拋光機(jī)設(shè)計(jì)

拋光機(jī)設(shè)計(jì),拋光機(jī)設(shè)計(jì),拋光機(jī),設(shè)計(jì) 技術(shù)學(xué)院 畢業(yè)設(shè)計(jì)（論 文） 題目 拋光機(jī)設(shè)計(jì) 系 (部) 專業(yè) 班級(jí) 姓名 指導(dǎo)老師 系主任 年 月 日 1 目 錄 綜 述 .2 1. 拋光桶設(shè)計(jì)參數(shù) .5 2. 傳動(dòng)方案 .6 3. V 帶的設(shè)計(jì) .6 3.1 確定設(shè)計(jì)功率 .6 3.2 選擇帶的型號(hào) .7 3.3 確定帶輪的基準(zhǔn)直徑 21d和 .7 3.4 驗(yàn)算帶的速度 .7 3.5 確定中心距 A 和 V 帶基準(zhǔn)長度 dL.7 3.6 確定中心距和小輪包角 .8 3.7 確定 V 帶根數(shù) Z .8 3.8 確定初拉力 0F.9 3.9 計(jì)算作用在軸上的壓力 .9 3.10 帶輪結(jié)構(gòu)設(shè)計(jì) .9 4. 滾筒的設(shè)計(jì) .10 4.1 滾筒結(jié)構(gòu) .10 4.2 軸承的選擇 .11 4.3 鍵的校核 .11 5. 結(jié)論 .12 6. 參考文獻(xiàn) .12 2 綜 述 機(jī)械零件投入機(jī)械加工的每張圖紙都有去毛刺的技術(shù)要求，去毛刺工序， 工藝人員往往無法編 制工藝文件，通常采用銼刀、布輪、砂布、砂帶等辦法來 去除毛刺。隨著科學(xué)技術(shù)的進(jìn)步和生產(chǎn)的發(fā)展，人工去毛刺已不能適應(yīng)現(xiàn)代市 場(chǎng)竟?fàn)幍漠a(chǎn)品質(zhì)量和生產(chǎn)方式的要求，光整加工技術(shù)逐步取代了傳統(tǒng)的去毛刺 工藝，而且越來越被人們所重視，目前有些先進(jìn)企業(yè)機(jī)械零件的精整與光飾已 被技術(shù)人員編入圖紙技術(shù)要求的內(nèi)容，并形成了標(biāo)準(zhǔn)工序。 滾磨光整加工技術(shù)的實(shí)用工藝過程是：除油處理光整加工及去毛刺分 選清洗烘干防銹處理 除油處理：光整前的零件要進(jìn)行徹底除油處理，常采用超聲波清洗方法 效果最佳。如果工件上油污進(jìn)入，磨塊切削力明顯減弱，磨劑作用會(huì)降低、光 整效果、效率下降，光整后的零件表面不光亮。 光整加工：光整加工主要是根據(jù)被光整零件件的結(jié)構(gòu)形狀、尺寸大小及 光整要求選擇或確定設(shè)備形式、設(shè)備規(guī)格、工藝用料、工藝參數(shù)等內(nèi)容。 光整加工后處理包括三方面：磨塊與工件的分選、磨塊與工件的清洗及 工件的脫水防銹。 磨塊與工件的分選常用方法有：手工篩選、機(jī)械篩選、振動(dòng)篩選、手工電 磁分選和傳送帶式磁力分選，可根據(jù)實(shí)際情況選用。磨塊與工件的清洗采用超 聲波清洗方法最佳，再用清請(qǐng)水沖洗干凈，要特別注意工件的脫水烘干和防銹 處理。 大量工藝試驗(yàn)發(fā)現(xiàn)，工件經(jīng)滾磨光整加工后表面光潔錚亮，其表層的活躍 金屬分子赤裸暴露在空氣中很快氧化變黑，繼而生銹，原因清洗后留在零件表 面上的水膜形成了電化學(xué)腐蝕所必須的一層電解質(zhì)溶液。水的電離度雖小，但 仍可電離成 H + 和OH - ，這種電離過程隨溫度升高而加快。同時(shí)水中還溶 解有 CO 2 、SO 2 等，都極易與水結(jié)合。 H 2 OH + + OH CO 2 + H 2 OH 2 CO 3 H+ + HCO 3 - 3 鐵和鐵中的雜質(zhì)浸泡在有 H+、OH - 和HCO 3 - 等多種離子的溶液中 一樣，形成了腐蝕電池，鐵是陽極、雜質(zhì)是陰極。一般情況下，水膜里含有氧 氣，陽極上的鐵被氧化成 Fe 2+ 離子，在陽極上獲得電子的是氧，然后與水結(jié) 合成OH-離子。腐蝕反應(yīng)為： 2 Fe+ O 2 +2 H 2 O2Fe（OH） 2 由此看來，光整前除油處理和光整后的脫水烘干、防銹處理是非常必要的， 二者缺一不可，其方法也很多。脫水烘干通常采用工業(yè)型甩干機(jī)，防銹油用主 要成份是羊毛脂，石油磺酸鋇，石油磺酸鈉及助劑。 磨粒流拋光 原理:在磨粒流加工過程中，夾具配合工件形成加工通道，兩個(gè)相對(duì)的磨料 缸使磨料在這個(gè)通道中來回?cái)D動(dòng)（如圖 1）。磨料均勻而漸進(jìn)地對(duì)通道表面或 邊角進(jìn)行研磨，產(chǎn)生拋光、倒角作用。 圖 1 磨粒流加工原理 機(jī)床、磨料和夾具是磨粒流加工的三個(gè)要素： 擠壓研磨機(jī)床：其作用是固定工件和夾具，控制擠出壓力。在一定的壓 力作用下，使磨料研磨被加工表面，得到去毛刺、倒角的效果。機(jī)床壓力范圍 從 7224 kg/cm 2 ； 磨料 ：是由一種具有粘彈性、柔軟性和切割性的半固態(tài)載體和一定量磨 砂拌和而成。不同載體的粘度、磨砂種類、磨粒大小，可以產(chǎn)生不同的效果。 常用磨料類型有：碳化硅、立方氮化硼、氧化鋁和金鋼砂。砂粒尺寸在 0.0051.5mm。高粘度磨料可用于對(duì)零件的壁面和大通道進(jìn)行均勻研磨；低粘 度磨料用于對(duì)零部件邊角倒圓和小通道進(jìn)行研磨； 夾具：使零件定位，并引導(dǎo)磨料到達(dá)被加工部位，堵住不需要加工的部 位。 