溫控器墊塊塑料模具設(shè)計(jì)
溫控器墊塊塑料模具設(shè)計(jì),溫控,墊塊,塑料,模具設(shè)計(jì)
嘉興學(xué)院南湖學(xué)院外文文獻(xiàn)翻譯譯文
題 目： 拉鉤的冷沖模設(shè)計(jì)
系 別： 機(jī)電工程系 專 業(yè)： 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
班 級： 機(jī)械N061 學(xué) 號(hào)： 2006456790601
學(xué)生姓名： 潘曉慧
二、翻譯文章
注塑模的參數(shù)控制型腔布局設(shè)計(jì)系統(tǒng)
M. L. H. Low and K. S. Lee
機(jī)械工程系，新加坡大學(xué)，新加坡
如今，塑料產(chǎn)品的上市時(shí)間變的越來越短，因此，制造注塑模的可用交貨時(shí)間也變的少了。在模具的設(shè)計(jì)階段有個(gè)省時(shí)的潛在方法，因?yàn)橛捎诿總€(gè)模具設(shè)計(jì)可以是標(biāo)準(zhǔn)化的，所以一個(gè)設(shè)計(jì)程序可以被重復(fù)使用。本文提出了一種通過使用標(biāo)準(zhǔn)模版來控制幾何參數(shù)的方法來設(shè)計(jì)注塑模的型腔布局。標(biāo)準(zhǔn)模版的型腔布局設(shè)計(jì)包括可能布局的配置。每個(gè)布局設(shè)計(jì)的配置都有其特有的由所有幾何參數(shù)構(gòu)成的布局設(shè)計(jì)表格。這個(gè)標(biāo)準(zhǔn)模版是預(yù)定義在合型設(shè)計(jì)的布局設(shè)計(jì)的級別時(shí)的。這樣就能夠確保要求的配置能夠被快速地輸入到模具裝配設(shè)計(jì)中，而不需要重新設(shè)計(jì)布局。這使得它在模具制造前產(chǎn)品設(shè)計(jì)師和模具設(shè)計(jì)師之間的技術(shù)討論上更有用。在討論時(shí)直接改變3D型腔的布局設(shè)計(jì)，這樣可以節(jié)省時(shí)間和避免錯(cuò)誤傳達(dá)。型腔設(shè)計(jì)的標(biāo)準(zhǔn)模版便于各個(gè)模具制造公司依照顧客具體要求而制造他們各自的規(guī)格。
關(guān)鍵詞：型腔布局設(shè)計(jì)；幾何參數(shù)；合型；注塑模設(shè)計(jì)；標(biāo)準(zhǔn)模板
1．簡介
注塑法是在一個(gè)較好的公差范圍內(nèi)生產(chǎn)大量塑料零件的最簡單的方法。在注塑法中有兩個(gè)主要的要求。那就是注塑設(shè)備和注塑模。注塑制模機(jī)上有安裝好的模具并且提供有將熔融的塑料從機(jī)器中轉(zhuǎn)移到模具中的機(jī)械設(shè)，利用壓力應(yīng)用程序來加緊模具來噴出成型的塑料部件。注塑模是將熔融的塑料轉(zhuǎn)變成最終具有詳細(xì)尺寸形狀的塑料部件的工具。如今，隨著塑料部件的上市時(shí)間變得越來越短，在一個(gè)更短的時(shí)間里生產(chǎn)注塑模變得更加必要。
注塑模具的設(shè)計(jì)及其相關(guān)的領(lǐng)域有很多工作都是依靠電腦技術(shù)來完成的。知識(shí)庫系統(tǒng)例如IMOLD[1.2]，IKMOULD[3]，ESMOLD[4]，臺(tái)灣[5]的國家程康大學(xué)[6]的知識(shí)庫系統(tǒng)，德雷塞爾大學(xué)的知識(shí)庫系統(tǒng)等都是注塑模具設(shè)計(jì)較發(fā)達(dá)的。如HyperQ/Plastic[7]，CIMP[8]，F(xiàn)IT[9]系統(tǒng)等,通過使用知識(shí)庫系統(tǒng)在挑選塑性材料方面有了發(fā)展。在注塑法[10-12]的分離設(shè)計(jì)技術(shù)上也同樣有所提高。
據(jù)觀察盡管模具制造公司仍在使用3D CAD軟件來進(jìn)行模具設(shè)計(jì)，大量的時(shí)間都浪費(fèi)在了仔細(xì)檢查每個(gè)項(xiàng)目的同一設(shè)計(jì)程序。在模具設(shè)計(jì)階段如果重復(fù)的設(shè)計(jì)程序能夠標(biāo)準(zhǔn)化進(jìn)而避免了常規(guī)任務(wù)就能夠更好的節(jié)省時(shí)間。在合型方面一個(gè)有條理的樹形分層設(shè)計(jì)也同樣是個(gè)重要因素[13,14]。然而，在型腔的布局設(shè)計(jì)中有極少的工作是控制參數(shù)，這樣，這片領(lǐng)域?qū)⑹俏覀冎饕慕裹c(diǎn)。盡管在設(shè)計(jì)型腔的布局時(shí)有很多的方法[15,16]，模具設(shè)計(jì)師們更傾向于使用最常見的設(shè)計(jì)方法，這樣就有必要在型腔布局設(shè)計(jì)層面上制定標(biāo)準(zhǔn)。
本文介紹了基于標(biāo)準(zhǔn)模板通過控制參數(shù)來設(shè)計(jì)注塑模的型腔布局設(shè)計(jì)的方法。首先，必須確定一個(gè)有條理的樹形合型分層設(shè)計(jì)。其次，對標(biāo)準(zhǔn)配置和不標(biāo)準(zhǔn)配置之間不同型腔配置進(jìn)行分類。在配置數(shù)據(jù)庫中將標(biāo)準(zhǔn)配置列表，并且每個(gè)配置有其自己的布局設(shè)計(jì)表來控制它自身的幾何參數(shù)。這個(gè)標(biāo)準(zhǔn)模板在模具合型設(shè)計(jì)的布局設(shè)計(jì)階段進(jìn)行先驗(yàn)。
圖1.前嵌入（型腔）和后嵌入（型芯）
