軸承座零件的機(jī)械加工工藝規(guī)程及鉆4-φ12孔工藝夾具設(shè)計(jì)【說(shuō)明書+CAD】
軸承座零件的機(jī)械加工工藝規(guī)程及鉆4-12孔工藝夾具設(shè)計(jì)【說(shuō)明書+CAD】,說(shuō)明書+CAD,軸承座零件的機(jī)械加工工藝規(guī)程及鉆4-12孔工藝夾具設(shè)計(jì)【說(shuō)明書+CAD】,軸承,零件,機(jī)械,加工,工藝,規(guī)程,12,十二,夾具,設(shè)計(jì),說(shuō)明書,仿單,cad
機(jī)械加工工藝過程卡片產(chǎn)品型號(hào)零件圖號(hào)產(chǎn)品名稱軸承座零件名稱軸承座共1頁(yè)第1頁(yè)材 料 牌 號(hào) HT200毛 坯 種 類鑄件毛坯外形尺寸215x156每毛坯可制件數(shù)1每 臺(tái) 件 數(shù)1備 注 工 序 號(hào)工 名序 稱工 序 內(nèi) 容 車 間 工 段設(shè) 備工 藝 裝 備 工 時(shí) 準(zhǔn)終 單件1125前端面半精銑軸承座125前端面,使前后端面距為85mm立式銑床高速鋼套式面銑刀、游標(biāo)卡尺、專用夾具2125后端面半精銑軸承座125后端面,使前后端面距為85mm立式銑床高速鋼套式面銑刀、游標(biāo)卡尺、專用夾具362 .5內(nèi)端面先鉆孔在擴(kuò)孔至62.5mm立式銑床高速鋼套式面銑刀、游標(biāo)卡尺、專用夾具4圓頂臺(tái)面粗銑軸承座圓頂臺(tái)面至2.5mm立式銑床高速鋼套式面銑刀、游標(biāo)卡尺、專用夾具5底座底面半精銑軸承座底面,使其與定圓臺(tái)面距146mm立式銑床高速鋼套式面銑刀、游標(biāo)卡尺、專用夾具612孔 鉆、鉸孔至12mmZ525型立式鉆床高速鋼鉆刀鉸刀塞規(guī).卡尺8.4716孔 锪孔至16mmZ525型立式鉆床高速鋼鉆刀锪刀、塞規(guī).卡尺8去毛刺鉗工臺(tái)平銼9中檢塞規(guī)、百分表、卡尺等10時(shí)效處理11清洗清洗機(jī)12終檢塞規(guī)、百分表、卡尺等 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 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)產(chǎn)品名稱零件名稱軸承座共1頁(yè)第1頁(yè) 6鉆鉸12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215x15611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)看立式鉆床Z5251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) (分)準(zhǔn)終單件8.4s工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速切削速度進(jìn)給量切削深度進(jìn)給次數(shù)工步工時(shí)r/minm/minmm/rmm機(jī)動(dòng)輔助1鉆孔至11mm高速鋼鉆刀、游標(biāo)卡尺960200.111mm14.5s2s2鉸孔至11.95mm 鉸刀、塞規(guī).、卡尺97210.95mm1 3.96s36.8s 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)河南工業(yè)職業(yè)技術(shù)學(xué)院機(jī)械加工工序卡產(chǎn)品型號(hào)零件圖號(hào)01共 頁(yè)產(chǎn)品名稱軸承座零件名稱軸承座第1 頁(yè)材料牌號(hào)HT200毛坯種類鑄鐵毛坯外形尺寸215x150x89每毛坯件數(shù)1每臺(tái)件數(shù)備注車間工序號(hào)工序名稱材料牌號(hào)10粗銑底面HT200毛坯種類毛坯外形尺寸每毛坯件數(shù)每臺(tái)件數(shù)HT200215x150x891設(shè)備名稱設(shè)備編號(hào)同時(shí)加工件數(shù)銑床X6132夾具編號(hào)夾具名稱切削液工序工時(shí)準(zhǔn)終單件工步號(hào)工步內(nèi)容工藝裝備主軸轉(zhuǎn)速/rmin切削速度/mmin進(jìn)給量/rmm切削深度/mm進(jìn)給次數(shù)工時(shí)定額機(jī)動(dòng)輔助1粗銑底面,保證尺寸30和815056.521.81繪制(日期)審核(日期)會(huì)簽(日期)標(biāo)記處記更改簽字日期標(biāo)記處記更改簽字日期 附表20河南工業(yè)職業(yè)技術(shù)學(xué)院機(jī)械加工工序卡產(chǎn)品型號(hào)零件圖號(hào)02共 