小型面條壓延機(jī)的設(shè)計(jì)【壓面條機(jī)】
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湖南農(nóng)業(yè)大學(xué)東方科技學(xué)院畢業(yè)論文(設(shè)計(jì))任務(wù)書學(xué)生姓名徐貞學(xué) 號(hào)200841914624年級(jí)專業(yè)及班級(jí)2008級(jí)機(jī)械設(shè)計(jì)制造及其自動(dòng)化(6)班指導(dǎo)教師及職稱高英武教授學(xué) 部理工學(xué)部20 年 月 日 填 寫 說 明一、畢業(yè)論文(設(shè)計(jì))任務(wù)書是學(xué)院根據(jù)已經(jīng)確定的畢業(yè)論文(設(shè)計(jì))題目下達(dá)給學(xué)生的一種教學(xué)文件,是學(xué)生在指導(dǎo)教師指導(dǎo)下獨(dú)立從事畢業(yè)論文(設(shè)計(jì))工作的依據(jù)。此表由指導(dǎo)教師填寫。二、此任務(wù)書必須針對(duì)每一位學(xué)生,不能多人共用。三、選題要恰當(dāng),任務(wù)要明確,難度要適中,份量要合理,使每個(gè)學(xué)生在規(guī)定的時(shí)限內(nèi),經(jīng)過自己的努力,可以完成任務(wù)書規(guī)定的設(shè)計(jì)研究內(nèi)容。四、任務(wù)書一經(jīng)下達(dá),不得隨意更改。五、各欄填寫基本要求。(一)主要內(nèi)容和要求:1工程設(shè)計(jì)類選題明確設(shè)計(jì)具體任務(wù),設(shè)計(jì)原始條件及主要技術(shù)指標(biāo);設(shè)計(jì)方案的形成(比較與論證);該生的側(cè)重點(diǎn);應(yīng)完成的工作量,如圖紙、譯文及計(jì)算機(jī)應(yīng)用等要求。2實(shí)驗(yàn)研究類選題明確選題的來源,具體任務(wù)與目標(biāo),國內(nèi)外相關(guān)的研究現(xiàn)狀及其評(píng)述;該生的研究重點(diǎn),研究的實(shí)驗(yàn)內(nèi)容、實(shí)驗(yàn)原理及實(shí)驗(yàn)方案;計(jì)算機(jī)應(yīng)用及工作量要求,如論文、文獻(xiàn)綜述報(bào)告、譯文等。3文法經(jīng)管類論文明確選題的任務(wù)、方向、研究范圍和目標(biāo);對(duì)相關(guān)的研究歷史和研究現(xiàn)狀簡要介紹,明確該生的研究重點(diǎn);要求完成的工作量,如論文、文獻(xiàn)綜述報(bào)告、譯文等。(二)主要參考文獻(xiàn)與外文資料:在確定了畢業(yè)論文(設(shè)計(jì))題目和明確了要求后,指導(dǎo)教師應(yīng)給學(xué)生提供一些相關(guān)資料和相關(guān)信息,或劃定參考資料的范圍,指導(dǎo)學(xué)生收集反映當(dāng)前研究進(jìn)展的近13年參考資料和文獻(xiàn)。外文資料是指導(dǎo)老師根據(jù)選題情況明確學(xué)生需要閱讀或翻譯成中文的外文文獻(xiàn)。(三)畢業(yè)論文(設(shè)計(jì))的進(jìn)度安排:1設(shè)計(jì)類、實(shí)驗(yàn)研究類課題實(shí)習(xí)、調(diào)研、收集資料、方案制定約占總時(shí)間的20%;主體工作,包括設(shè)計(jì)、計(jì)算、繪制圖紙、實(shí)驗(yàn)及結(jié)果分析等約占總時(shí)間的50%;撰寫初稿、修改、定稿約占總時(shí)間的30%。2文法經(jīng)管類論文實(shí)習(xí)、調(diào)研、資料收集、歸檔整理、形成提綱約占總時(shí)間的60%;撰寫論文初稿,修改、定稿約占總時(shí)間的40%。六、各欄填寫完整、字跡清楚。應(yīng)用黑色簽字筆填寫,也可使用打印稿,但簽名欄必須相應(yīng)責(zé)任人親筆簽名。畢業(yè)論文(設(shè)計(jì))題目小型面條壓延機(jī)的設(shè)計(jì)主要內(nèi)容和要求(宋體五號(hào),行間距單倍行距)1主要內(nèi)容包括: 1.1本項(xiàng)目研究的目的、意義、國內(nèi)外研究的動(dòng)態(tài); 1.2總體方案的擬定和主要參數(shù)的設(shè)計(jì)計(jì)算; 1.3傳動(dòng)方案的確定及設(shè)計(jì)計(jì)算,主要工作部件的設(shè)計(jì); 1.4主要受力零件的強(qiáng)度或壽命校核計(jì)算; 1.5裝配總圖、部件圖、零件工作圖的繪制。2要求2.1主要技術(shù)參數(shù):生產(chǎn)率2.2查閱資料15篇以上,翻譯一定數(shù)量的外文資料;2.3機(jī)構(gòu)設(shè)計(jì)可靠、布局合理、與各執(zhí)行機(jī)構(gòu)協(xié)調(diào)工作;2.4畫圖相當(dāng)于3-4張A0圖紙的工作量(包括2張以上CAD圖紙);2.5設(shè)計(jì)計(jì)算說明書1萬字以上,條理清楚,計(jì)算有據(jù)。格式按湖南農(nóng)業(yè)大學(xué)全日制普通本科生畢業(yè)論文(設(shè)計(jì))規(guī)范化要求;2.6設(shè)計(jì)說明書的內(nèi)容包括:課題的目的、意義、國內(nèi)外動(dòng)態(tài);研究的主要內(nèi)容;總體方案的擬定和主要參數(shù)的設(shè)計(jì)計(jì)算;傳動(dòng)方案的確定及設(shè)計(jì)計(jì)算,主要工作部件的設(shè)計(jì);主要零件分析計(jì)算和校核;參考文獻(xiàn);鳴謝。注:此表如不夠填寫,可另加附頁。主【1】劉曉杰 食品加工機(jī)械與設(shè)備 高等教育出版社 2010要參考資料(具體格式以規(guī)范化要求規(guī)定為準(zhǔn)) 工作進(jìn)度安排(宋體五號(hào),行間距固定值22磅)起止日期主要工作內(nèi)容2010、10、20選題2010、10、30下達(dá)任務(wù)書2010、11、4查找資料,開題2010、12、1設(shè)計(jì)計(jì)算,畫圖2011、3、20中期考核2011、4、20完善,交設(shè)計(jì)初稿2011、5、10完善,交設(shè)計(jì)二稿2010、5、20修改,答辯,交終稿要求完成日期:20 年 月 日 指導(dǎo)教師簽名: 接受任務(wù)日期:20 年 月 日; 學(xué)生本人簽名: 注:簽名欄必須由相應(yīng)責(zé)任人親筆簽名。目 錄摘要1關(guān)鍵詞11 前言12 總體結(jié)構(gòu)23 壓輥的設(shè)計(jì)43.1 壓輥的結(jié)構(gòu)和規(guī)格43.2 壓輥的軸承43.3 壓輥與軸系零件的連接53.4 壓輥的表面技術(shù)參數(shù)53.4.1 齒數(shù)53.4.2 壓齒的斜度53.4.3 齒形53.4.4 壓輥的表面參53.4.5 在選擇輥速時(shí)考慮的因素63.4.6 橫壓力63.4.7 壓輥的清理及冷卻64 進(jìn)料機(jī)構(gòu)64.1 進(jìn)料板75 切面棍76 計(jì)算部分86.1 傳動(dòng)設(shè)計(jì)、選配電機(jī)86.1.1 傳動(dòng)方案的擬定86.1.2 電機(jī)的選擇86.1.3 V帶的設(shè)計(jì)96.1.4 雙面圓弧同步帶的設(shè)計(jì)106.2 壓延輥齒輪傳動(dòng)設(shè)計(jì)計(jì)算116.2.1 選用齒輪類型、精度等級(jí)、材料及齒數(shù)126.2.2 按齒面接觸強(qiáng)度設(shè)計(jì)K1T1126.2.3 按齒根彎曲強(qiáng)度設(shè)計(jì)136.2.4 幾何尺寸計(jì)算146.3 壓輥和切面棍受力分析146.3.1 結(jié)構(gòu)設(shè)計(jì)156.3.2 壓輥受力分析及校核156.4壓輥軸承的選擇計(jì)算166.4.1 壓輥軸承的選擇166.4.2 軸承校核設(shè)計(jì)167 結(jié)論17參考文獻(xiàn)17致謝18小型面條壓延機(jī)的設(shè)計(jì)學(xué) 生:徐貞 指導(dǎo)老師:高英武(湖南農(nóng)業(yè)大學(xué)東方科技學(xué)院,長沙410128)摘 要:本文對(duì)小型面條壓延機(jī)進(jìn)行了總體方案設(shè)計(jì),確定了面條機(jī)的技術(shù)參數(shù)。同時(shí)對(duì)面條機(jī)使用過程中可能出現(xiàn)的問題做了詳細(xì)的分析,并提出了相應(yīng)的解決方法,且對(duì)面條機(jī)中的主要零件進(jìn)行了結(jié)構(gòu)設(shè)計(jì)、分析計(jì)算和校核。此次設(shè)計(jì)的面條機(jī)是將已經(jīng)揉好的面團(tuán)經(jīng)過面輥相對(duì)轉(zhuǎn)動(dòng)擠壓形成面片,再經(jīng)壓面棍對(duì)面片進(jìn)行切條。此面條機(jī)的傳動(dòng):以電動(dòng)機(jī)為動(dòng)力源,電機(jī)和切面輥之間通過皮帶輪傳動(dòng),兩壓面棍之間的傳動(dòng)是齒輪傳動(dòng)。