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塑料注塑成型模塑的自動化裝配組件
摘要 一個注射成型機是一個包含了產(chǎn)品生產(chǎn)部分和與之相關(guān)的非生產(chǎn)部分自動化裝配組件,本篇論文論述了注射成型模塑的兩個關(guān)鍵的裝配組件。顧名思義,它們是由計算機設(shè)計出來,并且決定非生產(chǎn)部件在裝配組件中的位置和取向,這種從表官現(xiàn)象和客觀取向所設(shè)計的組件,是意欲表現(xiàn)出注射成型裝配組件的。據(jù)此,這種設(shè)計允許設(shè)計者忽略一個模塑制件的細節(jié),直接描述只見的那一部分的重要及其原因,因此它給設(shè)計者提供了一次設(shè)計裝配的機會,一個系統(tǒng)的簡單幾何方法通常意欲在相同的條件下推斷出一個客觀配件在裝配組件中的位置,而在這種粗略設(shè)計和系統(tǒng)簡單的幾何方法的基礎(chǔ)上,模塑自動化裝配組件被進一步研究。
關(guān)鍵詞:模塑裝配組件,表觀現(xiàn)象,注射成型,客觀取向,
1 簡介
注射成型是生產(chǎn)塑料注塑模塑的重要過程。它所必需的設(shè)備包含了兩個關(guān)鍵的部分:注射成型機和注射模具。今天所用的注射模具機就是所謂的萬能機。不同尺寸的塑件通過它而被生產(chǎn)出來,但是這些尺寸被限制在一定的范圍內(nèi)。這些模具是根據(jù)塑件設(shè)計出來的。對于不同的模具形狀就需要有不同的模具布局與之對應(yīng),一個注射成型模具的最基本的任務(wù)就是將熔化了的材料生產(chǎn)成不同形狀的制品,這個任務(wù)是由包含了陽模、型腔、嵌件、一級頂出機構(gòu)的型腔系統(tǒng)完成的。一個型腔系統(tǒng)的幾何形狀和尺寸是由塑件直接決定的,因此一個型腔所有的構(gòu)件都叫做產(chǎn)品生產(chǎn)部分(產(chǎn)品就是指塑件,部件就是指注射模具的構(gòu)件,另外產(chǎn)品成型是最基本任務(wù),一個注射成型機需要完成很多任務(wù),例如,分配,熔料,冷卻融化物注射塑件,功能部件所完成的這些任務(wù)與注射成型不同結(jié)構(gòu)和尺寸的塑件非常相似,他們的結(jié)構(gòu)和幾何形狀與塑件成型模具不相關(guān),但是他們的尺寸可以根據(jù)塑件的尺寸而不斷改變,因此我們可以從中得到結(jié)論,一個注射成型機包含了塑件生產(chǎn)部分和與之相關(guān)的非生產(chǎn)部分的自動化裝配組件。)
生產(chǎn)部分的設(shè)計師在總結(jié)了所生產(chǎn)塑件的幾何性能而得到的,在最幾年CAD/CAM技術(shù)已經(jīng)被成功的應(yīng)用在幫助模具設(shè)計者設(shè)計的塑件生產(chǎn)部分,一個塑件的自動化的生產(chǎn)受到了越來越大的重視,然而幾乎沒有相關(guān)的作品被刊登出來,盡管他同生產(chǎn)部分的設(shè)計營養(yǎng)重要,當應(yīng)用CAD系統(tǒng)設(shè)計產(chǎn)品生產(chǎn)部分和所有的注射成型裝配組件時模具工業(yè)免領(lǐng)著以下兩種困難,第一,在一個模具系統(tǒng)中往往有一百多個廠品生產(chǎn)部分,并且這些部分之間互相聯(lián)系互相制約,對于模具設(shè)計者在一個裝配組件取向和安排這些組件時非常浪費時間的,另外當模具設(shè)計者大部分的時間用來思考實際存在的客觀部件的選用原則,例如,螺絲、底座,系統(tǒng)應(yīng)用了一個完全不同的客觀無體幾何水平,結(jié)果高水平的客觀取向想法不得不翻譯成低水平的CAD系統(tǒng),例如,線、平面、塊,因此,發(fā)展一個模塑自動化裝配組件顯得非常重要,在這篇論文中我們論述了模塑自動化組建的兩個關(guān)鍵因素。在計算機中涉及一個模具生產(chǎn)部分和一個模具生產(chǎn)裝配組件,并且決定組成部分在一個裝配組件中的位置和客觀取向。
這篇論文簡要地描述了模塑裝配組件的相關(guān)研究并且論述了注射成型模塑一個裝配組件的一個不可缺少的設(shè)計,一個簡單的幾何方法被用來決定一個部件在模具裝配組件中的位置和客觀取向,介紹了注塑成型模塑的自動化裝配組件的一個例子。
2 相關(guān)的研究
關(guān)于模塑注塑這個課題,已經(jīng)在很多領(lǐng)域被廣泛研究,例如,動力機體學(xué),人工智能,和模塑幾何性能學(xué)。湯木編輯了一本模塑組件的書,他在其中報道了許多關(guān)于模塑裝配組件的專業(yè)術(shù)語,再這些專業(yè)術(shù)語中,一些組件被比喻成鼻子。一些感觀機體被弧線連接起來。然而,這些感官機體并沒有重合在一起。這就嚴重的影響了改性過程。例如,一個幾何裝配移動所有與之相關(guān)的部件沒有相應(yīng)的移動。邁克發(fā)明了一種支持包含了最基本信息的數(shù)據(jù)庫的有等級差別的裝配組建系統(tǒng),這些最基本的信息包含了兩個部件之間的墊片,這些改型基體之際取決于與之相關(guān)的實體,但是這些有等級模具差別的模具組建僅僅代表了這些模具中的一部分。
