鉆撥叉雙孔鉆模 撥叉加工工藝及夾具設(shè)計(jì)
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畢業(yè)設(shè)計(jì)(論文)任務(wù)書(shū) 機(jī)電工程 院 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 系(教研室)系(教研室)主任: (簽名) 年 3月 9日學(xué)生姓名: 學(xué)號(hào): 專(zhuān)業(yè): 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 1 設(shè)計(jì)(論文)題目及專(zhuān)題: 某撥叉零件加工工藝及其夾具設(shè)計(jì) 2 學(xué)生設(shè)計(jì)(論文)時(shí)間:自 2015 年 3 月 9 日開(kāi)始至 2015 年 5 月 22 日止3 設(shè)計(jì)(論文)所用資源和參考資料:零件圖一張;上一學(xué)期搜集的資料相關(guān)教材及設(shè)計(jì)、工藝手冊(cè)。4 設(shè)計(jì)(論文)應(yīng)完成的主要內(nèi)容:零件結(jié)構(gòu)特征、性能的分析;機(jī)械加工工藝過(guò)程設(shè)計(jì);機(jī)械加工工序卡片(一套);夾具裝配圖的設(shè)計(jì)、零件工作圖的設(shè)計(jì);編寫(xiě)設(shè)計(jì)說(shuō)明書(shū);5 提交設(shè)計(jì)(論文)形式(設(shè)計(jì)說(shuō)明與圖紙或論文等)及要求:零件圖一張(1或2號(hào)圖一張);夾具設(shè)計(jì),工藝過(guò)程設(shè)計(jì)完成后指定(一套,零件圖、裝配圖);編寫(xiě)的設(shè)計(jì)說(shuō)明書(shū)及典型零件的加工程序(說(shuō)明書(shū)不少于35頁(yè),圖紙量:折合1號(hào)圖4張);課題相關(guān)論文的翻譯(英譯中,不少于1500字)一篇6 發(fā)題時(shí)間: 2015 年 1 月 10 日指導(dǎo)教師: (簽名)學(xué) 生: (簽名)1 畢 業(yè) 設(shè) 計(jì)( 論 文 )題目某撥叉零件加工工藝及其夾具設(shè)計(jì)作者學(xué)院專(zhuān)業(yè)學(xué)號(hào)指導(dǎo)教師 畢業(yè)設(shè)計(jì)(論文)指導(dǎo)人評(píng)語(yǔ)指導(dǎo)人: (簽名)年 月 日 指導(dǎo)人評(píng)定成績(jī): 畢業(yè)設(shè)計(jì)(論文)評(píng)閱人評(píng)語(yǔ)評(píng)閱人: (簽名)年 月 日 評(píng)閱人評(píng)定成績(jī): 畢業(yè)設(shè)計(jì)(論文)答辯記錄日期: 學(xué)生: 學(xué)號(hào): 班級(jí): 題目: 提交畢業(yè)設(shè)計(jì)(論文)答辯委員會(huì)下列材料:1 設(shè)計(jì)(論文)說(shuō)明書(shū)共頁(yè)2 設(shè)計(jì)(論文)圖 紙共頁(yè)3 指導(dǎo)人、評(píng)閱人評(píng)語(yǔ)共頁(yè)畢業(yè)設(shè)計(jì)(論文)答辯委員會(huì)評(píng)語(yǔ):答辯委員會(huì)主任: (簽名)委員: (簽名)(簽名)(簽名)(簽名) 答辯成績(jī): 總評(píng)成績(jī): 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第1頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)1 鉆孔QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)搖臂鉆床Z5301夾具編號(hào)夾具名稱(chēng)切削液撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 鉆9mm孔,Ra6.3m高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺475270.513.79s0.57s 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第2頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)2 鉆孔QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)搖臂鉆床Z5301夾具編號(hào)夾具名稱(chēng)切削液 撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 鉆A23mm孔高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺475270.5130.32s4.55s2 鉆B11mm孔高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺475270.517.07s1.06s 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第3頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)3銑削上端面QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)立式銑床X511夾具編號(hào)夾具名稱(chēng)切削液撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 粗銑上端面A至123.2mm,Ra12.5mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺500600.651.819.03s1.35s2 粗銑上端面B至123.2mm,Ra12.5mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺500600.651.814.80s0.72s 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第4頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)4 銑削上端反面QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)立式銑床X511夾具編號(hào)夾具名稱(chēng)切削液撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 粗銑上端面反面至29.4mm,Ra12.5m YT15硬質(zhì)合金面銑刀、游標(biāo)卡尺500600.651.817.75s1.16s 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第5頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)5銑下端面QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)立式銑床X511夾具編號(hào)夾具名稱(chēng)切削液撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 