齒輪軸承座零件機(jī)械加工工藝規(guī)程及銑底端面夾具設(shè)計(jì)

齒輪軸承座零件機(jī)械加工工藝規(guī)程及銑底端面夾具設(shè)計(jì),齒輪軸承座零件機(jī)械加工工藝規(guī)程及銑底端面夾具設(shè)計(jì),齒輪,軸承,零件,機(jī)械,加工,工藝,規(guī)程,底端,夾具,設(shè)計(jì) 零 件 號(hào) 材料 HT120 編制 日期 機(jī)械加工工藝過(guò)程綜合卡片 零件名稱(chēng) 齒輪軸承座 毛坯重量 指導(dǎo) 生產(chǎn)類(lèi)型 批量 毛坯種類(lèi) 鑄件 審核 工序 安裝工位 工步 工 序 說(shuō) 明 工序簡(jiǎn)圖 機(jī)床 夾具或輔助工具 刀具 量具 走刀次數(shù) 走刀長(zhǎng)度(mm) 切削深度(mm) 進(jìn)給量(mm/r) 主軸轉(zhuǎn)數(shù)(r/min) 切削速度(m/min) 工時(shí)定額(min) 基本時(shí)間 輔助時(shí)間 服務(wù)時(shí)間 1 2 1 1 1 鑄造 時(shí)效處理 3 1 以φ100和φ87外圓作為定位基準(zhǔn)，銑Φ87上端面 立式銑床X51 專(zhuān)用夾具 端銑刀 卡尺 1 87 3 0.2 500 136 0.99 4 1 以φ100和φ87外圓和一側(cè)面作為定位基準(zhǔn)，銑底端面 立式銑床X51 專(zhuān)用夾具 端銑刀 卡尺 1 317 3 0.4 600 263.7 2.74 5 1 1 以加工過(guò)的底端面φ100和φ87外圓作為定位基準(zhǔn)， 鉆，擴(kuò)，鉸Φ52孔 立式鉆床Z525 專(zhuān)用夾具 麻花鉆，擴(kuò)孔鉆，鉸刀 卡尺 1 1 1 100 100 100 3 3 3 0.32 0.57 0.35 200 68 200 32 11 9.33 1.75 1.81 1.6 6 1 1 以加工過(guò)的Φ52孔，φ87端面，底端面和一側(cè)面作為定位基準(zhǔn)， 銑Φ100端面 立式銑床 X51 專(zhuān)用夾具 端銑刀 卡尺 1 100 3 0.2 750 235.5 0.75 7 1 1 以加工過(guò)的Φ52孔，φ87端面，底端面和一側(cè)面作為定位基準(zhǔn)， 鏜Φ80孔 臥式鏜床T716 專(zhuān)用夾具 彎頭鏜刀 卡板 1 20 3 0.5 1800 80 0.01 8 1 1 以加工后的φ52和Φ80孔內(nèi)孔及其端面作為定位基準(zhǔn)，采用一面兩銷(xiāo)定位， 銑70x140端面 立式銑床X51 專(zhuān)用夾具 端銑刀 卡尺 1 140 3 0.4 800 175.8 0.76 9 1 以加工后的φ52和Φ80孔內(nèi)孔及其端面作為定位基準(zhǔn)，采用一面兩銷(xiāo)定位， 鉆Φ87上端面3-M12螺紋孔 立式鉆床Z525 專(zhuān)用夾具 麻花鉆 絲錐 卡尺 1 1 16 12 3 3 0.28 1.25 500 275 15.7 6.8 0.157 0.052 10 1 1 以加工后的φ52和Φ80孔內(nèi)孔及其端面作為定位基準(zhǔn)，采用一面兩銷(xiāo)定位， 鉆Φ87下端面3-M12螺紋孔 立式鉆床Z525 專(zhuān)用夾具 麻花鉆，絲錐 卡尺 1 1 16 12 3 3 0.28 1.25 500 275 15.7 6.8 0.157 0.052 11 1 1 檢驗(yàn) 機(jī)械加工工藝過(guò)程卡片 產(chǎn)品型號(hào) 零件圖號(hào) 產(chǎn)品名稱(chēng) 齒輪軸承座 零件名稱(chēng) 齒輪軸承座 共 1 頁(yè) 第 1 頁(yè) 材 料 牌 號(hào) 45 毛 坯 種 類(lèi) 鍛件 毛坯外形尺寸 每毛坯件數(shù) 1 每 臺(tái) 件 數(shù) 備 注 工 序 號(hào) 工 名 序 稱(chēng) 工 序 內(nèi) 容 車(chē) 間 工 段 設(shè) 備 工 藝 裝 備 工 時(shí) 準(zhǔn)終 單件 1 鑄造 鑄造 2 時(shí)效處理 時(shí)效處理 3 銑 銑Φ87上端面 X51 專(zhuān)用夾具，端銑刀，游標(biāo)卡尺 4 銑 銑底端面 X51 專(zhuān)用夾具，端銑刀，游標(biāo)卡尺 5 鉆 鉆，擴(kuò)，鉸Φ52孔 Z525 專(zhuān)用夾具，麻花鉆，擴(kuò)孔鉆，鉸刀，游標(biāo)卡尺 6 銑 銑Φ100端面 X51 專(zhuān)用夾具，端銑刀，游標(biāo)卡尺 7 鏜 鏜Φ80孔 T716 專(zhuān)用夾具，彎頭鏜刀，游標(biāo)卡尺 8 銑 銑70x140端面 X51 專(zhuān)用夾具，端銑刀，游標(biāo)卡尺 9 鉆 鉆Φ87上端面3-M12螺紋孔 Z525 專(zhuān)用夾具，麻花鉆，絲錐，螺紋量規(guī)，游標(biāo)卡尺 10 鉆 鉆Φ87下端面3-M12螺紋孔 Z525 專(zhuān)用夾具，麻花鉆，絲錐，螺紋量規(guī)，游標(biāo)卡尺 11 檢驗(yàn) 檢驗(yàn)，入庫(kù) 設(shè) 計(jì)（日 期） 校 對(duì)（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 目 錄 序言…………………………………………………………………1 一. 零件分析 ……………………………………………………2 1.1 零件作用 ………………………………………………2 1.2零件的工藝分析 …………………………………………2 二. 工藝規(guī)程設(shè)計(jì)…………………………………………………3 2.1確定毛坯的制造形式 ……………………………………4 2.2基面的選擇傳 ……………………………………………5 2.3制定工藝路線 ……………………………………………5 2.4機(jī)械加工余量、工序尺寸及毛坯尺寸的確定 …………6 2.5確定切削用量及基本工時(shí)………………………………14 三 夾具設(shè)計(jì)……………………………………………………15 3.1問(wèn)題的提出………………………………………………15 3.2定位基準(zhǔn)的選擇…………………………………………15 3.3切削力及夾緊力計(jì)算……………………………………16 3.4定位誤差分析……………………………………………17 3.5夾具設(shè)計(jì)及簡(jiǎn)要操作說(shuō)明………………………………18 總 結(jié)………………………………………………………………19 致 謝………………………………………………………………22 參考文獻(xiàn) …………………………………………………………23 機(jī) 械 制 造 技 術(shù) 基 礎(chǔ) 課 程 設(shè) 計(jì) 題 目：齒輪軸承座零件的工藝規(guī)程及銑底端面夾具設(shè)計(jì) 班　　級(jí)：機(jī)械工程及其自動(dòng)化 姓　　名： 指導(dǎo)教師： 完成日期：2010年 6 月30日 摘 要 本次設(shè)計(jì)內(nèi)容涉及了機(jī)械制造工藝及機(jī)床夾具設(shè)計(jì)、金屬切削機(jī)床、公差配合與測(cè)量等多方面的知識(shí)。 齒輪軸承座零件的工藝規(guī)程及銑底端面夾具設(shè)計(jì)是包括零件加工的工藝設(shè)計(jì)、工序設(shè)計(jì)以及專(zhuān)用夾具的設(shè)計(jì)三部分。在工藝設(shè)計(jì)中要首先對(duì)零件進(jìn)行分析，了解零件的工藝再設(shè)計(jì)出毛坯的結(jié)構(gòu)，并選擇好零件的加工基準(zhǔn)，設(shè)計(jì)出零件的工藝路線；接著對(duì)零件各個(gè)工步的工序進(jìn)行尺寸計(jì)算，關(guān)鍵是決定出各個(gè)工序的工藝裝備及切削用量；然后進(jìn)行專(zhuān)用夾具的設(shè)計(jì)，選擇設(shè)計(jì)出夾具的各個(gè)組成部件，如定位元件、夾緊元件、引導(dǎo)元件、夾具體與機(jī)床的連接部件以及其它部件；計(jì)算出夾具定位時(shí)產(chǎn)生的定位誤差，分析夾具結(jié)構(gòu)的合理性與不足之處，并在以后設(shè)計(jì)中注意改進(jìn)。 關(guān)鍵詞：工藝、工序、切削用量、夾緊、定位、誤差。 ABSTRCT This design content has involved the machine manufacture craft and the engine bed jig design, the metal-cutting machine tool, the common difference coordination and the survey and so on the various knowledge. The reduction gear box body components technological process and its the processing hole jig design is includes the components processing the technological design, the working procedure design as well as the unit clamp design three parts. Must first carry on the analysis in the technological design to the components, understood the components the craft redesigns the semi finished materials the structure, and chooses the good components the processing datum, designs the components the craft route; After that is carrying on the size computation to a components each labor step of working procedure, the key is decides each working procedure the craft equipment and the cutting specifications; Then carries on the unit clamp the design, the choice designs the jig each composition part, like locates the part, clamps the part, guides the part, to clamp concrete and the engine bed connection part as well as other parts; Position error which calculates the jig locates when produces, analyzes the jig structure the rationality and the deficiency, and will design in later pays attention to the improvement. Keywords: The craft, the working procedure, the cutting specifications, clamp, the localization, the error 目 錄 序言…………………………………………………………………1 一. 