1qx0qg1qy0qg1qz0qg1qy0qg1qf0qg1qc0:qgiqx0qgiqy0qgiqz0qgiqy0qgiqf0qgiqc0:qgnqx0qgnqy0qgnqz0qgnqy0qgnqf0qgnqc026666666664377777777758:9=; 6.(3)Upon given a 3-2-1 locating scheme, the rank of a Jacobian matrix for constraint equations tells the constraint statusas shown in Table 1. If the rank is less than six, the workpiece is under-constrained, i.e., there exists at least one freemotion of the workpiece that is not constrained by locators. If the matrix has full rank but the locating scheme hasmore than six locators, the workpiece is over-constrained, which indicates there exists at least one locator such that itcan be removed without affecting the geometry constrain status of the workpiece.For locating a model other than 3-2-1, datum frame can be established to extract equivalent locating points. Hu 6has developed a systematic approach for this purpose. Hence, this criterion can be applied to all locating schemes.ARTICLE IN PRESSX Y Z O X Y Z O (x0,y0,z0) gi UCS WCS Workpiece Fig. 1. Fixturing system model.H. Song, Y. Rong / Robotics and Computer-Integrated Manufacturing 21 (2005) 368378369Kang et al. 7 followed these methods and implemented them to develop a geometry constraint analysis module intheir automated computer-aided fixture design verification system. Their CAFDV system can calculate the Jacobianmatrix and its rank to determine locating completeness. It can also analyze the workpiece displacement and sensitivityto locating error.Xiong et al. 8 presented an approach to check the rank of locating matrix WL(see Appendix). They also intro-duced left/right generalized inverse of the locating matrix to analyze the geometric errors of workpiece. It hasbeen shown that the position and orientation errors DX of the workpiece and the position errors Dr of locators arerelated as follows:Well-constrained :DX WLDr,(4)Over-constrained :DX WTLWL?1WTLDr,(5)Under-constrained :DX WTLWLWTL?1Dr I6?6? WTLWLWTL?1WLl,(6)where l is an arbitrary vector.They further introduced several indexes derived from those matrixes to evaluate locator configurations, followed byoptimization through constrained nonlinear programming. Their analytical study, however, does not concern therevision of non-deterministic locating. Currently, there is no systematic study on how to deal with a fixture design thatfailed to provide deterministic location.2. Locating completeness evaluationIf deterministic location is not achieved by designed fixturing system, it is as important for designers to knowwhat the constraint status is and how to improve the design. If the fixturing system is over-constrained, informa-tion about the unnecessary locators is desired. While under-constrained occurs, the knowledge about all the un-constrained motions of a workpiece may guide designers to select additional locators and/or revise the locatingscheme more efficiently. A general strategy to characterize geometry constraint status of a locating scheme is describedin Fig. 2.In this paper, the rank of locating matrix is exerted to evaluate geometry constraint status (see Appendixfor derivation of locating matrix). The deterministic locating requires six locators that provide full rank locatingmatrix WL:As shown in Fig. 3, for given locator number n; locating normal vector ai;bi;ci? and locating position xi;yi;zi? foreach locator, i 1;2;.;n; the n ? 6 locating matrix can be determined as follows:WLa1b1c1c1y1? b1z1a1z1? c1x1b1x1? a1y1:aibiciciyi? biziaizi? cixibixi? aiyi:anbncncnyn? bnznanzn? cnxnbnxn? anyn2666666437777775.(7)When rankWL 6 and n 6; the workpiece is well-constrained.When rankWL 6 and n46; the workpiece is over-constrained. This means there are n ? 6 unnecessary locatorsin the locating scheme. The workpiece will be well-constrained without the presence of those n ? 