2．注塑模的型腔布局設(shè)計(jì)
注塑模是將熔融的塑料轉(zhuǎn)變成最終具有詳細(xì)尺寸形狀的塑料部件的工具。這樣，一個(gè)模具的最后部分要包含有推出機(jī)構(gòu)。大多數(shù)的模具由兩部分構(gòu)成：動(dòng)模板和定模板。在有些模具制造公司，動(dòng)模板也被稱為凹模，定模板也被稱為凸模。 表一所示為動(dòng)模板（凹模）和定模板（凸模）。熔融的塑性材料被注射進(jìn)型腔中。熔融的塑性材料固化后就形成了部件。表二所示為一個(gè)簡單的兩板式注塑模。
圖2 單型腔合型
2.1單型腔和多型腔的區(qū)別
通常，熔融塑性材料所注入的空間被稱為型腔。型腔的排列被稱為型腔的布置。當(dāng)模具包含有超過一個(gè)的型腔時(shí)被稱為多型腔模具。圖3（a）和圖2（b）所示為一個(gè)單型腔模具和一個(gè)多型腔模具。
單型腔模具通常用來制造大的直方的部件例如打印機(jī)的外殼和電視機(jī)的外殼。對于較小的部件如手機(jī)外殼和齒輪，一般更經(jīng)濟(jì)的用多型腔模具來生產(chǎn)，這樣每個(gè)模具周期能夠生產(chǎn)更多的部件。顧客通常決定型腔的數(shù)目，所以他們不得不平衡機(jī)器設(shè)備的費(fèi)用和部件的費(fèi)用。
2.2多型腔的布局
同時(shí)能生產(chǎn)不同產(chǎn)品的多型腔模具稱為一個(gè)系列模具。然而，它并不經(jīng)常用來設(shè)計(jì)有不同型腔的模具，因?yàn)樾颓徊灰欢芡瑫r(shí)在同一個(gè)溫度下被熔融的塑性材料填充滿。
另一方面，一個(gè)多型腔模具在整個(gè)的模具周期中生產(chǎn)相同的產(chǎn)品會(huì)用到平衡布局和不平衡布局。平衡布局是指型腔能夠在相同的熔融條件下同時(shí)全部被填充滿[15,16]。當(dāng)使用不平衡布局時(shí)可能會(huì)產(chǎn)生成型不完全的模具，但是可以通過修改分型面的澆流道（熔融塑性材料從澆口流到型腔的通道）的長度來克服。然而這不是一個(gè)高效的方法，在可能的情況下避免使用。圖4所示為由于使用不平衡布局而導(dǎo)致了成型不完全的情況。
平衡布局能更進(jìn)一步的分為兩類：線形和環(huán)形。平衡線形布局適用于2、4、8、16、32等型腔，也就是說它遵循系列。平衡環(huán)形布局可以有3、4、5、6或者更多的型腔，但是由于空間限制在平衡環(huán)形布局的型腔布置上有數(shù)量的限制。圖5所示是討論過的多型腔布局。
3.設(shè)計(jì)方法
本章概況地介紹注塑模的高級參數(shù)控制型腔布局設(shè)計(jì)系統(tǒng)的設(shè)計(jì)方法。模具設(shè)計(jì)的有效工作方法包括將大量的組件和部件安排到設(shè)計(jì)樹的最合適的層次上。圖6所示為第一級的組件和部件在設(shè)計(jì)樹的合型層。設(shè)計(jì)樹的第二層向前直到第N層的合型層上的組件和部件將被組合。在這個(gè)系統(tǒng)中，重點(diǎn)是“型腔的布局設(shè)計(jì)”。
圖3（a）單型腔模具。（b）多型腔模具
圖4 不平衡布局而導(dǎo)致了成型不完全
3.1標(biāo)準(zhǔn)化程序
在模具設(shè)計(jì)過程中為節(jié)約時(shí)間，有必要鑒別通常使用的設(shè)計(jì)方法的特點(diǎn)。每個(gè)模具設(shè)計(jì)中重復(fù)使用的設(shè)計(jì)步驟可以被標(biāo)準(zhǔn)化。從圖7中可以看出在型腔布局設(shè)計(jì)的標(biāo)準(zhǔn)化程序中有兩個(gè)部分是互相影響的：零部件裝配的標(biāo)準(zhǔn)化和型腔布局配置的標(biāo)準(zhǔn)化。
圖5 多型腔布局
圖6 合型分層設(shè)計(jì)樹
圖7 在標(biāo)準(zhǔn)化程序中的相互關(guān)系
3.1.1零件裝配標(biāo)準(zhǔn)化
在型腔布局配置標(biāo)準(zhǔn)化前，有必要識(shí)別在型腔布局中在大量型腔中重復(fù)使用的零部件。表8所示為一個(gè)詳細(xì)的型腔布局設(shè)計(jì)的樹形層次設(shè)計(jì)結(jié)構(gòu)圖。在樹形層次設(shè)計(jì)結(jié)構(gòu)圖的第二層中主要的嵌入部件有大量在層次設(shè)計(jì)樹中第三層以前的被直接裝配的零部件。它們可以被看做是主要成分和次要成分。主要成分存在于每個(gè)模具設(shè)計(jì)中。次要成分取決于所生產(chǎn)的塑料部件，所以它們可能出現(xiàn)也可能不出現(xiàn)在模具設(shè)計(jì)中。
圖8詳細(xì)型腔布局設(shè)計(jì)的樹形層次設(shè)計(jì)結(jié)構(gòu)圖
結(jié)果，將這些零部件直接放到主要嵌入部件下，確保每個(gè)重復(fù)使用的主要嵌入（型腔）將延續(xù)層次設(shè)計(jì)樹第三層以前的相同零部件的使用。這樣，就沒有必要重復(fù)設(shè)計(jì)在型腔布局中的每個(gè)型腔中的相同零部件了。
3.1.2型腔布局的結(jié)構(gòu)標(biāo)準(zhǔn)化
有必要學(xué)習(xí)和將型腔布局標(biāo)準(zhǔn)化分類為標(biāo)準(zhǔn)化和非標(biāo)準(zhǔn)化。圖9所示為型腔布局結(jié)構(gòu)的標(biāo)準(zhǔn)化程序。
圖9型腔布局結(jié)構(gòu)的標(biāo)準(zhǔn)化程序。