零件分析 ……………………………………………………2 1.1 零件作用 ………………………………………………2 1.2零件的工藝分析 …………………………………………2 二. 工藝規(guī)程設(shè)計(jì)…………………………………………………3 2.1確定毛坯的制造形式 ……………………………………4 2.2基面的選擇傳 ……………………………………………5 2.3制定工藝路線 ……………………………………………5 2.4機(jī)械加工余量、工序尺寸及毛坯尺寸的確定 …………6 2.5確定切削用量及基本工時(shí)………………………………14 三 夾具設(shè)計(jì)……………………………………………………15 3.1問(wèn)題的提出………………………………………………15 3.2定位基準(zhǔn)的選擇…………………………………………15 3.3切削力及夾緊力計(jì)算……………………………………16 3.4定位誤差分析……………………………………………17 3.5夾具設(shè)計(jì)及簡(jiǎn)要操作說(shuō)明………………………………18 總 結(jié)………………………………………………………………19 致 謝………………………………………………………………22 參考文獻(xiàn) …………………………………………………………23 序 言 機(jī)械制造業(yè)是制造具有一定形狀位置和尺寸的零件和產(chǎn)品，并把它們裝備成機(jī)械裝備的行業(yè)。機(jī)械制造業(yè)的產(chǎn)品既可以直接供人們使用，也可以為其它行業(yè)的生產(chǎn)提供裝備，社會(huì)上有著各種各樣的機(jī)械或機(jī)械制造業(yè)的產(chǎn)品。我們的生活離不開(kāi)制造業(yè)，因此制造業(yè)是國(guó)民經(jīng)濟(jì)發(fā)展的重要行業(yè)，是一個(gè)國(guó)家或地區(qū)發(fā)展的重要基礎(chǔ)及有力支柱。從某中意義上講，機(jī)械制造水平的高低是衡量一個(gè)國(guó)家國(guó)民經(jīng)濟(jì)綜合實(shí)力和科學(xué)技術(shù)水平的重要指標(biāo)。 齒輪軸承座零件的工藝規(guī)程及銑底端面夾具設(shè)計(jì)是在學(xué)完了機(jī)械制圖、機(jī)械制造技術(shù)基礎(chǔ)、機(jī)械設(shè)計(jì)、機(jī)械工程材料等進(jìn)行課程設(shè)計(jì)之后的下一個(gè)教學(xué)環(huán)節(jié)。正確地解決一個(gè)零件在加工中的定位，夾緊以及工藝路線安排，工藝尺寸確定等問(wèn)題，并設(shè)計(jì)出專(zhuān)用夾具，保證零件的加工質(zhì)量。本次設(shè)計(jì)也要培養(yǎng)自己的自學(xué)與創(chuàng)新能力。因此本次設(shè)計(jì)綜合性和實(shí)踐性強(qiáng)、涉及知識(shí)面廣。所以在設(shè)計(jì)中既要注意基本概念、基本理論，又要注意生產(chǎn)實(shí)踐的需要，只有將各種理論與生產(chǎn)實(shí)踐相結(jié)合，才能很好的完成本次設(shè)計(jì)。 本次設(shè)計(jì)水平有限，其中難免有缺點(diǎn)錯(cuò)誤，敬請(qǐng)老師們批評(píng)指正。 一、 零件的分析 1.1 零件的作用 齒輪軸承座零件作用，待查 1.2 零件的工藝分析 齒輪軸承座有2個(gè)加工面他們相互之間沒(méi)有任何位置度要求。 1：以底端面為基準(zhǔn)的加工面，這組加工的主要是銑Φ100端面和鉆，擴(kuò)，鉸Φ52孔。 2：以Φ52孔為基準(zhǔn)的加工面，這組加工面主要是各個(gè)孔端面及其螺紋孔。 二. 工藝規(guī)程設(shè)計(jì) 2.1 確定毛坯的制造形式 零件材料為HT120，考慮到運(yùn)行時(shí)經(jīng)常需要掛倒檔以倒行或輔助轉(zhuǎn)向，因此零件在工作過(guò)程中經(jīng)常受到?jīng)_擊性載荷，采用這種材料零件的強(qiáng)度也能保證。由于零件成批生產(chǎn)，而且零件的輪廓尺寸不大，選用砂型鑄造，采用機(jī)械翻砂造型，鑄造精度為2級(jí)，能保證鑄件的尺寸要求，這從提高生產(chǎn)率和保證加工精度上考慮也是應(yīng)該的。 2.2 基面的選擇 粗基準(zhǔn)選擇應(yīng)當(dāng)滿足以下要求： （1）粗基準(zhǔn)的選擇應(yīng)以加工表面為粗基準(zhǔn)。目的是為了保證加工面與不加工面的相互位置關(guān)系精度。如果工件上表面上有好幾個(gè)不需加工的表面，則應(yīng)選擇其中與加工表面的相互位置精度要求較高的表面作為粗基準(zhǔn)。以求壁厚均勻、外形對(duì)稱(chēng)、少裝夾等。 （2） 選擇加工余量要求均勻的重要表面作為粗基準(zhǔn)。例如：機(jī)床床身導(dǎo)軌面是其余量要求均勻的重要表面。因而在加工時(shí)選擇導(dǎo)軌面作為粗基準(zhǔn)，加工床身的底面，再以底面作為精基準(zhǔn)加工導(dǎo)軌面。這樣就能保證均勻地去掉較少的余量，使表層保留而細(xì)致的組織，以增加耐磨性。 （3） 應(yīng)選擇加工余量最小的表面作為粗基準(zhǔn)。這樣可以保證該面有足夠的加工余量。 （4） 應(yīng)盡可能選擇平整、光潔、面積足夠大的表面作為粗基準(zhǔn)，以保證定位準(zhǔn)確夾緊可靠。有澆口、冒口、飛邊、毛刺的表面不宜選作粗基準(zhǔn)，必要時(shí)需經(jīng)初加工。 （5） 粗基準(zhǔn)應(yīng)避免重復(fù)使用，因?yàn)榇只鶞?zhǔn)的表面大多數(shù)是粗糙不規(guī)則的。多次使用難以保證表面間的位置精度。 基準(zhǔn)的選擇是工藝規(guī)程設(shè)計(jì)中的重要工作之一，他對(duì)零件的生產(chǎn)是非常重要的。先選取底端面作為定位基準(zhǔn)，。 精基準(zhǔn)的選擇 精基準(zhǔn)的選擇應(yīng)滿足以下原則： （1）“基準(zhǔn)重合”原則 應(yīng)盡量選擇加工表面的設(shè)計(jì)基準(zhǔn)為定位基準(zhǔn)，避免基準(zhǔn)不重合引起的誤差。 （2）“基準(zhǔn)統(tǒng)一”原則 盡可能在多數(shù)工序中采用同一組精基準(zhǔn)定位，以保證各表面的位置精度，避免因基準(zhǔn)變換產(chǎn)生的誤差，簡(jiǎn)化夾具設(shè)計(jì)與制造。 （3）“自為基準(zhǔn)”原則 某些精加工和光整加工工序要求加工余量小而均勻，應(yīng)選擇該加工表面本身為精基準(zhǔn)，該表面與其他表面之間的位置精度由先行工序保證。 （4）“互為基準(zhǔn)”原則 當(dāng)兩個(gè)表面相互位置精度及自身尺寸、形狀精度都要求較高時(shí)，可采用“互為基準(zhǔn)”方法，反復(fù)加工。 （5）所選的精基準(zhǔn) 應(yīng)能保證定位準(zhǔn)確、夾緊可靠、夾具簡(jiǎn)單、操作方便。 以已經(jīng)加工好的Φ52孔和端面為定位精基準(zhǔn)，加工其它表面及孔。主要考慮精基準(zhǔn)重合的問(wèn)題，當(dāng)設(shè)計(jì)基準(zhǔn)與工序基準(zhǔn)不重合的時(shí)候，應(yīng)該進(jìn)行尺寸換算，這在以后還要進(jìn)行專(zhuān)門(mén)的計(jì)算，在此不再重復(fù)。 2.3 制定工藝路線 制訂工藝路線的出發(fā)點(diǎn)，應(yīng)當(dāng)是使零件的幾何形狀、尺寸精度及位置精度等技術(shù)要求能得到合理的保證。在生產(chǎn)綱領(lǐng)已確定為成批生產(chǎn)的條件下，可以考慮采用萬(wàn)能型機(jī)床配以專(zhuān)用夾具，并盡量使工序集中在提高生產(chǎn)率。除此以外，還應(yīng)當(dāng)考慮經(jīng)濟(jì)效果，以便使生產(chǎn)成本盡量降下來(lái)。 制定以下兩種工藝方案： 方案一 1 鑄造 鑄造 2 時(shí)效處理 時(shí)效處理 3 銑 銑Φ87上端面 4 銑 銑底端面 5 鉆 鉆，擴(kuò)，鉸Φ52孔 6 銑 銑Φ100端面 7 鏜 鏜Φ80孔 8 銑 銑70x140端面 9 鉆 鉆Φ87上端面3-M12螺紋孔 10 鉆 鉆Φ87下端面3-M12螺紋孔 11 檢驗(yàn) 檢驗(yàn)，入庫(kù) 方案二 1 鑄造 鑄造 2 時(shí)效處理 時(shí)效處理 3 銑 銑Φ87上端面 4 銑 銑底端面 5 鉆 鉆Φ52孔 6 銑 銑Φ100端面 7 鏜 鏜Φ80孔 8 銑 銑70x140端面 9 鉆 鉆Φ87上端面3-M12螺紋孔 10 鉆 鉆Φ87下端面3-M12螺紋孔 11 檢驗(yàn) 檢驗(yàn)，入庫(kù) 工藝方案一和方案二的區(qū)別在于方案一鉆，擴(kuò)，鉸Φ52孔，因?yàn)棣?2孔的粗糙度1.6，精度要求比較高，需要經(jīng)過(guò)鉆，擴(kuò)，鉸才能保證加工精度要求，有利用后面工序加工的時(shí)候利用鉆擴(kuò)鉸后的Φ52孔定位，這樣能能更好地保證工件鉆孔時(shí)的位置度要求，而方案二只有鉆Φ52孔這一工步，很難保證加工精度要求，綜合考慮我們選擇方案一。 