精煉爐鋼包設(shè)計(jì)【鋼包精煉爐】【說明書+CAD+PROE】,鋼包精煉爐,說明書+CAD+PROE,精煉爐鋼包設(shè)計(jì)【鋼包精煉爐】【說明書+CAD+PROE】,精煉爐,鋼包,設(shè)計(jì),說明書,仿單,cad,proe 機(jī)械工程系 機(jī)械設(shè)計(jì)與制造 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 十字軸 零件名稱 共 頁(yè) 第 1 頁(yè) 車間 工序號(hào) 工序名稱 材 料 牌 號(hào) 機(jī)加工車間 1 粗車四端面 16Mn 毛坯種類 毛坯外形尺寸 每毛坯可制件數(shù) 每 臺(tái) 件 數(shù) 模鍛件 1 1 設(shè)備名稱 設(shè)備型號(hào) 設(shè)備編號(hào) 同時(shí)加工件數(shù) 臥式車床 CA6140 1 夾具編號(hào) 夾具名稱 切削液 三抓卡盤 工位器具編號(hào) 工位器具名稱 工序工時(shí) (分) 準(zhǔn)終 單件 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/min m/min mm/r mm 機(jī)動(dòng) 輔助 1 粗車軸380端面1 YT5硬質(zhì)合金可轉(zhuǎn)位車刀 游標(biāo)卡尺 2.0 1.47 0.39 0.3 1 4s 2 粗車軸360端面2 2.0 1.47 0.39 0.3 1 4s 3 粗車軸285端面3 2.0 1.47 0.39 0.3 1 4s 4 精車軸380端面4 2.0 1.47 0.39 0.3 1 4s 5 精車軸360端面4 6 銑軸的斜端面 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） 肖楊閔 20130701 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 鋼包設(shè)計(jì) I 摘要 鋼包精煉爐，是用來對(duì)初煉爐（電弧爐、平爐、轉(zhuǎn)爐）所熔鋼水進(jìn)行精煉，并 且能調(diào)節(jié)鋼水溫度，工藝緩沖，滿足連鑄、連軋的重要冶金設(shè)備。鋼包爐是爐 外精煉的主要設(shè)備之一。鋼包精煉爐主要功能：1、使鋼液升溫和保溫功能。鋼 液通過電弧加熱獲得新的熱能，這不但能使鋼包精煉時(shí)可以補(bǔ)加合金和調(diào)整成 分，也可以補(bǔ)加渣料，便于鋼液深脫硫和脫氧。而且連鑄要求的鋼液開澆溫度 得到保證，有利干鑄坯質(zhì)量的提高。 關(guān)鍵詞：鋼包；液壓；滑動(dòng)水口 II Abstract Ladle Turret in continuous casting machine is pouring position over the top of the ladle used to carry cross and bearing steel casting equipment packages，it is the most commonly used in modern continuous casting and the most common bearing steel ladle for pouring the key machinery and equipment.In this paper, we make a design calculations for the Ladle Turret slewing device system, helping to optimize the large package of turret structure, reduce costs and increase the economic efficiency.This topic is mainly making a design calculation of correlation of Ladle Turret slewer , including the calculation of the drives power , the selection of the electrical machine and electrical machine ,the checking of exposed gear ,the selection and checking of exposed gear ,the checking of coupling bolt and foundation bolt. Keywords：The Ladle ；hydraulic；slide gate 3 第一章 總論 1.1 鋼包精練爐的簡(jiǎn)介 鋼包精煉爐，是用來對(duì)初煉爐（電弧爐、平爐、轉(zhuǎn)爐）所熔鋼水進(jìn)行精煉， 并且能調(diào)節(jié)鋼水溫度，工藝緩沖，滿足連鑄、連軋的重要冶金設(shè)備。鋼包爐是 爐外精煉的主要設(shè)備之一。鋼包精煉爐主要功能：1、使鋼液升溫和保溫功能。 鋼液通過電弧加熱獲得新的熱能，這不但能使鋼包精煉時(shí)可以補(bǔ)加合金和調(diào)整 成分，也可以補(bǔ)加渣料，便于鋼液深脫硫和脫氧。而且連鑄要求的鋼液開澆溫 度得到保證，有利干鑄坯質(zhì)量的提高。2、氬氣攪拌功能。氬氣通過裝在鋼包底 部的透氣磚向鋼液中吹氛，鋼液獲得一定的攪拌功能。3、真空脫氣功能。通過 鋼包吊入真空罐后，采用蒸汽噴射泵進(jìn)行真空脫氣，同時(shí)通過包底吹入氬氣攪 動(dòng)鋼液，可以去除鋼液中的氫含量和氮含量，并進(jìn)一步降低氧含量和硫含量， 最終獲得較高純凈度的鋼液和性能優(yōu)越的材質(zhì)。鋼包精煉爐的應(yīng)用對(duì)整個(gè)企業(yè) 來看，至少可增加如下得益：加快生產(chǎn)節(jié)奏，提高整個(gè)冶金生產(chǎn)效率。應(yīng)用領(lǐng) 域：鋼包精煉爐被廣泛用于工業(yè)、鋼鐵、冶金等行業(yè)。 1.2 鋼包精煉爐的研究意義 爐外精煉技術(shù)由于其具有提高鋼質(zhì)量、加快產(chǎn)量、降低成本、改善勞動(dòng)條件 和生產(chǎn)環(huán)境條件等優(yōu)點(diǎn)日益成為全世界鋼鐵行業(yè)的新寵。鋼包精煉爐以其冶金 效果好、具有設(shè)備費(fèi)用低、易于操作等特點(diǎn)而成為爐外精煉技術(shù)有代表性的設(shè) 備,正得到普遍應(yīng)用。 1.3 鋼包精煉爐的研究背景 鋼鐵是國(guó)民經(jīng)濟(jì)的中流破柱,是國(guó)家生存和發(fā)展的物質(zhì)保障。鋼鐵工業(yè)在國(guó) 民經(jīng)濟(jì)的發(fā)展過程中,起著舉足輕重的作用,是國(guó)民經(jīng)濟(jì)水平和綜合國(guó)力的重要 標(biāo)志。我國(guó)是發(fā)展中國(guó)家,正大力發(fā)展其國(guó)民經(jīng)濟(jì),這使得我國(guó)對(duì)鋼鐵材料的需 求量增大。同時(shí)我國(guó)也是鋼鐵產(chǎn)量世界第一的鋼鐵大國(guó),在國(guó)民經(jīng)濟(jì)高速發(fā)展的 今天,社會(huì)對(duì)鋼材尤其是高質(zhì)量鋼材的需求不斷加大,這就需要我們?yōu)殇撹F強(qiáng)國(guó) 的偉大目標(biāo)努力奮斗。在一段時(shí)期之內(nèi),鋼鐵工業(yè)仍將是我國(guó)經(jīng)濟(jì)的支柱之一。 20 世紀(jì)以來,鋼鐵產(chǎn)品被廣泛地應(yīng)用在建筑、機(jī)械、汽車、船舶、石油和 運(yùn)輸?shù)雀鱾€(gè)行業(yè)中。因此,鋼鐵一直是國(guó)民經(jīng)濟(jì)的基礎(chǔ)工業(yè)之一?，F(xiàn)如今,雖然 出現(xiàn)了許多新材料,例如陶瓷、塑料、高分子復(fù)合材料等等,這些新材料由于自 身的一些特點(diǎn)在一定程度上取代了鋼材,但是鋼材具有其它材料不可比擬的綜合 性能。同時(shí),與其它材料相比,鋼材價(jià)格波動(dòng)趨勢(shì)相對(duì)較小。所以,鋼鐵材料仍是 當(dāng)代最主要的材料之一。 隨著市場(chǎng)經(jīng)濟(jì)的持續(xù)高速發(fā)展,使得企業(yè)的規(guī)模和產(chǎn)量越來越大,鋼鐵工業(yè) 4 也通過加快結(jié)構(gòu)優(yōu)化與調(diào)整,不斷提高滿足國(guó)民經(jīng)濟(jì)對(duì)鋼材產(chǎn)量、品種、質(zhì)量、 成本等全面要求的能力。但是,隨之而來的市場(chǎng)競(jìng)爭(zhēng)又使各企業(yè)面臨著生產(chǎn)規(guī)模、 經(jīng)濟(jì)效益、產(chǎn)品質(zhì)量和環(huán)境保護(hù)等方面的嚴(yán)峻挑戰(zhàn)。企業(yè)要想立于不敗之地,必 須提高自身的競(jìng)爭(zhēng)能力,提高生產(chǎn)效率、降低成本、降低能源消耗和原材料消耗、 減輕對(duì)環(huán)境的污染和改進(jìn)產(chǎn)品質(zhì)量,以適應(yīng)快速多變的市場(chǎng)需求。 近 20 多年來,由于人類社會(huì)的飛速發(fā)展對(duì)鋼材尤其是優(yōu)質(zhì)鋼材、特殊鋼材 的需求越來越大,而隨著科學(xué)技術(shù)的發(fā)展,鋼材的冶煉技術(shù)也發(fā)生了質(zhì)的變化。 煉鋼爐的容量不斷擴(kuò)大,超高功率電爐普遍應(yīng)用于生產(chǎn),連續(xù)鑄鋼技術(shù)也円臻完 善。因此,煉鋼的方法也發(fā)生了巨大的變化,由原始的一步煉鋼法發(fā)展成為二步 煉鋼法即爐內(nèi)初煉、爐外精煉。