一個(gè)型腔布局設(shè)計(jì)，可以被理解為或者是多腔布局或者是單腔布局，但是通常是顧客來決定這個(gè)。單型腔布局總是被認(rèn)為有一個(gè)標(biāo)準(zhǔn)的配置。多型腔模具可以同時(shí)生產(chǎn)不同產(chǎn)品或者同時(shí)生產(chǎn)相同產(chǎn)品。一個(gè)模具同時(shí)生產(chǎn)不同產(chǎn)品被認(rèn)為是同系列的模具，這是不常見的設(shè)計(jì)。這樣，一個(gè)多型腔系列模具就有一個(gè)非標(biāo)準(zhǔn)配置。
多型腔模具生產(chǎn)相同產(chǎn)品可以包含要么平衡布局設(shè)計(jì)要么非平衡布局設(shè)計(jì)。非平衡布局設(shè)計(jì)很少使用，結(jié)果它被認(rèn)為是有一個(gè)非標(biāo)準(zhǔn)配置。然而，一個(gè)平衡布局設(shè)計(jì)也可以包含有一個(gè)線性布局設(shè)計(jì)或者是一個(gè)環(huán)形布局設(shè)計(jì)。這個(gè)取決于顧客要求的型腔的數(shù)目。這個(gè)必須注意，然而，布局設(shè)計(jì)也有其他非標(biāo)準(zhǔn)型腔數(shù)目也被分類在非標(biāo)準(zhǔn)配置中。
將這些布局設(shè)計(jì)分為標(biāo)準(zhǔn)化后，他們的詳細(xì)信息就可以列入標(biāo)準(zhǔn)模板中。在合型設(shè)計(jì)和支持所有的標(biāo)準(zhǔn)配置的型腔布局設(shè)計(jì)階段標(biāo)準(zhǔn)模板要進(jìn)行先驗(yàn)。這樣就能確保要求的配置能夠很快的載入到合型設(shè)計(jì)中而不用再次設(shè)計(jì)布局。
3.2標(biāo)準(zhǔn)化模板
從圖10中可以看出在標(biāo)準(zhǔn)模板中有兩部分：配置數(shù)據(jù)庫和部件設(shè)計(jì)表。配置數(shù)據(jù)庫包括有所有的標(biāo)準(zhǔn)布局配置，每個(gè)布局配置都有它自己的帶有幾何參數(shù)的布局設(shè)計(jì)表。由于模具制造工業(yè)有他們自己的標(biāo)準(zhǔn)，這樣配置數(shù)據(jù)庫可以根據(jù)顧客具體要求來運(yùn)用到那些預(yù)先被認(rèn)為是非標(biāo)準(zhǔn)化的設(shè)計(jì)中。
圖10 標(biāo)準(zhǔn)模板
3.2.1配置數(shù)據(jù)庫
一個(gè)數(shù)據(jù)庫可以用來包含了所有的不同標(biāo)準(zhǔn)配置的列表。在這個(gè)數(shù)據(jù)庫中的配置的總數(shù)目相當(dāng)于在模具設(shè)計(jì)裝配的型腔布局設(shè)計(jì)階段的可利用布局配置的數(shù)目。在數(shù)據(jù)庫所列信息就是配置數(shù)目、類型、和型腔數(shù)。表1所示是數(shù)據(jù)庫的一個(gè)例子。每個(gè)可利用的布局配置的一般類型和型腔的數(shù)目的名字是配置數(shù)目。當(dāng)布局的特殊類型和型腔的數(shù)目被要求時(shí)，適當(dāng)?shù)牟季峙渲脤?huì)被載入到型腔布局設(shè)計(jì)中。
3.2.2布局設(shè)計(jì)表
配置數(shù)據(jù)庫中所列的每個(gè)標(biāo)準(zhǔn)配置都有它自己的布局設(shè)計(jì)表。布局設(shè)計(jì)表包含有布局配置的幾何參數(shù)并且每個(gè)配置都是獨(dú)立的。更多的復(fù)合布局配置將有更多的幾何參數(shù)來控制型腔布局。
圖11（a）和11（b）所示為裝配相同四個(gè)型腔布局的有一個(gè)大腔和四個(gè)小腔的模板的背面。它一般更經(jīng)濟(jì)，與用機(jī)械設(shè)備在一大塊的鋼板上制造獨(dú)立的更小的腔相比，用機(jī)械設(shè)備在制造一個(gè)大的腔更加容易。用機(jī)械制造一個(gè)大的腔的優(yōu)點(diǎn)有：
1. 在腔與腔之間可以節(jié)省更過的空間，這樣更小塊的鋼板就可以被使用了。
2. 與加工多個(gè)小的腔相比加工一個(gè)大的腔的加工時(shí)間要更快。
3. 加工大腔比加工小腔能獲得更高的精確度。
結(jié)果，在布局設(shè)計(jì)表中的幾何參數(shù)的默認(rèn)值將導(dǎo)致腔于腔之間將沒有間隙。然而，為是系統(tǒng)更加靈活，幾何參數(shù)的默認(rèn)值在需要的地方可以修改以此來適應(yīng)每個(gè)模具設(shè)計(jì)。
圖11 模板背面
3.3幾何參數(shù)
幾何參數(shù)有三個(gè)變量：
1. 型腔之間的距離。布局設(shè)計(jì)表中所列出的型腔之間的距離可以由使用者來控制或修改。距離的默認(rèn)值就是這些型腔間沒有間隙的值。
2. 個(gè)別型腔的取向角。個(gè)別型腔的取向角也被列在了布局設(shè)計(jì)表中，這些數(shù)值用戶可以修改。對于一個(gè)多型腔布局，所有的型腔都必須如布局設(shè)計(jì)表中所說有相同的取向角。如果取向角被修改，所有的型腔將會(huì)旋轉(zhuǎn)相同的取向角而不受結(jié)構(gòu)配置的影響。
3. 型腔間的裝配關(guān)系。型腔間的方向與先驗(yàn)每個(gè)獨(dú)特的布局配置有關(guān)并且由型腔間的裝配關(guān)系控制。
圖12所示為一個(gè)單型腔布局配置和它的它的幾何參數(shù)的例子。主要嵌入/型腔的原點(diǎn)是在中心。X1和Y1的默認(rèn)值是0所以型腔的布局時(shí)在中心的（雙方起源重疊）。使用者可改變X1和Y1的值，所以型腔可以適當(dāng)?shù)钠啤?