頁(yè)產(chǎn)品名稱軸承座零件名稱軸承座第2 頁(yè)材料牌號(hào)HT200毛坯種類鑄鐵毛坯外形尺寸215x150x89每毛坯件數(shù)1每臺(tái)件數(shù)備注車間工序號(hào)工序名稱材料牌號(hào)20精銑底面HT200毛坯種類毛坯外形尺寸每毛坯件數(shù)每臺(tái)件數(shù)鑄鐵215x150x891設(shè)備名稱設(shè)備編號(hào)同時(shí)加工件數(shù)銑床X6132夾具編號(hào)夾具名稱切削液工序工時(shí)準(zhǔn)終單件工步號(hào)工步內(nèi)容工藝裝備主軸轉(zhuǎn)速/rmin切削速度/mmin進(jìn)給量/rmm切削深度/mm進(jìn)給次數(shù)工時(shí)定額機(jī)動(dòng)輔助1精銑底面, 保證精度3001130.21繪制(日期)審核(日期)會(huì)簽(日期)標(biāo)記處記更改簽字日期標(biāo)記處記更改簽字日期附表30河南工業(yè)職業(yè)技術(shù)學(xué)院機(jī)械加工工序卡產(chǎn)品型號(hào)零件圖號(hào)03共 頁(yè)產(chǎn)品名稱軸承座零件名稱軸承座第 3 頁(yè)材料牌號(hào)HT200毛坯種類鑄鐵毛坯外形尺寸215x150x89每毛坯件數(shù)1每臺(tái)件數(shù)備注車間工序號(hào)工序名稱材料牌號(hào)30銑端面HT200毛坯種類毛坯外形尺寸每毛坯件數(shù)每臺(tái)件數(shù)鑄鐵215x150x891設(shè)備名稱設(shè)備編號(hào)同時(shí)加工件數(shù)銑床X6132夾具編號(hào)夾具名稱切削液工序工時(shí)準(zhǔn)終單件工步號(hào)工步內(nèi)容工藝裝備主軸轉(zhuǎn)速/rmin切削速度/mmin進(jìn)給量/rmm切削深度/mm進(jìn)給次數(shù)工時(shí)定額機(jī)動(dòng)輔助1銑62.5孔的兩端面,保證85600117.75221繪制(日期)審核(日期)會(huì)簽(日期)標(biāo)記處記更改簽字日期標(biāo)記處記更改簽字日期附表40河南工業(yè)職業(yè)技術(shù)學(xué)院機(jī)械加工工序卡產(chǎn)品型號(hào)零件圖號(hào)04共 頁(yè)產(chǎn)品名稱軸承座零件名稱軸承座第4 頁(yè)材料牌號(hào)HT200毛坯種類鑄鐵毛坯外形尺寸215x150x89每毛坯件數(shù)1每臺(tái)件數(shù)備注車間工序號(hào)工序名稱材料牌號(hào)40銑頂面HT200毛坯種類毛坯外形尺寸每毛坯件數(shù)每臺(tái)件數(shù)鑄鐵215x150x891設(shè)備名稱設(shè)備編號(hào)同時(shí)加工件數(shù)銑床X6132夾具編號(hào)夾具名稱切削液工序工時(shí)準(zhǔn)終單件工步號(hào)工步內(nèi)容工藝裝備主軸轉(zhuǎn)速/rmin切削速度/mmin進(jìn)給量/rmm切削深度/mm進(jìn)給次數(shù)工時(shí)定額機(jī)動(dòng)輔助1銑12圓柱頂面,保證粗糙度12.560022.6081.53繪制(日期)審核(日期)會(huì)簽(日期)標(biāo)記處記更改簽字日期標(biāo)記處記更改簽字日期 附表50河南工業(yè)職業(yè)技術(shù)學(xué)院機(jī)械加工工序卡產(chǎn)品型號(hào)零件圖號(hào)05共 頁(yè)產(chǎn)品名稱軸承座零件名稱軸承座第5 頁(yè)材料牌號(hào)HT200毛坯種類鑄鐵毛坯外形尺寸215x150x89每毛坯件數(shù)1每臺(tái)件數(shù)備注車間工序號(hào)工序名稱材料牌號(hào)50鏜內(nèi)孔HT200毛坯種類毛坯外形尺寸每毛坯件數(shù)每臺(tái)件數(shù)鑄鐵215x150x891設(shè)備名稱設(shè)備編號(hào)同時(shí)加工件數(shù)鏜床TP619夾具編號(hào)夾具名稱切削液工序工時(shí)準(zhǔn)終單件工步號(hào)工步內(nèi)容工藝裝備主軸轉(zhuǎn)速/rmin切削速度/mmin進(jìn)給量/rmm切削深度/mm進(jìn)給次數(shù)工時(shí)定額機(jī)動(dòng)輔助1鏜62.5的內(nèi)孔,并保證62.561.15196.250.0821繪制(日期)審核(日期)會(huì)簽(日期)標(biāo)記處記更改簽字日期標(biāo)記處記更改簽字日期附表60河南工業(yè)職業(yè)技術(shù)學(xué)院機(jī)械加工工序卡產(chǎn)品型號(hào)零件圖號(hào)06共 頁(yè)產(chǎn)品名稱軸承座零件名稱軸承座第6 頁(yè)材料牌號(hào)HT200毛坯種類 鑄 