4 要順利完成零件的磨粒流加工，得到最佳加工效果，影響因素很多，除設(shè) 備以外，還包括磨料的選擇、擠壓力的大小、循環(huán)次數(shù)、夾具的合理設(shè)計(jì)等。 優(yōu)點(diǎn):擠壓研磨是對(duì)金屬材料進(jìn)行微量去除，對(duì)零件內(nèi)腔交叉部位去毛刺并 倒圓，達(dá)到精細(xì)加工的目的。磨粒流加工具有精確性、穩(wěn)定性和靈活性。廣泛 用于汽車業(yè)和各種生產(chǎn)制造業(yè)。它最根本的優(yōu)點(diǎn)是：可以通達(dá)零件復(fù)雜而難以 進(jìn)入的部位；拋光表面均勻、完整；批量零件的加工效果重復(fù)一致。這些加工 特點(diǎn)使零件性能得到改善，壽命延長，同時(shí)減免繁雜的手工勞動(dòng)，大大降低勞 動(dòng)強(qiáng)度。如汽車進(jìn)氣管，手工拋光其內(nèi)表面時(shí)，只能先切割開，拋光后再焊接 起來。而用磨粒流加工方法，不需要切割打開就可以完成內(nèi)表面拋光。除了作 為一種拋光手段，磨粒流工藝還可以對(duì)一些表面形狀公差、質(zhì)量要求極其嚴(yán)格 的零件進(jìn)行微量磨削加工。 應(yīng)用：磨料流加工適用于加工不同的零件和尺寸。小至 0.2mm 的小孔或 1.5mm 直徑的齒輪，大至 50mm 直徑的花鍵通道，甚至 1.2m 的透平葉輪。加工 大型零件的機(jī)床可以裝置回旋臂或輸送軌道。 該工藝已廣泛用于汽車零部件的精加工：進(jìn)排氣管、進(jìn)氣門、增壓腔、噴 油器、噴油嘴、氣缸頭、渦輪殼體和葉片、花鍵、齒輪、制動(dòng)器等。如：粗糙 的氣缸頭鑄造件在專門的二工位磨粒流生產(chǎn)線上，每小時(shí)生產(chǎn)量可達(dá)到 30 件， 粗糙度從 Ra4m 或 Ra5m 達(dá)到 Ra0.4m,可使廢氣排放量減少 7，發(fā)動(dòng)機(jī)功 率增加 6，行駛里程數(shù)增加 5。 近年來研制開發(fā)出的微孔磨粒流機(jī)床，在加工噴油嘴方面獨(dú)樹一幟。它根 據(jù)擠出壓力、磨料溫度和粘度之間的關(guān)系，進(jìn)行復(fù)雜的程序運(yùn)算。加工過程中， 當(dāng)噴油嘴的設(shè)定流量到達(dá)時(shí)，加工即自動(dòng)停止。加工時(shí)間在 10 秒左右，流量散 差可控制在1%。與此加工設(shè)備配套的還有流量測(cè)試儀以及高壓清洗設(shè)備。這 些設(shè)備可根據(jù)用戶需要，提供單工位或多工位的。也可以是帶機(jī)械手連接，包 括加工、測(cè)量、清洗的全套系統(tǒng)。 電化學(xué)去毛刺 零件內(nèi)通道相交處粗糙并帶有毛刺一直是令人頭痛的問題。電化學(xué)去毛刺 是解決這些問題的好方法。這一技術(shù)是用成形工裝，對(duì)工件的選定部位進(jìn)行加 工,接通電流的電解液在工件和工裝之間通過，瞬間溶解毛刺，去毛刺的同時(shí)， 5 在內(nèi)通道相交處產(chǎn)生均勻、精確的倒圓邊角。加工時(shí)間一般在 10 秒到 30 秒之 間。大多數(shù)工件采用多個(gè)電極頭工裝，可以達(dá)到更高的工作效率。去除量取決 于工件（正極）和工裝（負(fù)極）之間電流量的大小。電極頭通常設(shè)計(jì)成與工件 表面相對(duì)稱的形狀。對(duì)金屬材料制成的零件自動(dòng)地、有選擇地完成去毛刺作業(yè)。 它可廣泛用于氣動(dòng)、液壓、工程機(jī)械、油嘴油泵、汽車、發(fā)動(dòng)機(jī)等行業(yè)不同金 屬材質(zhì)的泵體、閥體、連桿、柱塞針閥偶件等零件的去毛刺加工。 圖 2 電化學(xué)加工原理圖 電化學(xué)去毛刺是一種有特色，效率高的生產(chǎn)技術(shù)，適宜加工各種金屬零件， 用以去毛刺，成形機(jī)加工，邊角倒圓、精整。鑄造的、鍛造的、機(jī)加工，或電 火花加工的零件都可以用電化學(xué)的方法拋光。去除量在 0.01mm 到 0.5mm 之間。 一般情況，光潔度可改善 5 到 10 個(gè)數(shù)量級(jí)。拋光后的產(chǎn)品表面均勻光滑，而且 鏡樣閃亮。 電化學(xué)拋光的典型應(yīng)用包括：有高純凈度要求的零件；人體手術(shù)植入件； 瓶模；以及各種各樣的不銹鋼零件。如：電解加工柴油機(jī)噴油嘴零件時(shí)，在中 孔處加工出一個(gè)壁面光滑的定量空腔，同時(shí)對(duì)交叉孔道、邊角倒圓。 美國的電解自動(dòng)去毛刺設(shè)備，具有一小時(shí)能加工成百件產(chǎn)品的能力。在電 化學(xué)去毛刺的自動(dòng)系統(tǒng)上加工汽車用安全氣囊裝置上的殼體，每個(gè)殼體上共有 48 個(gè)小孔，8 個(gè)殼體同時(shí)加工，10 秒鐘以內(nèi)完成所有孔的去毛刺加工。 拋光是制造型腔模具的一道重要工序。它的成本占模具成本的 5%30%，急 需使用的模具往往在拋光時(shí)間跟不上要求。電化學(xué)機(jī)械拋光，同時(shí)結(jié)合 SD1 型 獨(dú)有的液體拋光技術(shù)，應(yīng)用于各種復(fù)雜形狀的金屬模具的零件，收到了極佳效 果。 1. 拋光桶設(shè)計(jì)參數(shù) 拋光桶設(shè)計(jì)參數(shù)設(shè)定如下：動(dòng)力機(jī)為 Y 系列三相異步電動(dòng)機(jī)，功率 6 P=7.5KW，轉(zhuǎn)速 拋光桶轉(zhuǎn)速 每天工作 16h。