爐外精煉技術(shù)由于其具有提高鋼質(zhì)量、加快產(chǎn) 量、降低成本、改善勞動(dòng)條件、改善生產(chǎn)環(huán)境條件等等優(yōu)點(diǎn)已日益成為全世界 鋼鐵行業(yè)的新寵,發(fā)展極其迅速。全世界各大鋼鐵企業(yè)紛紛加大了對(duì)鋼水爐外精 煉的研究力度,研制了多種鋼水爐外精煉的設(shè)備,尤其是提出了各種各樣的理論 和控制方法,并已創(chuàng)造了極其可觀的經(jīng)濟(jì)效益。 1.4 實(shí)施方案及主要研究手段 （1）本課題對(duì)現(xiàn)有鋼包精煉爐進(jìn)行改進(jìn)，重點(diǎn)解決現(xiàn)有鋼包精煉爐的缺 陷。 （2）根據(jù)鋼包精煉爐的材料性質(zhì)，確定工藝材料的選擇（3）通過對(duì)已有的 鋼包精煉爐的結(jié)構(gòu)進(jìn)行改進(jìn)，主要改善鋼包包體、滑動(dòng)水口、吹氬口。 1.5 設(shè)計(jì)(論文)的主要內(nèi)容（理工科含技術(shù)指標(biāo)）： (1) 參閱相關(guān)資料，了解和掌握鋼包精煉爐工作原理及其發(fā)展，并查閱和收集 相關(guān)資料； (2) 完成原理方案設(shè)計(jì)和結(jié)構(gòu)方案設(shè)計(jì)，確定實(shí)施方案； (3) 對(duì)鋼包精煉爐結(jié)構(gòu)進(jìn)行設(shè)計(jì)； (4) 鋼包起吊軸加工工藝規(guī)程設(shè)計(jì)； (5) 對(duì)鋼包滑動(dòng)水口的結(jié)構(gòu)改善，并對(duì)結(jié)果進(jìn)行分析； (6) 完成所設(shè)計(jì)部件的裝配圖和零件圖。 5 第 2 章 鋼包設(shè)計(jì) 2.1、 鋼包尺寸計(jì)算 (1)鋼包容納鋼水量。鋼包的容量應(yīng)于轉(zhuǎn)爐的最大出鋼量相匹配，設(shè)鋼包的 額定容量為 。一般考慮應(yīng)用 10的過裝余量，則鋼包內(nèi)鋼水實(shí)際容量為()Pt =1.1250=275t0.1.P (2)鋼包內(nèi)渣量。出鋼時(shí)一般將爐內(nèi)熔渣全部或絕大部分隨鋼水水傾入鋼包。 采用留渣出鋼操作者除外，但留渣出鋼操作時(shí)在鋼桶中要新加渣料熔融成新渣 層覆蓋。渣量一般為金屬量的 35，設(shè)計(jì)時(shí)取較大比例為 15。即渣量為： 15%0.15P (3)鋼包的容積。根據(jù)鋼包實(shí)際容納金屬液與熔渣量計(jì)算容積。鋼液比容取 為 0.14 ，熔渣比容取為 0.28 。因此，鋼與渣的總體積即鋼包容積應(yīng)3/mt 3/mt 為： =0.141.1 +0.280.15 =0.20 ( )，若采用 1，錐度為VPP3DH 15，則鋼包下部?jī)?nèi)徑(鋼包內(nèi)空間尺寸見圖 1)： =0.8515%HDD 圖 1 鋼包內(nèi)空間尺寸 鋼包的容積按圓錐臺(tái)計(jì)算： 2()1HVD 6 將 ， 帶入上式得： HD0.85H 30.67VD 又因?yàn)殇摵驮w積為 =0.20 ，故 =0.20PVP3.1133.2()0.67 從而可得鋼包基本尺寸與容量的關(guān)系使如下: ； ； 130.67DP130.67HP130.567HDP 上面三個(gè)計(jì)算式是根據(jù)內(nèi)襯厚度上下一致的情況下推出的。各部設(shè)計(jì)過程 參考（鋼鐵廠設(shè)計(jì)下冊(cè)，李傳薪主編 P128-129）從而得到各部分參數(shù)如圖 2 所示。 圖 2 鋼包各部分尺寸 1) 0.1.dHJD1外 殼 內(nèi) 高 2) 2 D外 殼 全 高 = 3) 12.7.14bJ外 殼 上 部 內(nèi) 徑 + 4) 2 0.6外 殼 上 部 外 徑 D 5) 30.9HbJ外 殼 下 部 內(nèi) 徑 = 7 6) 4321.0bD外 殼 下 部 外 徑 = 說明： (1)盛鋼桶磚襯厚度。盛鋼桶磚襯包含保溫層(外層)與耐火工作層(外層)， 一 般砌筑總厚度 100250mm。工作層砌磚有多種型式，陳列入標(biāo)準(zhǔn)的盛鋼桶襯磚 磚型外，可針對(duì)專用盛鋼桶依據(jù)其錐度、直徑、高度等參數(shù)設(shè)計(jì)專用襯磚，則 砌筑工作更為方便順利，砌筑質(zhì)量也較高。 鋼桶桶壁厚度約等于 0.07D ； ：包壁厚度（上下一致） ，bJdJm D：鋼包上部?jī)?nèi)徑， m :鋼包底襯厚度， （ =0.10D）bJb ：鋼包殼壁厚， ( =0.01D) ：鋼包殼底厚， ( =0.012D)d d 磚襯部分加厚則須加以擴(kuò)大修正，亦即增大 值方能保證實(shí)際容積為 0.20P 表示為: K =0.20P 。K 為 0930.96 的一個(gè)系數(shù)。意義是磚襯部分加30.67D 厚使容積減小了 47，為彌補(bǔ)容積之不足故在式中乘以系數(shù) K 并得下部?jī)?nèi)徑 （一般 為 3060 ，取 為 45 ） 。.85HDm1/306(.9)P =4.289 1/37250.4 =3.4668HDm 表 1 鋼包各部分尺寸值 參數(shù)名稱 數(shù)值(mm) 參數(shù)名稱 數(shù)值(mm) D 4289 H4289 8 1D4889 1H47182 4975 247693 4246 dJ4294D 4332 b300d 51 43 上述鋼包設(shè)計(jì)的凈空高度為300400mm , 為了適應(yīng)現(xiàn)代真空冶煉的需要通常增 大鋼包的凈空高度。RH 要求鋼包的凈空達(dá)400mm 以上即可。本設(shè)計(jì)中取鋼包的 凈空高度為800mm 從而得到鋼包的各部分尺寸如下表2所示 表 2 改進(jìn)后鋼包各部分的值 參數(shù)名稱 數(shù)值(mm) 參數(shù)名稱 數(shù)值(mm) D 4289+120 H4289+8001 4889+137 14718+8002 4975+139 24769+8003 4246+119 dJ4294D 4332+121 b300d 51 43 2.2、鋼包質(zhì)量 鋼包質(zhì)量的精確計(jì)算須完成外殼、吊掛耳抽、支撐腿及滑動(dòng)水口等結(jié)構(gòu)計(jì) 算后，根據(jù)詳細(xì)圖紙進(jìn)行計(jì)算，但由上述已經(jīng)確定的主要尺寸參數(shù)與選材亦可 以較粗略地算出鋼包的質(zhì)量。 (1)包襯質(zhì)量。磚襯總體積體積與總質(zhì)量為： 桶壁磚襯體積為: 9 222223(1.4)(0.9).1.4(0.85).0.19bDVDDD 桶底磚襯體積為： 23(0.9).74d 磚襯總體積: 3330.219D.0.296DV襯 磚襯總質(zhì)量(現(xiàn)取平均密度約 1.81 計(jì)算)/tm33333W.71.80.19.5D襯 （2）外殼鋼板質(zhì)量 桶底鋼板體積： 23(.0).4D 桶壁鋼板體積: 3(1.6.)1.50.9D 外殼鋼板質(zhì)量: 3W09784殼 （3）空鋼包質(zhì)量 ，將式 代入得：3.1D1襯 殼 13.6P 0.273P 即空盛鋼桶質(zhì)量約為鋼桶額定容量值的 2728?？紤]到其它未計(jì)入的鋼 結(jié)構(gòu)件與耐火磚(塞仔磚或滑板)質(zhì)量，應(yīng)增加約 10，則空桶質(zhì)量為額定容量 值的 3031。 （取為 30%）103WP（ . ） =0.3250=75 （ t） （4）裝滿鋼水與熔渣后的總質(zhì)量。鋼包容量按過裝 10%計(jì)算，渣量為金屬量 15%計(jì) 算，則裝滿鋼水和渣后的質(zhì)量為： 21.P065.273P1.58 =1.538250=384.5t 10 因此，在選用澆注起重機(jī)時(shí)，其起重容量應(yīng)大于 加門形吊鉤的質(zhì)量。門2W 形吊鉤有固定在盛鋼桶上(與耳鈾餃接)和脫鉤式兩種，均須計(jì)入起重總量。 2.3 鋼包重心計(jì)算 計(jì)算鋼包的重心是為了確定鋼包耳軸的高低位置，使裝滿鋼水與熔渣的鋼包 吊運(yùn)與澆注過程穩(wěn)定，無傾翻的危險(xiǎn)；又要使其在傾倒出殘鋼與鋼水時(shí)不需太 費(fèi)力。計(jì)算重心是采用力學(xué)常規(guī)的計(jì)算方法。 對(duì)于盛鋼桶而言，如簡(jiǎn)化不計(jì)澆注操作機(jī)構(gòu)(塞桿或滑動(dòng)鑄口)的質(zhì)量，即 忽略它們?cè)谑撏吧纤鸬闹匦钠疲瑒t可視盛鋼桶桶體，內(nèi)襯及鋼水、熔 渣是圍繞鉛垂軸線完全對(duì)稱的。故計(jì)算重心只考慮堅(jiān)直方向的距離即可以了。 (1)鋼桶桶壁磚襯的重心點(diǎn) 由計(jì)算可得桶壁磚襯重心距上口為： 01.487yD (2)盛鋼桶底磚襯的重心點(diǎn) 由計(jì)算可得桶底磚襯重心距上口為： 02.5 (3)外殼側(cè)壁之重心點(diǎn) 由計(jì)算可得外殼側(cè)壁重心距上口為 03.7yD (4)底殼的重心點(diǎn) 由計(jì)算可得底殼重心距上口為 041.6 (5)渣層的重心點(diǎn) 由計(jì)算可得渣層重心距上口為 05.9yD (6)盛鋼桶內(nèi)金屬的重心點(diǎn) 由計(jì)算可得盛鋼桶內(nèi)金屬重心距上口為 06.581 (7)總重心。已知盛鋼桶各部分重心的所有數(shù)據(jù)，總重心就可以求出。因盛 鋼桶是對(duì)稱的，所有重心都在對(duì)稱袖上，根據(jù)合力靜力矩等于合力靜力 矩之和的原理，可列出下列方程式： 01020300.mWyyWy = 2.538P 11 裝滿鋼水的盛鋼桶質(zhì)量： 321.58.6WD 鋼水量: 31.6.70P 化簡(jiǎn)得： 02795D.4.y =0.544.289=2.3160 m 同時(shí)，為了使盛鋼桶穩(wěn)定，必須使耳軸中心線與盛鋼桶上緣的距離小于 0.54D。