鐵毛坯外形尺寸215x150x89每毛坯件數(shù)1每臺(tái)件數(shù)備注車間工序號(hào)工序名稱材料牌號(hào)60鉆12孔HT200毛坯種類毛坯外形尺寸每毛坯件數(shù)每臺(tái)件數(shù)鑄鐵215x150x891設(shè)備名稱設(shè)備編號(hào)同時(shí)加工件數(shù)鉆床Z3040夾具編號(hào)夾具名稱切削液工序工時(shí)準(zhǔn)終單件工步號(hào)工步內(nèi)容工藝裝備主軸轉(zhuǎn)速/rmin切削速度/mmin進(jìn)給量/rmm切削深度/mm進(jìn)給次數(shù)工時(shí)定額機(jī)動(dòng)輔助1鉆出4個(gè)12的孔,并保證兩孔的中心距40和12576.5421.850.25.81繪制(日期)審核(日期)會(huì)簽(日期)標(biāo)記處記更改簽字日期標(biāo)記處記更改簽字日期 附表70河南工業(yè)職業(yè)技術(shù)學(xué)院機(jī)械加工工序卡產(chǎn)品型號(hào)零件圖號(hào)07共 頁(yè)產(chǎn)品名稱軸承座零件名稱軸承座第7 頁(yè)材料牌號(hào)HT200毛坯種類鑄鐵毛坯外形尺寸215x150x89每毛坯件數(shù)1每臺(tái)件數(shù)備注車間工序號(hào)工序名稱材料牌號(hào)70鉆16孔HT200毛坯種類毛坯外形尺寸每毛坯件數(shù)每臺(tái)件數(shù)鑄鐵215x150x891設(shè)備名稱設(shè)備編號(hào)同時(shí)加工件數(shù)鉆床Z3040夾具編號(hào)夾具名稱切削液工序工時(shí)準(zhǔn)終單件工步號(hào)工步內(nèi)容工藝裝備主軸轉(zhuǎn)速/rmin切削速度/mmin進(jìn)給量/rmm切削深度/mm進(jìn)給次數(shù)工時(shí)定額機(jī)動(dòng)輔助1在鉆床上鉆出16的孔,保證中心證距40和深度5431.423.360.257.752繪制(日期)審核(日期)會(huì)簽(日期)標(biāo)記處記更改簽字日期標(biāo)記處記更改簽字日期 附表80河南工業(yè)職業(yè)技術(shù)學(xué)院機(jī)械加工工序卡產(chǎn)品型號(hào)零件圖號(hào)08共 頁(yè)產(chǎn)品名稱軸承座零件名稱軸承座第 8 頁(yè)材料牌號(hào)HT200毛坯種類鑄鐵毛坯外形尺寸215x150x89每毛坯件數(shù)1每臺(tái)件數(shù)備注車間工序號(hào)工序名稱材料牌號(hào)80去毛刺HT200毛坯種類毛坯外形尺寸每毛坯件數(shù)每臺(tái)件數(shù)鑄鐵215x150x891設(shè)備名稱設(shè)備編號(hào)同時(shí)加工件數(shù)鉗夾具編號(hào)夾具名稱切削液工序工時(shí)準(zhǔn)終單件工步號(hào)工步內(nèi)容工藝裝備主軸轉(zhuǎn)速/rmin切削速度/mmin進(jìn)給量/rmm切削深度/mm進(jìn)給次數(shù)工時(shí)定額機(jī)動(dòng)輔助1去毛刺手用鉸刀繪制(日期)審核(日期)會(huì)簽(日期)標(biāo)記處記更改簽字日期標(biāo)記處記更改簽字日期 附表90課 程 設(shè) 計(jì)題 目:軸承零件的機(jī)械加工工藝規(guī)程及4x12孔工藝裝備設(shè)計(jì) 課程設(shè)計(jì)任務(wù)書一、設(shè)計(jì)題目 設(shè)計(jì)軸承零件的機(jī)械加工工藝規(guī)程及4x12孔工藝裝備設(shè)計(jì) 二、原始資料(1) 被加工零件的零件草圖 1張(2) 生產(chǎn)類型: 50000件/年三、上交材料(1) 被加工工件的零件圖 1張(2) 工件的毛坯圖 1張(3) 機(jī)械加工工藝過程卡片 1張(4) 與所設(shè)計(jì)夾具對(duì)應(yīng)那道工序的工序卡片 1張(5) 夾具裝配圖 1張(7) 課程設(shè)計(jì)說(shuō)明書(7000-8000字) 1份說(shuō)明書主要包括以下內(nèi)容(章節(jié))目錄 摘要(中外文對(duì)照的,各占一頁(yè))零件工藝性分析機(jī)械加工工藝規(guī)程設(shè)計(jì) 指定工序的專用機(jī)床夾具設(shè)計(jì) 方案綜合評(píng)價(jià)與結(jié)論體會(huì)與展望參考文獻(xiàn) 列出參考文獻(xiàn)(包括書、期刊、報(bào)告等,10條以上)課程設(shè)計(jì)說(shuō)明書一律用A4紙、縱向打印.四、進(jìn)度安排(參考)(1) 熟悉零件,畫零件圖 2天 (2) 選擇工藝方案,確定工藝路線,填寫工藝過程綜合卡片 5天(3) 工藝裝備設(shè)計(jì)(畫夾具裝配圖及夾具體圖) 9天(4) 編寫說(shuō)明書 3天(5) 準(zhǔn)備及答辯 2天五、指導(dǎo)教師評(píng)語(yǔ)成 績(jī): 指導(dǎo)教師日期成績(jī)?cè)u(píng)定采用五級(jí)分制,即優(yōu)秀、良好、中等、及格和不及格。 