具體的加工路線如下： 1 鑄造 鑄造 2 時(shí)效處理 時(shí)效處理 3 銑 銑Φ87上端面 4 銑 銑底端面 5 鉆 鉆，擴(kuò)，鉸Φ52孔 6 銑 銑Φ100端面 7 鏜 鏜Φ80孔 8 銑 銑70x140端面 9 鉆 鉆Φ87上端面3-M12螺紋孔 10 鉆 鉆Φ87下端面3-M12螺紋孔 11 檢驗(yàn) 檢驗(yàn)，入庫(kù) 2.4 機(jī)械加工余量、工序尺寸及毛坯尺寸的確定 零件材料為HT120。 生產(chǎn)類(lèi)型為大批量生產(chǎn)，采用砂型機(jī)鑄造毛坯。 1、 不加工表面毛坯尺寸 不加工表面毛坯按照零件圖給定尺寸為自由度公差，由鑄造可直接獲得。 2、 底端面 由于底面要與其他接觸面接觸，同時(shí)又是Φ52孔的中心線的基準(zhǔn)。粗糙度要求為3.2，查相關(guān)資料知余量留2比較合適。 3、孔 毛坯為空心，鑄造出孔。孔的精度要求介于IT7—IT8之間，參照參數(shù)文獻(xiàn)，確定工藝尺寸余量為2mm 2.5 確定切削用量及基本工時(shí) 工序1：鑄造 工序2：時(shí)效處理 工序3：銑Φ87上端面 1. 選擇刀具 刀具選取端銑刀，刀片采用YG8, ，，，。 2. 決定銑削用量 1） 決定銑削深度 因?yàn)榧庸び嗔坎淮?，一次加工完? 2） 決定每次進(jìn)給量及切削速度 根據(jù)X51型銑床說(shuō)明書(shū)，其功率為為7.5kw，中等系統(tǒng)剛度。 根據(jù)表查出 ，則 按機(jī)床標(biāo)準(zhǔn)選?。?00 當(dāng)＝500r/min時(shí) 按機(jī)床標(biāo)準(zhǔn)選取 3） 計(jì)算工時(shí) 切削工時(shí)：，，，則機(jī)動(dòng)工時(shí)為 工序4：銑底端面 1. 選擇刀具 刀具選取不重磨損硬質(zhì)合金套式面銑刀，刀片采用YG8, ，，，。 2. 決定銑削用量 4） 決定銑削深度 因?yàn)榧庸び嗔坎淮?，故可在一次走刀?nèi)銑完，則 5） 決定每次進(jìn)給量及切削速度 根據(jù)X51型銑床說(shuō)明書(shū)，其功率為為6kw，中等系統(tǒng)剛度。 根據(jù)表查出 ，則 按機(jī)床標(biāo)準(zhǔn)選取＝600 當(dāng)＝600r/min時(shí) 按機(jī)床標(biāo)準(zhǔn)選取 6） 計(jì)算工時(shí) 切削工時(shí)：l=317 ，，則機(jī)動(dòng)工時(shí)為 工序5：鉆，擴(kuò)，鉸Φ52孔 工步1：鉆孔至φ51 確定進(jìn)給量：根據(jù)參考文獻(xiàn)Ⅳ表2-7，當(dāng)鋼的，時(shí)，。由于本零件在加工Φ51孔時(shí)屬于低剛度零件，故進(jìn)給量應(yīng)乘以系數(shù)0.75，則 根據(jù)Z525機(jī)床說(shuō)明書(shū)，現(xiàn)取 切削速度：根據(jù)參考文獻(xiàn)Ⅳ表2-13及表2-14，查得切削速度所以 根據(jù)機(jī)床說(shuō)明書(shū)，取，故實(shí)際切削速度為 切削工時(shí)：，，，則機(jī)動(dòng)工時(shí)為 工步:2：擴(kuò)孔 利用鉆頭將孔擴(kuò)大至，根據(jù)有關(guān)手冊(cè)規(guī)定，擴(kuò)鉆的切削用量可根據(jù)鉆孔的切削用量選取 根據(jù)機(jī)床說(shuō)明書(shū)，選取 則主軸轉(zhuǎn)速為，并按車(chē)床說(shuō)明書(shū)取，實(shí)際切削速度為 切削工時(shí)：，，，則機(jī)動(dòng)工時(shí)為 工步3：鉸孔 根據(jù)參考文獻(xiàn)Ⅳ表2-25，，，得 查參考文獻(xiàn)Ⅴ表4.2-2，按機(jī)床實(shí)際進(jìn)給量和實(shí)際轉(zhuǎn)速，取，，實(shí)際切削速度。 切削工時(shí)：，，，則機(jī)動(dòng)工時(shí)為 工序6：銑Φ100端面 1. 選擇刀具 刀具選取端銑刀，刀片采用YG8, ，，，。 2. 決定銑削用量 7） 決定銑削深度 因?yàn)榧庸び嗔坎淮?，一次加工完? 8） 決定每次進(jìn)給量及切削速度 根據(jù)X51型銑床說(shuō)明書(shū)，其功率為為7.5kw，中等系統(tǒng)剛度。 根據(jù)表查出 ，則 按機(jī)床標(biāo)準(zhǔn)選取＝750 當(dāng)＝750r/min時(shí) 按機(jī)床標(biāo)準(zhǔn)選取 9） 計(jì)算工時(shí) 切削工時(shí)：，，，則機(jī)動(dòng)工時(shí)為 工序7：鏜φ80孔 切削用量：ap=3 毛坯孔徑d=80 由表8.2-1得：f=0.5 m/r v=80 m/r 則n=318V/D=1817m/r 取D=1800r/min 實(shí)際切削速度 工作臺(tái)每分鐘進(jìn)給量 被切削層長(zhǎng)度 刀具切入長(zhǎng)度 刀具切出長(zhǎng)度 取 行程次數(shù)： 基本工時(shí)，由式（1.5）有： 工序8：銑70x140端面 1. 選擇刀具 刀具選取端銑刀，刀片采用YG8, ，，，。 2. 決定銑削用量 10） 決定銑削深度 因?yàn)榧庸び嗔坎淮?，一次加工完? 11） 決定每次進(jìn)給量及切削速度 根據(jù)X51型銑床說(shuō)明書(shū)，其功率為為6kw，中等系統(tǒng)剛度。 根據(jù)表查出 ，則 按機(jī)床標(biāo)準(zhǔn)選取＝800 當(dāng)＝800r/min時(shí) 按機(jī)床標(biāo)準(zhǔn)選取 12） 計(jì)算工時(shí) 切削工時(shí)：，，，則機(jī)動(dòng)工時(shí)為 工序9：鉆Φ87上端面3-M12螺紋孔 工步1：鉆M12螺紋底孔Φ10mm 選用高速鋼錐柄麻花鉆（《工藝》表3.1－6） 由《切削》表2.7和《工藝》表4.2－16查得 （《切削》表2.15） 按機(jī)床選取 基本工時(shí)： min 工步2：攻螺紋M12mm 選擇M12mm高速鋼機(jī)用絲錐 等于工件螺紋的螺距，即 按機(jī)床選取 基本工時(shí)： 工序10: 鉆Φ87下端面3-M12螺紋孔 鉆Φ87下端面3-M12螺紋孔切削用量工時(shí)計(jì)算與鉆Φ87上端面3-M12螺紋孔的相同，在此不再累述。 工序11：檢驗(yàn)，入庫(kù) 三、 夾具設(shè)計(jì) 為了提高勞動(dòng)生產(chǎn)率，保證加工質(zhì)量，降低勞動(dòng)強(qiáng)度，需要設(shè)計(jì)專(zhuān)用夾具。 由指導(dǎo)老師的分配第4道工序的銑底端面的銑床夾具。 3.1問(wèn)題的提出 本夾具主要用于銑底端面，粗糙度3.2，和基準(zhǔn)A有垂直度要求，底端面主要是其他加工面的定位基準(zhǔn)，加工時(shí)主要考慮如何提高生產(chǎn)效率上和精度要求。 3.2定位基準(zhǔn)的選擇 本道工序加工底端面，我們采用已加工 好的Φ87端面和外圓以及Φ100外圓定位，采用活動(dòng)V型塊和固定V型塊定位，再加上擋銷(xiāo)定位，由于銑削力比較大，我們采用可調(diào)節(jié)輔助支撐，使用手柄帶動(dòng)V型塊快速夾緊即可以滿足要求。 定位方案如下：1-1 3.3切削力和夾緊力的計(jì)算 粗銑時(shí)受力最大，　選用高速端面銑刀 刀具：高速鋼端面銑刀，φ140mm。 銑時(shí)的軸向力 查文獻(xiàn)[２]表15-31， 由于工件所受加緊力與切削力方向相互垂直，為防止工件在切削力作用下沿較小平面?zhèn)冗厓A斜，使工件離開(kāi)基面所需的夾緊力 ， 摩擦系數(shù)查[4]表3-19，=0.25。 安全系數(shù) ， 式中 K————基本安全系數(shù)1.5； K————加工狀態(tài)系數(shù)1.2； K————刀具鈍化系數(shù)1.5，由文獻(xiàn)[4]表3-20查得； K————切削特點(diǎn)系數(shù)1.0； K————考慮加緊動(dòng)力穩(wěn)定性系數(shù)1.3。 L=20mm, H=42mm, l=34mm 查文獻(xiàn)[4]表3-26，知手柄用夾緊力，因此選用該手柄夾緊足以滿足加緊要求。 3.4定位誤差分析 夾具的主要定位元件為活動(dòng)V型塊和固定V型塊和擋銷(xiāo)，該V型塊是根據(jù)零件定位方案設(shè)計(jì)的專(zhuān)用件，定位精度較高，同時(shí)銑面時(shí)，面自身沒(méi)有精度要求，因此定位誤差可以不予考慮。 3.5夾具設(shè)計(jì)及操作的簡(jiǎn)要說(shuō)明 使用V型塊和擋銷(xiāo)，采用手柄快速夾緊，即可指定可靠的卡緊力。同時(shí)我們采用圓形對(duì)刀塊，保證導(dǎo)向的精度，這樣就大大的提高了生產(chǎn)效率，適合于大批量生產(chǎn)。 裝配圖附圖如下：1-2 夾具體如下1-3 總 結(jié) 這次設(shè)計(jì)是大學(xué)學(xué)習(xí)中最重要的一門(mén)科目，它要求我們把大學(xué)里學(xué)到的所有知識(shí)系統(tǒng)的組織起來(lái)，進(jìn)行理論聯(lián)系實(shí)際的總體考慮，需把金屬切削原理及刀具、機(jī)床概論、公差與配合、機(jī)械加工質(zhì)量、機(jī)床夾具設(shè)計(jì)、機(jī)械制造工藝學(xué)等專(zhuān)業(yè)知識(shí)有機(jī)的結(jié)合起來(lái)。同時(shí)也培養(yǎng)了自己的自學(xué)與創(chuàng)新能力。因此本次設(shè)計(jì)綜合性和實(shí)踐性強(qiáng)、涉及知識(shí)面廣。所以在設(shè)計(jì)中既了解了基本概念、基本理論，又注意了生產(chǎn)實(shí)踐的需要，將各種理論與生產(chǎn)實(shí)踐相結(jié)合，來(lái)完成本次設(shè)計(jì)。 