同樣計(jì)算方法，可得空盛鋼桶之重心位置 ，亦即空盛鋼0.642yD 桶較盛滿鋼水、熔渣時(shí)重心為低，此時(shí)更為穩(wěn)定，無傾覆之危險(xiǎn)。 表 3 鋼包各部分參數(shù) 參數(shù)名稱 數(shù)值(mm) 參數(shù)名稱 數(shù)值(mm) D 4409 H50891 5026 155182 5114 255693 4365 dJ4294D 4453 b300d 51 430y 2.316 12 第三章 鋼包滑動(dòng)水口設(shè)計(jì) 隨著快速、高效連鑄和二次精煉技術(shù)及工藝的發(fā)展，滑動(dòng)水口 （Sliding Nozzle，簡(jiǎn)稱 SN）系統(tǒng)在現(xiàn)代鋼鐵冶煉過程中變得越來越重要， 成為冶煉中不可缺少的部分。它是連鑄機(jī)澆鑄過程中鋼水的控制裝置，能夠 精確地調(diào)節(jié)從鋼包到連鑄中間包的水流量，使流入和流出的鋼水達(dá)到平衡， 從而使連鑄操作更容易控制?；瑒?dòng)水口系統(tǒng)因其可控性好，能提高煉鋼生產(chǎn) 效率而得到了迅速發(fā)展?，F(xiàn)在，在鋼包、中間包上國(guó)內(nèi)外普遍使用了滑動(dòng)水 口系統(tǒng)。 滑動(dòng)水口的設(shè)計(jì)早在 1884 年就由美國(guó)人 D. Lewis 提出構(gòu)思并申請(qǐng)了專 利，后來也有不少類似的專利，但均因材質(zhì)不過關(guān)而未能實(shí)現(xiàn)。直到 1964 年， 西德本特勒鋼鐵公司在 22T 鋼包上，采用滑動(dòng)水口裝置代替塞棒系統(tǒng)進(jìn)行澆 鋼，首次獲得成功，并迅速推廣到許多國(guó)家。 滑動(dòng)水口一般由驅(qū)動(dòng)裝置、機(jī)械部分和耐火材料部分（即上下滑板、下 水口）組成?；瑒?dòng)水口的工作原理是通過滑動(dòng)機(jī)構(gòu)使上下滑板磚滑動(dòng)，從而 帶動(dòng)流鋼孔的開閉來調(diào)節(jié)鋼水流量大小的。 為獲得較長(zhǎng)的使用壽命和穩(wěn)定的操作條件，滑板作為滑動(dòng)水口系統(tǒng)的耐 火材料和機(jī)械構(gòu)件，都要求其具有優(yōu)良的性能。當(dāng)前，為了使滑動(dòng)水口系統(tǒng) 使用性能更加穩(wěn)定可靠，對(duì)滑板的形狀以及固定方式進(jìn)行了許多改進(jìn)和研究， 其主要目的是抑制滑板使用過程中工作面裂紋的產(chǎn)生和擴(kuò)展。 滑板（Sliding Plate，簡(jiǎn)稱 SP）是滑動(dòng)水口系統(tǒng)的主要部件之一。按 照組成滑動(dòng)水口系統(tǒng)的滑板塊數(shù)劃分，可分為兩層式和三層式。鋼包用滑板 一般為兩層式，操作時(shí)上滑板固定不動(dòng)，通過下滑板進(jìn)行截流和節(jié)流。中間 包用滑板一般為三層式，操作時(shí)將上滑板與上水口固定，下滑板與下水口固 定，通過中間滑板來進(jìn)行截流和節(jié)流。 3.1 負(fù)載與運(yùn)動(dòng)分析 3.1.1 計(jì)算工作負(fù)載 由任務(wù)書給出 缸1：F1=100KN 缸2：F2=100KN 13 3.1.2 摩擦及慣性負(fù)載 由于摩擦及慣性負(fù)載須由實(shí)驗(yàn)確定，且該系統(tǒng)的摩擦及慣性負(fù)載均 不大，故忽略不計(jì)。 3.1.3 工進(jìn)速度 由任務(wù)書給出 缸1：V1=15mm/s 缸2：V2=15mm/s 3.1.4 各工況負(fù)載 由于忽略了摩擦及慣性負(fù)載，且由任務(wù)書可知，整個(gè)工作過程中， 工 3.1.5 各工況時(shí)間 將啟動(dòng)和減速過程忽略 工進(jìn)：t1=7.33s 退回：t2=7.33s 3.2 確定液壓缸基本參數(shù) 3.2.1 初選系統(tǒng)壓力 由任務(wù)書給出系統(tǒng)工作壓力 P1=16MPa，液壓缸工作過程中，活塞桿 主要受壓，故取 d/D=0.7 系統(tǒng)對(duì)活塞桿速度有要求，初步構(gòu)想采用出口節(jié)流調(diào)速，故初取系 統(tǒng)背壓 P2=1MPa 3.2.2 計(jì)算液壓缸主要尺寸 A1= 14 去=0.9 =71.6846 = 則 A1=7168.46則液壓缸直徑 D=9.56cm 去標(biāo)準(zhǔn)值 D=100cm 由 d/D=0.7，則 A1=2A2，i=0.7 則 d=70mm 則液壓缸的有效面積： A1=/4=78.5 A2=( )=40.1 活塞桿直徑 A=A1-A2=38.4 3.3 擬定液壓系統(tǒng)圖 3.3.1 選擇基本回路 3.3.1.1 調(diào)速回路 由于出口節(jié)流調(diào)速始終存在背壓，故速度穩(wěn)定性好。 3.3.1.2 油源形式的確定 由第一部分分析看出，系統(tǒng)工作過程中主要由工進(jìn)（高壓大流量） 和退回（低壓大流量）兩個(gè)工況組成，即泵主要要滿足高壓大流量的 要求，故而，選擇軸向柱塞泵。 3.3.1.3卸荷回路的選擇 由于鋼水包滑動(dòng)水口特殊的工作條件，要求液壓系統(tǒng)在大部分時(shí)間 內(nèi)都處于不工作狀態(tài)，但頻繁的啟動(dòng)不僅消耗大量能量，而且對(duì)液壓 系統(tǒng)不利，故而系統(tǒng)應(yīng)采用卸荷回路，現(xiàn)提出以下卸荷回路： （1）換向閥卸荷 15 （2）先導(dǎo)式溢流閥卸荷 （3）先導(dǎo)式電磁卸荷溢流閥卸荷 3.3.1.4鎖止回路的確定 由于鋼水包滑動(dòng)水口要求在任何位置停止并鎖緊，以穩(wěn)定的調(diào)節(jié)鋼 水流出速率，故采用液控單向閥的鎖緊回路。 3.3.1.5系統(tǒng)圖的最終確定 (1) 16 （2） 3.1.3.6系統(tǒng)的比較 系統(tǒng)一采用雙缸串聯(lián)機(jī)構(gòu)，工作中從動(dòng)缸可隨主動(dòng)缸動(dòng)作，從動(dòng)缸 的啟動(dòng)與停止完全跟隨主動(dòng)缸動(dòng)作，運(yùn)動(dòng)控制精確，且系統(tǒng)簡(jiǎn)單，易 實(shí)現(xiàn)。 17 系統(tǒng)二中，從動(dòng)缸采用差動(dòng)連接，并靠主動(dòng)缸推動(dòng)滑動(dòng)水口為從動(dòng) 缸提供機(jī)械力，使從動(dòng)缸運(yùn)動(dòng)，在主動(dòng)缸停止運(yùn)動(dòng)時(shí)，從動(dòng)缸可能會(huì) 在慣性作用下繼續(xù)運(yùn)動(dòng)，從而造成滑動(dòng)水口的開度定位不精確，且此 系統(tǒng)復(fù)雜，使系統(tǒng)搭建、調(diào)試以及發(fā)快的設(shè)計(jì)變得復(fù)雜。 系統(tǒng)三才有用先導(dǎo)式卸荷溢流閥，卸荷溢流閥流量大，且系統(tǒng)簡(jiǎn)單。 系統(tǒng)四采用單缸系統(tǒng)，并利用換向閥中位鎖緊，系統(tǒng)簡(jiǎn)單易實(shí)現(xiàn)，但 單缸系統(tǒng)的液壓缸尺寸計(jì)算時(shí)，須按有桿腔提供工作壓力計(jì)算，導(dǎo)致 液壓缸尺寸變大，而由于此液壓缸需要經(jīng)常拆卸，過大的液壓缸對(duì)工 人操作不方便，且對(duì)機(jī)械機(jī)構(gòu)要求也更高，而換向閥中位機(jī)能鎖緊回 路鎖緊不可靠。 綜合以上分析，將系統(tǒng)一作為最終選定系統(tǒng)。 3.4液壓輔件的選擇 3.4.1 選擇液壓泵及驅(qū)動(dòng)電機(jī) 3.4.1.1確定液壓泵最大工作壓力 P1=16MPa 由于系統(tǒng)管路簡(jiǎn)單，取 P=0.5MPa 3.4.1.2確定液壓泵的流量 18 取泄露系數(shù) K=1.1 3.4.1.3選擇液壓泵型號(hào) 由以上計(jì)算數(shù)字查閱產(chǎn)品樣本，選用規(guī)格相近的華德公司的 A2F 10 R 2 P 1軸向柱塞泵 3.4.1.4確定驅(qū)動(dòng)液壓泵的功率 取泵的總效率=0.8 其中=10ml/r 1500r/min=15l/min =5KW 3.4.2 控制閥的選擇 3.4.2.1 先導(dǎo)式溢流閥 溢流閥通過的最大流量即為泵的額定流量，q=15L/min，最大調(diào)定 壓力 p16MPa 選擇華德公司的 DBW 10A-2-30B/315X/V 3.4.2.2 換向閥 通過換向閥最大流量為系統(tǒng)工進(jìn)時(shí)流量 q=7.065L/min，工作壓力 19 p=16MPa 系統(tǒng)電磁換向閥選擇4WE6 J 50B/ A G24 V 系統(tǒng)手動(dòng)換向閥選擇 H-4WMM 6JB/V 3.4.2.3調(diào)速閥及液控單向閥 調(diào)速閥及液控單向閥的最大流量為系統(tǒng)工進(jìn)工況時(shí)的流量 q=7.065L/min，工作壓力 p=16MPa 調(diào)速閥選擇 Z2F 6-30B/S2 V 單向閥選擇 Z2S 6-40 B/V 3.4.3 蓄能器的選擇 3.4.3.1蓄能器的參數(shù)計(jì)算 （1）蓄能器充氣壓力的確定 蓄能器的最低工作壓力應(yīng)由實(shí)驗(yàn)確定，但由于條件的限制，在此定 位12MPa。 