關(guān)鍵詞:壓面輥;皮帶輪;齒輪The Design of Small Noodles Rolling MachineStudent:Xu ZhenTutor:Gao Yingwu (Oriental Science Technology College of Hunan Agricultural University, Changsha 410128)Abstract:This thesis, the small noodles calender for the overall design, make sure the technical parameters of the pasta machine at the same time in the course of using the pasta machine problems that may occur has made the detailed analysis, and proposes the corresponding solution method, and the main parts of pasta machine for structure design analysis, check the design of the pasta machine is will have been knead dough after face relatively good roller rotation extrusion forming strips, then the pressure to cut across the face of the rod .The pasta machine article transmission: to the motor as power source, motor and cut between rollers through the pulley transmission, the two pressure surface of transmission between stick is gear transmission.Keywords: pressure roller;belt pulley;wheel gear1 前言20科技大革新,時(shí)代的進(jìn)步和經(jīng)濟(jì)的飛速發(fā)展使得人們的生活水平不斷提高,人們?nèi)粘I钪兴褂玫母鞣N類型產(chǎn)品的要求也逐漸升高,特別的對(duì)那些日常生活密切相關(guān)的廚房類電器產(chǎn)品-因?yàn)槿藗兠刻斓钠鹁语嬍扯茧x不開這類產(chǎn)品。人們對(duì)食品的口感也越來越挑剔,隨之一些大型的生產(chǎn)食品的機(jī)械紛紛都對(duì)機(jī)械進(jìn)行改進(jìn),產(chǎn)生了各種家用的食品生產(chǎn)機(jī)器1。面條機(jī)以其方便快捷逐漸成為了北方大部分家庭日常生活不可少的產(chǎn)品,這類產(chǎn)品須同時(shí)具有使用功能及相應(yīng)的審美形式,即具有物質(zhì)功能和文化功能雙重屬性。通過查閱資料對(duì)國內(nèi)外相關(guān)產(chǎn)品的了解,對(duì)其產(chǎn)品技術(shù)和機(jī)構(gòu)先進(jìn)行深入研究,對(duì)面條機(jī)已經(jīng)有了一定的了解。2 總體結(jié)構(gòu)進(jìn)料板:進(jìn)料板是敞開式的,由鋼板制成,可以觀察進(jìn)料情況,而且質(zhì)輕美觀。延壓部分:可以觀察到壓輥的轉(zhuǎn)動(dòng)及料流等情況切面部分:本機(jī)采用鋼板制造,焊接制成,切面到直接裝在罩殼上,因此此結(jié)構(gòu)拆裝方便,實(shí)用性強(qiáng),便于開啟關(guān)閉。罩殼:本機(jī)罩采用鋼板沖壓,焊接制成??傮w裝配圖如圖一 (a) (b) (c) 圖1 裝配圖 Fig1 assembly drawing 小型面條壓延機(jī)的工作過程是先將揉好面團(tuán)經(jīng)過兩壓輥壓成面皮,在經(jīng)過切面輥壓成面條,其中兩切面棍之間是用齒輪傳動(dòng)來帶動(dòng)兩輥轉(zhuǎn)動(dòng),然后是用電機(jī)與切面輥之間用帶輪傳動(dòng),切面棍和壓輥直接用也用皮帶輪來傳動(dòng)。關(guān)于具體的計(jì)算將在后面的設(shè)計(jì)計(jì)算中給出。3 壓輥的設(shè)計(jì)3.1 壓輥的結(jié)構(gòu)和規(guī)格如圖2為常用的壓輥結(jié)構(gòu)圖,它由輥體和兩根輥軸組成2。壓輥的輥體由雙金屬離心澆鑄而成,外層為保證輥面有一定硬度和耐磨性的合金鑄鐵,內(nèi)層為使壓輥具有一定韌性和吸振性能的灰口鑄鐵,輥軸材料為機(jī)械性能較好的45號(hào)鋼;輥體和兩只輥軸經(jīng)必要的機(jī)加工后,采用過盈配合壓配成一體,再一起加工到要求的幾何尺寸和形狀。圖2 壓輥結(jié)構(gòu)示意圖Fig 2 Pressure roller structure schematic drawing大量的實(shí)驗(yàn)研究和生產(chǎn)證明:壓輥直徑130mm時(shí),小型面條壓延機(jī)壓延效果和綜合技術(shù)經(jīng)濟(jì)指標(biāo)較好。根據(jù)小型面條壓延機(jī)標(biāo)準(zhǔn),選擇壓輥直徑為130mm,輥長為200mm,根據(jù)壓輥標(biāo)準(zhǔn),壓輥的動(dòng)平衡精度為G6.3;整個(gè)輥面上的硬度盡可能的均勻,硬度偏差要求達(dá)到HS4的水平;輥面的粗糙度要求為Ra0.08mm,圓柱度精度為9級(jí)。3.2 壓輥的軸承根據(jù)壓延機(jī)工藝要求的特點(diǎn),對(duì)壓輥軸承除載荷方面的基本要求,現(xiàn)糧食行業(yè)標(biāo)準(zhǔn)面條機(jī)規(guī)定,本機(jī)選用滾動(dòng)軸承3。此軸承有自位性能,而且承受載荷較大,為了便于拆裝壓輥,在軸承內(nèi)側(cè)和壓輥之間加了緊固軸套,軸承座為整體式4。3.3 壓輥與軸系零件的連接 絕大多數(shù)面條機(jī)上,壓輥與軸系零件大帶輪及同步帶輪的連接鍵,雖然鍵連接具有簡單、緊湊、可靠,成本低等優(yōu)點(diǎn)。但是,減少了被連接件的承載面積,特別是會(huì)引起高度的應(yīng)力集中,被連件也難以獲得精確的定心,而且裝拆也不方便,本機(jī)采用軸承座連接。軸承座連接的定心性好。輪轂可以相對(duì)于軸緊固在任意軸向位置上,裝拆方便,只要把緊固螺釘松開,軸承座連接避免軸因鍵槽等原因而削弱,承載能力高,可獲得緊密的連接,而且有安全保護(hù)作用,只要過載、內(nèi)、外環(huán)就會(huì)打滑,形成相對(duì)轉(zhuǎn)動(dòng),避免零件損壞,壓輥軸與軸承通過緊定套連接,這樣有利于拆裝軸承,兩輥帶輪的連接用螺釘,也便于裝拆5。3.4 壓輥的表面技術(shù)特征3.4.1齒數(shù)壓輥齒數(shù)的多少是根據(jù)需要壓延的物料、性質(zhì)以及要求達(dá)到的壓延厚度比來確定,齒數(shù)少時(shí),齒間距就大,齒槽也深,適用于壓延較多的物料;如用于壓延不多的的物料,則物料容易嵌在齒槽內(nèi)面得不到應(yīng)有的厚度;齒數(shù)多時(shí),齒間距就小齒槽也較淺,適用于壓延厚度較小的物料,如要壓延較多的物料,軋距小時(shí)會(huì)使面皮壓壞,軋距大是會(huì)使面皮厚度過大,得不到想要的效果,并且齒的磨損較塊6。齒數(shù)的多少還與入料的流量有關(guān),流量大時(shí),齒數(shù)應(yīng)少一些;流量小時(shí),齒數(shù)應(yīng)多一些。3.4.2 壓齒的斜度當(dāng)壓輥長度和齒數(shù)不變時(shí),斜度越大,交叉點(diǎn)數(shù)越多,功耗會(huì)降低,面皮就越厚;反之,面皮越薄,功耗會(huì)提高,齒的斜度最大不應(yīng)超過1:6,否則面團(tuán)將在壓輥表面作軸向移動(dòng),而削弱壓輥對(duì)物料的壓延作用。本機(jī)壓輥的斜度選為1:46。3.4.3齒形齒形的大小決定了壓延和切面作用力的性質(zhì),它直接影響著面團(tuán)的壓延程度、能耗以及中間產(chǎn)品的數(shù)量和質(zhì)量。隨著齒腳的增大,輥齒對(duì)面團(tuán)的擠壓力增強(qiáng),剪切力減小,易將面團(tuán)擠壓成面皮,然而可使能耗降低。目前面粉廠所采用的齒角一般在90100之間,其中鋒角2040,鈍角5570。齒頂平面可以緩和輥齒的剪切作用,減小面皮切壞的機(jī)會(huì),改善輥齒的耐磨性,提高輥齒一次拉絲的壽命。3.4.4 壓輥的表面參數(shù)表征壓延機(jī)的參數(shù)很多,其中主要有輥筒數(shù)目及其排列型式、輥筒的直徑和長度、輥筒的調(diào)速范圍、速比和生產(chǎn)能力、壓延制品的最小厚度和厚度公差、輥筒的橫壓力和驅(qū)動(dòng)功率等7。輥筒的長度和直徑是指輥筒工作部分的長度和直徑。壓輥輥面磨光后的粗糙度為Ra0.08mm,光輥的表面要求非常的光滑那樣壓延出來的面皮才有能細(xì)嫩平滑且美觀,保證物料能被壓輥進(jìn)去壓面區(qū)和切面區(qū),提高切面效果。光輥的硬度一般為Ra1.52.5m。光輥工作時(shí)的軋距較小但輥間壓力較大,壓輥會(huì)產(chǎn)生一定的彎曲變形,這樣軋距就會(huì)出現(xiàn)中間大兩端小的現(xiàn)象,造成壓延效果的不均勻和下降,甚至導(dǎo)致面條機(jī)不能正常工作。3.4.5 在選擇輥速時(shí)考慮的因素輥筒速度直接影響壓延機(jī)的功率消耗和生產(chǎn)能力。輥速越大,則功率與產(chǎn)量越高,對(duì)壓延機(jī)的機(jī)械化自動(dòng)化水平要求也越高。因此,在選擇輥速時(shí)要考慮: 1)壓延的工藝要求;2)壓延機(jī)的制造水平;3)壓延機(jī)組的自動(dòng)化水平;4)輥筒速度應(yīng)能廣泛的平穩(wěn)地調(diào)整;5)壓延時(shí)輥速盡可能用高值,這有利于發(fā)揮設(shè)備能力。可見輥速的高低標(biāo)志著壓延機(jī)組的先進(jìn)水平。近年來,由于采用電動(dòng)機(jī)單獨(dú)地傳動(dòng)每個(gè)輥筒,它可使輥筒間的速比在一定范圍內(nèi)(從1:1到高達(dá)1:1.3)任意調(diào)節(jié),從而可在一臺(tái)壓延機(jī)上完成多種作業(yè),這就使機(jī)臺(tái)的適應(yīng)性更加寬廣,并有利于提高輥速8。3.4.6 橫壓力橫壓力的概念:面團(tuán)通過輥筒間隙時(shí),對(duì)輥筒產(chǎn)生徑向作用力和切向作用力,徑向作用力垂直于輥面,力圖將輥筒分開,這個(gè)力就叫橫壓力,也叫分離力。輥筒橫壓力的特征,面團(tuán)通過壓延機(jī)輥筒輥隙時(shí),面團(tuán)的厚度逐漸由大變小,而壓力逐漸上升,在壓延過程中影響橫壓力的因素是多方面的:壓延制品的厚度; 制品厚度越薄,輥隙越小,分離力越大。輥筒直徑和壓延寬度越大,所產(chǎn)生的橫壓力也越大9。3.4.7 壓輥的清理與冷切清理方法;壓輥工作時(shí),輥面會(huì)粘附一些面制物料,物料水分越高、軋距越小,粘附情況就越嚴(yán)重。為了保證壓面機(jī)的機(jī)械和工藝性能,應(yīng)使用清理裝置來保持輥面的正常工作狀態(tài)。