自動化取向指代的是一些組件在裝配組件中的布局,這就意味著模具設(shè)計者可以避免直接定義這些改性機體,另外,一個部件位置的改變,將會隨著與之相連的任意一個部件的改動而變動,存在著三種技術(shù)推斷計算一個部件在一個裝配組件中的位置和取向,這三種技術(shù)分別是數(shù)字迭代技術(shù),系統(tǒng)代數(shù)技術(shù),和系統(tǒng)幾何技術(shù),邁克指出數(shù)字迭代技術(shù)使用計算存在與空間關(guān)系中任何一個部件的位置和取向,他們的方法包含了三個步驟,產(chǎn)生約束等式,減少約束等式的數(shù)量 和解決這些等式,存在著16個等式與條件不符,18個等式符合條件,6個對任何機體合適的等式,另外2個附加等式符合旋轉(zhuǎn)部分,通常這些等式的數(shù)量超過了可以利用的等式,因此這就需要一種技術(shù)篩選到不需要的公式,牛頓力學(xué)公式被用來解決這個問題。這種技術(shù)有兩個缺點:第一、這種方法嚴重的依賴這前面的方法;第二、數(shù)字迭代技術(shù)不能區(qū)別不同的數(shù)字基礎(chǔ),因此,他很可能緊急用在空間關(guān)系的問題上,這個領(lǐng)域不是數(shù)學(xué)方面的空白,但是在理論上還很模糊。
愛波和波斯提出了一種方法用來計算裝配組建中的每一個部件在兩個部件之間旋轉(zhuǎn)和改觀方面所需要的空間關(guān)系,每一個部件存在著關(guān)于空間關(guān)系的6個轉(zhuǎn)變(3個移動和三個旋轉(zhuǎn))。這種技術(shù)需要大量的計算機程序應(yīng)用和數(shù)據(jù)計算,同樣他不能用來解決在任何時間出現(xiàn)的所用問題,尤其是當一個等式不能在程序中被重寫的時候。
開若發(fā)明了一種能夠決定一個剛性物體的位置和趨向的集合方法,這種方法用來解決一系列的幾何約束.這種幾何方法是通過產(chǎn)生一系列畝任何約束的系統(tǒng)方法來解決問題的.這就導(dǎo)致了DOF數(shù)量的下降,開若利用了一種解決問題的技術(shù)稱作"上帝"這是一個包含了一個點,兩條標準角形軸線的技術(shù).7條約束現(xiàn)在圖表中被定義出來,關(guān)于這個圖表顯示了約束之間的關(guān)系.經(jīng)試驗分析后確定一個幾何物體的最終布局,一步一步的在每一部解決客觀物體的布局,分析的結(jié)果決定哪一種方法將會滿足一個物體同時解除約束,這考慮到不見自由運行的程度,然后得出哪一種行為約束了部件的自由運行,在每異步結(jié)束的時候一種正確的方法被應(yīng)用到確定裝配組建技術(shù)的計劃中.根據(jù)賽若和褥子開若的方法在發(fā)展莫塑裝配組建技術(shù)中起到了重大的作用,這種系統(tǒng)的幾何方法可以解決所有的約束條件,并且與數(shù)字迭代技術(shù)相比他擁有跟吸引人的數(shù)字計算技術(shù),但是要應(yīng)用這種方法就需要大量的應(yīng)用程序。
盡管和多的設(shè)計者積極的投入到莫塑裝配組建技術(shù)上,但是關(guān)于塑料注射成型莫塑裝配組建技術(shù)的成果很少被系統(tǒng)的報道.螺絲發(fā)明一種支持支持注射成型的設(shè)計系統(tǒng),這個系統(tǒng) 通過高水平的功能莫塑組建支持了注射成型莫塑技術(shù),因為其他人的技術(shù)僅僅是建立在AUTOCAD的基礎(chǔ)上,所以只能用寫簡單的塊和線框表示出來。
3 注射成型裝配組件的代表
注射成型模塑的自動化裝配組件的兩個關(guān)鍵技術(shù)是在計算機重將模塑裝配組件表示出來和決定部件的生產(chǎn)部分在裝配組件中的位置和取向,在這個階段我們可以利用客觀取祥和表管線向來代表注射成型的裝配組件。
在計算機中設(shè)計一個設(shè)計裝配組件,這個技術(shù)要求考慮到每一個部件的結(jié)構(gòu)和關(guān)系,這種設(shè)計必須支持所有的部件在裝配組件中的配合,所有部件間的改變關(guān)系和裝配組件作為一個整體的操作要求.另外,裝配組件的這種設(shè)計要求設(shè)計者在設(shè)計師必須滿足以下的要求:
1、到模具設(shè)計者考慮到實際存在的物體水平時就必須可以利用高水平的客觀技術(shù);
2、裝配組件的這種設(shè)計必須能夠正確的表現(xiàn)出自動生產(chǎn)過程的功能。