優(yōu)秀:設(shè)計(jì)方案合理并新穎,設(shè)計(jì)說(shuō)明書及設(shè)計(jì)圖紙規(guī)范、內(nèi)容豐富。在設(shè)計(jì)過程中勤奮好學(xué)、有創(chuàng)新思想; 良好:設(shè)計(jì)方案合理,設(shè)計(jì)說(shuō)明書及設(shè)計(jì)圖紙比較規(guī)范、內(nèi)容比較豐富。在設(shè)計(jì)過程中勤奮好學(xué)、有創(chuàng)新思想; 中等:設(shè)計(jì)方案一般,設(shè)計(jì)說(shuō)明書及設(shè)計(jì)圖紙欠規(guī)范、內(nèi)容一般。在設(shè)計(jì)過程中比較勤奮、創(chuàng)新思想不明顯; 及格:設(shè)計(jì)方案不完善,存在一些小錯(cuò)誤,說(shuō)明書及設(shè)計(jì)圖紙欠規(guī)范、內(nèi)容一般。在設(shè)計(jì)過程中勤奮精神不夠: 不及格:設(shè)計(jì)方案有嚴(yán)重錯(cuò)誤,設(shè)計(jì)說(shuō)明書及設(shè)計(jì)圖紙不規(guī)范、內(nèi)容淺薄。在設(shè)計(jì)過程中勤奮好學(xué)精神不夠。摘要軸承零件制造的工藝文件摘要:產(chǎn)品制造工藝過程各項(xiàng)內(nèi)容要求一定程序進(jìn)行編制,文件標(biāo)準(zhǔn)形式固定下來(lái)形成工藝文件。工藝文件分為綜合工藝文件,即將一個(gè)產(chǎn)品要求統(tǒng)一編制,一個(gè)文件簡(jiǎn)單明了。查詢適用于產(chǎn)品結(jié)構(gòu)簡(jiǎn)單生產(chǎn),批量場(chǎng)合類型工藝文件產(chǎn)品制造技術(shù)專業(yè)特點(diǎn)分類 2002:機(jī)床,入世是挑戰(zhàn)更是機(jī)遇,專家指出要加大我國(guó)數(shù)控機(jī)床研發(fā)力度,加快普及型數(shù)控機(jī)床的發(fā)展。漫話中國(guó)機(jī)床制造業(yè)的服務(wù)競(jìng)爭(zhēng)中國(guó)銑床和加工中心市場(chǎng)的現(xiàn)狀和展望國(guó)內(nèi)外車床的技術(shù)水平和發(fā)展方向,世界加工中心的生產(chǎn)、需求和發(fā)展動(dòng)向國(guó)內(nèi)外機(jī)床發(fā)展趨勢(shì)世界數(shù)控系統(tǒng)發(fā)展趨勢(shì),切削加工技術(shù)和數(shù)控機(jī)床的發(fā)展。 將產(chǎn)品制造工藝過程的各項(xiàng)內(nèi)容和要求按照一定的程序進(jìn)行編制,以文件和標(biāo)準(zhǔn)的形式固定下來(lái),就形成了工藝文件。工藝文件可以分為兩種:一是綜合型工藝文件,即將一個(gè)產(chǎn)品的所有要求統(tǒng)一編制在一個(gè)文件中,簡(jiǎn)單明了,便于查詢,適用于產(chǎn)品結(jié)構(gòu)簡(jiǎn)單、生產(chǎn)批量小的場(chǎng)合。二是分類型工藝文件,即根據(jù)產(chǎn)品制造技術(shù)的專業(yè)特點(diǎn)分類編制,突出專業(yè)特點(diǎn),適用于各類產(chǎn)品。 軸承作為一種標(biāo)準(zhǔn)化機(jī)械零件部件,除了個(gè)別品種外,大多數(shù)品種的生產(chǎn)流程基本相似。因此,軸承零件的制造工藝文件的編制便于實(shí)現(xiàn)規(guī)范化、系列化。 AbstractRolling parts manufacturing process document Abstract: manufacturing process requires the elements of procedure documentation standards down in the form of a document of paper documents into integrated technology products to be a requirement to prepare a document clear and simple query to the product mix Simple production quantities occasion type of paper products manufacturing technology professional characteristics of Category 2002: Machine, the WTO is a challenge more