min,/140rnmin,/6302rn 查表可得 Y 系列三相異步電動(dòng)機(jī)的型號(hào)及相關(guān)數(shù)據(jù)選擇可選擇 Y100L1-4。 可查得軸徑為 28mm,長為 50mm. 2. 傳動(dòng)方案 V 帶傳動(dòng)，傳動(dòng)圖如下圖所示 圖 3 傳動(dòng)原理：如圖 3 所示，異步電動(dòng)機(jī)通電后轉(zhuǎn)動(dòng)，帶動(dòng)帶輪 1 做回轉(zhuǎn)運(yùn)動(dòng)， 通過 V 帶，帶動(dòng)帶輪 2 轉(zhuǎn)動(dòng)，在軸承之間支撐著滾筒，滾筒通過鍵連接到帶輪 2 上面，隨著帶輪 2 轉(zhuǎn)動(dòng)而轉(zhuǎn)動(dòng)，當(dāng)要拋光工件時(shí)，先將小零件倒入滾筒，然 后加入木屑等磨料或添加劑，借助滾筒內(nèi)磨料與零件間的摩擦作用，磨掉零件 表面的氧化皮，產(chǎn)生拋光、倒角作用。 3. V 帶的設(shè)計(jì) 3.1 確定設(shè)計(jì)功率 dP 設(shè)計(jì)功率是根據(jù)需要傳遞的名義功率、載荷性質(zhì)、原動(dòng)機(jī)類型和每天連續(xù) 7 工作的時(shí)間長短等因素共同確定的，表達(dá)式如下： madPK 式中 需要傳遞的名義功率mP 工作情況系數(shù)，查機(jī)械設(shè)計(jì)表 11.5，得工作情況系數(shù) 選AK AK 取 =1.2； 所以 KWPmad 95.721 3.2 選擇帶的型號(hào) 查機(jī)械設(shè)計(jì)圖 11.15，選取 A 型帶。 3.3 確定帶輪的基準(zhǔn)直徑 21d和 查機(jī)械設(shè)計(jì)表 11.6，V 帶帶輪最小基準(zhǔn)直徑 知 A 型帶 =75mm,又mindmind 由教材表 7.3 選取 小帶輪基準(zhǔn)直徑：； md125 大帶輪基準(zhǔn)直徑： n28063/1425)0.(212 ）（ ，這里 %1設(shè) 大帶輪轉(zhuǎn)速 min/4.63280/145)0.1()(22 rdn 3.4 驗(yàn)算帶的速度 smndv /42.910654.3106 式中 ；電 動(dòng) 機(jī) 轉(zhuǎn) 速 小帶輪基準(zhǔn)直徑；1d 即 v=9.42m/s =25m/s,符合要求。maxv 3.5 確定中心距 a 和 V 帶基準(zhǔn)長度 dL 8 根據(jù)： 初步確定中心距)(27.021021dad）（ 0.7（125+280 ）=283.5 2（125+280）=8100 選取中心距 =650mm0 初算帶的基準(zhǔn)長度 ：dL mLaadL d20,650/.76502.14.3/)2(2 211 查 表 得 3.6 計(jì)算中心距和小輪包角 中心距： mddLdLa 4.67)(8)2/(412/)( 2111 小帶輪包角： 1203.604.675810618012ad 3.7 確定 V 帶根數(shù) Z 根據(jù) 確定帶的根數(shù)。0()dLPzK 式中 包角修正系數(shù)，考慮包角 對(duì)傳動(dòng)能力的影響 K 180 帶長修正系數(shù)，考慮帶長不為特定帶長時(shí)對(duì)使用壽命的影響L V 帶基本額定功率0P 由機(jī)械設(shè)計(jì)查取單根 V 帶所能傳遞的功率為 =1.93kW；0P 由式 計(jì)算功率增量 ；01()biKn0 其中 彎曲影響系數(shù)；b 傳動(dòng)比系數(shù)；i 1n電 機(jī) 軸 轉(zhuǎn) 速 9 查教材表 7.4（附表 5）得 = ；bK30.7251 查教材表 7.5 得 ；1.3i 故得 WP7.0 查教材表 7.8(附表 4)得 =0.969；K 查教材表 7.2 得 =1.03；L 所以， 0()dLPzK 所以，選取 V 帶根數(shù) z=5 3.8 確定初拉力 0F202.5()dPmvvzK 式中 d設(shè) 計(jì) 功 率 v帶 的 速 度 z帶的根數(shù) 包角修正系數(shù)K m普通 V 帶每米長度質(zhì)量 查教材表 7.1 得 m=0.1kg/m； 所以 NF 1.604.91096.524.9502）（ 3.9 計(jì)算作用在軸上的壓力 102cossin2QzzF 式中 初拉力0F z帶的根數(shù) 10 小輪包角；1 所以， NFQ 6.158923.6sin.052 3.10 帶輪結(jié)構(gòu)設(shè)計(jì) 1. 帶輪材料選擇 本設(shè)計(jì)中轉(zhuǎn)速要求不高，材料選用 HT200； 2. 帶輪結(jié)構(gòu)形式 本方案中帶輪為中小尺寸，選用腹板輪。 3. 帶輪結(jié)構(gòu)尺寸 查教材表 7.9 得 ， ，e=15 0.3， ， ，12chm.75e210f.db034。 B=(z-1)e+2f (3-1)x15+20=50mm; C=10mm; ； ，取 =55mm;0d(1.82).456kdmk 4 滾筒的設(shè)計(jì) 4.1 滾筒結(jié)構(gòu) 11 滾筒端面為正六面形，兩端用螺絲跟軸固定在一起，用于支撐和傳動(dòng)扭距， 因此選擇滾筒和軸的材料，確定許用應(yīng)力，選 45 鋼，正火處理。 根據(jù)許用切應(yīng)力強(qiáng)度極限估計(jì)軸的最小直徑，由帶輪外徑 100mm，估算滾 筒兩端軸直徑 25mm。 4.2 軸承的選擇 由工作需要的要求得：軸承的使用時(shí)間為 。