圖13所示是一個(gè)八型腔布局配置和它的幾何參數(shù)的例子。X和Y值是主要嵌入/型腔的大小。默認(rèn)X1、X2的值等于X，Y1的值等于Y，這樣型腔間就沒有間隙。考慮到設(shè)計(jì)中的型腔間的間隙X1、X2和Y1的值可以增加。這些數(shù)值在布局設(shè)計(jì)表中都有列出。
如果一個(gè)型腔的方向不得不調(diào)整90°，剩下的型腔也要旋轉(zhuǎn)相同的角度，但是布局設(shè)計(jì)的殘余也是同樣。使用者可以通過改變布局設(shè)計(jì)表的參數(shù)來旋轉(zhuǎn)型腔。最終的布局如圖14所示。一個(gè)復(fù)雜的型腔布局配置有更多的幾何參數(shù)，必須確保參數(shù)方程的聯(lián)系。
圖12 單型腔布局配置和幾何參數(shù)
圖13沒有型腔旋轉(zhuǎn)的八型腔布局配置
和幾何參數(shù)圖 圖14 型腔旋轉(zhuǎn)的八型腔布局配置和幾何參數(shù)
4.系統(tǒng)實(shí)現(xiàn)
注塑模的標(biāo)準(zhǔn)參數(shù)控制型腔布局設(shè)計(jì)系統(tǒng)通過奔騰III PC兼容機(jī)作為計(jì)算機(jī)硬件來執(zhí)行。這個(gè)原型系統(tǒng)使用商業(yè)CAD系統(tǒng)（SolidWorks2001）和商業(yè)數(shù)據(jù)庫系統(tǒng)（Microsoft Excel）作為軟件。成熟的原型系統(tǒng)在Windows NT環(huán)境下使用Microsoft Visual C++ V6.0編程語言和SolidWorks API（應(yīng)用程序設(shè)計(jì)接口）。
SolidWorks被挑選出來的兩個(gè)主要的原因是：
1. 在CAD/CAM工業(yè)放心日益增長的趨勢是向Windows-based PCs的使用來代替了UNIX工作站的使用，主要是因?yàn)榘徺I計(jì)算機(jī)硬件的花費(fèi)。
2. 三維CAD軟件是Windows系統(tǒng)完全兼容的，這樣它能夠平穩(wěn)地整合從Microsoft Excel文件到CAD文件（部分，裝配，圖紙）的信息[17]。
這個(gè)原型設(shè)計(jì)有一個(gè)列在Excel文件中的八個(gè)標(biāo)準(zhǔn)布局配置的配置數(shù)據(jù)庫。這個(gè)由圖15（a）所示。與這個(gè)配置數(shù)據(jù)庫一致，布局設(shè)計(jì)階段，SolidWorks中的一個(gè)裝配文件有相同的布局配置。在Excel文件中的配置名與圖15（b）所示的在布局裝配文件中的裝配名相對應(yīng)。
每個(gè)設(shè)計(jì)中的每個(gè)型腔布局裝配文件將會(huì)被這些布局配置預(yù)裝載。當(dāng)要求的布局結(jié)構(gòu)按要求通道到用戶界面，布局配置將被載入。用戶界面如圖16所示是在要求的布局配置載入之前的。在載入要求的布局配置之上，最近的布局配置信息將會(huì)被列入列表框中。
對在配置數(shù)據(jù)庫中找到的任何其他可用的布局結(jié)構(gòu)，用戶就能夠改變當(dāng)前布局結(jié)構(gòu)。這個(gè)由圖17舉例說明。
最近的布局結(jié)構(gòu)的布局設(shè)計(jì)表包含有當(dāng)用戶觸發(fā)了在用戶界面底部的按鈕時(shí)就能夠激活的幾何參數(shù)。當(dāng)幾何參數(shù)值改變，型腔布局設(shè)計(jì)將因此更新。圖18所示是激活了最近的布局結(jié)構(gòu)的布局設(shè)計(jì)表。
圖15 原型系統(tǒng)的配置數(shù)據(jù)庫和布局模板 圖16 要求的布局配置載入之前的用戶界面
圖17 要求的布局配置載入之后的用戶界面 圖18布局設(shè)計(jì)表的用戶界面
5.案例研究
如圖19所示的手機(jī)外殼的CAD模型，使用了如下的案例研究。
在型腔布局設(shè)計(jì)階段之前，原CAD模型必須根據(jù)使用的模具損耗值來修剪。主要的嵌入部分會(huì)制造的能夠壓縮進(jìn)收縮的部分。這個(gè)整個(gè)的部件被認(rèn)為是主要的嵌入部件(xxx cavity.sldasm),。“XXX”是項(xiàng)目名。圖20所示是主要的嵌入部件。在主要的嵌入部件創(chuàng)建后，型腔布局設(shè)計(jì)系統(tǒng)將會(huì)被用于準(zhǔn)備合型的型腔布局。
5.1方案1：最初的型腔布局設(shè)計(jì)
在一個(gè)模具設(shè)計(jì)中，建立在一個(gè)模具中的型腔的數(shù)目通常是有顧客建議的，這樣他們必須平衡工件方面的投資和零件的花費(fèi)。最初，顧客要求用一個(gè)兩個(gè)型腔的模具來設(shè)計(jì)這個(gè)手機(jī)外殼。在創(chuàng)建了主要的嵌入部件后，模具設(shè)計(jì)師載入了一個(gè)使用型腔布局設(shè)計(jì)系統(tǒng)有兩個(gè)型腔的線性布局結(jié)構(gòu)。對應(yīng)的配置名是L02如圖21所示列入了用戶列表中。
5.2方案2：型腔布局設(shè)計(jì)中的修改
顧客與模具設(shè)計(jì)者間的工藝討論會(huì)議是很普遍的。這樣在模具制造前就能夠盡可能早的修改三維CAD文件中的產(chǎn)品和模具。修改基本上是不可避免的，模具設(shè)計(jì)者也從不會(huì)在主要的時(shí)間上延期。
既然這樣，在工藝討論會(huì)議中，顧客改變他們的想法，需要一個(gè)線性的四個(gè)型腔的模具來代替兩個(gè)型腔的模具，所以手機(jī)外殼的價(jià)格就要增加。模具設(shè)計(jì)者可以使用型腔布局設(shè)計(jì)系統(tǒng)來修改目前的型腔布局設(shè)計(jì)為一個(gè)線性的四個(gè)型腔的模具。要求的新的布局結(jié)構(gòu)可以從配置數(shù)據(jù)庫所列的可利用的布局結(jié)構(gòu)中挑選出來。如圖22所示。
圖19 手機(jī)的CAD模型 圖20 主要嵌入包裝的收縮部分
圖21 線性兩型腔的配置 圖22 線性 四型腔布局配置（布局配置變化后）
5.3方案3：型腔間所要求的間隙
最后，在另一個(gè)工藝討論會(huì)議中，模具設(shè)計(jì)者被要求介紹在軸向方向上型腔間有20mm的間隙，如圖23所示。
圖23 型腔間有間隙的簡介
在型腔布局組件階段，模具設(shè)計(jì)者使用型腔布局系統(tǒng)來激活最近的布局結(jié)構(gòu)中的布局設(shè)計(jì)表。介紹的軸向方向上型腔間的間隙是20mm的Y1值是從50mm到70mm間變化的。圖24所示是在布局設(shè)計(jì)表中Y1值的變化。最終的設(shè)計(jì)結(jié)構(gòu)，在間隙增加后如圖25所示。
圖24 布局設(shè)計(jì)表中Y1值的變化 圖25 增加間隙后的最終設(shè)計(jì)
6.結(jié)論
在本文中，使用標(biāo)準(zhǔn)模板的方法是為參數(shù)控制的型腔布局設(shè)計(jì)系統(tǒng)的發(fā)展提出計(jì)劃。自從這個(gè)方法使用了標(biāo)準(zhǔn)化后，如果他們的設(shè)計(jì)程序是重復(fù)使用的或者他們有普遍應(yīng)用于每個(gè)模具的特點(diǎn)，它就可以更進(jìn)一步的應(yīng)用于其他的合型設(shè)計(jì)的部件。較成熟的型腔布局系統(tǒng)的優(yōu)點(diǎn)如下：
1. 該系統(tǒng)有容易使用的界面。
2. 自從它使用數(shù)據(jù)庫后，它就高度的靈活，有他們自己標(biāo)準(zhǔn)的模具制造公司可以根據(jù)顧客的具體要求來制定數(shù)據(jù)庫來迎合他們的需要。