這次設(shè)計(jì)是培養(yǎng)學(xué)生綜合運(yùn)用所學(xué)知識(shí),發(fā)現(xiàn),提出,分析和解決實(shí)際問(wèn)題,鍛煉實(shí)踐能力的重要環(huán)節(jié),更是在學(xué)完大學(xué)所學(xué)的所有專(zhuān)業(yè)課及生產(chǎn)實(shí)習(xí)的一次理論與實(shí)踐相結(jié)合的綜合訓(xùn)練。這次設(shè)計(jì)雖然只有三個(gè)月時(shí)間，但在這三個(gè)月時(shí)間中使我對(duì)這次課程設(shè)計(jì)有了很深的體會(huì)。 這次畢業(yè)設(shè)計(jì)使我以前所掌握的關(guān)于零件加工方面有了更加系統(tǒng)化和深入合理化的掌握。比如參數(shù)的確定、計(jì)算、材料的選取、加工方式的選取、刀具選擇、量具選擇等； 也培養(yǎng)了自己綜合運(yùn)用設(shè)計(jì)與工藝等方面的知識(shí)； 以及自己獨(dú)立思考能力和創(chuàng)新能力得到更進(jìn)一步的鍛煉與提高；再次體會(huì)到理論與實(shí)踐相結(jié)合時(shí)，理論與實(shí)踐也存在差異。 回顧起此次設(shè)計(jì)，至今我仍感慨頗多，的確，從選題到完成定稿，從理論到實(shí)踐，在整整一學(xué)期的日子里，可以說(shuō)學(xué)到了很多很多的的東西，同時(shí)鞏固了以前所學(xué)過(guò)的知識(shí)，而且學(xué)到了很多在書(shū)本上所沒(méi)有學(xué)到過(guò)的知識(shí)。通過(guò)這次畢業(yè)設(shè)計(jì)使我懂得了理論與實(shí)際相結(jié)合是很重要的，只有理論知識(shí)是遠(yuǎn)遠(yuǎn)不夠的，只有把所學(xué)的理論知識(shí)與實(shí)踐相結(jié)合起來(lái)，從理論中得出結(jié)論，才能真正的實(shí)用，在生產(chǎn)過(guò)程中得到應(yīng)用。在設(shè)計(jì)的過(guò)程中遇到了許多問(wèn)題，當(dāng)然也發(fā)現(xiàn)了自己的不足之處，對(duì)以前所學(xué)過(guò)的知識(shí)理解得不夠深刻，掌握得不夠牢固，通過(guò)這次畢業(yè)設(shè)計(jì)，讓自己把以前所學(xué)過(guò)的知識(shí)重新復(fù)習(xí)了一遍。 這次設(shè)計(jì)雖然順利完成了，也解決了許多問(wèn)題，也碰到了許多問(wèn)題，老師的辛勤指導(dǎo)下，都迎刃而解。同時(shí)，在老師的身上我也學(xué)得到很多額外的知識(shí)，在此我表示深深的感謝！同時(shí)，對(duì)給過(guò)我?guī)椭乃型瑢W(xué)和各位教研室指導(dǎo)老師再次表示忠心的感謝！ 致 謝 這次設(shè)計(jì)使我收益不小，為我今后的學(xué)習(xí)和工作打下了堅(jiān)實(shí)和良好的基礎(chǔ)。但是，查閱資料尤其是在查閱切削用量手冊(cè)時(shí)，數(shù)據(jù)存在大量的重復(fù)和重疊，由于經(jīng)驗(yàn)不足，在選取數(shù)據(jù)上存在一些問(wèn)題，不過(guò)我的指導(dǎo)老師每次都很有耐心地幫我提出寶貴的意見(jiàn)，在我遇到難題時(shí)給我指明了方向，最終我很順利的完成了畢業(yè)設(shè)計(jì)。 這次設(shè)計(jì)成績(jī)的取得，與指導(dǎo)老師的細(xì)心指導(dǎo)是分不開(kāi)的。在此，我衷心感謝我的指導(dǎo)老師，特別是每次都放下她的休息時(shí)間，耐心地幫助我解決技術(shù)上的一些難題，她嚴(yán)肅的科學(xué)態(tài)度，嚴(yán)謹(jǐn)?shù)闹螌W(xué)精神，精益求精的工作作風(fēng)，深深地感染和激勵(lì)著我。從課題的選擇到項(xiàng)目的最終完成，她都始終給予我細(xì)心的指導(dǎo)和不懈的支持。多少個(gè)日日夜夜，她不僅在學(xué)業(yè)上給我以精心指導(dǎo)，同時(shí)還在思想、生活上給我以無(wú)微不至的關(guān)懷，除了敬佩指導(dǎo)老師的專(zhuān)業(yè)水平外，她的治學(xué)嚴(yán)謹(jǐn)和科學(xué)研究的精神也是我永遠(yuǎn)學(xué)習(xí)的榜樣，并將積極影響我今后的學(xué)習(xí)和工作。在此謹(jǐn)向指導(dǎo)老師致以誠(chéng)摯的謝意和崇高的敬意。 參 考 文 獻(xiàn) 1. 切削用量簡(jiǎn)明手冊(cè),艾興、肖詩(shī)綱主編,機(jī)械工業(yè)出版社出版，1994年 2.機(jī)械制造工藝設(shè)計(jì)簡(jiǎn)明手冊(cè)，李益民主編，機(jī)械工業(yè)出版社出版，1994年 3.機(jī)床夾具設(shè)計(jì)，哈爾濱工業(yè)大學(xué)、上海工業(yè)大學(xué)主編，上海科學(xué)技術(shù)出版社出版，1983年 4.機(jī)床夾具設(shè)計(jì)手冊(cè)，東北重型機(jī)械學(xué)院、洛陽(yáng)工學(xué)院、一汽制造廠職工大學(xué)編，上?？茖W(xué)技術(shù)出版社出版，1990年 5.金屬機(jī)械加工工藝人員手冊(cè)，上海科學(xué)技術(shù)出版社，1981年10月 6.機(jī)械制造工藝學(xué)，郭宗連、秦寶榮主編，中國(guó)建材工業(yè)出版社出版，1997年 第 23 頁(yè) 共 28 頁(yè) 機(jī)械加工工序卡片 工件名稱(chēng) 工序號(hào) 4 零件名稱(chēng) 齒輪軸承座 零件號(hào) 零件重量 同時(shí)加工件數(shù) 1 材料 毛坯 牌號(hào) 硬度 型號(hào) 重量 鋼板 鑄件 設(shè)備 夾具 輔助工具 名稱(chēng) 型號(hào) 專(zhuān)用夾具 立式銑床 X51 安裝 工步 安裝及工步說(shuō)明 刀具 量具 走刀長(zhǎng)度mm 走刀次數(shù) 切削深度mm 進(jìn)給量mm/r 主軸轉(zhuǎn)速r/min 切削速度m/min 基本工 時(shí)min 1 銑底端面 端銑刀 游標(biāo)卡尺 317 1 設(shè)計(jì)者 劉宗津 指導(dǎo)老師 孫遠(yuǎn)敬 共 1 頁(yè) 第 1 頁(yè) Proceedings ofthe2006 IEEE/RSJ International Conference on Intelligent Robots and Systems October9- 15, 2006, Beijing, China ANovelModularFixtureDesignandAssemblySystem BasedonVR PengGaoliang, LiuWenjian SchoolofMechatronicsEngineering HarbinInstituteofTechnology Harbin, 150001, China pgl7782a Abstract - Modular fixtures are one oftheimportant aspects ofmanufacturing. This paper presents a desktop VR system for modular fixture design. The virtual environmentis designed and the design procedure is proposed. It assists the designer to make the feasible design decisions effectively and efficiently. A hierarchical data model is proposed to represent the modular fixture assembly. Based on this structure, the user can manipulate the virtual models precisely in VE during the design and assembly processes. Moreover, the machining simulation for manufacturing interaction checking is discussed and implemented. Finally, the case study has demonstrated the functionality of the proposed system. Compared with the immersive VR system, the proposed system has offered an affordable andportable solutionformodularfixtures design. Index Terms - Modularfixture, desktop VR, assembly design, machiningsimlulation. I. INTRODUCTION Modular fixtures are one of the important aspects of manufacturing. Proper fixture design is crucial to product quality in terms of precision, accuracy, and finish of the machined part. Modular fixture is a system of interchange- eable and highly standardized components designed to securely and accurately position, hold, and support the workpiece throughout the machining process 1. Tradition- ally, fixture designers rely on experience or use trial-and- error methods to determine