粗銑短端面A至121.4mm,Ra12.5mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺500600.651.819.03s1.35s2 粗銑短端面B至121.4mm,Ra12.5mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺500600.651.813.69s0.55s 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第6頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)6銑削上端面QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)立式銑床X511夾具編號(hào)夾具名稱(chēng)切削液撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 半精銑上端面A至120.7mm,Ra6.3mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺600750.450.7111.11s1.67s2 半精銑上端面B至120.7mm,Ra6.3mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺600750.450.717.78s1.15s 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第7頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)7銑削上端反面QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)立式銑床X511夾具編號(hào)夾具名稱(chēng)切削液撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 半精銑上端面的反端面至28mm,Ra6.3mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺600750.450.719.33s1.40s 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第8頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)8 銑削下端面QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)立式銑床X511夾具編號(hào)夾具名稱(chēng)切削液撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 半精銑短端面A至120mm,Ra6.3mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺600750.450.7111.11s1.67s2 半精銑短端面B至120mm,Ra6.3mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺600750.450.714.45s0.67s3 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第9頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)9鉆10mm孔QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)搖臂鉆床X511夾具編號(hào)夾具名稱(chēng)切削液撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 半精加工10mm孔,Ra3.2mYT15硬質(zhì)合金面銑刀、游標(biāo)卡尺500400.41.815.28s0.79s2 3 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(chēng)零件名稱(chēng) 撥叉共10頁(yè)第10頁(yè) 車(chē)間工序號(hào)工序名材 料 牌 號(hào)10 鉆孔QT40-17毛 坯 種 類(lèi)毛坯外形尺寸每毛坯可制件數(shù)每 臺(tái) 件 數(shù)鑄件11設(shè)備名稱(chēng)設(shè)備型號(hào)設(shè)備編號(hào)同時(shí)加工件數(shù)搖臂鉆床Z5301夾具編號(hào)夾具名稱(chēng)切削液撥叉夾具 乳化液 工位器具編號(hào)工位器具名稱(chēng) 工序工時(shí) 準(zhǔn)終 單件 0 工步號(hào)工 步 內(nèi) 容工 藝 裝 備主軸轉(zhuǎn)速(r/min)切削速度(m/min)進(jìn)給量(mm/r)背吃刀量(mm)進(jìn)給次數(shù)工步工時(shí)機(jī)動(dòng)輔助1 半精加工A25mm孔,Ra3.2m高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺500600.41.8136.74s5.51s2 半精加工B12mm孔,Ra3.2m高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺500300.40.819.24s1.38s3 精加工A25mm孔,Ra1.6m高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺700850.250.2141.52s6.23s4 精加工B12mm孔,Ra1.6m高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺700420.250.2111.87s1.78s 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 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)零件名稱(chēng) 拔叉共1頁(yè)第1 頁(yè) 材料牌號(hào) QT40-17 毛坯種類(lèi) 鑄件 毛坯外形尺寸 每毛坯可制件數(shù) 1 每臺(tái)件數(shù) 1 備注工序號(hào)工序名稱(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2 人工時(shí)效3 劃線 04 粗加工10孔 鉆9mm孔,Ra6.3mZ530高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺05 粗加工2512孔 鉆23mm孔 鉆11mm孔Z530高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺0 6 粗銑長(zhǎng)端面粗銑上端面A至123.2mm,Ra12.5m粗銑上端面B至123.2mm,Ra12.5mX51YT15硬質(zhì)合金面銑刀、游標(biāo)卡尺 0 7 粗銑長(zhǎng)端面反面粗銑上端面反面至29.4mm,Ra12.5mX51YT15硬質(zhì)合金面銑刀、游標(biāo)卡尺08 