opportunities experts pointed out that Chinas CNC machine tools to increase research and development efforts to speed up the popularization of CNC machine tools Talking about the development of Chinas machine tool manufacturing services competition Milling and processing centres in China market status and prospects at home and abroad lathe technology and development of the processing center of world production, demand and the development trends of world development trend of domestic and foreign machine tool CNC machining technology development trends and the development of CNC machine tools Product manufacturing process of the content and requirements in accordance with certain procedures for the preparation, documentation and standards in the form of fixed, the formation of a document. Technology files can be divided into two types: First General of documents, to be a product of all the requirements of unity in the preparation of a document, clear and simple, readily accessible and applicable to the product structure is simple, the production of small quantities of occasions. Second, the type of classified documents, namely, manufacturing technology products in accordance with the classification of professional characteristics, prominent professional characteristics, applicable to all types of products. Rolling as a standardized machine parts components, in addition to individual species, most species of similar production processes. Therefore, bearing parts of the manufacturing process for the preparation of documents to achieve standardized, and serialization. 目錄1.零件的工藝分析12.機(jī)械加工工藝設(shè)計(jì)22.1 毛坯的制造形式22.2 基面23.制訂機(jī)械加工工藝路線33.1表面加工方法的確定33.2工序順序的安排43.3確定工藝路線54.機(jī)械加工余量、工序尺寸及公差的確定64.1確定切削用量及時(shí)間定額:65.夾具設(shè)計(jì)85.1夾具選擇8心得體會(huì) .12參考文獻(xiàn)131.零件的工藝分析該設(shè)計(jì)是軸承零件的加工工藝和4x12孔的工藝裝備要求:4x12在軸承零件底座的左右2邊,每邊孔心距40 mm,2邊孔心距180 mm。分析如表:項(xiàng)目公差等級(jí)尺寸及偏差mm 粗糙度um圓頂臺(tái)面IT111212.5125的前端面IT111256.3125的后端面IT111256.3底座底端面IT112156.362.5的內(nèi)端面IT11856.316的孔IT11166.32.機(jī)械加工工藝設(shè)計(jì)2.1 毛坯的制造形式零件材料為HT200,考慮到零件材料的綜合性能及材料成本和加工成本,保證零件工作的可靠,采用鑄造。由于年產(chǎn)量為4000件,屬于中批生產(chǎn)的水平,而且零件輪廓尺寸不大,故可以采用鑄造成型。