6 locators. Themathematical representation for this status is that there are n ? 6 row vectors in locating matrix that can be expressedas linear combinations of the other six row vectors. The locators corresponding to that six row vectors consist oneARTICLE IN PRESSTable 1RankNumber of locatorsStatuso 6Under-constrained 6 6Well-constrained 646Over-constrainedH. Song, Y. Rong / Robotics and Computer-Integrated Manufacturing 21 (2005) 368378370locating scheme that provides deterministic location. The developed algorithm uses the following approach todetermine the unnecessary locators:1. Find all the combination of n ? 6 locators.2. For each combination, remove that n ? 6 locators from locating scheme.3. Recalculate the rank of locating matrix for the left six locators.4. If the rank remains unchanged, the removed n ? 6 locators are responsible for over-constrained status.This method may yield multi-solutions and require designer to determine which set of unnecessary locators shouldbe removed for the best locating performance.When rankWLo6; the workpiece is under-constrained.3. Algorithm development and implementationThe algorithm to be developed here will dedicate to provide information on un-constrained motions of theworkpiece in under-constrained status. Suppose there are n locators, the relationship between a workpieces position/ARTICLE IN PRESSFig. 2. Geometry constraint status characterization.X Z Y (a1,b1,c1) 2,b2,c2) (x1,y1,z1) (x2,y2,z2) (ai,bi,ci) (xi,yi,zi) (aFig. 3. A simplified locating scheme.H. Song, Y. Rong / Robotics and Computer-Integrated Manufacturing 21 (2005) 368378371orientation errors and locator errors can be expressed as follows:DX DxDyDzaxayaz2666666666437777777775w11:w1i:w1nw21:w2i:w2nw31:w3i:w3nw41:w4i:w4nw51:w5i:w5nw61:w6i:w6n2666666666437777777775?Dr1:Dri:Drn2666666437777775,(8)where Dx;Dy;Dz;ax;ay;azare displacement along x, y, z axis and rotation about x, y, z axis, respectively. Driisgeometric error of the ith locator. wijis defined by right generalized inverse of the locating matrix Wr WTLWLWTL?15.To identify all the un-constrained motions of the workpiece, V dxi;dyi;dzi;daxi;dayi;dazi? is introduced such thatV DX 0.(9)Since rankDXo6; there must exist non-zero V that satisfies Eq. (9). Each non-zero solution of V represents an un-constrained motion. Each term of V represents a component of that motion. For example, 0;0;0;3;0;0? says that therotation about x-axis is not constrained. 0;1;1;0;0;0? means that the workpiece can move along the direction given byvector 0;1;1?: There could be infinite solutions. The solution space, however, can be constructed by 6 ? rankWLbasic solutions. Following analysis is dedicated to find out the basic solutions.From Eqs. (8) and (9)VX dxDx dyDy dzDz daxDax dayDay dazDaz dxXni1w1iDri dyXni1w2iDri dzXni1w3iDri daxXni1w4iDri dayXni1w5iDri dazXni1w6iDriXni1Vw1i;w2i;w3i;w4i;w5i;w6i?TDri 0.10Eq. (10) holds for 8Driif and only if Eq. (11) is true for 8i1pipn:Vw1i;w2i;w3i;w4i;w5i;w6i?T 0.(11)Eq. (11) illustrates the dependency relationships among row vectors of Wr: In special cases, say, all w1jequal to zero,V has an obvious solution 1, 0, 0, 0, 0, 0, indicating displacement along the x-axis is not constrained. This is easy tounderstand because Dx 0 in this case, implying that the corresponding position error of the workpiece is notdependent of any locator errors. Hence, the associated motion is not constrained by locators. Moreover, a combinedmotion is not constrained if one of the elements in DX can be expressed as linear combination of other elements. Forinstance, 9w1ja0;w2ja0; w1j ?w2jfor 8j: In this scenario, the workpiece cannot move along x- or y-axis. However, itcan move along the diagonal line between x- and y-axis defined by vector 1, 1, 0.To find solutions for general cases, the following strategy was developed:1. Eliminate dependent row(s) from locating matrix. Let r rank WL; n number of locator. If ron; create a vectorin n ? r dimension space U u1:uj:un?rhi1pjpn ? r; 1pujpn: Select ujin the way that rankWL r still holds after setting all the terms of all the ujth row(s) equal to zero. Set r ? 