則蓄能器的充氣壓力 （2）蓄能器總?cè)莘e V0的計(jì)算 由于蓄能器做應(yīng)急能源使用，并要求在泵不工作時(shí)，靠蓄能器可工 作2-3次，以下按工作三次計(jì)算 則蓄能器有效工作容積 V=A1S3 其中取 =1.2 V=3.2L 20 工作過程可看做等溫過程 則 3.4.3.2蓄能器的選擇 有以上計(jì)算選擇力士樂公司的 HAB 20-262-2X/10 G09 2N111-SQLO- 皮囊式蓄能器 3.4.4管道的選擇 3.4.4.1 管道內(nèi)徑的計(jì)算 管道內(nèi)徑計(jì)算公式 d=1.13 吸油管路: 取 v=3m/s d=10.3mm 回油管路：取 v=3.5m/s d=9.5mm/s 壓油管路：取 v=8.5m/s d=6mm/s 3.4.4.2 管道的選擇 液壓泵至閥塊之間管道的選擇:由泵的 p 口螺紋尺寸為 M221.5， 選擇 M221.5的卡套式管接頭，據(jù)此選擇泵至閥塊之間的管道為外徑 18，內(nèi)徑 12的鋼管。 閥塊至油箱之間管道的選擇：由回油管路的上述計(jì)算，取內(nèi)徑 21 10mm，外徑 14mm 的鋼管，選擇 M181.5的卡套式管接頭。 閥塊上 A、B 口至液壓缸之間的管道選擇：由亞油管路計(jì)算，選擇 內(nèi)徑 6mm，外徑 10mm 的鋼管，管接頭選擇 M141.5的卡套式管接 頭。 3.5 確定油箱容量 油箱容量由經(jīng)驗(yàn)公式確定：V=q q=15L/min，取 =6 即油箱容量 V=90L 3.6過濾系統(tǒng)的設(shè)計(jì) 3.6.1 過濾器的位置設(shè)置 系統(tǒng)采用軸向柱塞泵，受泵的吸油特性限制，不采用吸油過濾由系 統(tǒng) 要求知道，系統(tǒng)大部分時(shí)間處于卸荷狀態(tài)，故只采用壓油路過濾， 且過濾器裝在溢流閥的上游，既可起到對(duì)泵下游液壓元件的保護(hù)，又 可保證流回油箱油液的清潔。 3.6.2 過濾器精度的選擇 （1）系統(tǒng)中最敏感元件為液壓泵 （2）由 ISO4406標(biāo)注及水乙二醇為工作介質(zhì)，選擇清潔度為 17/15/13。 （3）考慮到系統(tǒng)工作的高溫環(huán)境，及系統(tǒng)的故障可能威脅設(shè)備及 人員安全，目標(biāo)清潔度再增加一級(jí)，選擇16/14/12。 22 （4）由目標(biāo)清潔度選擇過濾器清潔度，查表可得過濾精度為 5m。 3.6.3過濾器尺寸確定 （1）根據(jù)環(huán)境污染狀況和對(duì)污染物的控制程度，查處環(huán)境等級(jí) 由于鋼廠環(huán)境較差，但系統(tǒng)所用缸較少，故選環(huán)境等級(jí)為5級(jí)。 （2）確定流量增大倍數(shù) 選擇 ZU-H 系列高壓過濾器，最大允許壓力將為0.35MPa，據(jù)此查表 增大倍數(shù)為2倍 3.7液壓油的選用 由于鋼水包滑動(dòng)水口液壓系統(tǒng)在鋼水包附近工作，工作環(huán)境溫度較 高，且有發(fā)生火災(zāi)的危險(xiǎn)，故采用抗燃液壓油水乙二醇。 23 結(jié)論 經(jīng)過對(duì)鋼包設(shè)計(jì)計(jì)算，可以得出以下結(jié)論： （1）設(shè)計(jì)了鋼包體結(jié)構(gòu)； （2）設(shè)計(jì)了鋼包滑動(dòng)水口； （3）設(shè)計(jì)了鋼包滑動(dòng)水口液壓系統(tǒng)。 通過本次畢業(yè)設(shè)計(jì)，我全面的進(jìn)行了一次機(jī)械設(shè)計(jì)基本技能訓(xùn)練，對(duì)所學(xué) 的課程進(jìn)行了一次全面系統(tǒng)的復(fù)習(xí)，并融會(huì)貫通。綜合運(yùn)用所學(xué)知識(shí)，遇到問 題，分析問題，并解決問題。經(jīng)過這次畢業(yè)設(shè)計(jì)，我的計(jì)算機(jī)和外語應(yīng)用能力 得到了一定的提高，并且提高了我的機(jī)械設(shè)計(jì)與應(yīng)用能力。 不過在本次設(shè)計(jì)計(jì)算過程也有不少問題，比如查閱的資料可能還不夠完善， 考慮的工況還不夠周全。計(jì)算時(shí)我也遇到了許多困難，但是通過自己不斷查閱 相關(guān)資料和請(qǐng)教老師等途徑，最終將一個(gè)個(gè)困難解決了。在本次設(shè)計(jì)過程中鍛 煉和加強(qiáng)了自己獨(dú)立分析、解決問題的能力。這些必將使我在以后的生活與學(xué) 習(xí)中受益匪淺。 24 致謝 本次畢業(yè)設(shè)計(jì)是在 xx 老師的親切關(guān)懷和悉心指導(dǎo)下完成的。xx 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，xx 老師都始終給予我細(xì)心的指導(dǎo)和不懈的支持。 xx 老師不僅在學(xué)業(yè)上給我以精心指導(dǎo)，同時(shí)還在思想給我以鼓舞，在此謹(jǐn)向 xx 老師致以誠(chéng)摯的謝意和崇高的敬意。 最后再一次感謝所有在畢業(yè)設(shè)計(jì)中曾經(jīng)幫助過我的良師益友和同學(xué)，以及 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唐中銀，杜元雙，鋼包回轉(zhuǎn)臺(tái)回轉(zhuǎn)軸承連接螺栓的緊固J, 中國(guó)第十八冶 金建設(shè)公司機(jī)電公司,2005.3,142(3)，2226 17卜炎編.螺紋聯(lián)結(jié)設(shè)計(jì)與計(jì)算M.北京：高等教育出版社，1993 18百度文庫(kù) .軸承摩擦系數(shù)A ，專業(yè)文獻(xiàn)/行業(yè)資料，機(jī)械制造，15 19洛陽礦山機(jī)械研究所等.國(guó)際齒輪裝置與傳動(dòng)會(huì)議論文集A.北京：機(jī)械工業(yè) 出版社，1977 20齒輪手冊(cè)編委會(huì)編 .齒輪手冊(cè)M.北京：機(jī)械工業(yè)出版社，1990 DOI 10.1007/s00170-004-2328-8 ORIGINAL ARTICLE Int J Adv Manuf Technol (2006) 28: 6166 Fang-Jung Shiou Chao-Chang A. Chen Wen-Tu Li Automated surface finishing of plastic injection mold steel with spherical grinding and ball burnishing processes Received: 30 March 2004 / Accepted: 5 July 2004 / Published online: 30 March 2005 Springer-Verlag London Limited 2005 Abstract This study investigates the possibilities of automated spherical grinding and ball burnishing surface finishing pro- cesses in a freeform surface plastic injection mold steel PDS5 on a CNC machining center. The design and manufacture of a grinding tool holder has been accomplished in this study. The optimal surface grinding parameters were determined using Taguchis orthogonal array method for plastic injection molding steel PDS5 on a machining center. The optimal surface grind- ing parameters for the plastic injection mold steel PDS5 were the combination of an abrasive material of PA Al 2 O 3 , a grind- ing speed of 18 000 rpm, a grinding depth of 20 m, and a feed of 50 mm/min. The surface roughness R a of the specimen can be improved from about 1.60 mto0.35 m by using the optimal parameters for surface grinding. Surface roughness R a can be further improved from about 0.343 mto0.06 mbyusingthe ball burnishing process with the optimal burnishing parameters. Applying the optimal surface grinding and burnishing parame- ters sequentially to a fine-milled freeform surface mold insert, the surface roughness R a of freeform surface region on the tested part can be improved from about 2.15 mto0.07 m. Keywords Automated surface finishing Ball burnishing process Grinding process Surface roughness Taguchis method 1 Introduction Plastics are important engineering materials due to their specific characteristics, such as corrosion resistance, resistance to chemi- cals, low density, and ease of manufacture, and have increasingly F.