粗銑短端面粗銑短端面A至121.4mm,Ra12.5m粗銑短端面B至121.4mm,Ra12.5mX51YT15硬質(zhì)合金面銑刀、游標(biāo)卡尺09半精銑上端面半精銑上端面A至120.7mm,Ra6.3m半精銑上端面B至120.7mm,Ra6.3mX51YT15硬質(zhì)合金面銑刀、游標(biāo)卡尺010半精銑上端反面半精銑上端面的反端面至28mm,Ra6.3mX51YT15硬質(zhì)合金面銑刀、游標(biāo)卡尺011半精銑短端面半精銑短端面A至120mm,Ra6.3m半精銑短端面B至120mm,Ra6.3mX51YT15硬質(zhì)合金面銑刀、游標(biāo)卡尺012半精加工10孔半精加工10mm孔,Ra3.2mZ530高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺013精加工2512孔半精加工A25mm孔,Ra3.2m半精加工B12mm孔,Ra3.2m精加工A25mm孔,Ra1.6m精加工B12mm孔,Ra1.6mZ530高速鋼鑲齒三面刃銑刀、游標(biāo)卡尺014 去毛刺平銼15 中檢塞規(guī)、百分表、卡尺等16 校直手錘17 清洗清洗機(jī)18 終檢塞規(guī)、百分表、卡尺等19 入庫(kù) 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 期第 2 頁(yè) 共 2 頁(yè)Abstract Cubic boron nitride (cBN) is a unique synthetic material on account of its high hardness, high wear resistance, excellent cutting edge stability and relative chemical inertness compared to diamond. The introduction of monolayer electroplated cBN wheels replaced the complex pre-grinding wheel preparation work (truing and dressing) of composite cBN wheels and thereby extensively facilitating the application in high-efficiency deep grinding, creep feed grinding, etc. The present work has aimed at developing a precisely controlled brazing technique suitable for bonding the cBN grits to a steel substrate in mono layer form with higher bond strength, larger grit protrusion and more uniform grit distribution compared to that in the currently used galvanically bonded wheels. Experimental investigation have clearly demonstrated the potential of the newly developed brazed wheels under varying grinding conditions for processing materials like bearing steel. Improved capability of these wheels over galvanically bonded wheels could be better recognised during dry grinding at high material removal rate and for large stock removal when galvanically bonded wheels were found to suffer from severe wheel loading in grinding bearing steel and from unusual increase in grinding forces due to grit pullout. Creation of wider inter-grit spaces with strong bonding and uniform grit spacing happened to be the essence of the present brazed cBN wheel.1 IntroductionSuper abrasive wheels are widely used essentially for grinding strong, hard, heat-resistive and abrasive-type materials like exotic steels, glass, ceramics, stones, plastics and fibrere in forced plastics with high stock removal rate as well as high precision. Mono layer cubic boron nitride (cBN) super abrasive wheels are especially suitable for constricted applications like internal grinding, form grinding and stress-free precision grinding. The mono layer cBN super abrasive wheels presently manufactured by galvanic bonding suffer from inadequate bond (mechanical) strength, no control over grit distribution and lesser protrusion of the grits. Keeping all such points in view in the present work, an attempt has been made to develop small monolayer brazed cBN wheels where cBN grits are uniformly spaced and strongly bonded (chemical and mechanical) on the peripheral steel shank by special brazing technique. Brazing of ceramic particles like cBN calls for flux-less brazing because of disintegration of the flux under the high brazing temperature. Wetting of cBN by braze alloy is greatly affected even in the inert atmosphere provided by technical quality