6 modified locating matrixWLMa1b1c1c1y1? b1z1a1z1? c1x1b1x1? a1y1:aibiciciyi? biziaizi? cixibixi? aiyi:anbncncnyn? bnznanzn? cnxnbnxn? anyn2666666437777775r?6,where i 1;2;:;niauj:ARTICLE IN PRESSH. Song, Y. Rong / Robotics and Computer-Integrated Manufacturing 21 (2005) 3683783722. Compute the 6 ? n right generalized inverse of the modified locating matrixWr WTLMWLMWTLM?1w11:w1i:w1rw21:w2i:w2rw31:w3i:w3rw41:w4i:w4rw51:w5i:w5rw61:w6i:w6r26666666664377777777756?r3. Trim Wrdown to a r ? rfull rank matrix Wrm: r rankWLo6: Construct a 6 ? r dimension vector Q q1:qj:q6?rhi1pjp6 ? r; 1pqjpn: Select qjin the way that rankWr r still holds after setting all theterms of all the qjth row(s) equal to zero. Set r ? r modified inverse matrixWrmw11:w1i:w1r:wl1:wli:wlr:w61:w6i:w6r26666664377777756?6,where l 1;2;:;6 laqj:4. Normalize the free motion space. Suppose V V1;V2;V3;V4;V5;V6? is one of the basic solutions of Eq. (10) withall six terms undetermined. Select a term qkfrom vector Q1pkp6 ? r: SetVqk ?1;Vqj 0 j 1;2;:;6 ? r;jak;(5. Calculated undetermined terms of V: V is also a solution of Eq. (11). The r undetermined terms can be found asfollows.v1:vs:v62666666437777775wqk1:wqki:wqkr2666666437777775?w11:w1i:w1r:wl1:wli:wlr:w61:w6i:w6r2666666437777775?1,where s 1;2;:;6saqj;saqk;l 1;2;:;6 laqj:6. Repeat step 4 (select another term from Q) and step 5 until all 6 ? r basic solutions have been determined.Based on this algorithm, a C+ program was developed to identify the under-constrained status and un-constrained motions.Example 1. In a surface grinding operation, a workpiece is located on a fixture system as shown in Fig. 4. The normalvector and position of each locator are as follows:L1:0, 0, 10, 1, 3, 00,L2:0, 0, 10, 3, 3, 00,L3:0, 0, 10, 2, 1, 00,L4:0, 1, 00, 3, 0, 20,L5:0, 1, 00, 1, 0, 20.Consequently, the locating matrix is determined.WL0013?100013?300011?20010?203010?2012666666437777775.ARTICLE IN PRESSH. Song, Y. Rong / Robotics and Computer-Integrated Manufacturing 21 (2005) 368378373This locating system provides under-constrained positioning since rankWL 5o6: The program then calculatesthe right generalized inverse of the locating matrix.Wr000000:50:5?1?0:51:50:75?1:251:5000:250:25?0:5000:5?0:50000000:5?0:526666666643777777775.The first row is recognized as a dependent row because removal of this row does not affect rank of the matrix. Theother five rows are independent rows. A linear combination of the independent rows is found according therequirement in step 5 of the procedure for under-constrained status. The solution for this special case is obvious that allthe coefficients are zero. Hence, the un-constrained motion of workpiece can be determined as V ?1; 0; 0; 0; 0; 0?:This indicates that the workpiece can move along x direction. Based on this result, an additional locator should beemployed to constraint displacement of workpiece along x-axis.Example 2. Fig. 5 shows a knuckle with 3-2-1 locating system. The normal vector and position of each locator in thisinitial design are as follows:L1:0, 1, 00, 896, ?877, ?5150,L2:0, 1, 00, 1060, ?875, ?3780,L3:0, 1, 00, 1010, ?959, ?6120,L4:0.9955, ?0.0349, 0.0880, 977, ?902, ?6240,L5:0.9955, ?0.0349, 0.0880, 977, ?866, ?6240,L6:0.088, 0.017, ?0.9960, 1034, ?864, ?3590.The locating matrix of this configuration isWL010515:000:8960010378:001:0600010612:001:01000:9955?0:03490:0880?101:2445?707:26640:86380:9955?0:03490:0880?98:0728?707:26640:82800:08800:0170?0:9960866:6257998:24660:093626666666643777777775,rankWL 