an appropriate fixturing scheme. With the advent of computer technology, computer aided design has been prevalent in the area of modular fixture design. In general, the associated fixture design activities, namely setup planning, fixture element design, and fixture layout design are often dealt with at the downstream end of the machine tool development life-cycle. These practices do not lend themselves well to the bridging of design and manufacturing activities. Forexample, very few systems have incorporated the functionality of detecting machining interference. This leads to a gap between the fixture design andmanufacturing operationswheretheaspectofcutterpaths is not considered during the design stage 2. As a result, re- designcannotbeavoidedwhenthecutterisfoundtointerfere with the fixture components in the manufactu- ring set-up. Therefore, in orderto bring machining fixture design into the arenaofflexiblemanufacturing, amoresystematicandnatural designenvironmentisrequired. As a synthetic, 3D, interactive environment typically generated by a computer, VR has been recognized as a very powerful human-computer interface for decades 4. VR holds great potential in manufacturing applications to solve problems before being employed in practical manufacturing thereby preventing costly mistakes. The advances in VR technology in the last decade have provided the impetus for applying VR to different engineering applications such as product design 5, assembly 6, machining simulation 7, andtraining 8. The goal ofthis paper is to develop a VR- basedmodular fixtures design system (VMJFDS). This is the firststepto develop anintegratedandimmersiveenvironment for modular fixture design. This application has the advantages of making the fixture design in a natural and instructive manner, providing better match to the working conditions, reducing lead-time, and generally providing a significantenhancementoffixtureproductivityandeconomy. II. OVERVIEWOFTHEPROPOSEDSYSTEM The system architecture of the proposed desktop VR systemismodularisedbasedonthefunctionalrequirements of thesystem,whichisshowninFig.1. Atthesystemlevel,three modules of proposed system, namely, Graphic interface (GUI), Virtual environment (VE) and Database modules are designed. For each ofthe modules, a set ofobjects has been identified to realize its functional requirements. The detailed objectdesignandimplementation are omittedfromthispaper. Instead, the briefdescription ofthese three modules is given below. 1) Graphic Interface (GUI): The GUI is basically a friendly graphic interface that is used to integrate the virtual environmentandmodularfixturedesignactions. 2) Virtual environment (VE): TheVEprovidestheusers with a 3D display for navigating and manipulating the models of modular fixture system and its components in the virtual environment. As shown in Fig. 1, the virtual environment module comprises two parts, namely assembly design environment andmachiningsimulationenvironment. Theuser selects appropriate elements andputs downthese elements on the desk in the assembly design area. Then he assembles the selected elements one by one to build up the final fixture systemwiththeguidanceofthesystem. 1-4244-0259-X/06/$20.00 C)2006IEEE 2650 Authorized licensed use limited to: Nanchang University. Downloaded on December 20, 2009 at 22:44 from IEEE Xplore. Restrictions apply. Fig.1.OverviewofthedesktopVRbasedmodularfixturedesignsystem. 3) Database: The database deposit all of the models of environment and modular fixture elements, as well as the domain knowledge and useful cases. There are 5 databases shown in Fig.1. Among them, knowledge & rule base governing all fixture planning principles forms the brains of thesystem. III. PROCEDUREOFMODULARFIXTUREDESIGN In this section, an instructive modular fixture design procedure within VE is presented. Besides the 3D depth that the users feel and the real-world like operation process, this procedure features intelligence and introduction. During the design process, some useful cases and suggestion will be presented to the user for reference based on intelligent inference method such as Case based reasoning (CBR) and Rule based reasoning (RBR). Further more, relative knowledge andrules arepresented ashelppages thattheuser caneasilybrowsedduringthedesignprocess. Overview of modular fixture design process is summarized in Fig. 2. After the VE environment is initialed andthe workpiece is loaded, the first step is fixtureplanning. Inthis step, theuserfirstdecides thefixturing scheme, thatis specifies