為了滿足這些要求一種具有表觀現(xiàn)象和客觀趨向的有等級差別的模具被應(yīng)用在注射成型技術(shù)中,一個裝配組件可以被分成很多集合裝配,這個集合裝配有包含了很多的構(gòu)件,因此有等級差別的模具能夠分成合適的代表兩個構(gòu)件之間的結(jié)構(gòu).一個等級差別的模具暗示了一個明確的裝配組件組,另外,一個等級差別的膜具能夠直接表現(xiàn)出一個構(gòu)件對另一個構(gòu)件的依賴。帶有表觀現(xiàn)象,要求設(shè)計者站在一個比實際應(yīng)用模具更高的水平線。幾何形狀是直接的有尺寸的,和有設(shè)計者能夠通過一系列參數(shù)直接定位的.然而,客觀趨向的模具設(shè)計者超出了這些細節(jié).另外,他同樣也可以使設(shè)計者由于幾何形狀之間的關(guān)系筆可觀趨向的模具設(shè)計者容易做出變動.沒有客觀取向設(shè)計者就要根據(jù)模具要求這的要求考慮到所有的幾何結(jié)構(gòu),因此,這就是設(shè)計的每一次改變直接根據(jù)模具要求這的改變而改變.另外,客觀取向的設(shè)計能夠給設(shè)計者提供更高水平的組件物體,例如,當模具設(shè)計者考慮到物體的真實水平時,如一個冷卻水孔相關(guān)的客觀表象在計算機中表現(xiàn)出來。
客觀取向模具設(shè)計是一個在考慮到現(xiàn)實事件中的模具技術(shù)的基礎(chǔ)上所應(yīng)用的一種新的方法,它的基礎(chǔ)是客觀物體,這個物體結(jié)合了數(shù)據(jù)結(jié)構(gòu)和性能客觀取向方法被用來理解問題和設(shè)計程序和數(shù)據(jù)庫,另外,客觀取向代表了裝配組件制造時單位客觀物體和總的組件的包含與被包含關(guān)系。
4 注射成型模塑的自動化裝配組件
許多注塑成型的裝配組件包含了生產(chǎn)部分合非生產(chǎn)部分, 生產(chǎn)部分單個組件的設(shè)計師在塑件幾何性能的基礎(chǔ)上得到的,通常產(chǎn)品生產(chǎn)部分應(yīng)由于高水平裝配組件相同的取向,通常這些構(gòu)件的位置和大小直接由設(shè)計者制定,對于產(chǎn)品省唱本的設(shè)計,傳統(tǒng)的方法是設(shè)計者從目錄冊中直接選擇所需要的模型,對這些選擇的產(chǎn)品生產(chǎn)部分建立幾何模型塊,然后再將這些塊加入到注射成型裝配組件中,這樣的設(shè)計及浪費時間與錯誤百出.在我們所應(yīng)用的新的設(shè)計方法中所有生產(chǎn)部分的設(shè)計數(shù)據(jù)實在裝配組件和客觀需要的基礎(chǔ)上得到的,這些數(shù)據(jù)不僅包含了幾何形狀和生產(chǎn)部分的尺寸,而且還包含了部件之間的空間約束.另外,許多有固定路線的部件例如:頂出和復(fù)位同樣也在這個數(shù)據(jù)庫中,因此,模具設(shè)計必須選則應(yīng)用這要求的模具生產(chǎn)部分而確定它的結(jié)構(gòu),然后計算機軟件會自動的確定出這些部分所要求的部件的取向和位置,然后再將這些部件加入到裝配組件中。
5 模具非標準的集合裝配
產(chǎn)品的生產(chǎn)部分可以進一步分為標準件合非標準件。這些非標準件使用與一系列,底座,導(dǎo)向機構(gòu)等裝配組件構(gòu)成的.除了確定產(chǎn)品的性狀外,一個模具還必須同時完成許多其他的功能,例如冷卻,注射產(chǎn)品,頂出,合模導(dǎo)向等,許多的模具應(yīng)有相似的性能因此這就導(dǎo)致了他們在結(jié)構(gòu)上的相似.抹具結(jié)構(gòu)設(shè)計中有許多標準要求,抹具非標準部件就是在這些標準組件的基礎(chǔ)上設(shè)計而成的。
根據(jù)裝配組件設(shè)計師的客觀取祥和表關(guān)現(xiàn)象,模具組件的表觀現(xiàn)象是非標準件首先應(yīng)該考慮到的,另外,客觀組件的設(shè)計受到組件構(gòu)件之間的相互關(guān)系和構(gòu)件的功能的限制,然后利用這些客觀組件一個有等級差比的集合裝配(模具的非標準部件)就形成了,這些模具的生產(chǎn)部分可以直接由目錄數(shù)據(jù)庫中的數(shù)據(jù)確定。
5.1 標準件的自動設(shè)計
一個標準件就是一個自動組件,在數(shù)據(jù)庫中他的空間約束是由墊片,平面直線和弧線確定的但是他與非標準件不同,標準件的位置和客觀取向并不確定.在設(shè)計時軟件通過簡單的公事之直接推斷出標準件地幾何形狀。
5.2裝配組件的復(fù)位設(shè)計
自動化設(shè)計的一個關(guān)鍵考慮因素是復(fù)位過程,復(fù)位是指嵌件在設(shè)計過程中流出的相應(yīng)的一定空間使之歸位的操作。當一個噴出設(shè)備加入到裝配組件中就要求在設(shè)計過程中留出相應(yīng)的孔,以便復(fù)位。
既然利用了客觀取向技術(shù),每一個裝配組件都可以有兩種表示方式:實際存在的和客觀設(shè)計。實際存在的物體空間時根據(jù)一個真實物體索要占據(jù)的空間決定的.無論何時一個客觀構(gòu)件被加入到裝配組件中,它的這是空間尺寸也同時被設(shè)計出來.復(fù)位操作技術(shù)是根據(jù)相關(guān)構(gòu)件的相互關(guān)系而設(shè)計的.另外由于實際空間和真實空間的關(guān)系,復(fù)位技術(shù)的設(shè)計也要根據(jù)實際物體做出相應(yīng)的改變.這種自動復(fù)位功能進一步說明了客觀取向的優(yōu)點。
5.3 系統(tǒng)應(yīng)用技術(shù)