52081hL 第一對(duì)軸承的當(dāng)量動(dòng)載荷 P； 。()prafXFY 查手冊(cè)取 1.2pf 假設(shè)取 6204 軸承 計(jì)算步驟與內(nèi)容 計(jì)算結(jié)果 1.查手冊(cè)查出 、 值（GB/T 2761994）rCor 2. 61tan20.3941tan20748.9cs2cosrTF Nd 3 61.t t5.a 4.計(jì)算 /498.3/aororFCN 5.查手冊(cè) e 值 6.計(jì)算 /./702.1.ar 7.查手冊(cè)：X、Y 的值 8. 查載荷系數(shù). 。.pf 9. praPfF 10.計(jì)算軸承壽命： 3106716709512684.hCLn 11.結(jié)論：符合要求，選用此軸承。 9380rC52or.7rFN64a0.59.263e085.6,1.7082XY pf94.P125360 12 4.3 鍵的校核 在工作軸中，鍵的選擇大小由軸的大小確定，校核公式： 2ppTdlk 齒輪 2 的安裝鍵型為 A 型鍵 L=30, 為 ， ，因?yàn)檗D(zhuǎn)動(dòng)件的齒輪是經(jīng)過淬火bh87 的，所以許用扭轉(zhuǎn)應(yīng)力 ：04paMP 2643258.pTdlk 鍵符合扭轉(zhuǎn)應(yīng)力的要求。 5 結(jié)論 本論文寫出了符合課題參數(shù)要求的拋光桶的設(shè)計(jì)過程。在文中完成了以下 幾方面的內(nèi)容： 1）完成了拋光桶的總圖設(shè)計(jì)，確定整機(jī)安裝形式； ）確定用 V 帶傳動(dòng)方式，并對(duì) V 帶進(jìn)行進(jìn)行了設(shè)計(jì)； ）分析軸承的選用； 4）確定了用于傳動(dòng)的鍵，并對(duì)鍵進(jìn)行了校核； 5）確定了電動(dòng)機(jī)、帶輪尺寸和形狀；完成拋光機(jī)的裝配圖。 6 參考文獻(xiàn) 1 王文斌， 機(jī)械設(shè)計(jì)手冊(cè) ，機(jī)械工業(yè)出版社 2 吳宗澤，機(jī)械設(shè)計(jì)手冊(cè)，機(jī)械工業(yè)出版社，2002 13 附錄 1 拋光桶傳動(dòng)簡圖 附錄 2 14 裝配總圖 Lapping and polishing process for obtaining super-smooth surfaces of quartz crystal J.L. Yuan * , P. Zhao, J. Ruan, Z.X. Cao, W.H. Zhao, T. Xing Research Center of Science, Zhejiang University of Technology, Hangzhou 310014, PR China Abstract The lapping and polishing processes to obtain the damage-free surfaces and A level surface roughness of quartz crystal is discussed and realized by adopting soft material polishers, fine abrasive powders, and suitable working environments, by taking account of the minimization of mechanical actions in polishing process. The material removal mechanism in the process of ultra-precision polishing is discussed, and the basic formation models of surface roughness are also put forward. A super-smooth surface of quartz crystal with 12 A level roughness have been obtained by adopting the SiO 2 abrasive powders and the K3 pitch polisher in the experiments. # 2003 Elsevier Science B.V. All rights reserved. Keywords: Lapping and polishing; Super-smooth surface; Quartz crystal 1. Introduction Material science and technology make remarkable pro- gress and the application of newly developed materials to various devices have increased rapidly. In particular, when fabricating a high-performance device, it is often necessary to adopt high-level lapping and polishing. Recently, the study of ultra-precision machining, which forms the van- guard of machining methods, has developed rapidly and its contributions