鑄件需經(jīng)時(shí)效處理。毛坯工藝確定毛坯的尺寸公差和加工余量鑄造類型(砂型)基本尺寸尺寸公差等級(jí)加工余量等級(jí)公差CT加工余量底座底面215CT9MA-G2.85圓頂臺(tái)面12CT9MA-G1.62.5孔內(nèi)面85CT9MA-G2.25大圓前后面125CT9MA-G2.55 2.2基面 基面選擇是工藝規(guī)程設(shè)計(jì)中的重要的設(shè)計(jì)之一,基面的選擇正確與合理,可以使加工質(zhì)量得到保證,生產(chǎn)率得到提高。否則,加工工藝過程中會(huì)問題百出,更有甚者,還會(huì)造成零件大批量的報(bào)廢,使生產(chǎn)無(wú)法進(jìn)行。2.2.1 粗基面的選擇 作為粗基準(zhǔn)的表面應(yīng)平整,沒有飛邊、毛刺或其他表面缺欠。該工件選擇125圓后面和62.5的內(nèi)面。采用125圓面定位加工其前面,用62.5的內(nèi)面加工軸承零件底座底面。可以為后續(xù)工序準(zhǔn)備好精基準(zhǔn)。2.2.2 精基面的選擇 選加工后的125后面為精基準(zhǔn)面來(lái)加工其前面 。選軸承零件底座底面為精基準(zhǔn)面來(lái)加工62.5的內(nèi)面和圓頂臺(tái)面。3.制訂機(jī)械加工工藝路線 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。 1. 工序 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(wàn)能性機(jī)床配以專用工卡具,并盡量使工序集中來(lái)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(yè)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: 軸承零件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?jìng)渥?25前端面IT116 .3粗銑-半精銑表1-8125后端面IT116.3粗銑-半精銑表1-862 .5內(nèi)端面IT116.3鉆-擴(kuò)表1-7圓頂臺(tái)面IT1112.5粗銑表1-8底座底面IT116.3粗銑-半精銑表1-816孔IT76.3锪表1-712孔IT8鉆-鉸表1-103.2工序順序的安排機(jī)械加工工序(1)遵循“先基準(zhǔn)后其他”原則,首先加工基準(zhǔn)曲柄左端面和右端面。(2)遵循“先粗后精”原則,先安排粗加工工序,后安排精加工工序。(3)遵循“先主后次”原則,先加工主要表面(4)遵循“先面后孔”原則,先加工曲柄端面,再加工孔,確定工藝路3.3確定工藝路線在綜合考慮上述工序順序安排原則的基礎(chǔ)上,表列出了曲柄的工藝路線。工序號(hào)工序名稱機(jī)床裝備刀具量具1125前端面 銑床銑刀游標(biāo)卡尺2125后端面銑床銑刀游標(biāo)卡尺362 .5內(nèi)端面鉆床鉆刀游標(biāo)卡尺4圓頂臺(tái)面銑床銑刀游標(biāo)卡尺5底座底面銑床銑刀游標(biāo)卡尺612孔鉆床鉆刀鉸刀塞規(guī).卡尺716孔鉆床锪刀塞規(guī).卡尺8去毛刺鉗工臺(tái)平銼9中檢塞規(guī)、百分表、卡尺等10時(shí)效處理11清洗清洗機(jī)12終檢塞規(guī)、百分表、卡尺等加工設(shè)備和工藝設(shè)備1 機(jī)床的選擇:采用Z525立式鉆床、鉆床。 2 選擇夾具:該曲柄的生產(chǎn)綱領(lǐng)為大批生產(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。4選擇量具:采用塞規(guī).雙用游標(biāo)卡尺。4.機(jī)械加工余量、工序尺寸及公差的確定孔12的工序尺寸由表2-28課查得,鉆孔余量Z=1mm,粗鉸余量M=0.05,錐銷孔加工工序的加工余量項(xiàng)目?jī)?nèi)容精度等級(jí)工序尺寸工序余量12孔鉆IT111111鉸IT81211.954.1確定切削用量及時(shí)間定額:主軸轉(zhuǎn)速的確定1.鉆、鉸12錐孔,以軸承底座右端面為基準(zhǔn)。刀具:鉆頭直徑為11mm的高速鋼鉆頭,錐度鉸刀頭直徑為12mm高速鋼鉸刀。機(jī)床:Z525立式鉆床2.鉆孔工步背刀吃量p的選擇粗加工時(shí)根據(jù)加工余量和工藝系統(tǒng)剛度確定p=11mm。進(jìn)給量的確定 由表5-22,選取該工步得進(jìn)量f=0.1mm/r。切削速度的計(jì)算 由表5-31,按工件材料為鑄鐵的條件選取,切削速度v=20m/min選取。由公式n=1000v/d可求得該工序鉆頭鉆速n=960r/min,參照表4-9所列Z525型立式鉆床得主軸轉(zhuǎn)速,取轉(zhuǎn)速n=960r/min。