-J. Shiou (a117) C.-C.A. Chen W.-T. Li Department of Mechanical Engineering, National Taiwan University of Science and Technology, No. 43, Section 4, Keelung Road, 106 Taipei, Taiwan R.O.C. E-mail: shioumail.ntust.edu.tw Tel.: +88-62-2737-6543 Fax: +88-62-2737-6460 replaced metallic components in industrial applications. Injec- tion molding is one of the important forming processes for plas- tic products. The surface finish quality of the plastic injection mold is an essential requirement due to its direct effects on the appearance of the plastic product. Finishing processes such as grinding, polishing and lapping are commonly used to improve the surface finish. The mounted grinding tools (wheels) have been widely used in conventional mold and die finishing industries. The geometric model of mounted grinding tools for automated surface finish- ing processes was introduced in 1. A finishing process model of spherical grinding tools for automated surface finishing sys- tems was developed in 2. Grinding speed, depth of cut, feed rate, and wheel properties such as abrasive material and abrasive grain size, are the dominant parameters for the spherical grind- ing process, as shown in Fig. 1. The optimal spherical grinding parameters for the injection mold steel have not yet been investi- gated based in the literature. In recent years, some research has been carried out in de- termining the optimal parameters of the ball burnishing pro- cess (Fig. 2). For instance, it has been found that plastic de- formation on the workpiece surface can be reduced by using a tungsten carbide ball or a roller, thus improving the surface roughness, surface hardness, and fatigue resistance 36. The burnishing process is accomplished by machining centers 3, 4 and lathes 5, 6. The main burnishing parameters having signifi- cant effects on the surface roughness are ball or roller material, burnishing force, feed rate, burnishing speed, lubrication, and number of burnishing passes, among others 3. The optimal sur- face burnishing parameters for the plastic injection mold steel PDS5 were a combination of grease lubricant, the tungsten car- bide ball, a burnishing speed of 200 mm/min, a burnishing force of 300 N, and a feed of 40 m 7. The depth of penetration of the burnished surface using the optimal ball burnishing parameters was about 2.5 microns. The improvement of the surface rough- ness through burnishing process generally ranged between 40% and 90% 37. The aim of this study was to develop spherical grinding and ball burnishing surface finish processes of a freeform surface 62 plastic injection mold on a machining center. The flowchart of automated surface finish using spherical grinding and ball bur- nishing processes is shown in Fig. 3. We began by designing and manufacturing the spherical grinding tool and its alignment de- vice for use on a machining center. The optimal surface spherical grinding parameters were determined by utilizing a Taguchis orthogonal array method. Four factors and three corresponding levels were then chosen for the Taguchis L 18 matrix experiment. The optimal mounted spherical grinding parameters for surface grinding were then applied to the surface finish of a freeform surface carrier. To improve the surface roughness, the ground surface was further burnished, using the optimal ball burnishing parameters. Fig. 1. Schematic diagram of the spherical grinding process Fig. 2. Schematic diagram of the ball-burnishing process Fig. 3. Flowchart of automated surface finish using spherical grinding and ball burnishing processes 2 Design of the spherical grinding tool and its alignment device To carry out the possible spherical grinding process of a freeform surface, the center of the ball grinder should coincide with the z-axis of the machining center. The mounted spherical grinding tool and its adjustment device was designed, as shown in Fig. 4. The electric grinder was mounted in a tool holder with two ad- justable pivot screws. The center of the