to industry have been notable. When elevating such lapping and polishing methods to ultra-precision machining, it is essential to improve conventional polishing techniques steadily or add new working principles, thus ensuring the highest qualities and accuracy on worked surfaces. Ref. 1 shows that a soft polisher will reduce the deterioration of surface roughness, if meeting unfortu- nately with large abrasives or dusts in polishing. It is the most important to get satisfactorily a smooth working face and suitable elastic polisher. To obtain the super-smooth surface, it is also extremely important to select abrasives. The report 2 has shown that the ultra-precision polishing of quartz crystal can be realized by using SiO 2 fine powders. In this report, the processes to obtain the damage-free surfaces and A level surface roughness of quartz crystal is discussed and realized by adopting soft material polishers, fine abrasive powders, and suitable working environments, by taking account of the minimization of mechanical actions in polishing process. 2. Lapping mechanism and polishing mechanism In the process of lapping, the action effect of abrasives and the properties of lap material have the close relation. Abra- sives in the ways of rolling and micro-cutting remove the quartz crystal. The micro-cracks are produced on the quartz crystal surface due to the action of abrasives. It is the main way to remove quartz material in lapping. The crack area will burst apart because of micro-cracks extension and intersection, so quartz crystal is removed. The length dis- tribution of micro-cracks beneath the quartz surface is nearly equal. The higher is the load, the longer are the cracks. The general conclusion is that the propagation depth beneath the quartz surface is one-third of average abrasive size. The properties of polisher material and abrasive powders are the essential conditions to ensure the super-smooth surfaces. A soft polisher will reduce the deterioration of surface roughness 1, if meeting unfortunately with large abrasive or dusts in polishing. To obtain the super-smooth surface, it is extremely important both to select abrasives and get satisfactorily a smooth face and suitable elastic polisher. Hard abrasive will generate grooves, on material surface during lapping and polishing in general. However, this Journal of Materials Processing Technology 138 (2003) 116119 * Corresponding author. Tel.: 86-571-85132902. E-mail address: (J.L. Yuan). 