5o6 reveals that the workpiece is under-constrained. It is found that one of the first five rows can beremoved without varying the rank of locating matrix. Suppose the first row, i.e., locator L1is removed from WL; theARTICLE IN PRESSXZYL3L4L5L2L1Fig. 4. Under-constrained locating scheme.H. Song, Y. Rong / Robotics and Computer-Integrated Manufacturing 21 (2005) 368378374modified locating matrix turns intoWLM010378:001:0600010612:001:01000:9955?0:03490:0880?101:2445?707:26640:86380:9955?0:03490:0880?98:0728?707:26640:82800:08800:0170?0:996866:6257998:24660:09362666666437777775.The right generalized inverse of the modified locating matrix isWr1:8768?1:8607?20:666521:37160:49953:0551?2:0551?32:444832:44480?1:09561:086212:0648?12:4764?0:2916?0:00440:00440:0061?0:006100:0025?0:00250:0065?0:00690:0007?0:00040:00040:0284?0:0284026666666643777777775.The program checked the dependent row and found every row is dependent on other five rows. Without losinggenerality, the first row is regarded as dependent row. The 5 ? 5 modified inverse matrix isWrm3:0551?2:0551?32:444832:44480?1:09561:086212:0648?12:4764?0:2916?0:00440:00440:0061?0:006100:0025?0:00250:0065?0:00690:0007?0:00040:00040:0284?0:028402666666437777775.The undetermined solution is V ?1; v2; v3; v4; v5; v6?:To calculate the five undetermined terms of V according to step 5,1:8768?1:8607?20:666521:37160:499526666666643777777775T?3:0551?2:0551?32:444832:44480?1:09561:086212:0648?12:4764?0:2916?0:00440:00440:0061?0:006100:0025?0:00250:0065?0:00690:0007?0:00040:00040:0284?0:0284026666666643777777775?1 0; ?1:713; ?0:0432; ?0:0706; 0:04?.Substituting this result into the undetermined solution yields V ?1;0; ?1:713; ?0:0432; ?0:0706; 0:04?ARTICLE IN PRESSFig. 5. Knuckle 610 (modified from real design).H. Song, Y. Rong / Robotics and Computer-Integrated Manufacturing 21 (2005) 368378375This vector represents a free motion defined by the combination of a displacement along ?1, 0, ?1.713 directioncombined and a rotation about ?0.0432, ?0.0706, 0.04. To revise this locating configuration, another locator shouldbe added to constrain this free motion of the workpiece, assuming locator L1was removed in step 1. The program canalso calculate the free motions of the workpiece if a locator other than L1was removed in step 1. This provides morerevision options for designer.4. SummaryDeterministic location is an important requirement for fixture locating scheme design. Analytical criterion fordeterministic status has been well established. To further study non-deterministic status, an algorithm for checking thegeometry constraint status has been developed. This algorithm can identify an under-constrained status and indicatethe un-constrained motions of workpiece. It can also recognize an over-constrained status and unnecessary locators.The output information can assist designer to analyze and improve an existing locating scheme.Appendix. Locating matrixConsider a general workpiece as shown in Fig. 6. Choose reference frame fWg fixed to the workpiece. Let fGg andfLig be the global frame and the ith locator frame fixed relative to it. We haveFiXw;Hw;rwi fiXli;Hli;rli,(12)where Xw2 3?1and Hw2 3?1(Xli2 3?1and Hli2 3?1) are the position and orientation of the workpiece(the ith locator) in the global frame fGg; rwi2 3?1(rli2 3?1) is the position of the ith contact point between theworkpiece and the ith locator in the workpiece frame fWg (the ith locator frame fLig).Assume that DXw2 3?1(DHw2 3?1) and Drwi2 3?1are the deviations of the position Xw2 3?1(orientationHw2 3?1) of the workpiece and the position of the ith contact point rwi2 3?1; respectively. Then we have the actualcontact on the wor