3. 因?yàn)橄闰?yàn)標(biāo)準(zhǔn)模板在合型設(shè)計(jì)中的布局設(shè)計(jì)階段是可利用的，所以要求的布局結(jié)構(gòu)可以很快地載入到合型設(shè)計(jì)中而不需要再次設(shè)計(jì)布局。
4. 這個(gè)系統(tǒng)能夠使產(chǎn)品設(shè)計(jì)者和模具設(shè)計(jì)者在模具制造前，在討論中直接改變布局有更多的有用的工藝討論。
5. 這個(gè)系統(tǒng)這模具設(shè)計(jì)程序能夠節(jié)省時(shí)間，因?yàn)樗∪チ硕嘤嗟墓ぷ鳌＿@對于在模具制造工業(yè)自從模具制造的生產(chǎn)周期日益提高是很重要的。
較發(fā)達(dá)的系統(tǒng)有相同的局限性。盡管數(shù)據(jù)庫和布局設(shè)計(jì)表可以根據(jù)顧客的具體要求來制定，客制化將會(huì)由于更多的復(fù)雜的非標(biāo)準(zhǔn)化配置而變的能困難，因?yàn)檎_的幾何參數(shù)有待確定。我們一般工作都要求有一個(gè)標(biāo)準(zhǔn)的模板來制造模具設(shè)計(jì)中的其他部件。
參考文獻(xiàn)
1. K. S. Lee, J. Y. H, Fuh, Y. F. Zhang, A. Y. C. Nee and Z. Li,“IMOLD: an intelligent plastic injection mold design and assembly system”, Proceedings of the 4th International Conference On Die and Mould Technology, pp. 30–37, Malaysia, 4–6 June 1997.
2. K. S. Lee, Z. Li, J. Y. H, Fuh, Y. F. Zhang and A. Y. C.Nee, “Knowledge-based injection mold design system”, CIRP International Conference and Exhibition on Design and Production of Dies and Moulds, pp. 45–50, Turkey, 19–21 June 1997.
3. C. K. Mok, K. S. Chin and John K. L. Ho, “An interactive knowledge-based CAD system for mould design in injection moulding processes”, International Journal of Advanced Manufacturing Technology, 17, pp. 27–38, 2001.
4. Kwai-Sang Chin and T. N. Wong, “Knowledge-based evaluation for the conceptual design development of injection molding parts”,Engineering Application of Artificial Intelligence, 9(4), pp. 359–376, 1996.
5. Rong-Shean Lee, Yuh-Min Chen and Chang-Zou Lee, “Development of a concurrent mold design system: a knowledge-based approach”, Computer Integrated Manufacturing Systems, 10(4), pp. 287–307, 1997.
6. A. A. Tseng, J. D. Kaplan, O. B. Arinze and T. J. Zhao, “Knowledge-based mold design for injection molding processing”,Proceedings of the 5th International Symposium on Intelligent Control, pp. 1199–1204, 1990.
7. K. Beiter, S. Krizan and K. Ishii, “HyperQ/Plastics: an expert system for plastic material and process selection”, Proceedings Computers in Engineering, ASME, 1, pp. 71–76, 1991.
8. W. R. Jong and K. K. Wang, “An intelligent system for resin selection”, Proceedings ANTEC’89, SPE, pp. 367–370, 1989.
9. M. Wiggins, “Expert systems in polymer selection”, Proceedings ANTEC’86, SPE, pp. 1393–1395, 1986.
10. L. L. Chen, S. Y. Chou and T. C. Woo, “Parting directions for mould and die design”, Computer-Aided Design, 25(12), pp. 762–768, 1993.
11. A. Y. C. Nee and M. W. Fu, “Determination of optimal parting directions in plastic injection mold design”, Annals CIRP, 46(1),pp. 429–432, 1997.
12. B. Ravi and M. N. Srinivasan, “Decision criteria for computeraided parting surface design”, Computer-Aided Design, 22(1),pp. 11–18, 1990.
13. X. G. Ye, “Feature and associativity-based computer-aided design for plastic injection moulds”, PhD thesis, National University ofSingapore, 2000.
14. X. G. Ye, J. Y. H. Fuh and K. S. Lee, “Automated assembly modeling for plastic injection moulds”, International Journal of Advanced Manufacturing Technology, 16, pp. 739–747, 2000.
15. G. Menges, How to Make Injection Molds, Chapter 4, Hanser, Munich, 1986.
16. Joseph B. Dym, Injection Molds and Molding: A Practical Manual,Chapter 7, Van Nostrand Reinhold, New York, 1989.
17. SolidWorks 2001 Training Manual, “SolidWorks Essentials parts assemblies and drawings”, SolidWorks Corporation, Concord, Massachusetts 01742, 2001.