0924-0136/03/$ see front matter # 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0924-0136(03)00058-X mechanism does not apply to the ultra-precision polishing if the hardness of abrasive powder is equivalent to that of worked material. It has shown that the material removal process, containing both the initiation of point defects and the stochastic fracture at an atomic scale due to the bom- bardment of SiO 2 particles on the quartz crystal surface, may be considered as the essential part of the mechanism of ultra- precision polishing 2. 3. Experimental procedures 3.1. Determination of optimum lapping parameters The machining margin of quartz crystal is almost removed in lapping process, so the lapping efficiency makes great effect on the whole machining time. On the other hand, the lapped surface integrity will effect polishing time and quality. Experiment shows that the process parameters affecting surface roughness and lapping efficiency are abra- sive properties and size, concentration of lapping slurry, lapping speed and lapping pressure, etc. To ensure the surfaces machining accuracy of the quartz crystal, initial parallelism of the quartz specimens is adjusted to less than 0.5 mm. Then their roughness is improved on a conditioning ring-type lapping machine with #1000, #2000 and #4000 Al 2 O 3 powders. The lapping parameters (lapping speed and lapping pressure) effecting on the stock removal of quartz crystal are changed, and the relations between stock removal and the parameters are shown in Figs. 1 and 2. Fig. 1 shows that lapping speed is proportional to the stock removal. This is because, the bigger is the speed, the longer are the machining micro-cracks caused by abrasives cutting in unit time; as a result, the stock removal becomes larger. The experiments also show that the higher is the lapping speed, the smaller is the surface roughness. Fig. 2 shows the relation between lapping pressure and stock removal. It shows that stock removal is proportional to lapping pressure. This is because that, with the increase of lapping pressure, the single abrasive grain force exert- ing on the surface of the specimen and crack length beneath the surface of specimen relatively increase; this also causes the increase of the stock removal. But the increasing of lapping pressure is not unconstrained, as when the pressure increases too much, the quartz specimen will