目前,一般是在壓面切面完成以后,可以拆下來對(duì)其進(jìn)行清理,清洗干凈在將輥和切面刀安裝上去。這既有利于壓輥和切面輥的保養(yǎng)因而使其壽命增長10。冷卻問題:本機(jī)沒有設(shè)計(jì)專門的冷卻裝置,而是利用空氣自行冷卻。目前,國外先進(jìn)的面條機(jī)不采用專門的冷卻裝置,而是靠空冷。4 進(jìn)料機(jī)構(gòu)4.1 進(jìn)料板進(jìn)料板位于壓面機(jī)的頂部,它的主要作用是:連接進(jìn)料板和壓延部分,并對(duì)物料起一定的緩存作用;將物料盡可能地沿壓輥輥軸敞開;便于觀察物料的壓延和切面部分。簡體的上端安裝有進(jìn)料口的頂蓋下端有與壓面機(jī)機(jī)架連接的法蘭;相比平截正圓錐形形狀,平截長方形錐形進(jìn)料筒具有更大的容量,同時(shí)物料也更容易沿壓輥軸向分布。5 切面輥切面刀可根據(jù)個(gè)人愛好選擇,選擇需要的面寬厚度與寬度,切面輥與軸連接,面輥的設(shè)計(jì)方便拆裝,結(jié)果簡單,適合于家庭用。傳動(dòng):面條機(jī)的傳動(dòng)是指動(dòng)力輸入和壓輥之間傳動(dòng)兩部分。壓輥采用一臺(tái)電動(dòng)機(jī)獨(dú)立驅(qū)動(dòng),電動(dòng)機(jī)通過V帶一級(jí)減速直接拖動(dòng)壓輥。兩輥之間采用同步齒形帶傳動(dòng)。雙面齒形帶為了雙面嚙合的撓性傳動(dòng),傳動(dòng)比精確,結(jié)構(gòu)也能自動(dòng)適應(yīng)離合軋和軋距調(diào)節(jié)所引起的兩輥中心距變化;當(dāng)壓輥磨損引起較大的中心距變化時(shí),可通過調(diào)節(jié)緊張輪補(bǔ)償。改變兩輥帶輪的齒數(shù),就可方便地提供多種傳動(dòng)比11。該傳動(dòng)平穩(wěn),噪聲較小,且無需潤滑。其基本構(gòu)造與壓輥相似。6 計(jì)算部分6.1 傳動(dòng)設(shè)計(jì)、選配電機(jī)6.1.1傳動(dòng)方案的擬定V帶傳動(dòng)具有的結(jié)構(gòu)特點(diǎn):傳動(dòng)效率高;傳動(dòng)摩擦力大;整體尺寸較小,結(jié)構(gòu)較為緊湊。所以,在高速級(jí)布置一級(jí)V帶傳動(dòng),電機(jī)直接通過V帶拖動(dòng)輥軸。6.1.2 電機(jī)的選擇(1)電動(dòng)機(jī)類型的選擇:Y系列三相異步電動(dòng)機(jī)(2)電動(dòng)機(jī)的功率選擇表1 機(jī)械傳動(dòng)的效率值Chart1 The mechanical transmission efficiency value種類 效率滾動(dòng)軸承 0.99/對(duì)V帶傳動(dòng) 0.96同步齒形帶 0.97傳動(dòng)裝置的總效率: 總=軸承軸承帶V =0.990.970.960.894 (1)電動(dòng)機(jī)所需的功率 Pd= P帶/=0.62Kw (2)(3)確定電動(dòng)機(jī)轉(zhuǎn)速12V帶輪傳動(dòng)比:24,為了防止打滑,增大帶輪包角,傳動(dòng)比盡量取小。 n帶=(24)750=15003000r/min 符合這一范圍的同步速度為:1500r/min(4)確定電動(dòng)機(jī)型號(hào)根據(jù)以上選用的電動(dòng)機(jī)的類型,所需的額定功率及同步轉(zhuǎn)速選定電動(dòng)機(jī)的型號(hào)為Y80M2-4調(diào)速電機(jī),其主要性能: P額=0.75Kw n滿載=130r/minT額=2.3Nmm運(yùn)動(dòng)參數(shù)、動(dòng)力參數(shù)計(jì)算 實(shí)際傳動(dòng)比:i=n滿載/nk=1.85P1=P額V帶=0.7Kw0p=P1軸承帶=0.67 KwP= P軸承帶=0.65 Kw6.1.3 V帶的設(shè)計(jì)(1)選擇V帶的帶型12:表查的工作情況系數(shù)KA=1.1,故計(jì)算功率Pca=KAP=1.10.75=0.825Kw根據(jù)Pca,選用A型帶2。(2)確定帶輪的基準(zhǔn)直徑dd112。取小帶輪的基準(zhǔn)直徑;(3)驗(yàn)算帶速V12: V=m/s=5.46m/s (3)因?yàn)?m/sV25 m/s,故此帶輪適合。(4)計(jì)算大帶輪基準(zhǔn)直徑12。 dd2=idd1=1.8575mm=138.75mm (4)圓整為dd2=140mm12.(5)確定V帶的中心距a和基準(zhǔn)長度Ld120.7(dd1+dd2)a02(dd1+dd2),150.5a0430初定中心距a0=300mm.計(jì)算帶輪所需的基準(zhǔn)長度12 Ld02a0+(dd1+dd2)+ (5)=2300(75140)mm941mm選帶的基準(zhǔn)長度Ld=1000mm12計(jì)算實(shí)際中心距a。12 aa0+=(300+)mm329.5mm (6)計(jì)算中心距的變化范圍12amin=a+0.015Ld=314.5;amax=a+0.03Ld=359.5中心距的變化范圍為314.5359.5mm(6)驗(yàn)算小帶輪上的包角11=180(dd2dd1)180(14075)=17490 (7)(7)計(jì)算帶的根數(shù)Z計(jì)算單根V帶的額定功率P112由dd1=75mm和n1=1390r/min,得P0=0.68Kw。根據(jù)n1=1390r/min,i=1.85和A型帶12,得P0=0.15Kw。得包角修正系數(shù)Ka=0.9912,得KL=0.89,于是Pr=(P0P)KaKL=(0.68+0.15) 0.990.89Kw=0.73Kw 計(jì)算V帶的根數(shù)Z。 Z=1.13 (8)取2根。(8)計(jì)算單根V帶的初拉力的最小值(F0)min12得A型帶的單位長度質(zhì)量q=0.1Kg/m,所以 (F0)min=500+qv (9)=500+0.15.46N=60.6N應(yīng)使帶的實(shí)際初拉力F0(F0)min(9)計(jì)算壓軸力Fp壓軸力的最小值為 (Fp)min=2z(F0)minsin=2260.6sin=241.3N (10)(10)帶輪結(jié)構(gòu)設(shè)計(jì)帶輪的材料采用HT200。根據(jù)軸徑的大小,選擇帶輪孔徑,大帶輪孔徑d1=42mm,小帶輪孔徑d2=32mm。根據(jù)經(jīng)驗(yàn)公式,大帶輪結(jié)構(gòu)形式采用腹板式,小帶輪采用實(shí)心式,具體尺寸見零件圖。6.1.4 雙面圓弧同步帶的設(shè)計(jì)(1)確定設(shè)計(jì)功率Pd=KAPkw取KA=1.6,計(jì)算得Pd=1.2kw。(2)選擇帶型按n1=750rpm,Pd=1.2kw,根據(jù)JB/T7512.3,選5M型。(3)確定帶輪直徑確定帶輪齒數(shù):小帶輪齒數(shù)按Z1Zmin原則確定,Zmin根據(jù)JB/T7512.3選14.大帶輪直徑Z2=i ;Z1=66,帶輪節(jié)圓直徑d1、d2和帶輪外徑dn1、dn2由 JB/T7512.2 中查的。d1=54.65mm,d2=166.70mm, dn1=56.02mm,dn2=168.07mm。(4)確定帶的基本額定功率P0 根據(jù)GB/T 7512.3中表查的P0=1.225Kw。(5)確定帶的額定功率Pr帶的額定功率按GB/T 7512.3中表公式計(jì)算: Pr=KLKZKWP0kW=2.31kw (11)查GB/T 7512.3, KL=1.2,KZ=1,KW=(bs/bs0)=1.57(6)確定帶和帶輪的寬度按PdPr的原則選擇帶的寬度bs,則: bsbs0 (12)式中bs0見GB/T7512.3中表6,bs0=20,計(jì)算得bs57.45mm。按計(jì)算結(jié)果從JB/T7512.1表2中選擇標(biāo)準(zhǔn)bs=60mm,并從JB/T7512.2 表3中確定帶輪寬度br=62.7mm, 取br=69.0mm。(7)計(jì)算壓力軸帶的緊邊張力F1和松邊張力F2計(jì)算13:F1=1250Pd/v=792.77N F2=250Pd/v=158.55N式中:v帶速,m/s;v=d1n1/6000壓力軸由GB/T 7512.3式(13)計(jì)算:當(dāng)工況系數(shù)KA1.3時(shí),Q=0.77KF(F1+F2)=717.87N式中:矢量相加修正系數(shù)KF=0.9813。6.2 壓延輥齒輪傳動(dòng)設(shè)計(jì)計(jì)算6.2.1 選用齒輪類型、精度等級(jí)、材料及齒數(shù)(1) 選用直齒圓柱齒輪傳動(dòng)。(2) 面條機(jī)為一般工作機(jī)器,速度不高,故選用7級(jí)精度(GB1009588)14。(3) 材料選擇12,選擇齒輪材料為40Cr(調(diào)質(zhì)),硬度為280HBS,兩齒輪選一樣大小。6.2.2按齒面接觸強(qiáng)度設(shè)計(jì)K1T1先進(jìn)行試算12,即 (13)(1) 確定公式內(nèi)的個(gè)計(jì)算數(shù)值1) 試選載荷系數(shù)K1=1.12) 計(jì)算齒輪傳遞的轉(zhuǎn)矩。 T1=8.356103Nmm (14)3)選取齒寬系數(shù)d=0.6124)查得材料的彈性影響系數(shù)ZE=189.8Mpa12。5)按齒面硬度查得齒輪的接觸疲勞強(qiáng)度極限min1=600 Mpa 12;大齒輪的接觸疲勞強(qiáng)度極限min2=550Mpa.6)計(jì)算應(yīng)力循環(huán)次數(shù)12。 N1=60n1jLh=60 801(300815)=1.728108(次) (15)N2=1.728108/2.25=7.68107(次)7)取接觸疲勞壽命系數(shù)KHN1=1.15,KHN2=1.17128)計(jì)算接觸疲勞許用應(yīng)力12取失效概率為1%,安全系數(shù)S=1,得: H1= KHN1Lim1/S=1.15600=690Mp (16)H2= KHN2Lim2/S=1.17550=643.5Mp(2)計(jì)算1)計(jì)算齒輪分度圓的直徑d1t,帶入H中較小的值。 (17)2)計(jì)算圓周速度 V=0.12m/s (18)3)計(jì)算齒寬b及模數(shù)mnt。