在客觀取祥和表管線向基礎(chǔ)上設(shè)計而出的末塑自動化裝配組件技術(shù),已經(jīng)在美國國立大學(xué)被應(yīng)用在IMOLD領(lǐng)域內(nèi).這種繪圖技術(shù)提高了應(yīng)用程序的一個有效方式 ,通過這種技術(shù)使用這可以將其他部分加入到裝配組件中修改參數(shù)等.盡管繪圖技術(shù)提供了很好的功能但是上文提到的方法仍然被用來推斷構(gòu)件的布局,因為在設(shè)計過程中必須考慮到構(gòu)件自由運行的程度和檢查構(gòu)件在加入到裝配組件以前所需要的空間.這種系統(tǒng)的約簌條件和圖表約束是相輔相成的。
這種裝配組件使用IMOLD技術(shù)設(shè)計的,模具中的每一個非標準件被自動的安置在裝配組件。同樣,標準件例如螺釘也是被自動的加入到裝配組件中,復(fù)位技術(shù)也不例外。
6 結(jié)論
在表觀現(xiàn)象和客觀取向技術(shù)上所設(shè)計的具有等級差別的具有注射模塑裝配組件不僅僅提高了裝配組件設(shè)計技術(shù),而且同時提高了操作功能和幾何約束性,例如自由的程度,配合條件,鑲嵌和取向約束.因為,裝配組件設(shè)計的這一技術(shù)的提高,它的變動例如,裝配組件中某一構(gòu)件的尺寸變化可以在整體設(shè)計完以后在做出變動。裝配組件構(gòu)件的封鑄有以下兩個特點:1因為配合技術(shù)在裝配構(gòu)件中封鑄自動化裝配組件設(shè)計就可以被容易的利用;2裝配組件的封鑄使得裝配組件的設(shè)計在應(yīng)用過程中自動完成,例如復(fù)位和構(gòu)件檢查。提出了簡單的統(tǒng)計方法可以直接降低自動化設(shè)計過程中程序的難度。
編號
無錫太湖學(xué)院
畢業(yè)設(shè)計(論文)
相關(guān)資料
題目:基于Pro/E的便攜式手機充電器
上蓋注塑模設(shè)計
信機 系 機械工程及其自動化 專業(yè)
學(xué) 號: 0923225
學(xué)生姓名: 顧 亞 勵
指導(dǎo)教師: 曹亞玲 (職稱:講 師)
(職稱: )
2013年5月25日
目 錄
一、畢業(yè)設(shè)計(論文)開題報告
二、畢業(yè)設(shè)計(論文)外文資料翻譯及原文
三、學(xué)生“畢業(yè)論文(論文)計劃、進度、檢查及落實表”
四、實習(xí)鑒定表
無錫太湖學(xué)院
畢業(yè)設(shè)計(論文)
開題報告
題目:基于Pro/E的便攜式手機充電器
上蓋注塑模設(shè)計
信機 系 機械工程及自動化 專業(yè)
學(xué) 號: 0923225
學(xué)生姓名: 顧 亞 勵
指導(dǎo)教師: 曹亞玲 (職稱:講師 )
(職稱: )
2012年11月25日
課題來源
本課題來源于生活生產(chǎn)實際。
科學(xué)依據(jù)(包括課題的科學(xué)意義;國內(nèi)外研究概況、水平和發(fā)展趨勢;應(yīng)用前景等)
(1)課題科學(xué)意義
隨著現(xiàn)代制造技術(shù)的迅速發(fā)展、計算機技術(shù)的應(yīng)用,在玩具產(chǎn)業(yè)中模具已經(jīng)成為生產(chǎn)各種玩具不可缺少的重要工藝裝備。特別是在塑料產(chǎn)品的生產(chǎn)過程中,塑料模具的應(yīng)用及其廣泛,在各類模具中的地位也越來越突出,成為各類模具設(shè)計、制造與研究中最具有代表意義的模具之一。而注塑模具已經(jīng)成為制造塑料制造品的主要手段之一,且發(fā)展成為最有前景的模具之一。注射成型是當今市場上最常用、最具前景的塑料成型方法之一,因此注塑模具作為塑料模的一種,就具有很大的市場需求量。所以我選充電器注塑模具設(shè)計作為我畢業(yè)設(shè)計的課題。
本課題應(yīng)用性強,涉及的知識面與知識點較多,如注塑成型、模具設(shè)計、三維造型、運動仿真以及二維三維軟件的應(yīng)用。
(2) 研究狀況及其發(fā)展前景
近年來我國的模具技術(shù)有了很大的發(fā)展,在大型模具方面,已能生產(chǎn)大屏彩電注塑模具、大容量洗衣機全套塑料模具以及汽車保險杠和整體儀表板等塑料模具。機密塑料模具方面,已能生產(chǎn)照相機塑料件模具、多型腔小模數(shù)齒輪模具及塑封模具。
在成型工藝方面,多材質(zhì)塑料成行模、高效多色注塑模、鑲件互換結(jié)構(gòu)和抽芯脫模機構(gòu)的創(chuàng)新業(yè)取得了較大進展。氣體輔助注射成形技術(shù)的使用更趨成熟。熱流道模具開始推廣,有些單位還采用具有世界先進水平的高難度針閥式熱流道模具。
在制造方面,CAD/CAM/CAE技術(shù)的應(yīng)用上了一個新臺階,一些企業(yè)引進CAD/CAM系統(tǒng),并能支持CAE技術(shù)對成形過程進行分析。近年來我國自主開發(fā)的塑料膜CAD/CAM系統(tǒng)有了很大發(fā)展,如北航華正軟件工程研究所開發(fā)的CAXA系統(tǒng)、華中理工大學(xué)開發(fā)的注塑模HSC5.0系統(tǒng)及CAE軟件等。