the fixturing faces of the workpiece interactively. Forhelptheusersdecision-making, someusefulcasesaswell as their fixturing scheme will be presented via the automatic CBR retrieval method. Once the fixturing faces are selected, theusermaybepromptto specifythefixturingpoints. Inthis task, somesuggestions andrulesaregiven. After the fixturing planning, the next step is fixture FUs design stage. In this stage, the user may be to select suitable fixture elements andassembletheseindividualparts into FUs. According to the spatial information ofthe fixturingpoints in relation to the fixture base and the workpiece, some typical FUs and suggestions may be presented automatically. These willbehelpfulfortheuser. AftertheplanningandFUs design stage, the next stage is interactively assembling the designed fixtureFUstoconnecttheworkpiecetothebaseplate. When the fixture configuration is completed, the result will be checked and evaluated within the machining environment. The tasks executed in this environment including assembly planning, machining simulation, and fixture evaluation. Assemblyplanning isusedto gain optimal assembly sequence and assembly path of each component. Machining simulation is responsible for manufacturing interaction detection. Fixture evaluation will check and evaluate the design result. In conclusion, the whole design process isinanaturemannerforthebenefitofVE. Moreover, the presented information of suggestion and knowledge can advise the user on how to make decisions ofthe best design selection. IV. ASSEMBLYMODELINGOFMODULARFIXTURE A. Modularfixturestructureanalysis A functionalunit(FU) is acombination offixture elements to provide connectionbetweenthebaseplate and aworkpiece 11. Generally, modularfixture structuremaybe dividedinto three functional units according to its basic structure characteristics, namely locating unit, clamping unit, and supporting unit. The number offixture elements in aFU may consist ofone or more elements, in which only one element serves as a locator, support or clamp. The major task ofthe modularfixture assembly is to selectthe supporting, locating, clamping and accessory elements to generate the fixture FUs toconnecttheworkpiecetothebaseplate. By analyzing the practical application ofmodular fixtures, it is found that the assembly ofmodular fixtures begins by selecting the suitable fixture elements to construct FUs, then subsequentlymountingtheseFUs onthebaseplate. Therefore, the FUs can be regarded as subassemblies ofmodular fixture system.Further,thestructureofmodularfixturesystemcanbe representedasahierarchalstructureasshowninFig.3. 2651 Authorized licensed use limited to: Nanchang University. Downloaded on December 20, 2009 at 22:44 from IEEE Xplore. Restrictions apply. UsefTa6 *T- siikg&Sugge lr,l Fixtui e Elemenets rUetrieval i0 Tools rKetrieval 4 Fig.2Modularfixturedesignprocedureinproposedsystem B. Hierarchically structured data modelfor modularfixture representation in VE It is common that the corresponding virtual environment may contain millions ofgeometric polygon primitives. Over thepastyears, anumberofmodel sub-division schemes, such asBSP-tree 10 andOctrees,havebeenproposedto organize largepolygonalmodels.However, formodular Ba 1I_ 1 Hsreplalte Bansepla1nte Elements *Locatng ElementsL,cating Units AccessoryEllements ClamnpingElemnents !ClampingUnits SupportingElemntsSupporting Ufnits Accessory Elements Fig. 3Hierarchical structureofmodularfixture system design applications, the scene is also dynamically changing, due to interactions. For example, in design process, the part object may change its spatial position, orientation and assembly relations. This indicates that a static representation, such as BSP-tree, is not sufficient. Further more, the above models can only represent the topology structure of fixture system in the component level. However, to the assembly relationship among fixture components, which refers to the mating relationship between assembly features that is not concerned. In this section, we present a hierarchically structuredandconstraint-baseddatamodelformodularfixture system representation, real-time visualization and precise 3D manipulationinVE. As shown in Fig.4, the high-level component based model is used for interactive operations involving assemblies or disassembles. It provides both topological structure and link relationsbetweencomponents. Theinformationrepresent- ed in the high-level model can be divided into two types, i.e. component objects and assembly relationships. Component objects can be a