grinder ball was well aligned with the help of the conic groove of the alignment com- ponents. Having aligned the grinder ball, two adjustable pivot screws were tightened; after which, the alignment components could be removed. The deviation between the center coordi- nates of the ball grinder and that of the shank was about 5 m, which was measured by a CNC coordinate measuring machine. The force induced by the vibration of the machine bed is ab- sorbed by a helical spring. The manufactured spherical grind- ing tool and ball-burnishing tool were mounted, as shown in Fig. 5. The spindle was locked for both the spherical grinding process and the ball burnishing process by a spindle-locking mechanism. 63 Fig. 4. Schematic illustration of the spherical grinding tool and its adjust- ment device 3 Planning of the matrix experiment 3.1 Configuration of Taguchis orthogonal array The effects of several parameters can be determined efficiently by conducting matrix experiments using Taguchis orthogonal array 8. To match the aforementioned spherical grinding pa- rameters, the abrasive material of the grinder ball (with the diam- eter of 10 mm), the feed rate, the depth of grinding, and the revolution of the electric grinder were selected as the four experi- mental factors (parameters) and designated as factor A to D (see Table 1) in this research. Three levels (settings) for each factor were configured to cover the range of interest, and were identi- Fig. 5. a Photo of the spherical grinding tool b Photo of the ball burnishing tool Table 1. The experimental factors and their levels Factor Level 123 A. Abrasive material SiC Al 2 O 3 ,WA Al 2 O 3 ,PA B. Feed (mm/min) 50 100 200 C. Depth of grinding (m) 20 50 80 D. Revolution (rpm) 12 000 18 000 24 000 fied by the digits 1, 2, and 3. Three types of abrasive materials, namely silicon carbide (SiC), white aluminum oxide (Al 2 O 3 , WA), and pink aluminum oxide (Al 2 O 3 , PA), were selected and studied. Three numerical values of each factor were determined based on the pre-study results. The L 18 orthogonal array was se- lected to conduct the matrix experiment for four 3-level factors of the spherical grinding process. 3.2 Definition of the data analysis Engineering design problems can be divided into smaller-the- better types, nominal-the-best types, larger-the-better types, signed-target types, among others 8. The signal-to-noise (S/N) ratio is used as the objective function for optimizing a product or process design. The surface roughness value of the ground sur- face via an adequate combination of grinding parameters should be smaller than that of the original surface. Consequently, the spherical grinding process is an example of a smaller-the-better type problem. The S/N ratio, , is defined by the following equation 8: =10 log 10 (mean square quality characteristic) =10 log 10 bracketleftBigg 1 n n summationdisplay i=1 y 2 i bracketrightBigg . (1) where: y i : observations of the quality characteristic under different noise conditions n: number of experiment After the S/N ratio from the experimental data of each L 18 orthogonal array is calculated, the main effect of each factor was determined by using an analysis of variance (ANOVA) tech- nique and an F-ratio test 8. The optimization strategy of the 64 smaller-the better problem is to maximize ,asdefinedbyEq.1. Levels that maximize will be selected for the factors that have a significant effect on . The optimal conditions for spherical grinding can then be determined. 4 Experimental work and results The material used in this study was PDS5 tool steel (equiva- lent to AISI P20) 9, which is commonly used for the molds of large plastic injection products in the field of automobile com- ponents and domestic appliances. The hardness of this material is about HRC33 (HS46) 9. One specific advantage of this ma- terial is that after machining, the mold can be directly used for further finishing processes without heat treatment due to its special pre-treatment. The specimens were designed and manu- factured so that they could be mounted on a dynamometer to measure the reaction force. The PDS5 specimen was roughly ma- chined and then mounted on the dynamometer to carry out the fine milling on a three-axis machining center made by Yang- Iron Company (type