齒寬:b=dd1t=0.629mm=17.4mm模數(shù):mnt=d1t/z1=1.45mm齒高:h=2.25 mnt=2.251.45=3.26mm齒寬與齒高之比 b/h=17.4/3.26=5.34mm4)計(jì)算載荷系數(shù)K根據(jù)v=0.12m/s,7級(jí)精度12,查得動(dòng)載系數(shù)Kv=1.03;直齒輪,KH=KF=1;查的使用系數(shù)KA=112;用插值法查的7級(jí)精度、小齒輪懸臂布置時(shí)12,KH=1.35。由b/h=5.34,KH=1.35得KF=1.2812;故載荷系數(shù) K=KAKVKHKH=11.0311.351.39 (19)5)按實(shí)際的載荷系數(shù)校正所算得的分度圓直徑,得12 d1=d1t=29=31.35mm (18)6)計(jì)算模數(shù)mn。 mn=d1/z1=1.57mm (19)6.2.3按齒根彎曲強(qiáng)度設(shè)計(jì)得彎曲強(qiáng)度的設(shè)計(jì)公式為12 (20)(1) 確定公式內(nèi)的個(gè)計(jì)算數(shù)值1) 查的齒輪的彎曲疲勞強(qiáng)度極限FE1=500Mpa12; 2)取彎曲疲勞壽命系數(shù)KFN1=0.8512;3)計(jì)算彎曲疲勞許用應(yīng)力。取彎曲疲勞安全系數(shù)S=1.3,得12 (21)4)計(jì)算載荷系數(shù)K。K= KAKVKFKF=11.0311.281.318a) 查取齒形系數(shù)12。得YF1=2.80。b) 查取應(yīng)力校正系數(shù)12。查的Ys1=1.55。 5)計(jì)算齒輪的YFYs/F并加以比較。 (22)大齒輪的數(shù)值大( 2 ) 設(shè)計(jì)計(jì)算 (23)對(duì)比計(jì)算結(jié)果,由接觸疲勞強(qiáng)度計(jì)算的模數(shù)m大于由齒根彎曲疲勞強(qiáng)度計(jì)算模數(shù);由于齒輪模數(shù)m的大小主要取決于彎曲強(qiáng)度所決定的承載能力,而齒面接觸疲勞強(qiáng)度所決定的承載能力,僅與齒輪直徑(即模數(shù)與齒數(shù)的乘積)有關(guān)15??扇澢鷱?qiáng)度算得的模數(shù)2.05。并就近圓整為標(biāo)準(zhǔn)值m=2mm,按接觸強(qiáng)度算得的分度圓直徑d1=31.35mm,算出小齒輪齒數(shù)Z1= d1/m=31.35/2=15,取166.2.4幾何尺寸計(jì)算(1) 計(jì)算分度圓直徑d1=z1m=162mm=32mm(2) 計(jì)算中心距a=( d1+ d2)/2=56mm(3)計(jì)算齒輪寬度b=dd1=0.640=24mm 取B2 =28mm,B1 =33mm6.3壓輥和切面棍受力分析6.3.1結(jié)構(gòu)設(shè)計(jì)初步計(jì)算壓輥軸的結(jié)構(gòu)尺寸:壓輥軸為實(shí)心軸,按鈕轉(zhuǎn)強(qiáng)度15: d=A (24)A=103126 取A=110P=0.55Kw n=750rpm計(jì)算得:d=9.92mm按扭轉(zhuǎn)剛度:d=B (25)取B=109,得:d=17.94mm,取整d=18mm。6.3.2壓輥受力分析及校核壓輥受力分析時(shí),略去壓輥齒形及斜度的影響;略去壓輥支承處的摩擦阻力;略去皮帶傳動(dòng)的損失;略去壓延傳動(dòng)中皮帶輪的作用力16。以壓輥受力分析為例;(1) 輥壓力:P=qL=121030.35=4200N (26)(2) 同步齒形帶張力產(chǎn)生的力矩:MN=F=12.12(Nm) (27)(3) 通過物料對(duì)壓輥的摩擦力(均布輥長上): F1=P=42000.43=1806N (28)(4) 電機(jī)輸入扭矩M=9549=9549=66.59Nm; (29)(5) 皮輪作用在輥軸上的力Q=1553N;(6) 壓輥皮帶輪的扭矩 M1=36.68Nm從軸的結(jié)構(gòu)圖以及彎矩圖中可以看出軸的危險(xiǎn)截面17。 圖2 載荷分析圖 Fig 2 Load were載荷水平面H垂直面V進(jìn)行校核時(shí),通常只校核軸上承受最大彎矩和扭矩的截面的強(qiáng)度12,以及軸單向旋轉(zhuǎn),扭轉(zhuǎn)切應(yīng)力為脈動(dòng)循環(huán)應(yīng)力,取=0.6,軸的計(jì)算應(yīng)力 ca=MPa=5.22MPa (30)前面選定軸的材料為45號(hào)鋼,調(diào)質(zhì)處理,查得-1=60 MPa12。因此ca -1,故安全6.4 壓輥軸承的選擇計(jì)算6.4.1壓輥軸承的選擇根據(jù)分析,采用雙向向心球面柱輥?zhàn)虞S承,因?yàn)槊鏃l機(jī)沖擊載荷很小,又考慮到減小軸承座的直徑,所以采用輕寬系列的軸承18。由于采用了緊定錐套,所以軸承內(nèi)經(jīng)d=45mm,外徑D=85mm,軸承型號(hào)為22209C/W33的雙列向心球面圓柱棍子軸承12。6.4.2軸承校核設(shè)計(jì)壓輥和切面棍共有四個(gè)軸承,只要校核受力最大的一個(gè)就可以了19。根據(jù)對(duì)軸的受力分析,只需對(duì)壓輥A端的軸承進(jìn)行校核。(1) 計(jì)算動(dòng)載荷C: Fr=RA=7150NP=fpFr= fpRA因無沖擊, fp取1.2,e=0.2714。雙面向心球面圓柱滾子軸承 C0=97.2KN=0e, c=n=250r/min,=10/3Lh=500020000,因連續(xù)工作,故取最大值。P=1.22595=8580Nc=8580=47492NC0=97.5KN故選用的軸承都合格。(2) 壽面校核20Lh=122573h按一年300天工作,一天工作10個(gè)小時(shí)。L=40.9(年)所以軸承全用22209C/W33型,非常合理。7 結(jié)論本機(jī)的設(shè)計(jì)綜合了國內(nèi)外先進(jìn)面條機(jī)的優(yōu)點(diǎn),并對(duì)某些結(jié)構(gòu)進(jìn)行了改進(jìn),使其更加完善,可以說是一臺(tái)先進(jìn)的小型面條壓延機(jī)。本機(jī)的結(jié)構(gòu)簡單、緊湊,實(shí)用性強(qiáng),裝拆檢修方便,而且各個(gè)結(jié)構(gòu)的尺寸都比較小。其壓延性能和切面性能都比較好,并便于操作人觀察和及時(shí)發(fā)現(xiàn)問題,拆換壓輥和切面刀也方便。面條機(jī)上的大皮帶輪和同步帶輪均采用脹緊連結(jié),裝拆方便。小型面條壓延機(jī)采用圓弧雙面同步齒形帶,其結(jié)構(gòu)簡單、緊湊;趕得上國際先進(jìn)水平。參考文獻(xiàn)1 阮競蘭.武文斌.糧食機(jī)械原理及應(yīng)用技術(shù)M.北京:中國輕工業(yè)出版社,2006:45. 2 鄭惠強(qiáng).張氫.機(jī)械結(jié)構(gòu)設(shè)計(jì)M.北京:同濟(jì)大學(xué)出版社,2009:55-56. 3 郭禎祥.小麥加工技術(shù)M.北京:化學(xué)工業(yè)出版社,2003:187.4 羅宗澤.羅圣國.機(jī)械設(shè)計(jì)課程設(shè)計(jì)手冊M.北京:高等教育出版社,2006:35-83. 5 趙如福.金屬機(jī)械加工工藝人員手冊M.上海:上??茖W(xué)技術(shù)出版公司,2008:51-52. 6 齒輪手冊編委會(huì).齒輪手冊.北京:機(jī)械工業(yè)出版社,1990:35-100.7 孫桓.陳作模,葛文杰.機(jī)械原理M.北京:高等教育出版社,2006:135-169. 8 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House,1985:55.17 張淑娟,全臘珍.畫法幾何與機(jī)械制圖M.北京:中國農(nóng)業(yè)出版社,2007:1-25.18 Mechanical Drive(Reference Issue).Machine Design.52(14),1980:103.19 周開勤.機(jī)械零件手冊.4版.北京:高等教育出版社,1991:69.20 趙如福.機(jī)械加工工藝手冊M.上海:科學(xué)技術(shù)出版社,2007:10.致 謝經(jīng)過半年的忙碌和工作,本次畢業(yè)設(shè)計(jì)已經(jīng)接近尾聲,作為一個(gè)本科生的畢業(yè)設(shè)計(jì),由于經(jīng)驗(yàn)的匱乏,難免有許多考慮不周全的地方,如果沒有導(dǎo)師的督促指導(dǎo),以及一起工作的同學(xué)們的支持,想要完成這個(gè)設(shè)計(jì)是難以想象的。 在這里首先要感謝我的導(dǎo)師高老師。高老師平日里工作繁多,但在我做畢業(yè)設(shè)計(jì)的每個(gè)階段,從查閱資料到設(shè)計(jì)草案的確定和修改,中期檢查,后期詳細(xì)設(shè)計(jì),裝配草圖等整個(gè)過程中都給予了我悉心的指導(dǎo)。我的設(shè)計(jì)較為復(fù)雜煩瑣,但是高老師仍然細(xì)心地糾正圖紙中的錯(cuò)誤。除了敬佩高老師的專業(yè)水平外,豐富的專業(yè)知識(shí)、嚴(yán)謹(jǐn)求實(shí)的治學(xué)態(tài)度、治學(xué)嚴(yán)謹(jǐn)和科學(xué)研究的精神對(duì)教學(xué)科研事業(yè)孜孜不倦的追求以及高度的敬業(yè)愛崗精神,時(shí)刻鞭策著我,使我受益頗深。是我永遠(yuǎn)學(xué)習(xí)的榜樣,并將積極影響我今后的學(xué)習(xí)和工作。 其次要感謝我的同學(xué)對(duì)我無私的幫助,特別是在軟件的使用方面,正因?yàn)槿绱宋也拍茼樌耐瓿稍O(shè)計(jì),我要感謝我的母校湖南農(nóng)業(yè)大學(xué),是母校給我們提供了一個(gè)優(yōu)良的學(xué)習(xí)環(huán)境。在論文工作期間,還得到許多同學(xué)的大力支持與幫助。給予我很多的建議,使我的試驗(yàn)工作非常順利的進(jìn)行。我的深刻教導(dǎo),都會(huì)以老師為心中的一個(gè)基點(diǎn),我想這樣無論在什么時(shí)候,也無論在什么地方,我都不會(huì)迷失自我。