指導(dǎo)教師評語
簽字： 年 月 日
14
廣東工業(yè)大學(xué)華立學(xué)院本科生畢業(yè)設(shè)計(jì)（論文）任務(wù)書
題目名稱
溫控器墊塊塑料模具設(shè)計(jì)
系 部
機(jī)電及信息工程學(xué)部
專業(yè)班級
機(jī)械設(shè)計(jì)制造及其自動(dòng)化專業(yè)
11級第4班
姓 名
姚頌勤
學(xué) 號(hào)
12011104039
一、 畢業(yè)設(shè)計(jì)（論文）的內(nèi)容
本課題對生產(chǎn)實(shí)踐中的實(shí)際塑件—溫控器墊塊進(jìn)行塑料模具工程圖設(shè)計(jì)。
要求完成部件設(shè)計(jì)，重要零件設(shè)計(jì)、設(shè)計(jì)計(jì)算、設(shè)計(jì)說明書撰寫。及學(xué)校的其他相關(guān)設(shè)計(jì)內(nèi)容。
二、畢業(yè)設(shè)計(jì)（論文）的要求與數(shù)據(jù)
本科題圖紙工作量：不應(yīng)少于累計(jì)A0圖紙3張。其中至少有一張是裝配圖。
設(shè)計(jì)說明書：字?jǐn)?shù)及說明書寫作要求符合學(xué)校相關(guān)規(guī)定。
設(shè)計(jì)后交付的圖紙、電子文檔及其他文件數(shù)量符合學(xué)校相關(guān)規(guī)定。
三、畢業(yè)設(shè)計(jì)（論文）應(yīng)完成的工作
本課題要求完成：
1、裝配總圖設(shè)計(jì)
2、模架、推出機(jī)構(gòu)（含復(fù)雜推出機(jī)構(gòu)）設(shè)計(jì)
3、溫度調(diào)節(jié)系統(tǒng)設(shè)計(jì)
4．其他必要的模具結(jié)構(gòu)設(shè)計(jì)
5. 零件名細(xì)表、
6. 主要零件圖
7. 設(shè)計(jì)計(jì)算
8. 設(shè)計(jì)說明書。
9．塑件圖（可為立體圖）
四、畢業(yè)設(shè)計(jì)（論文）進(jìn)程安排
序號(hào)
設(shè)計(jì)（論文）各階段內(nèi)容
地點(diǎn)
起止日期
1
完成設(shè)計(jì)開題
學(xué)校
第1周-第3周
2．
完成調(diào)研、方案設(shè)計(jì)
各設(shè)
計(jì)點(diǎn)
第4周
3
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第4周
4
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各設(shè)
計(jì)點(diǎn)
第5周—第7周
5
期中檢查
學(xué)校
第7周
6
完成設(shè)計(jì)說明書撰寫
出圖
各設(shè)
計(jì)點(diǎn)
第8周—第9周
7
交畢業(yè)設(shè)計(jì)
學(xué)校
第9周
8
檢查、評閱、修改畢業(yè)設(shè)計(jì)
學(xué)校
第9周—第10周
9
畢業(yè)答辯（含準(zhǔn)備）（2周）
學(xué)校
第11周—第12周
五、應(yīng)收集的資料及主要參考文獻(xiàn)
1）《塑料成型工藝與模具設(shè)計(jì)》（修訂版） 曲華昌主編
高等教育出版社 2010年8月
2）《塑料成型工藝與模具設(shè)計(jì)》（第二版） 齊衛(wèi)東主編
高等教育出版社 2011年8月
3）《塑料模具課程設(shè)計(jì)指導(dǎo)與范例》（第二版）楊占堯主編
化學(xué)工業(yè)出版社 2009年6月
4）《塑料模具典型結(jié)構(gòu)設(shè)計(jì)實(shí)例》 楊占堯 白柳主編
化學(xué)工業(yè)出版社 2009年1月
5）《塑料模具設(shè)計(jì)師手冊》 王鵬駒 張杰主編 機(jī)械工業(yè)出版社 2008年10月
6）《機(jī)械設(shè)計(jì)設(shè)計(jì)手冊—零部件設(shè)計(jì)常用基礎(chǔ)標(biāo)準(zhǔn)》
機(jī)械設(shè)計(jì)手冊編委會(huì) 機(jī)械工業(yè)出版社 2007年8月
7）資料：《機(jī)械零部件標(biāo)準(zhǔn)匯編》 北京機(jī)床研究所
2009年10月
8）《模具設(shè)計(jì)指導(dǎo)》 史鐵良 機(jī)械工業(yè)出版社 2003年7月
9）《塑料模典型結(jié)構(gòu)100例》 黃曉燕 上?？茖W(xué)技術(shù)出版社
2008年9月
10）《塑料模具結(jié)構(gòu)圖冊》 王忠銀主編 湖南科學(xué)技術(shù)出版社
1999年9月
發(fā)出任務(wù)書日期： 2015 年 3 月 22 日
指導(dǎo)教師簽名：
預(yù)計(jì)完成日期： 2015年 5 月 28 日
專業(yè)負(fù)責(zé)人簽章：
系部主任簽章：
塑件名稱：溫控器墊塊
注：未注明尺寸可自行確定
嘉興學(xué)院南湖學(xué)院外文文獻(xiàn)翻譯譯文
題 目： 拉鉤的冷沖模設(shè)計(jì)
系 別： 機(jī)電工程系 專 業(yè)： 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
班 級： 機(jī)械N061 學(xué) 號(hào)： 2006456790601
學(xué)生姓名： 潘曉慧
一、 外文原文
A Parametric-Controlled Cavity Layout Design System for a Plastic Injection Mould
M. L. H. Low and K. S. Lee
Department of Mechanical Engineering, National University of Singapore, Singapore
Today, the time-to-market for plastic products is becoming shorter, thus the lead time available for making the injection mould is decreasing. There is potential for timesaving in the mould design stage because a design process that is repeatable for every mould design can be standardised. This paper presents a methodology for designing the cavity layout for plastic injection moulds by controlling the geometrical parameters using a standardisation template. The standardization template for the cavity layout design consists of the configurations for the possible layouts. Each configuration of the layout design has its own layout design table of all the geometrical parameters. This standardisation template is pre-defined at the layout design level of the mould assembly design. This ensures that the required configuration can be loaded into the mould assembly design very quickly, without the need to redesign the layout. This makes it useful in technical discussions between the product designers and mould designers prior to the manufacture of the mould. Changes can be made to the 3D cavity layout design immediately during the discussions, thus saving time and avoiding miscommunication. This standardisation template for the cavity layout design can be customised easily for each mould making company to their own standards.
Keywords: Cavity layout design; Geometrical parameters;
Mould assembly; Plastic injection mould design; Standardisation
template
1. Introduction
Plastic injection moulding is a common method for the mass production of plastic parts with good tolerances. There are two main items that are required for plastic injection moulding. They are the injection-moulding machine and the injection mould. The injection-moulding machine has the mould mountedon it and provides the mechanism for molten plastic transfer from the machine to the mould, clamping the mould by the application of pressure and the ejection of the formed plastic part. The injection mould is a tool for transforming the molten plastic into the final shape and dimensional details of the plastic part. Today, as the time-to-market for plastic parts is becoming shorter, it is essential to produce the injection mould in a shorter time.