be broken. Fig. 3(a)(c) shows correspondingly roughness profiles of quartz crystal lapped by #1000, #2000 and #4000 Al 2 O 3 abrasives, respectively. The results show that the finer are the abrasives, the smaller are the scratches and indentation of single abrasive, and also the smaller is the micro-crack length. As a result, the smaller is the surface roughness, the smaller is the corresponding stock removal. Fig. 4 shows the relations among abrasive size, stock removal and surface roughness. In order to get higher quality and higher stock removal, the reasonable scopes of lapping parameters are as follows: concentration of lapping slurry is 2030 wt.%, lapping speed is 80170 m/min and lapping pressure is 100 150 g/cm 2 . 3.2. Ultra-precision polishing machining After lapping, the specimens are rinsed with distilled water and then wiped clean with absorbent cotton soaked with acetone. Then, put the quartz specimens together with the stainless steel jig on the conditioning ring-type polishing machine. Soft K3 pitch polisher (with 4 mm mesh groove) and SiO 2 powders were applied to polish of quartz crystal to obtain A level surface roughness. First, the quartz specimens are polished with 0.3 mm CeO 2 powders for 210 min to remove the damaged layer left by the lapping machining. Then, the specimens are polished with 500 A SiO 2 fine powders to obtain perfect surface. TheFig. 1. The relation between lapping speed and stock removal. Fig. 2. The relation between lapping pressure and stock removal. J.L. Yuan et al. / Journal of Materials Processing Technology 138 (2003) 116119 117 experimental process is carried in a clean room without dusts. The polishing conditions are as follows: polishing pressure is 18 g/cm 2 and polishing speed is 143.4 m/min. 4. Results and discussion In order to compare the polishing results, several kinds of powders are used in this study under the same polishing conditions. Fig. 5 shows the stock removals of quartz with varied abrasives. Figs. 68 show the roughness profiles relative to the abrasives of Fe 2 O 3 ,CeO 2 and SiO 2 , respec- tively. The stock removals calculated from Fig. 5 are: l.4, 7, and 8.4 A /s corresponding to Fe 2 O 3 , CeO 2 , and SiO 2 powders and the maximum roughness are 15, 25 and 12A corre- sponding to Fe 2 O 3 , CeO 2 , and SiO 2 powders. On the polished surfaces by SiO 2 powders, the maximum roughness is within 12A . This result means that the super-smooth