很感謝老師賦予我們的這生動(dòng)的一課我還要感謝那些一位優(yōu)秀的老師不僅要有淵博的學(xué)識(shí),而且還要有和藹可親的一面,處處為學(xué)生著想,處處給同學(xué)方便,但從不計(jì)較個(gè)人的得與失,我想我們的導(dǎo)師就是屬于這樣的人。用這些短短的文字來表達(dá)我對(duì)老師的感激和致謝。我希望我以后無論在崗位,都會(huì)清楚記得老師在這段時(shí)間給曾給我授過課的每一位老師,是你們教會(huì)我專業(yè)知識(shí)。在此,我再說一次謝謝!謝謝大家!Int J Adv Manuf Technol (2005) 25: 551559DOI 10.1007/s00170-003-1843-3ORIGINAL ARTICLES.H. Masood B. Abbas E. Shayan A. KaraAn investigation into design and manufacturing of mechanical conveyors systemsfor food processingReceived: 29 March 2003 / Accepted: 21 June 2003 / Published online: 23 June 2004 Springer-Verlag London Limited 2004Abstract This paper presents the results of a research investi-gation undertaken to develop methodologies and techniques thatwill reduce the cost and time of the design, manufacturing andassembly of mechanical conveyor systems used in the food andbeverage industry. The improved methodology for design andproduction of conveyor components is based on the minimisa-tion of materials, parts and costs, using the rules of design formanufacture and design for assembly. Results obtained on a testconveyor system verify the benets of using the improved tech-niques. The overall material cost was reduced by 19% and theoverall assembly cost was reduced by 20% compared to conven-tional methods.Keywords Assembly Cost reduction Design DFA DFM Mechanical conveyor1 IntroductionConveyor systems used in the food and beverage industry arehighly automated custom made structures consisting of a largenumber of parts and designed to carry products such as foodcartons, drink bottles and cans in fast production and assemblylines. Most of the processing and packaging of food and drink in-volve continuous operations where cartons, bottles or cans are re-quired to move at a controlled speed for lling or assembly oper-ations. Their operations require highly efcient and reliable me-chanical conveyors, which range from overhead types to oor-mounted types of chain, roller or belt driven conveyor systems.In recent years, immense pressure from clients for low costbut efcient mechanical conveyor systems has pushed con-veyor manufacturers to review their current design and assemblymethods and look at an alternative means to manufacture moreeconomical and reliable conveyors for their clients. At present,S.H. Masood (u) B. Abbas E. Shayan A. KaraIndustrial Research Institute Swinburne,Swinburne University of Technology,Hawthorn, Melbourne 3122, AustraliaE-mail: smasoodswin.edu.aumost material handling devices, both hardware and software, arehighly specialised, inexible and costly to congure, install andmaintain 1. Conveyors are xed in terms of their locations andthe conveyor belts according to their synchronised speeds, mak-ing any changeover of the conveyor system very difcult and ex-pensive. In todays radically changing industrial markets, there isa need to implement a new manufacturing strategy, a new systemoperational concept and a new system control software and hard-ware development concept, that can be applied to the design ofa new generation of open, exible material handling systems 2.Ho and Ranky 3 proposed a new modular and recongurable2D and 3D conveyor system, which encompasses an open re-congurable software architecture based on the CIM-OSA (opensystem architecture) model. It is noted that the research in thearea of improvement of conveyor systems used in beverage in-dustry is very limited. Most of the published research is directedtowards improving the operations of conveyor systems and inte-gration of system to highly sophisticated software and hardware.This paper presents a research investigation aimed at im-proving the current techniques and practices used in the de-sign, manufacturing and assembly of oor mounted type chaindriven mechanical conveyors in order to reduce the manufactur-ing lead time and cost for such conveyors. Applying the con-cept of concurrent engineering and the principles of design formanufacturing and design for assembly 4, 5, several criticalconveyor parts were investigated for their functionality, materialsuitability, strength criterion, cost and ease of assembly in theoverall conveyor system. The critical parts were modied andredesigned with new shape and geometry, and some with newmaterials. The improved design methods and the functionality ofnew conveyor parts were veried and tested on a new test con-veyor system designed, manufactured and assembled using thenew improved parts.2 Design for manufacturing and assembly (DFMA)In recent years, research in the area of design for manufacturingand assembly has become very useful for industries that are con-552sidering improving their facilities