優(yōu)化模具系統(tǒng)結(jié)構(gòu)設(shè)計和型件的CAD/CAE/CAM,并使之趨于智能化,提高型件成形加工工藝和模具標準化水平,提高模具制造精度與質(zhì)量,降低型件表面研磨、拋光作業(yè)量和縮短制造周期;研究、應(yīng)用針對各類模具型件所采用的高性能、易切削的專用材料,以提高模具使用性能;為適應(yīng)市場多樣化和個性化,應(yīng)用快速原型制造技術(shù)和快速制模技術(shù),以快速制造成塑料注塑模,縮短新產(chǎn)品試制周期。這些是未來5~20年注塑模具生產(chǎn)技術(shù)的總體發(fā)展趨勢,具體表現(xiàn)在以下幾個方面:
1.提高大型、精密、復(fù)雜、長壽命模具的設(shè)計水平及比例。這是由于塑料模成型的制品日漸大型化、復(fù)雜化和高精度要求以及因高生產(chǎn)率要求而發(fā)展的一模多腔所致。
2.在塑料模設(shè)計制造中全面推廣應(yīng)用CAD/CAM/CAE技術(shù)。CAD/CAM軟件的智能化程度將逐步提高;塑料制件及模具的3D設(shè)計與成型過程的3D分析將在我國塑料模具工業(yè)中發(fā)揮越來越重要的作用。
3.推廣應(yīng)用熱流道技術(shù)、氣輔注射成型技術(shù)和高壓注射成型技術(shù)。采用熱流道技術(shù)的模具可提高制件的生產(chǎn)率和質(zhì)量,并能大幅度節(jié)省塑料制件的原材料和節(jié)約能源,所以廣泛應(yīng)用這項技術(shù)是塑料模具的一大變革。制訂熱流道元器件的國家標準,積極生產(chǎn)價廉高質(zhì)量的元器件,是發(fā)展熱流道模具的關(guān)鍵。氣體輔助注射成型可在保證產(chǎn)品質(zhì)量的前提下,大幅度降低成本。氣體輔助注射成型比傳統(tǒng)的普通注射工藝有更多的工藝參數(shù)需要確定和控制,而且常用于較復(fù)雜的大型制品,模具設(shè)計和控制的難度較大,因此,開發(fā)氣體輔助成型流動分析軟件,顯得十分重要。另一方面為了確保塑料件精度,繼續(xù)研究開發(fā)高壓注射成型工藝與模具也非常重要。
4.開發(fā)新的成型工藝和快速經(jīng)濟模具。以適應(yīng)多品種、少批量的生產(chǎn)方式。
5.提高塑料模標準化水平和標準件的使用率。我國模具標準件水平和模具標準化程度仍較低,與國外差距甚大,在一定程度上制約著我國模具工業(yè)的發(fā)展,為提高模具質(zhì)量和降低模具制造成本,模具標準件的應(yīng)用要大力推廣。為此,首先要制訂統(tǒng)一的國家標準,并嚴格按標準生產(chǎn);其次要逐步形成規(guī)模生產(chǎn),提高商品化程度、提高標準件質(zhì)量、降低成本;再次是要進一步增加標準件的規(guī)格品種。
6.應(yīng)用優(yōu)質(zhì)材料和先進的表面處理技術(shù)對于提高模具壽命和質(zhì)量顯得十分必要。
研究內(nèi)容
本課題主要是針對顯示器后蓋的模具設(shè)計,通過對塑件進行工藝的分析和比較,最終設(shè)計出一副注塑模。
該課題從產(chǎn)品結(jié)構(gòu)工藝性,具體模具結(jié)構(gòu)出發(fā),通過查閱相關(guān)資料,對塑件的材料進行分析和選用,并且對塑件的結(jié)構(gòu),成型工藝進行分析和確定。
模具的設(shè)計需要對的澆注系統(tǒng)、模具成型部分的結(jié)構(gòu)、頂出系統(tǒng)、冷卻系統(tǒng)、注塑機的選擇及有關(guān)參數(shù)的校核、都有詳細的設(shè)計,同時并簡單的編制了模具的加工工藝。其中模具的成型部分的設(shè)計包括分型面的設(shè)計,澆注系統(tǒng)的設(shè)計,成型零件的工作尺寸和外形尺寸的設(shè)計
模架的設(shè)計包括模架的組成,相關(guān)零部件的尺寸設(shè)計,各零部件的用途,以及模擬模架的開模,合模。
最后還要有對成型零件,模架的安裝尺寸,合模力,頂出力,開模行程的校核,確保所設(shè)計的模具符合要求。
擬采取的研究方法、技術(shù)路線、實驗方案及可行性分析
研究方法:通過閱讀有關(guān)資料,文獻,收集篩選,整理課題研究所需的有關(guān)數(shù)據(jù),理論依據(jù),綜合運用所學(xué)理論知識研究論文課題。
方案設(shè)計:在工藝分析的基礎(chǔ)上,綜合考慮產(chǎn)品的產(chǎn)量和精度要求。所用材料的性能,設(shè)備情況及模具制造情況,確定該工件的工藝規(guī)程和每道工序的注塑模結(jié)構(gòu)形式。
結(jié)構(gòu)設(shè)計:在方案設(shè)計的基礎(chǔ)上,進一步設(shè)計模具各部分零件的具體結(jié)構(gòu)尺寸。
1.注塑的工藝分析:分析塑件的結(jié)構(gòu)形狀,尺寸精度,材料是否符合,注塑工藝要求,從而確定注塑的可能性。
2.確定注塑模工藝方案及模具結(jié)構(gòu)形式:工序數(shù)目,工序性質(zhì),工序順序,工序組合及模具結(jié)構(gòu)形式。