argon because of the presence of the oxygen.Presence of even a few partsper million of oxygen can prevent proper wetting. High vacuum environment beyond 105torr can offer a solution to the problem of brazing cBN . A lot of work has been carried out to braze cBN on steel shank, but the potential of cBN grits were not been fully utilised due to non-uniform distribution . The cBN grits of size B151 (150/125-m mesh width) were used and micro crystalline in nature which,unlike mono crystalline grits, are free from well-defined cleavage plane.Their cutting tips under grinding forces and offer better auto sharpening character in comparison to mono crystalline cBN. This self-sharpening property of cBN is very much desirable in a single-layer wheel. Micro crystalline cBN grits also possess higher toughness and high-temperature stability than the mono crystalline counterpart. Evaluation of the performance of the new brazed cBN wheel compared to that of galvanically bonded cBN wheel has been carried out in a surface grinding machine fitted with the high-speed spindle . A recent investigation has shown that the grit can be distributed uniformly on the flat surface. This paper evaluates the comprehensive performance of the newly developed peripheral tools in the comparative grinding tests with the electroplated counterparts on bearing steel with high speed, high feed and moderate depth of cut for longer duration to use the maximum potential of cBN grit before dislodging. It is also proven that newly developed cBN brazed wheel has performed much better than electroplated wheel in ductile mode dry grinding.2 Experimental procedure2.1 BrazingIn the present study, a AgCu base alloy of eutectic composition (72% Ag and 28% Cu) and melting point 780C was made active by adding TiH2 instead of a prealloyed braze material. The mixture in the form of paste was uniformly applied on the peripheral surface of the wheel blank. The cBN grits were laid uniformly in desired spacing on the periphery of the wheel. It was possible to distribute the grits in a monolayer configuration without undesirable clustering. The laying of the grits has been done essentially in such a way that adequate spaces are provided for free accommodation of the grinding chips without wheel loading. Figure 1 shows the preparation ofdistribution of grits on the peripheral surface of the wheel. During brazing, it was observed through the glass windows repeatedly that wetting of the cBN grits by the active alloy occurred almost instantaneously when the temperature was raised to 850C. The tool specimen was kept at that temperature just for 1 min to achieve good bond strength. The surface of both the brazed and the standard galvanic wheels were visually examined under SEM. The surface topography of SEM micrographs of the brazed type wheel (BT) and the galvanically bonded (GB) wheel are shown in Fig. 2. The first impression gathered through visual inspection was that the cBN grits in the galvanically bonded wheel were seen to lie embedded in the Ni matrix in a closely packed and non-uniform manner. In contrast, the cBN grits in the brazed wheel were found to be fairly uniformly distributedbutwellprojectedabovethebondinglayer.Themean grit protrusion was found to be 3555 m for GB wheel. The same was found to