and manufacturing methodol-ogy. However, there has not been enough work done in the areaof design for conveyor components, especially related to the is-sue of increasing numbers of drawing data and re-engineeringof the process of conveyor design based on traditional methods.Emphasise standardisationUse the simplest possible operationsUse operations of known capabilityMinimise setups and interventionsUndertake engineering changes in batchesA vast amount of papers have been published that have investi-gated issues related to DFMA and applied to various methodolo-gies to achieve results that proved economical, efcient and costeffective for the companies under investigation.The main classications of DFMA knowledge can be iden-tied as (1) General guidelines, (2) Company-specic best prac-tice or (3) Process and or resource-specic constraints. Generalguidelines refer to generally applicable rules-of-thumb, relat-ing to a manufacturing domain of which the designer shouldbe aware. The following list has been compiled for DFMguidelines 6.These design guidelines should be thought of as “optimalsuggestions”. They typically will result in a high-quality, low-cost, and manufacturable design. Occasionally compromisesmust be made, of course. In these cases, if a guideline goesagainst a marketing or performance requirement, the next bestalternative should be selected 7.Company-specic best practice refers to the in-house designrules a company develops, usually over a long period of time, andwhich the designer is expected to adhere to. These design rulesare identied by the company as contributing to improved qualityand efciency by recognising the overall relationships betweenDesign for a minimum number of partsDevelop a modular designMinimise part variationsDesign parts to be multifunctionalDesign parts for multiuseDesign parts for ease of fabricationAvoid separate fastenersMaximise compliance: design for ease of assemblyMinimise handling: design for handling presentationEvaluate assembly methodsEliminate adjustmentsAvoid exible components: they are difcult to handleUse parts of known capabilityAllow for maximum intolerance of partsUse known and proven vendors and suppliersUse parts at derated values with no marginal overstressMinimise subassembliesparticular processes and design decisions. Companies use suchguidelines as part of the training given to designers of productsrequiring signicant amounts of manual assembly or mainte-nance. Note that most of the methodologies are good at eitherbeing quick and easy to start or being more formal and quanti-tative. For example, guidelines by Boothroyd and Dewhurst 8on DFA are considered as being quantitative and systematic.Whereas the DFM guidelines, which are merely rules of thumbderived from experienced professionals, are more qualitative andless formal 9.3 Conventional conveyor system designDesign and manufacturing of conveyor systems is a very com-plex and time-consuming process. As every conveyor system isa custom-made product, each project varies from every otherproject in terms of size, product and layout. The system designFig. 1. Layout of conveyor sys-tem for labelling plasic bottles553is based on client requirements and product specications. More-over, the system layout has to t in the space provided by thecompany. The process of designing a layout for a conveyor sys-tem involve revisions and could take from days to months or insome instances years. One with the minimum cost and maximumclient suitability is most likely to get approval.Figure 1 shows a schematic layout of a typical conveyorsystem installed in a production line used for labelling ofplastic bottles. Different sections of the conveyor system areidentied by specic technical names, which are commonlyused in similar industrial application. The “singlizer” sec-tion enables the product to form into one lane from multiplelanes. The “slowdown table” reduces the speed of productonce it exits from ller, labeller, etc. The “mass ow” sec-tion is used to keep up with high-speed process, e.g., ller,labeller, etc. The “transfer table” transfers the direction of prod-uct ow. The purpose of these different conveyor sections isthus to control the product ow through different processingmachines.A typical mechanical conveyor system used in food and bev-erage applications consists of over two hundred mechanical andelectrical parts depending on the size of the system. Some ofthe common but essential components that could be standard-ised and accumulated into families of the conveyor system areside frames, spacer bars, end