3.注塑模具的設(shè)計計算。注塑壓力、注射的塑件的體積,所需原來的體積,成型時間確定,確定各主要零件的外形尺寸,計算模具的閉合高度,確定所用注塑機。
4. 繪制注塑??傃b圖
5.通過對論文課題的學(xué)習(xí)研究,達到鞏固,擴大,深化已學(xué)理論知識,提高思考分析解決實際問題等綜合素質(zhì)的目的。
研究計劃及預(yù)期成果
研究計劃:實習(xí)調(diào)研、開題準備、工藝設(shè)計和擬定、模具結(jié)構(gòu)設(shè)計、編寫設(shè)計說明書。
2012年11月12日-2012年12月12日:查閱論文相關(guān)參考資料,填寫開題報告書。
2012年12月30日-2013年1月20日:填寫畢業(yè)實習(xí)報告。
2013年3月11日-2013年3月15日:學(xué)習(xí)模具設(shè)計以及相關(guān)知識,考慮設(shè)計。
2013年3月16日-2013年3月17日:翻譯一篇相關(guān)的英文材料,規(guī)劃整體方案。
2013年3月18日-2013年4月26日:明確塑件設(shè)計要求及批量,計算塑件的體積和質(zhì)量,注塑機的確定;模具成型零件的工作尺寸有關(guān)計算;圖表配圖設(shè)計及相關(guān)計算。
2013年4月22日-2013年4月26日:Pro/E、CAD繪圖。
2013年5月6日-2013年5月24日:畢業(yè)論文撰寫和修改工作。
預(yù)期成果:
本課題旨在通過對顯示器外殼產(chǎn)品的模具設(shè)計,系統(tǒng)的了解塑料及塑料的成型基本理論,能夠正確分析成型工藝對模具的要求。掌握塑件的成型工藝分析方法,能根據(jù)塑件的正確使用和工藝要求進行一般的塑件產(chǎn)品設(shè)計。掌握各類塑料模具結(jié)構(gòu)特點,零部件設(shè)計與計算,具備獨立中等復(fù)雜的注射模具的能力。了解塑料模具材料的選用和新技術(shù)發(fā)展等其他知識。培養(yǎng)分析問題以及運用所學(xué)知識解決實際工程問題的綜合能力。
特色或創(chuàng)新之處
手機充電器是我們?nèi)粘I钪胁豢扇鄙俚碾娖?,各個廠商生產(chǎn)的便攜式手機充電器都不一樣,但是現(xiàn)在越來越多的消費者注重了便攜式手機充電器的外觀、實用性等等。有著新穎外觀切使用的顯示器是非常受廣大消費者的喜愛,所以各個生產(chǎn)廠商努力設(shè)計生產(chǎn)出各種新穎時尚切安全使用的便攜式手機充電器吸引消費者的眼球。
已具備的條件和尚需解決的問題
已具備的條件:
已具備的條件:已學(xué)過的塑料成型加工工藝、注塑模具的設(shè)計,并結(jié)合日常生活中所積累的相關(guān)知識,詢問老師和有工作經(jīng)驗者,同時有部分可參考的同類設(shè)計資料及圖紙。
尚需解決的問題:缺乏實踐經(jīng)驗,并需要老師在設(shè)計過程中加以指導(dǎo)
尚需解決的問題:
理論與實踐有著不可避免的差距,由于沒有設(shè)計經(jīng)驗,在實際設(shè)計時,會遇到許多問題。而且平時沒把三維軟件學(xué)好,設(shè)計繪圖時耗費很大精力和時間。自身設(shè)計能力需要實踐經(jīng)驗進一步加強鞏固。
指導(dǎo)教師意見
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教研室(學(xué)科組、研究所)意見
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系意見
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年 月 日
英文原文
CONCURRENT DESIGN OF PLASTICS INJECTION MOULDS
Assist.Prof.Dr. A. YAYLA /Prof.Dr. Pa? a YAYLA
Abstract
The plastic product manufacturing industry has been growing rapidly in recent years. One of the most popular processes for making plastic parts is injection moulding. The design of injection mould is critically important to product quality and efficient product processing. Mould-making companies, who wish to maintain the competitive edge, desire to shorten both design and manufacturing leading times of the by applying a systematic mould design process.