be in the range 85100 m for BT wheel.2.2 Grinding setupThe grinding experiments for evaluating the performance of the new brazed cBN wheel compared to that of galvanically Fig. 1 Uniform placing of cBN grits in mono layer configuration bonded cBN wheel have been carried out in a surface grinding machine fitted with the high-speed spindle (Fig. 3). The maximum run out on the wheel was checked and found to be less than 5 m. The job specimen, 80 mm long, 20 mm deep and 3 mm wide, was held in a specially designed fixture which was mounted on a 3D Kistler dy namometer (KISTLER 9257B, Switzerland). Experimental conditions have been given in Table 1. The performance of the present BT cBN wheel in comparison to that of the galvanically GB standard cBN wheel has been assessed for the present grinding tests primarily on the basis of grinding forces, specific energy consumption, wheel condition (wheel loading and fracture, wear and pullout of the grits) during grinding operation and effective service in longer duration grinding.3 Result and discussion3.1 Grinding forces, specific energy, metal removal rateThe roles of variation in the major grinding process parameters, viz. wheel speed, Vc, table speed, vw, and downfeed,d, on the magnitude of the tangential component, Ft, and the normal component, Fn, of the grinding force recorded during grinding the bearing steel by BT wheel and GB wheel have been shown in Fig. 4. It can be seen from those figures that the magnitude of both Ft and Fn decreased or tended to decrease with the increase in Vc and increased with the increase in vw and d for all the present workwheel combinations. In grinding, the magnitude of the cutting forces depend primarily on the property of the work material, crosssectional area of the layer to be removed from the work surface in each pass, i.e. total chip load and the form factors which again are governed by the cutting tip geometry (sharpness), and interaction at the chiptool interfaces. Specific forces and hence specific energy requirement are always larger in grinding where the rake angle is adverse in the order of 35 to 80. In addition, the rubbing or interactions at the chipbond, chipworkpiece or bond workpiece interfaces in different degrees can also be attributed to high force and specific energy of grinding. All along in the present grinding experiments, Fn has been much larger (almost double) than Ft under all the conditions undertaken, as can be seen in the concerned figures. The ratio between the tangential force and the normal force in any machining process is governed mainly by the tool rake angle and friction at the chiptool interface. Large negative rake, lack of sharpness of the grits due to rounding and flattening (by micro fracturing and wear) of the grit tips and relatively much smaller penetration of the cutting points in the work surface are the main causes behind the unusually very large value of Fn compared to Ft in grinding. This unique feature of grinding process as such has also been noted in the present grinding experiments with the monolayer cBN wheels. Figure 4 shows that for both the wheels, Ft and Fn gradually decreased with the ncrease in Vc. In any machining of ductile metals, the cutting forces decrease sizeably with the increase in cutting velocity due to plasticisation and shrinkage of the shear zone ahead the cutting edge.