Much work had been done on applying computer technologies to injection mould design and the related field. Knowledge-based systems (KBS) such as IMOLD [1,2], IKMOULD[3], ESMOLD [4], the KBS of the National Cheng Kang University, Taiwan [5], the KBS of Drexel University [6], etc. were developed for injection mould design. Systems such as HyperQ/Plastic [7], CIMP [8], FIT [9], etc. are developed for the selection of plastic materials using a knowledge-based approach. Techniques have also been developed for parting design in injection moulding [10–12].
It has been observed that although mould-making industries are using 3D CAD software for mould design, much time is wasted in going through the same design processes for every project. There is great potential for timesaving at the mould design stage if the repeatable design processes can be standardized to avoid routine tasks. A well-organised hierarchical design tree in the mould assembly is also an important factor [13,14].However, little work has been done in controlling the parameters in the cavity layout design; thus this area will be our main focus. Although there are many ways of designing the cavity layout [15,16], mould designers tend to use only conventional designs, thus there is a need to apply standardisation at the cavity layout design level.
This paper presents a methodology for designing the cavity layout for plastic injection moulds by controlling the parameters based on a standardisation template. First, a well-organised mould assembly hierarchy design tree had to be established. Then, the classification of the cavity layout configuration had to be made to differentiate between those with standard configurations and those with non-standard configurations. The standard configurations will be listed in a configuration database and each configuration has its own layout design table that controls its own geometrical parameters. This standardization template is pre-defined at the layout design level of the mould assembly design.
2. Cavity Layout Design for a Plastic Injection Mould
An injection mould is a tool for transforming molten plastic into the final shape and dimensional details of a plastic part. Thus, a mould contains an inverse impression of the final part. Most of the moulds are built up of two halves: the front insert and the back insert. In certain mould-making industries, the front insert is also known as the cavity and the back insert is known as the core. Figure 1 shows a front insert (cavity) and a back insert (core). Molten plastic is injected into the impression to fill it. Solidification of the molten plastic then forms the part. Figure 2 shows a simple two-plate mould assembly.
2.1 Difference Between a Single-Cavity and a Multi-Cavity Mould
Very often, the impression in which molten plastic is being filled is also called the cavity. The arrangement of the cavities is called the cavity layout. When a mould contains more than one cavity, it is referred to as a multi-cavity mould. Figures 3(a) and 3(b) shows a single-cavity mould and a multi-cavity mould.
A single-cavity mould is normally designed for fairly large parts such as plotter covers and television housings. For smaller parts such as hand phone covers and gears, it is always more economical to design a multi-cavity mould so that more parts can be produced per moulding cycle. Customers usually determine the number of cavities, as they have to balance the investment in the tooling against the part cost.
2.2 Multi-Cavity Layout
A multi-cavity mould that produces different products at the same time is known as a family mould. However, it is not usual to design a mould with different cavities, as the cavities may not all be filled at the same time with molten plastic of the same temperature.
On the other hand, a multi-cavity mould that produces the same product throughout the moulding cycle can have a balanced layout or an unbalanced layout. A balanced layout is one in which the cavities are all uniformly filled at the same time under the same melt conditions [15,16]. Short moulding can occur if an unbalanced layout is being used, but this can be overcome by modifying the length and cross-section of the runners (passageways for the molten plastic flow from the sprue to the cavity). Since this is not an efficient method, it is avoided where possible. Figure 4 shows a short moulding situation due to an unbalanced layout.
A balanced layout can be further classified into two categories: linear and circular. A balanced linear layout can accommodate 2, 4, 8, 16, 32 etc. cavities, i.e. it follows a 2n series. A balanced circular layout can have 3, 4, 5, 6 or more cavities, but there is a limit to the number of cavities that can be accommodated in a balanced circular layout because of space constraints. Figure 5 shows the multi-cavity layouts that have been discussed.
3. The Design Approach
This section presents an overview of the design approach for the development of a parametric-controlled cavity layout design system for plastic injection moulds. An effective working method of mould design involves organising the various subassemblies and components into the most appropriate hierarchy design tree. Figure 6 shows the mould assembly hierarchy design tree for the first level subassembly and components. Other subassemblies and components are assembled from the second level onwards to the nth level of the mould assembly hierarchy design tree. For this system, the focus will be made only on the “cavity layout design”.
3.1 Standardisation Procedure
In order to save time in the mould design process, it is necessary to identify the features of the design that are commonly used. The design processes that are repeatable for every mould design can then be standardised. It can be seen from Fig. 7 that there are two sections that interplay in the standardization procedure for the “cavity layout design”: component assembly standardisation and cavity layout configuration standardisation.
3.1.1 Component Assembly Standardisation
Before the cavity layout configuration can be standardised, there is a need to recognise the components and subassemblies that are repeated throughout the various cavities in the cavity layout. Figure 8 shows a detailed “cavity layout design” hierarchy design tree. The main insert subassembly (cavity) in thesecond level of the hierarchy design tree has a number of subassemblies and components that are assembled directly to it from the third level onwards of the hierarchy design tree. They can be viewed as primary components and secondary components. Primary components are present in every mould design. The secondary components are dependent on the plastic part that is to be produced, so they may or may not be present
in the mould designs.
As a result, putting these components and subassemblies directly under the main insert subassembly, ensures that every repeatable main insert (cavity) will inherit the same subassemblies and components from the third level onwards of the hierarchy design tree. Thus, there is no need to redesign similar subassemblies and components for every cavity in the cavity layout.
3.1.2 Cavity Layout Configuration Standardisation
It is necessary to study and classify the cavity layout configurations into those that are standard and those that are nonstandard. Figure 9 shows the standardisation procedure of the cavity layout configuration.
A cavity layout design, can be undertaken either as a multicavity layout or a single-cavity layout, but the customers always determine this decision. A single-cavity layout is always considered as having a standard configuration. A multi-cavity mould can produce different products at the same time or the same products at the same time. A mould that produces different products at the same time is known as a family mould, which is a non-conventional design. Thus, a multicavity family mould has a non-standard configuration.
A multi-cavity mould that produces the same product can contain either a balanced layout design or an unbalanced layout design. An unbalanced layout design is seldom used and, as a result, it is considered to possess a non-standard configuration. However, a balanced layout design can also encompass either a linear layout design or a circular layout design. This depends on the number of cavities that are required by the customers. It must be noted, however, that a layout design that has any other non-standard number of cavities is also classified as having a non-standard configuration.