The mould industry is an important support industry during the product development process, serving as an important link between the product designer and manufacturer. Product development has changed from the traditional serial process of design, followed by manufacture, to a more organized concurrent process where design and manufacture are considered at a very early stage of design. The concept of concurrent engineering (CE) is no longer new and yet it is still applicable and relevant in today’s manuf acturing environment. Team working spirit, management involvement, total design process and integration of IT tools are still the essence of CE. The application of The CE process to the design of an injection process involves the simultaneous consideration of plastic part design, mould design and injection moulding machine selection, production scheduling and cost as early as possible in the design stage.
This paper presents the basic structure of an injection mould design. The basis of this system arises from an analysis of the injection mould design process for mould design companies. This injection mould design system covers both the mould design process and mould knowledge management. Finally the principle of concurrent engineering process is outlined and then its principle is applied to the design of a plastic injection mould.
Keywords :Plastic injection mould design, Concurrent engineering, Computer aided engineering, Moulding conditions, Plastic injection moulding, Flow simulation
1. Introduction
Injection moulds are always expensive to make, unfortunately without a mould it can not be possible ho have a moulded product. Every mould maker has his/her own approach to design a mould and there are many different ways of designing and building a mould. Surely one of the most critical parameters to be considered in the design stage of the mould is the number of cavities, methods of injection, types of runners, methods of gating, methods of ejection, capacity and features of the injection moulding machines. Mould cost, mould quality and cost of mould product are inseparable
In today’s completive environment, computer aided mould filling simulation packages can accurately predict the fill patterns of any part. This allows for quick simulations of gate placements and helps finding the optimal location. Engineers can perform moulding trials on the computer before the part design is completed. Process engineers can systematically predict a design and process window, and can obtain information about the cumulative effect of the process variables that influence part performance, cost, and appearance.
2. Injection Moulding
Injection moulding is one of the most effective ways to bring out the best in plastics. It is universally used to make complex, finished parts, often in a single step, economically, precisely and with little waste. Mass production of plastic parts mostly utilizes moulds. The manufacturing process and involving moulds must be designed after passing through the appearance evaluation and the structure optimization of the product design. Designers face a huge number of options when they create injection-moulded components. Concurrent engineering requires an engineer to consider the manufacturing process of the designed product in the development phase. A good design of the product is unable to go to the market if its manufacturing process is impossible or too expensive. Integration of process simulation, rapid prototyping and manufacturing can reduce the risk associated with moving from CAD to CAM and further enhance the validity of the product development.
3. Importance of Computer Aided Injection Mould Design
The injection moulding design task can be highly complex. Computer Aided Engineering (CAE) analysis tools provide enormous advantages of enabling design engineers to consider virtually and part, mould and injection parameters without the real use of any manufacturing and time. The possibility of trying alternative designs or concepts on the computer screen gives the engineers the opportunity to eliminate potential problems before beginning the real production. Moreover, in virtual environment, designers can quickly and easily asses the sensitivity of specific moulding parameters on the quality and manufacturability of the final product. All theseCAE tools enable all these analysis to be completed in a meter of days or even hours, rather than weeks or months needed for the real experimental trial and error cycles. As CAE is used in the early design of part, mould and moulding parameters, the cost savings are substantial not only because of best functioning part and time savings but also the shortens the time needed to launch the product to the market.
The need to meet set tolerances of plastic part ties in to all aspects of the moulding process, including part size and shape, resin chemical structure, the fillers used, mould cavity layout, gating, mould cooling and the release mechanisms used. Given this complexity, designers often use computer design tools, such as finite element analysis (FEA) and mould filling analysis (MFA), to reduce development time and cost. FEA determines strain, stress and deflection in a part by dividing the structure into small elements where these parameters can be well defined. MFA evaluates gate position and size to optimize resin flow. It also defines placement of weld lines, areas of excessive stress, and how wall and rib thickness affect flow. Other finite element design tools include mould cooling analysis for temperature distribution, and cycle time and shrinkage analysis for dimensional control and prediction of frozen stress and warpage.
The CAE analysis of compression moulded parts is shown in Figure 1. The analysis cycle starts with the creation of a CAD model and a finite element mesh of the mould cavity. After the injection conditions are specified, mould filling, fiber orientation, curing and thermal history, shrinkage and warpage can be simulated. The material properties calculated by the simulation can be used to model the structural behaviour of the part. If required, part design, gate location and processing conditions can be modified in the computer until an acceptable part is obtained. After the analysis is finished an optimized part can be produced with reduced weldline (known also knitline), optimized strength, controlled temperatures and curing, minimized shrinkage and warpage.
Machining of the moulds was formerly done manually, with a toolmaker checking each cut. This process became more automated with the growth and widespread use of computer numerically controlled or CNC machining centres. Setup time has also been significantly reduced through the use of special software capable of generating cutter paths directly from a CAD data file. Spindle speeds as high as 100,000 rpm provide further advances in high speed machining. Cutting materials have demonstrated phenomenal performance without the use of any cutting/coolant fluid whatsoever. As a result, the process of machining complex cores and cavities has been accelerated.
It is good news that the time it takes to generate a mould is constantly being reduced. The bad news, on the other hand, is that even with all these advances, designing and manufacturing of the mould can still take a long time and can be extremely expensive.