摘要 立方氮化硼(CBN)是一種獨(dú)特的合成材料,由于其高硬度、高耐磨、抗疲勞性、優(yōu)良的切削刃穩(wěn)定性和相對(duì)化學(xué)惰性能與鉆石相差無(wú)幾。為了復(fù)合CBN砂輪的廣泛應(yīng)用,所以引入單層電鍍CBN砂輪來(lái)取代復(fù)雜的立輪做準(zhǔn)備工作(校準(zhǔn)和整合)。目前的工作是為了發(fā)展精確控制的釬焊技術(shù),由于CBN磨粒在單層鋼底形成的粘結(jié)強(qiáng)度較高,較大磨粒突出和更均勻分布,所以使用電流的保稅輪子。實(shí)驗(yàn)研究清楚地表明在不同的加工材料,如軸承鋼的磨削條件下更能開(kāi)發(fā)釬焊車(chē)輪的潛力。改善這些輪子的功能在通電的保稅輪子下可以更好的去磨削并且能使材料去除率高,但對(duì)于大型切削時(shí),電流的保稅輪子在磨軸承鋼輪中很難加載。為了建立更廣泛的加工空間,能到達(dá)較強(qiáng)的結(jié)合和統(tǒng)一性,這是目前焊接CBN砂輪的本質(zhì)。 1介紹 超硬磨料砂輪廣泛主要用于磨削強(qiáng)、硬、熱電阻和耐磨類(lèi)型的材料。如玻璃,陶瓷,鋼材,石材,塑料和纖維增強(qiáng)塑料,能達(dá)到高材料去除率以及高精度。單層立方氮化硼(CBN)超硬磨料砂輪特別適用于狹窄的應(yīng)用如內(nèi)圓磨削,成型磨削和無(wú)壓力的精密磨削。目前通過(guò)電偶結(jié)合制造的單層CBN超硬磨料砂輪機(jī)械強(qiáng)度不足,無(wú)法控制粒度分布和較小的顆粒突起。在目前為了解決這些問(wèn)題,已嘗試開(kāi)發(fā)小型單層釬焊CBN砂輪,通過(guò)特殊的釬焊技術(shù)(化學(xué)和機(jī)械)使CBN磨粒在外圍的鋼圈分布均勻間隔緊密。陶瓷釬焊就像量少的CBN釬焊,由于釬焊溫度較高而造成解體。因?yàn)檠鯕獾拇嬖?,所以在釬焊時(shí)需要提供稀有氣體氬做保護(hù)氣,防止CBN釬焊時(shí)對(duì)合金的影響。這樣即使外圍有數(shù)以百萬(wàn)計(jì)的氧也能防止被濕潤(rùn)。超過(guò)105托的真空環(huán)境給CBN釬焊提供了一個(gè)解決辦法。大量的工作已經(jīng)在釬焊CBN鋼柄中進(jìn)行,但由于CBN磨粒沒(méi)有分布均勻所以使它的潛力沒(méi)有得到充分的利用。 CBN磨粒在B151尺寸時(shí)(150/125m網(wǎng)格的寬帶)跟自然界的微晶差不多,不像單結(jié)晶粉末,我明確的理解面。這種通過(guò)高溫高壓技術(shù)使砂結(jié)構(gòu)由微米級(jí)單晶粘貼在一起的技術(shù),與單晶CBN比較能造成磨粒進(jìn)行微壓使能在刀片的磨削力和提供更好的自動(dòng)銳化特性。這種自銳性CBN為單層盤(pán)是非??扇〉摹N⒕BN磨粒具有比單晶硅對(duì)應(yīng)更高的韌性和高溫穩(wěn)定性。對(duì)新的釬焊CBN砂輪的性能評(píng)價(jià)相比,電鍍CBN砂輪進(jìn)行表面研磨機(jī)配有高速電主軸。最近的一項(xiàng)調(diào)查表明,砂可以在平坦的表面均勻分布。本文對(duì)新開(kāi)發(fā)的外圍工具綜合性能比較磨削試驗(yàn)與電鍍同行對(duì)高速軸承鋼,持續(xù)時(shí)間較長(zhǎng),在去除使用CBN磨粒的最大潛力降低深度適中。這也證明,新開(kāi)發(fā)的CBN砂輪比電鍍輪更能抗干擾。2 實(shí)驗(yàn)步驟 2.1釬焊 在目前的研究中,銀銅合金的共晶組成(72%銀和28%銅)合金熔點(diǎn)為780有由于通過(guò)添加TiH代替了原來(lái)的纖材料,在表面形成混合武均勻地施加在輪坯外表面。CBN粒子被放置在間距均勻的輪坯外圓上。這些均勻分配的粒子在單層結(jié)構(gòu)表面沒(méi)有聚集。粒子的鋪設(shè)已基本存在這樣一種形式,有足夠的空間用于粒子屑的存在。 釬焊過(guò)程中,觀察到的玻璃窗,通過(guò)反復(fù)的潤(rùn)濕CBN磨粒的活性合金幾乎在瞬間升溫到850C.刀具試樣保持在該溫度下才1分鐘,就達(dá)到了良好的粘結(jié)強(qiáng)度。釬焊和標(biāo)準(zhǔn)電偶的表面在視覺(jué)掃描電子顯微鏡下檢查。發(fā)現(xiàn)釬焊式車(chē)輪SEM表面形貌(BT)和電連接(GB),通過(guò)視覺(jué)的第一印象是電鍍砂輪CBN粒子被發(fā)現(xiàn)通過(guò)一個(gè)緊密的和非均勻的方式嵌入鎳基,相比之下,在釬焊砂輪CBN粒子被發(fā)現(xiàn)是相當(dāng)均勻的。平均磨粒出刃是3555MGB輪。同樣是在范圍85100m之內(nèi)。 2.2 磨削裝置 通過(guò)磨削實(shí)驗(yàn),新的釬焊CBN砂輪相比電鍍CBN砂輪在性能上表面研磨機(jī)配有高速主軸。輪的最大消耗檢查發(fā)現(xiàn)是小于5M。這個(gè)樣本,長(zhǎng)80毫米,深20毫米,寬3毫米,在一個(gè)被安裝在一個(gè)三維的測(cè)力計(jì)的專(zhuān)門(mén)設(shè)計(jì)的夾具中進(jìn)行(Kistler 9257B,瑞士)。得到的實(shí)驗(yàn)條件在表一中給出。目前磨削試驗(yàn)主要是對(duì)BT CBN砂輪與電鍍CBN砂輪的性能比較磨削力為主,在進(jìn)行長(zhǎng)時(shí)間的磨削中具體的能源消耗情況,輪的狀態(tài)(輪的載荷和斷裂,粒子的磨損和抗壓)。3 結(jié)果與討論 3.1磨削力,具體的能耗,金屬去除率 在主要的磨削工藝參數(shù)變化的作用下,即輪速,線速度,進(jìn)給速度,角速度,供水和直徑,對(duì)于切向分量的大小,正常組成部分的Ft和在磨削過(guò)程中對(duì)于軸承鋼輪和BTGB輪的磨削力Fn已在圖4所示。從這些數(shù)據(jù)中可以發(fā)現(xiàn),F(xiàn)t和Fn的下降幅度或趨于在線速度與加速度的增加,并且直徑對(duì)于目前所有的工作輪組合都有影響。在磨削加工中,切削力的大小主要取決于工件材料的性質(zhì),是在每一個(gè)經(jīng)過(guò)的工作表面去除的橫截面積,即總芯片負(fù)載,又是由刀片幾何形式的因素(鋒利度),并在芯片工具界面相互作用。因此具體的能源需求總是大于的磨削力的需求,并且刀具傾斜角度在35到80是不利的。 在目前的磨削實(shí)驗(yàn)中,通過(guò)有關(guān)數(shù)據(jù)可以看到,在所有條件下進(jìn)行的,F(xiàn)N都比FT要大的多(幾乎一倍)。切向力和法向力是任何加工過(guò)程主要受刀具前角和摩擦在芯片工具界面之間的比率。大的負(fù)前角,由于舍入和壓扁的磨粒鋒利的缺乏(由微破裂和磨損),砂的技巧和在工作面切削點(diǎn)的滲透相對(duì)較小的背后是非常非常大的價(jià)值比較磨FN FT的主要原因。這種獨(dú)特的功能磨削工藝等也已經(jīng)在在目前與單層CBN砂輪磨削實(shí)驗(yàn)中引起了了注意。顯示了兩個(gè)輪子,在VC的增加FT和FN逐漸降低。在任何加工韌性金屬時(shí),由于剪切帶的前面的切削刃的增塑和收縮切削速度增加會(huì)使切削力降低。
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