plates, cover plates, inside bendplates, outside bend plates, bend tracks and shafts (drive, tail andslave). The size and quantity of these parts vary according to thelength of conveyor sections and number of tracks correspond-ing to the width and types of chains required. The problems andshortcomings in the current design, manufacturing and assemblyof mechanical conveyors are varied, but include:4 Areas of improvementIn order to identify the areas of cost reduction in material andlabour, a cost analysis of all main conveyor parts was conductedto estimate the percentage of cost of each part in relation to thetotal cost of all such parts. The purpose of this analysis was toidentify the critical parts, which are mainly responsible for in-creasing the cost of the conveyor and thereby investigate meansfor reducing the cost of such parts.Table 1 shows the cost analysis of a 50-section conveyor sys-tem. The analysis reveals that 12 out of 15 parts constitute 79%of the total material cost of the conveyor system, where furtherimprovements in design to reduce the cost is possible. Out ofthese, seven parts were identied as critical parts (shown by anasterisk in Table 1) constituting maximum number of compo-nents in quantity and comprising over 71% of overall materialcost. Among these, three components (leg set, side frame andsupport channel) were found to account for 50% of the totalconveyor material cost. A detailed analysis of each of these 12parts was carried out considering the principles of concurrent en-gineering, design for manufacture and design for assembly, anda new improved design was developed for each case 10. De-tails of design improvement of some selected major componentare presented below.5 Redesign of leg set assemblyIn a conveyor system, the legs are mounted on the side frame tokeep the entire conveyor system off the oor. The existing designof conveyor legs work, but they are costly to manufacture, theyOver design of some partsHigh cost of some componentsLong hours involved in assembly/maintenanceUse of non-standard partshave stability problems, and cause delays in deliveries. The delayis usually caused by some of the parts not arriving from over-seas suppliers on time. The most critical specications requiredfor the conveyor legs are:Table 1. Conveyor critical parts based on parts cost analysisProduct descriptionLeg setSide frameSupport channelBend tracksRt. roller shaftTail shaftSpacer barSupport wear stripSupport side wear stripEnd plateCover plateBend platesTorque arm bracketSlot coverInside bend plateQty68804008139391354001323939818978Material usedPlastic leg + SS tube2.5 mm SSC channel SSPlastic20 dia. SS shaft35 dia. Stainless steel50X50X6 SS40 10 mm plasticPlastic2.5 mm/SS1.6 mm S/S2.5 mm/SS6 mm S/S plateStainless steel2.5 mm/SSCost (%)20.2216.0715.0014.366.706.275.435.363.011.881.571.291.210.970.66Improvement possible (Yes/No)YesYesYesNoYesNoYesYesYesYesNoYesYesYesYesTotalCriticalparts100.00554Strength to carry conveyor loadStabilityEase of assemblyEase of exibility (for adjusting height)1 and part 3 in Fig. 2) was not rigid enough. The connectionsfor these parts are only a single 6 mm bolt. At times, when theconveyor system was carrying full product loads, it was observedthat the conveyor legs were unstable and caused mechanical vi-bration. One of the main reasons for this was due to a single boltFigure 2 indicates all the parts for the existing design ofthe conveyor leg. The indicated numbers are the part numbersdescribed in Table 2, which also shows a breakdown of cost an-alysis complete with the labour time required to assemble a com-plete set of legs. The existing leg setup consists of plastic legbrackets ordered from overseas, stainless steel leg tubes, whichare cut into specied sizes, leg tube plastic adjustments, whichare clipped onto the leg tube at the bottom as shown in Fig. 2.Lugs, which are cut in square sizes, drilled and welded to the legtube to bolt the angle cross bracing and backing plate to supportleg brackets bolts. The # of parts in Table 2 signies the numberof components in each part number and the quantity is the con-sumption of each part in the leg design. Companies have usedthis design for many years but one of the common complaintsreported by the clients was of the instability of legs.From an initial investigation, it became clear that the connec-tion between the stainless steel tube and plastic legs bracket (partFig. 