surfaces of quartz crystal are obtained by taking account of the minimization of mechanical actions in polishing process. The material is removed at the atomic scale. Fig. 3. The roughness profiles of lapped quartz crystal. Fig. 4. The lapping relations among abrasives size, stock removal and surfaces roughness. Fig. 5. The polishing relations among abrasives size, stock removal and surfaces roughness. Fig. 6. Roughness profile polished by Fe 2 O 3 (by Talystep). 118 J.L. Yuan et al. / Journal of Materials Processing Technology 138 (2003) 116119 5. Conclusions The optimum scopes of lapping parameters of quartz crystal are determined by experiments. A conventional optical polishing method has been improved to ensure the super-smooth surfaces on quartz crystal. Soft K3 pitch polisher and SiO 2 powders were applied to polishing of quartz crystal to obtain A level surfaces roughness: (1) The mechanical action of abrasives includes rolling and micro-cutting in lapping process of quartz crystal. (2) The rolling actions of the abrasives form the indenta- tion with micro-cracks, the micro-cutting actions of the abrasives form scratches with cracks under the bottom. (3) Lapping speed and lapping pressure are proportional to lapping stock removal of quartz crystal. The finer abrasives will cause smaller surface roughness and lower stock removal. (4) The determined scopes of lapping parameters are as follows: concentration is 2030 wt.%, lapping speed is 80170 m/min and lapping pressure is 100150 g/cm 2 . (5) The properties of the polisher material and abrasive powders are essential conditions to ensure the super- smooth surfaces. (6) Under the given experimental conditions, 12A sur- face roughness of quartz crystal was obtained. (7) The stock removal polished with SiO 2 powders is 1.4 A /s, which confirms that the material removal is at the atomic scale. Acknowledgements The authors are thankful for the financial aid to this project supplied by Zhejiang Provincial Natural Science Foundation of China (501097) and Young Scientist Training Project of Zhejiang Provincial Natural Science Foundation of China (RC RC02066). References 1 T. Kasai, K. Horio, T. Karaki-Doy, Ann. CIRP 39 (1) (1990). 2 J.L. Yuan, Z.F. Tong, SME MR 91-193, 1991. Fig. 7. Roughness profile polished by CeO 2 . Fig. 8. Roughness profile polished by SiO 2 (by Talystep). J.L. Yuan et al. / Journal of Materials Processing Technology 138 (2003) 116119 119