再將此轉(zhuǎn)速代入公式v=nd/1000=33.16m/min。3.粗鉸孔工步1)背吃刀量的確定 取p=0.95mm。2)進(jìn)給量的確定 由表5-31,選取該工步得進(jìn)給量f=1mm/r。3切削速度的計(jì)算 由表5-31,按工件材料為鑄鐵的條件選取,切削速度v=2m/min選取。由公式n=1000v/d可求得該工序鉆頭鉆速n=80r/min,參照表4-9所列Z525型立式鉆床得主軸轉(zhuǎn)速,取轉(zhuǎn)速n=97r/min。再將此轉(zhuǎn)速代入公式v=nd/1000=3.64m/min時(shí)間定額的計(jì)算:工序6:鉆、鉸12孔1) 鉆孔工步根據(jù)表5-51,鉆孔的基本時(shí)間可由公式 求得。l=30mm,l2=1mm,l1=D/2cotkr+(12)=5.0mm;f=0.1mm/r;n=960r/min。則該工步的基本時(shí)間t=(30+5.0+1)/0.1mm/r /960r/min=22.5s 2) 粗鉸孔工步 根據(jù)表5-41,鉸孔基本時(shí)間可由公式t=L/fn=(l+l2+l1 )/fn, LP=(D-d)/2, kr=15,l1=1mm,f=1mm/r,n=97r/min則該工步的基本時(shí)間t=19.8s。3) 輔助時(shí)間的計(jì)算tf輔助時(shí)間tf基本時(shí)間t之間的關(guān)系為tf=(0.15-0.2)t鉆孔輔助時(shí)間tf=0.222.5=4.5s鉸孔輔助時(shí)間tf=0.219.8=3.96s其它時(shí)間計(jì)算除了作業(yè)時(shí)間以外,每道工序的單件時(shí)間還包括布置工作時(shí)間、休息與生理需要時(shí)間和準(zhǔn)備與終結(jié)時(shí)間。由于該設(shè)計(jì)的生產(chǎn)類型為大批量生產(chǎn),分?jǐn)偟矫總€(gè)工件上的準(zhǔn)備與終結(jié)時(shí)間甚微,可忽略不計(jì)。布置工作地時(shí)間tb是作業(yè)時(shí)間的2%-7%,休息與生理時(shí)間tx是作業(yè)時(shí)間的2%-4%,本設(shè)計(jì)均取3%,則工序的其他時(shí)間(tb +tx)可按關(guān)系式(3%+3%)(tf+t)計(jì)算。工序9的其他時(shí)間:tb +tx=6%(10.8s+20s+4s)=2s單件計(jì)算時(shí)間td=2s+10.8s+20s+4s=36.8s。5.夾具設(shè)計(jì)5.1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(cè)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。(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,短圓柱銷限制2個(gè)自由度,削邊銷限制1個(gè)自由度。(2)怎樣夾緊;設(shè)計(jì)夾具由螺旋夾緊配合V形塊夾緊工件,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和鉸刀,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。(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(lái)對(duì)12孔進(jìn)行加工,這個(gè)孔尺寸精度為IT12,表面粗糙度W為毛坯的粗糙度,鉆、粗鉸以可滿足其精度。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。(三)夾具設(shè)計(jì)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12孔時(shí),采用軸承底座右端面和軸承底座底面作為定位基準(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面與面定位,因?yàn)樵摱ㄎ辉亩ㄎ换鶞?zhǔn)為面的軸線,存在間隙,定位基準(zhǔn)會(huì)發(fā)生相對(duì)位置的變化即存在基準(zhǔn)位移誤差。=90,hH時(shí)dw(B)=2(H-h)tangdw(H)=0 2、切削力及夾緊力的計(jì)算刀具:11的麻花鉆,12的錐度鉸刀。