2. Existing leg design assembly with partnames shown in Table 1Table 2. Cost analysis for old leg design assemblyconnection at each end of the lugs in part 3 and part 7. The sta-bility of the conveyor is considered critical matter and requiresrectication immediately to satisfy customer expectations.Considering the problems of the existing conveyor leg de-sign and the clients preferences, a new design for the conveyorleg was developed. Generally the stability and the strength ofthe legs were considered as the primary criteria for improve-ment in the new design proposal but other considerations werethe simplicity of design, minimisation of overseas parts and easeof assembly at the point of commissioning. Figure 3 shows, thenew design of the conveyors leg assembly, and Table 3 gives adescription and the cost of each part.Figure 3 shows that the new design consists of only ve mainparts for the conveyors leg compared to eight main parts in theold design. In the old design, the plastic leg bracket, the legtube plastic adjustment and the leg tube were the most expensiveitems accounting for 72% of the cost of leg assembly. In the newPart no.15, 647238Part descriptionPlastic leg bracketLeg tube plastic adjustmentLugAngle cross bracingBacking plateLeg tubeBolts# of parts2421226Qty2221226Cost$ 30.00$ 28.00$ 4.00$ 5.00$ 4.00$ 25.00$ 3.00SourceOverseasOverseasIn-houseIn-houseIn-houseIn-houseIn-houseTotal assembly cost (welding)$ 15.00In-houseTotal1917$ 114.00555Fig. 3. New design for leg assembly with partnames in Table 3Table 3. Cost analysis for new design leg assemblyPart no.13452Part descriptionStainless steel angle (50 50 3 mm)Leg plastic adjustmentCross brassingBoltsBacking plate# of parts22182Qty22142Cost$ 24.00$ 10.00$ 7.00$ 4.00$ 4.00SourceIn-houseOverseasIn-houseIn-houseIn-houseTotal assembly cost$ 10.00In-houseTotaldesign, those parts have been replaced by a stainless steel angleand a new plastic leg adjustment reducing the cost of leg assem-bly by almost 50%. Thus the total numbers of parts in the leghave been reduced from 19 to 15 and the total cost per leg setup1511Size of side frame (depth)Strength of the materialEase for assemblyEase for manufacturing$ 59.00has been reduced by $ 55 in the new design.The new conveyor leg design, when tested, was found to bemore secure and stable than the old design. The elimination ofpart number 1 and 5 from old conveyor design has made the newdesign more stable and rigid. In addition, the width of the crossbracing has also been increased with two bolts mount instead ofone in old design. This has provided the entire conveyor leg setupan additional strength.6 Redesign of the side framesThe side frame is the primary support of a conveyor systemthat provides physical strength to conveyors and almost all theparts are mounted on it. The side frame is also expected to havea rigid strength to provide support to all the loads carried onthe conveyor. It also accommodates all the associated conveyorcomponents for the assembly. The critical considerations of sideframe design are:Figure 4 shows the side frame dimension and parameters.The side frame used in existing design appears to be of rea-sonable depth in size (dimension H in Fig. 4). From the initialinvestigation, it was found that the distance between spacer barholes and return shaft (dimensions G and F in Fig. 4) could bereduced, as there was some unnecessary gap between those twocomponents. The important point to check before redening thedesign parameters was to make sure that after bringing those twocloser, the return chains would not catch the spacer bar while theconveyor is running. The model of the new side frame design wasdrawn on CAD to ensure all the specications are sound and theparts are placed in the position to check the clearances and thets. Using the principle of design for manufacturing the new sideframe design was made symmetrical so that it applies to all typesof side frames. This change is expected to reduce the size of sideframe signicantly for all sizes of chains.Table 4 shows a comparison of dimensions in the old designand the new design of side frames for the same chain type. It556Fig. 4. Side frame dimensionsTable 4. New and old side frame dimension parametersOld designChain type3.25 LF/SSSTR/LBP/MAGA31B92C71D196E65F105G211H241I136J58K85L196TAB2283621875696202232127New designChain type3.25 LF/SSSTR/LBP/MAG/TABA31B100C73D173E67F107G167H199I92J58K85L152is noted that the overall size (depth) of the conveyor has beenreduced from 241 mm to 199 mm (dimension H), which givesa saving of 42 mm of stainless steel on every side frame manu-factured. Thus, from a stainless steel sheet 1500 3000 mm, theold design parameter
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