MV-3A), equipped with a FUNUC Com- pany NC-controller (type 0M) 10. The pre-machined surface roughness was measured, using Hommelwerke T4000 equip- ment, to be about 1.6 m. Figure 6 shows the experimental set-up of the spherical grinding process. A MP10 touch-trigger probe made by the Renishaw Company was also integrated with the machining center tool magazine to measure and determine the coordinated origin of the specimen to be ground. The NC codes needed for the ball-burnishing path were generated by PowerMILL CAM software. These codes can be transmitted to the CNC controller of the machining center via RS232 serial interface. Table 2 summarizes the measured ground surface roughness value R a and the calculated S/N ratio of each L 18 orthogonal ar- ray using Eq. 1, after having executed the 18 matrix experiments. The average S/N ratio for each level of the four factors can be obtained, as listed in Table 3, by taking the numerical values pro- vided in Table 2. The average S/N ratio for each level of the four factors is shown graphically in Fig. 7. Fig. 6. Experimental set-up to determine the op- timal spherical grinding parameters Table 2. Ground surface roughness of PDS5 specimen Exp. Inner array Measured surface Response no. (control factors) roughness value (R a ) ABCD y 1 y 2 y 3 S/N ratio Mean (m) (m) (m) (dB) y (m) 1 1 1 1 1 0.35 0.35 0.35 9.119 0.350 2 1 2 2 2 0.37 0.36 0.38 8.634 0.370 3 1 3 3 3 0.41 0.44 0.40 7.597 0.417 4 2 1 2 3 0.63 0.65 0.64 3.876 0.640 5 2 2 3 1 0.73 0.77 0.78 2.380 0.760 6 2 3 1 2 0.45 0.42 0.39 7.520 0.420 7 3 1 3 2 0.34 0.31 0.32 9.801 0.323 8 3 2 1 3 0.27 0.25 0.28 11.471 0.267 9 3 3 2 1 0.32 0.32 0.32 9.897 0.320 10 1 1 2 2 0.35 0.39 0.40 8.390 0.380 11 1 2 3 3 0.41 0.50 0.43 6.968 0.447 12 1 3 1 1 0.40 0.39 0.42 7.883 0.403 13 2 1 1 3 0.33 0.34 0.31 9.712 0.327 14 2 2 2 1 0.48 0.50 0.47 6.312 0.483 15 2 3 3 2 0.57 0.61 0.53 4.868 0.570 16 3 1 3 1 0.59 0.55 0.54 5.030 0.560 17 3 2 1 2 0.36 0.36 0.35 8.954 0.357 18 3 3 2 3 0.57 0.53 0.53 5.293 0.543 Table 3. Average S/N ratios by factor levels (dB) Factor A B C D Level 1 8.099 7.655 9.110 6.770 Level 2 5.778 7.453 7.067 8.028 Level 3 8.408 7.176 6.107 7.486 Effect 2.630 0.479 3.003 1.258 Rank2413 Mean 7.428 The goal in the spherical grinding process is to minimize the surface roughness value of the ground specimen by determin- ing the optimal level of each factor. Since log is a monotone decreasing function, we should maximize the S/N ratio. Conse- quently, we can determine the optimal level for each factor as being the level that has the highest value of . Therefore, based 65 Fig. 7. Plots of control factor effects on the matrix experiment, the optimal abrasive material was pink aluminum oxide; the optimal feed was 50 mm/min; the optimal depth of grinding was 20 m; and the optimal revolution was 18 000 rpm, as shown in Table 4. The main effect of each factor was further determined by using an analysis of variance (ANOVA) technique and an F ratio test in order to determine their significance (see Table 5). The F 0.10,2,13 is 2.76 for a level of significance equal to 0.10 (or 90% confidence level); the factors degree of freedom is 2 and the degree of freedom for the pooled error is 13, according to F-distribution table 11. An F ratio value greater than 2.76 can be concluded as having a significant effect on surface roughness and is identified by an asterisk. As a result, the feed and the depth of grinding have a significant effect on surface roughness. Five verification experiments were carried out to observe the repeatability of using the optimal combination of grinding pa- rameters, as shown in Table 6. The obtainable surface roughness value R a of such specimen was measured to be about 0.35 m. Surface roughness was improved by about 78% in using the op- Table 4. Optimal combination of spherical grinding parameters Factor Level Abrasive Al 2 O 3 ,PA Feed 50 mm/min Depth of grinding 20 m Revolution 18 000 rpm Table 5. ANOVA table for S/N ratio of surface roughness Factor Degrees Sum Mean F ratio of freedom of squares squares A 2 24.791 12.396 3.620 B 2 0.692 0.346 C 2 28.218 14.109 4.121 D 2 4.776 2.388 Error 9 39.043 Total 17 97.520 Pooled to error 13 44.511 3.424 F ratio value 2.76 has significant effect on surface roughness Table 6. Surface roughness