subassembly or a part. A subassembly consists of individual parts and assembly relationships betweentheparts. Component Level (Pt Part S Subassembly Assembly relationship Feature Level Ft3 Feature Feature mating relationship t- -t Polygon Level FZ-ll. Polygon Fig.4ThehierarchicalstructuredatamodelinVE Themiddle-levelfeaturebasedmodelisbuiltuponfeatures and feature constraints. In general, the assembly relationship often treated as the mating relationships between assembly features. Thus the featurebasedmodel isusedto describethe assembly relationship andprovides necessary information for spatial relationship calculating during assembly operation. In this model, only the feature relationships between two different components are considered. The relationship between features ofone element will be discussed in feature basedmodularfixtureelementmodelingbelow. The low-level polygon based model corresponds to the above two level models for real-time visualization and interaction. It describes the entire surface as an inter- connected triangular surface mesh. More about how the polygons organized of a single element will be discussed is thenextsection. C. Modularfixtureelementsmodeling As we know, in VE, the part is only represented as a number ofpolygon primitives. This result in the topological 2652 Authorized licensed use limited to: Nanchang University. Downloaded on December 20, 2009 at 22:44 from IEEE Xplore. Restrictions apply. relations- hips and parametric information are lost during the translation process of models from CAD systems to VR systems. However, this important information is necessary in design and assembly process. In order to fulfill the requirements, we present a modeling scheme for fixture elementsrepresentationinthissection. The modular fixture elements are pre-manufactured parts withstandarddimensions. Afterthefixturingschemedesigned, the left job is to select suitable standard elements and assemblethese elements to formafixture systeminafeasible andeffectivemanner. Therefore, intheproposed system, only the assembly features of the fixture elements need to be considered. Inthispaperanassemblyfeature isdefinedas apropertyof afixture element, whichprovidesrelatedinformationrelevant to modular fixture design and assembly/disassembly. The following eight function faces are defined as assembly featuresoffixtureelements: supportingfaces, supportedfaces, locating holes, counterbore holes, screw holes, fixing slots, andscrewbolts. Besidestheinformation aboutthefeaturelike typeanddimension, otherparameters, i.e. therelativeposition andorientationofthe featureintheelements localcoordinate system are recorded with the geometric model in the fixture element database. When one element assembles with another, the information aboutthematedfeatures isretrieved andused to decide the spatial relationship ofthe two elements. More information about the assembly features and their mating relationship arediscusseddetailedinRef 1. D. Constraintbasedfixtureassemblyin VE 1)Assemblyrelationshipbetweenfixtureelements Mating relationships have been used to define assembly relationships between part components in the field of assembly. According to the assembly features summarized in the above section, there are fivetypes ofmating relationships between fixture elements. Namely against, fit, screw fit, across, andT-slotfit,which are illustrated inFig. 5. Based on these mating relationships, we can reason the possible assemblyrelationshipofanytwoassembledfixtureelements. 2)Assemblyrelationshipreasoning Ingeneral, the assemblyrelationship oftwo assembledpart isrepresented as thematedassembly featurepairs ofthem. In the above section, we defined five basic mating relationships between fixture elements. Therefore, it is enabled to decide the possible assembly relationships through finding the possible mating assembly feature pairs. These possible assembly relationships are saved in assembly relationships database(ARDB)forfixtureassemblyinnextstage. However, when the fixture is complicated and the numbers ofcomposite fixture elements is large, the possible assembly relationships are too much to take much time for reasoning andtreating. To avoidthis situation, wefirstdecide the possible assembled elements pairs. That is to avoid reasoning the assembly relationship between a clamp andthe baseplate, for they never were assembled together. In this stage, some rules are utilized to find the possible assembled elementspairs. The algorithm of assembly relationships reasoning is similar to what discussed in Ref 