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, 30mmS每轉(zhuǎn)進(jìn)給量, 0.1mmD麻花鉆直徑, 11mmHB布氏硬度,140HBS 所以 =1687(N)鉆孔的扭矩: 式中 S每轉(zhuǎn)進(jìn)給量, 0.25mmD麻花鉆直徑, 11mmHB布氏硬度,140HBS=361.3(NM)鉸孔時(shí)的切削力: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切削力t鉆削深度,30mmS每轉(zhuǎn)進(jìn)給量, 1mmD鉸孔鉆直徑, 12mmHB布氏硬度,140HBS 所以 = 873(N)鉸孔的扭矩: 式中 t鉆削深度, 80mmS每轉(zhuǎn)進(jìn)給量, 0.3mmD麻花鉆直徑, 12mmHB布氏硬度,140HBS =10476(NM)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:W=K(F2(L+cf)+F1b)/(cf+Lf+a) =807(N)根據(jù)手冊(cè)查得該夾緊力滿足要求,故此夾具可以安全工作。3、夾具操作說(shuō)明此次設(shè)計(jì)的夾具夾緊原理為:通過軸承底座底面和側(cè)面為定位基準(zhǔn),在墊塊平面和實(shí)現(xiàn)完全定位,以鉆模板引導(dǎo)刀具進(jìn)行加工。采用手動(dòng)螺栓和螺母夾緊機(jī)構(gòu)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(lái)實(shí)現(xiàn)工件定位。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、鉸的加工,最終達(dá)到工序簡(jiǎn)圖上規(guī)定的加工要求,故選用快換鉆套作為刀具的導(dǎo)向元件,查表9-13,確定鉆套高度H=2d=24.8=9.6mm,排泄空間h=0.7d=3.4mm。d:基本偏差F7(0.0100.022);D=10mm,偏差m6(0.0010.010)。心得體會(huì)專家曾指出要加大我國(guó)數(shù)控機(jī)床研發(fā)力度,加快普及型數(shù)控機(jī)床的發(fā)展。中國(guó)機(jī)床制造業(yè)的服務(wù),競(jìng)爭(zhēng)中國(guó)銑床和加工中心市場(chǎng)的現(xiàn)狀和展望國(guó)內(nèi)外車床的技術(shù)水平和發(fā)展方向,世界加工中心的生產(chǎn)、需求和發(fā)展動(dòng)向國(guó)內(nèi)外機(jī)床發(fā)展趨勢(shì)世界數(shù)控系統(tǒng)發(fā)展趨勢(shì),切削加工技術(shù)和數(shù)控機(jī)床的發(fā)展 。這些都是我們這一代所要面臨的,所以我們要更加努力的掌握我們學(xué)到的知識(shí)。課程設(shè)計(jì)是我們必須要正確面對(duì)的。通過這次對(duì)軸承座的加工工藝和對(duì)孔設(shè)計(jì)夾具的過程中,我收益良多。這次設(shè)計(jì)不僅使我對(duì)本專業(yè)有了更深的了解,還使我對(duì)課本上的知識(shí)有了更深入的體會(huì),俗話說(shuō):實(shí)踐出真知。這是完全正確的。這次課程設(shè)計(jì)就是使我得到了對(duì)課本知識(shí)的更深層了解,對(duì)我以前不明白的知識(shí)有了確切的概述。總上 這次設(shè)計(jì)對(duì)我的知識(shí)有了加深和拓寬,使我在知識(shí)的領(lǐng)域上又前進(jìn)了一大步。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 2000.52、機(jī)床夾具的現(xiàn)代設(shè)計(jì)方法 秦國(guó)華、張衛(wèi)紅主編 航空工業(yè)出版社 2006.113、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 2005.114、機(jī)床夾具設(shè)計(jì) 秦寶榮主編 中國(guó)建材工業(yè)出版社 1998.25、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 2007.26、機(jī)械制造與模具制造工藝學(xué) 陳國(guó)香主編 情話大學(xué)出版社 2006.57、機(jī)械精度設(shè)計(jì)與檢測(cè)技術(shù) 李彩霞主編 上海交通大學(xué)出版社 2006.18、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 2002.1211、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 2004.8Proceedings 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
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