value of the tested specimen after verification experiment Exp. no. Measured value R a (m) Mean y (m) S/N ratio y 1 y 2 y 3 1 0.30 0.31 0.33 0.313 10.073 2 0.36 0.37 0.36 0.363 8.802 3 0.36 0.37 0.37 0.367 8.714 4 0.35 0.37 0.34 0.353 9.031 5 0.33 0.36 0.35 0.347 9.163 Mean 0.349 9.163 timal combination of spherical grinding parameters. The ground surface was further burnished using the optimal ball burnishing parameters. A surface roughness value of R a = 0.06 m was ob- tainable after ball burnishing. Improvement of the burnished sur- face roughness observed with a 30 optical microscope is shown in Fig. 8. The improvement of pre-machined surfaces roughness was about 95% after the burnishing process. The optimal parameters for surface spherical grinding ob- tained from the Taguchis matrix experiments were applied to the surface finish of the freeform surface mold insert to evalu- ate the surface roughness improvement. A perfume bottle was selected as the tested carrier. The CNC machining of the mold in- sert for the tested object was simulated with PowerMILL CAM software. After fine milling, the mold insert was further ground with the optimal spherical grinding parameters obtained from the Taguchis matrix experiment. Shortly afterwards, the ground surface was burnished with the optimal ball burnishing parame- ters to further improve the surface roughness of the tested object (see Fig. 9). The surface roughness of the mold insert was meas- ured with Hommelwerke T4000 equipment. The average surface roughness value R a on a fine-milled surface of the mold insert was 2.15 m on average; that on the ground surface was 0.45 m Fig. 8. Comparison between the pre-machined surface, ground surface and the burnished surface of the tested specimen observed with a toolmaker microscope (30) 66 Fig. 9. Fine-milled, ground and burnished mold insert of a perfume bottle on average; and that on burnished surface was 0.07 monaver- age. The surface roughness improvement of the tested object on ground surface was about (2.150.45)/2.15 = 79.1%, and that on the burnished surface was about (2.150.07)/2.15 = 96.7%. 5 Conclusion In this work, the optimal parameters of automated spheri- cal grinding and ball-burnishing surface finishing processes in a freeform surface plastic injection mold were developed suc- cessfully on a machining center. The mounted spherical grinding tool (and its alignment components) was designed and manu- factured. The optimal spherical grinding parameters for surface grinding were determined by conducting a Taguchi L 18 matrix experiments. The optimal spherical grinding parameters for the plastic injection mold steel PDS5 were the combination of the abrasive material of pink aluminum oxide (Al 2 O 3 ,PA),afeed of 50 mm/min, a depth of grinding 20 m, and a revolution of 18 000 rpm. The surface roughness R a of the specimen can be improved from about 1.6 mto0.35 m by using the optimal spherical grinding conditions for surface grinding. By applying the optimal surface grinding and burnishing parameters to the surface finish of the freeform surface mold insert, the surface roughness improvements were measured to be ground surface was about 79.1% in terms of ground surfaces, and about 96.7% in terms of burnished surfaces. Acknowledgement The authors are grateful to the National Science Coun- cil of the Republic of China for supporting this research with grant NSC 89-2212-E-011-059. References 1. Chen CCA, Yan WS (2000) Geometric model of mounted grinding tools for automated surface finishing processes. In: Proceedings of the 6th International Conference on Automation Technology, Taipei, May 911, pp 4347 2. Chen CCA, Duffie NA, Liu WC (1997) A finishing model of spherical grinding tools for automated surface finishing systems. Int J Manuf Sci Prod 1(1):1726 3. Loh NH, Tam SC (1988) Effects of ball burnishing parameters on surface finisha literature survey and discussion. Precis Eng 10(4):215 220 4. Loh NH, Tam SC, Miyazawa S (1991) Investigations on the sur- face roughness produced by ball burnishing. Int J Mach Tools Manuf 31(1):7581 5. Yu X, Wang L (1999) Effect of various parameters on the surface roughness of an aluminum alloy burnished with a spherical surfaced polycrystalline diamond tool. 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