12. Thus the detailed descriptionofthealgorithmisomittedfromthispaper. (a) AIlai.ns .2 l.I.F LIi I7 F d) Asicmie 1f-isxkt Elmn Fig. 5Fivebasicmatingrelationshipsbetweenfixtureelements 3)Constraint-basedfixtureassembly Aftercarrying outthe assemblyrelationships reasoning, all possible assembly relationships ofthe selected elements are establishedandsavedinARDB. Basedontheserelationships, the trainee can assemble these individual parts to a fixture system. This section is about the discussion of interactive assembly operation in VE. The process ofa single assembly operation is presented in Fig.5 and illustrated by two simple partsassemblyasshowninFig.6. In general, the assembly operation process is divided into three steps, namely assembly relationship recognizing, constraint analysis and applying, constraint-based motion. Firstly, the trainee selects an element and moves it to the assembled component. Once an inference between the assembling and assembled component is detected during the moving,the inferredfeatures is checked. Ifthetwo features is one of the assembly relationships in ARDB, they will be highlighted and will await the users confirmation. Once it is confirmed, the recognized assembly relationship will be appliedby constraint analyzing and solving, that is adjustthe translationandorientationoftheassemblingelementtosatisfy the position relationship ofthese two components, as well as applythenew constrainttotheassemblingelement.Whenthe new constraint is applied, the motion of the assembling element will be mapped into a constraint space. This is done bytransferring 3Dmotiondatafromtheinputdevicesintothe allowable motions ofthe object. The constraint-based motion notonlyensuresthattheprecisepositionsofacomponentcan be obtained, but also guarantee that the existing constraints will not be violated during the future operations. The assembling element will reach to the final position through succession assembly relationship recognizing and constraint applying. 2653 Ii 1-11 4- (b) F.t Authorized licensed use limited to: Nanchang University. Downloaded on December 20, 2009 at 22:44 from IEEE Xplore. Restrictions apply. NO Assembly relationship Iis possible checking elatioohship? Fig. 6Processofassemblyconstraintestablishment No V. MACHINING SIMULATION A. Manufacturinginteractions During the machining process, there are many types of manufacturing interactions associated with the fixture may occur. These interactions can be divided into two broad categories illustrated below, namely static interactions and dynamicinteractions. 1) Static interactions refer to the interference between fixture components, the interference between fixture components and machine tool, and the interference between fixture components andmaching feature ofworkpiece during theworkpiecesetup. 2)Dynamicinteractionsrefertothetool-fixtureinteractions, which occur within a single operation when the tool and the fixtureusedinthatoperationmaycollideduringcutting. Generally, the aspects of machining process and cutter paths are not considered duringthe fixture design stage. As a result, these interactions may often occur during the practical manufacturing. Thus the human machinists have to spend muchoftheirtimeidentifyingtheseinteractions andresolving them. Itis oftenresults inmodification orre-designoffixture system. Thatistediousandtimecostly. B.Interferencedetection Although the currently commercial software, like VERICUT, can simulates NC machining to detect tool path errors and inefficient motion prior to machining an actual workpiece. It is available to eliminate errors that could ruin the part, damage the fixture, break the cutting tool, or crash the machine during the part programming stage. However, these software are expensive and oriented to NC program- mertherebynotsuitableforfixturedesigners. During the fixture design stage, it should be ensured that the associated fixture interactions can be avoided. In this system, after the fixture configuration is complete, the machining simulation module is presented to the user to identifytheinteractionsandresolvethem. Within the machining simulation environment, the 3D digitalmodelofmachinetoolispresented. The canassemble the fixture components on the work bench and setup the workpiece, just as what the machining engineers do in the actual site. During the setup, the fixture components and the workpiece are move to their assembly position under manipulation. Theinterferencecheckingmoduleiscarriedout. Ifinterference occurs, the inferred objectwill be highlight. It is p