Figure 1 CAE analysis of injection moulded parts
Many company executives now realize how vital it is to deploy new products to market rapidly. New products are the key to corporate prosperity. They drive corporate revenues, market shares, bottom lines and share prices. A company able to launch good quality products with reasonable prices ahead of their competition not only realizes 100% of the market before rival products arrive but also tends to maintain a dominant position for a few years even after competitive products have finally been announced (Smith, 1991). For most products, these two advantages are dramatic. Rapid product development is now a key aspect of competitive success. Figure 2 shows that only 3–7% of the product mix from the average industrial or electronics company is less than 5 years old. For companies in the top quartile, the number increases to 15–25%. For world-class firms, it is 60–80% (Thompson, 1996). The best companies continuously develop new products. At Hewlett-Packard, over 80% of the profits result from products less than 2 years old! (Neel, 1997)
Figure 2. Importance of new product (Jacobs, 2000)
With the advances in computer technology and artificial intelligence, efforts have been directed to reduce the cost and lead time in the design and manufacture of an injection mould. Injection mould design has been the main area of interest since it is a complex process involving several sub-designs related to various components of the mould, each requiring expert knowledge and experience. Lee et. al. (1997) proposed a systematic methodology and knowledge base for injection mould design in a concurrent engineering environment.
4. Concurrent Engineering in Mould Design
Concurrent Engineering (CE) is a systematic approach to integrated product development process. It represents team values of co-operation, trust and sharing in such a manner that decision making is by consensus, involving all per spectives in parallel, from the very beginning of the product life-cycle (Evans, 1998). Essentially, CE provides a collaborative, co-operative, collective and simultaneous engineering working environment. A concurrent engineering approach is based on five key elements:
1. process
2. multidisciplinary team
3. integrated design model
4. facility
5. software infrastructure
Figure 3 Methodologies in plastic injection mould design, a) Serial engineering b) Concurrent engineering
In the plastics and mould industry, CE is very important due to the high cost tooling and long lead times. Typically, CE is utilized by manufacturing prototype tooling early in the design phase to analyze and adjust the design. Production tooling is manufactured as the final step. The manufacturing process and involving moulds must be designed after passing through the appearance evaluation and the structure optimization of the product design. CE requires an engineer to consider the manufacturing process of the designed product in the development phase. A good design of the product is unable to go to the market if its manufacturing process is impossible. Integration of process simulation and rapid prototyping and manufacturing can reduce the risk associated with moving from CAD to CAM and further enhance the validity of the product development.
For years, designers have been restricted in what they can produce as they generally have to design for manufacture (DFM) – that is, adjust their design intent to enable the component (or assembly) to be manufactured using a particular process or processes. In addition, if a mould is used to produce an item, there are therefore automatically inherent restrictions to the design imposed at the very beginning. Taking injection moulding as an example, in order to process a component successfully, at a minimum, the following design elements need to be taken into account:
1. . geometry;
. draft angles,
. Non re-entrants shapes,
. near constant wall thickness,
. complexity,
. split line location, and
. surface finish,
2. material choice;
3. rationalisation of components (reducing assemblies);
4. cost.
In injection moulding, the manufacture of the mould to produce the injection-moulded components is usually the longest part of the product development process. When utilising rapid modelling, the CAD takes the longer time and therefore becomes the bottleneck.
The process design and injection moulding of plastics involves rather complicated and time consuming activities including part design, mould design, injection moulding machine selection, production scheduling, tooling and cost estimation. Traditionally all these activities are done by part designers and mould making personnel in a sequential manner after completing injection moulded plastic part design. Obviously these sequential stages could lead to long product development time. However with the implementation of concurrent engineering process in the all parameters effecting product design, mould design, machine selection, production scheduling, tooling and processing cost are considered as early as possible in the design of the plastic part.
When used effectively, CAE methods provide enormous cost and time savings for the part design and manufacturing. These tools allow engineers to virtually test how the part will be processed and how it performs during its normal operating life. The material supplier, designer, moulder and manufacturer should apply these tools concurrently early in the design stage of the plastic parts in order to exploit the cost benefit of CAE. CAE makes it possible to replace traditional, sequential decision-making procedures with a concurrent design process, in which all parties can interact and share information, Figure 3. For plastic injection moulding, CAE and related design data provide an integrated environment that facilitates concurrent engineering for the design and manufacture of the part and mould, as well as material selection and simulation of optimal process control parameters.
Qualitative expense comparison associated with the part design changes is shown in Figure 4 , showing the fact that when design changes are done at an early stages on the computer screen, the cost associated with is an order of 10.000 times lower than that if the part is in production. These modifications in plastic parts could arise fr om mould modifications, such as gate location, thickness changes, production delays, quality costs, machine setup times, or design change in plastic parts.
Figure 4 Cost of design changes during part product development cycle (Rios et.al, 2001)
At the early design stage, part designers and moulders have to finalise part design based on their experiences with similar parts. However as the parts become more complex, it gets rather difficult to predict processing and part performance without the use of CAE tools. Thus for even relatively complex parts, the use of CAE tools to prevent the late and expensive design changesand problems that can arise during and after injection. For the successful implementation of concurrent engineering, there must be buy-in from everyone involved.
4. Case Study
Figure 5 shows the initial CAD design of plastics part used for the sprinkler irrigation hydrant leg. One of the essential features of the part is that the part has to remain flat