After classifying those layout designs that are standard, their detailed information can then be listed into a standardization template. This standardisation template is pre-defined in the cavity layout design level of the mould assembly design and supports all the standard configurations. This ensures that the required configuration can be loaded very quickly into the mould assembly design without the need to redesign the layout.
3.2 Standardisation Template
It can be seen from Fig. 10 that there are two parts in the standardisation template: a configuration database and a layoutde sign table. The configuration database consists of all the standard layout configurations, and each layout configuration has its own layout design table that carries the geometrical parameters. As mould-making industries have their own standards, the configuration database can be customised to take into account those designs that are previously considered as non-standard.
3.2.1 Configuration Database
A database can be used to contain the list of all the different standard configurations. The total number of configurations in this database corresponds to the number of layout configurations available in the cavity layout design level of the mould design assembly. The information listed in the database is the configuration number, type, and the number of cavities. Table 1 shows an example of a configuration database. The configuration number is the name of each of the available layout configurations with the corresponding type and number of cavities. When a particular type of layout and number of cavities is called for, the appropriate layout configuration will be loaded into the cavity layout design.
3.2.2 Layout Design Table
Each standard configuration listed in the configuration database has its own layout design table. The layout design table contains the geometrical parameters of the layout configuration and is independent for every configuration. A more complex layout configuration will have more geometrical parameters to control the cavity layout.
Figures 11(a) and 11(b) show the back mould plate (core plate) with a big pocket and four small pockets for assembling the same four-cavity layout. It is always more economical and easier to machine a large pocket than to machine individual smaller pockets in a block of steel. The advantages of machining a large pocket are:
1. More space between the cavities can be saved, thus a smaller block of steel can be used.
2. Machining time is faster for creating one large pocket compared to machining multiple small pockets.
3. Higher accuracy can be achieved for a large pocket than for multiple smaller pockets.
As a result, the default values of the geometrical parameters in the layout design table results in there being no gap between the cavities. However, to make the system more flexible, the default values of the geometrical parameters can be modified to suit each mould design where necessary.
3.3 Geometrical Parameters
There are three variables that establish the geometrical parameters:
1. Distances between the cavities (flexible). The distances between the cavities are listed in the layout design table and they can be controlled or modified by the user. The default values of the distances are such that there are no gaps between the cavities.
2. Angle of orientation of the individual cavity (flexible). The angle of orientation of the individual cavity is also listed in the layout design table which the user can change. For a multi-cavity layout, all the cavities have to be at the same angle of orientation as indicated in the layout design table. If the angle of orientation is modified, all the cavities will be rotated by the same angle of orientation without affecting the layout configuration.
3. Assembly mating relationship between each cavities (fixed). The orientation of the cavities with respect to each other is pre-defined for each individual layout configuration and is controlled by the assembly mating relationship between cavities. This is fixed for every layout configuration unless it is customised.
Figure 12 shows an example of a single-cavity layout configuration and its geometrical parameters. The origin of the main insert/cavity is at the centre. The default values of X1 and Y1 are zero so that the cavity is at the centre of the layout (both origins overlap each other). The user can change the values of X1 and Y1, so that the cavity can be offset appropriately.
Figure 13 shows an example of an eight-cavity layout configuration and its geometrical parameters. The values of X and Y are the dimensions of the main insert/cavity. By default, the values of X1 and X2 are equal to X, the value of Y1 is equal to Y, and thus there is no gap between the cavities. The values of X1, X2, and Y1 can be increased to take into account the gaps between the cavities in the design. These values are listed in the layout design table.
If one of the cavities has to be oriented by 90°, the rest of the cavities will be rotated by the same angle, but the layout design remains the same. The user is able to rotate the cavities by changing the parameter in the layout design table. The resultant layout is shown in Fig. 14.
A complex cavity layout configuration, which has more geometrical parameters, must make use of equation to relate the parameters.
4. System Implementation
A prototype of the parametric-controlled cavity layout design system for a plastic injection mould has been implemented using a Pentium III PC-compatible as the hardware. This prototype system uses a commercial CAD system (SolidWorks 2001) and a commercial database system (Microsoft Excel?) as the software. The prototype system is developed using the Microsoft Visual C++ V6.0 programming language and the SolidWorks API (Application Programming Interface) in a Windows NT? environment. SolidWorks is chosen primarily for two reasons:
1. The increasing trend in the CAD/CAM industry is to move towards the use of Windows-based PCs instead of UNIX workstations mainly because of the cost involved in purchasing the hardware.
2. The 3D CAD software is fully Windows-compatible, thus it is capable of integrating information from Microsoft Excel files into the CAD files (part, assembly, and drawing) smoothly [17].
This prototype system has a configuration database of eight standard layout configurations that are listed in an Excel file. This is shown in Fig. 15(a). Corresponding to this configuration database, the layout design level, which is an assembly file in SolidWorks (layout.sldasm), has the same set of layout configurations. The configuration name in the Excel file corresponds to the name of the configurations in the layout assembly file, which is shown in Fig. 15(b).
Every cavity layout assembly file (layout.sldasm) for each project will be pre-loaded with these layout configurations. When a required layout configuration is requested via the user interface, the layout configuration will be loaded. The user interface shown in Fig. 16 is prior to the loading of the requested layout configuration. Upon loading the requested layout configuration, the current layout configuration information will be listed in the list box.
The user is then able to change the current layout configuration to any other available layout configurations that are found in the configuration database. This is illustrated in Fig. 17.
The layout design table for the current layout configuration that contains the geometrical parameters can be activated when the user triggers the push button at the bottom of the user interface. When the values of the geometrical parameters are changed, the cavity layout design will be updated accordingly. Figure 18 shows the activation of the layout design table of the current layout configuration.
5. A Case Study
A CAD model of a hand phone cover, shown in Fig. 19, is used in the following case study.
Prior to the cavity layout design stage, the original CAD model has to be scaled according to the shrinkage value of the moulding resin to be used. The main insert is then created to encapsulate the shrunk part. This entire subassembly is known as the main insert subassembly (xxx cavity. sldasm), where “xxx” is the project name. Figure 20 shows the main insert subassembly. After the main insert subassembly is created, the cavity layout design system can be used to prepare the cavity layout of the mould assembly.
5.1 Scenario 1: Initial Cavity Layout Design
In a mould design, the number of cavities to be built in a mould is always suggested by the customers, as they have to balance the investment in the tooling against the part cost. Initially, the customers had requested a two-cavity mould to be designed fo
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