打印機(jī)上蓋的注塑模設(shè)計(jì)【全套含CAD圖紙、說(shuō)明書(shū)】
打印機(jī)上蓋的注塑模設(shè)計(jì)【全套含CAD圖紙、說(shuō)明書(shū)】,全套含CAD圖紙、說(shuō)明書(shū),打印機(jī),注塑,設(shè)計(jì),全套,CAD,圖紙,說(shuō)明書(shū)
編號(hào)：
畢業(yè)設(shè)計(jì)開(kāi)題報(bào)告
題 目： 打印機(jī)上蓋的注塑模設(shè)計(jì)
院 （系）： 機(jī)電工程學(xué)院
專 業(yè)： 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
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題目類型：¨理論研究 ¨實(shí)驗(yàn)研究 t工程設(shè)計(jì) ¨工程技術(shù)研究 ¨軟件開(kāi)發(fā)
年3月1日
1．畢業(yè)設(shè)計(jì)的主要內(nèi)容、重點(diǎn)和難點(diǎn)等
一、畢業(yè)設(shè)計(jì)的主要內(nèi)容
模具是工業(yè)生產(chǎn)中的重要工藝裝備，模具工業(yè)是國(guó)民經(jīng)濟(jì)各部門發(fā)展的重要基礎(chǔ)之一。塑料模具是指用于成型塑料制作的模具，它是一種型腔模。隨著工業(yè)塑料制件和日用塑料制件的品種和需求量的日益增加，塑料成型工業(yè)在基礎(chǔ)工業(yè)中的地位和對(duì)國(guó)民經(jīng)濟(jì)的影響越來(lái)越重要。注射模又稱為注塑模，是塑料模具的一種，其產(chǎn)量占世界塑料成型模具產(chǎn)量的一半以上。注射成型能成型形狀復(fù)雜的制件及具有生產(chǎn)效率高等特點(diǎn)，因此在塑料制件的生產(chǎn)中占有很大的比重。此次設(shè)計(jì)主要是圍繞打印機(jī)上蓋注塑模具設(shè)計(jì)，其主要內(nèi)容如下：
1、 對(duì)塑料制件的結(jié)構(gòu)進(jìn)行工藝性分析，選擇合適的塑料模具；
2、 確定塑件在模具中的位置以及澆注系統(tǒng)的設(shè)計(jì)；
3、 成型零部件的設(shè)計(jì)，其中包括成型零部件的結(jié)構(gòu)設(shè)計(jì)、工作尺寸計(jì)算、強(qiáng)度和剛度計(jì)算及繪制零件圖；
4、 結(jié)構(gòu)零部件的設(shè)計(jì)，其中包括模架的選用、支承零部件、動(dòng)定模座板的設(shè)計(jì)等；
5、 推出機(jī)構(gòu)的設(shè)計(jì)和側(cè)向分型與抽芯機(jī)構(gòu)的設(shè)計(jì)，其中包括推出機(jī)構(gòu)的類型、推出力的計(jì)算、側(cè)向分型與抽芯機(jī)構(gòu)的類型等；
6、 模具的溫度調(diào)節(jié)系統(tǒng)設(shè)計(jì)。
二、畢業(yè)設(shè)計(jì)的重點(diǎn)
1、對(duì)零件的結(jié)構(gòu)工藝性分析，擬定打印機(jī)上蓋的工藝方案及模具結(jié)構(gòu)方案的設(shè)計(jì)；
2、對(duì)打印機(jī)上蓋成型零部件的工作尺寸的計(jì)算及強(qiáng)度與剛度的計(jì)算；
3、打印機(jī)上蓋注塑模模具裝配圖和零件圖的繪制。
三、畢業(yè)設(shè)計(jì)的難點(diǎn)
1、主要的工藝參數(shù)的設(shè)計(jì)與計(jì)算；
2、成型零部件的結(jié)構(gòu)設(shè)計(jì)和結(jié)構(gòu)零部件的設(shè)計(jì)；
3、推出機(jī)構(gòu)的設(shè)計(jì)和側(cè)向分型與抽芯機(jī)構(gòu)的設(shè)計(jì)；
4、溫度調(diào)節(jié)系統(tǒng)的設(shè)計(jì)。
四、可加以創(chuàng)新點(diǎn)
查閱國(guó)內(nèi)外相關(guān)資料與文獻(xiàn)，了解模具新技術(shù)和注塑成型新工藝，對(duì)我國(guó)模具工業(yè)的現(xiàn)狀與發(fā)達(dá)國(guó)家模具工業(yè)的現(xiàn)狀進(jìn)行比較分析，了解成型優(yōu)質(zhì)塑件所需的重要條件，結(jié)合實(shí)際和所設(shè)計(jì)內(nèi)容，尋找一種更為理想的方案。
2．準(zhǔn)備情況（查閱過(guò)的文獻(xiàn)資料及調(diào)研情況、現(xiàn)有設(shè)備、實(shí)驗(yàn)條件等）
一、調(diào)研情況
塑料具有質(zhì)量輕、比強(qiáng)度大、絕緣性能好、成型生產(chǎn)率高和價(jià)格低廉等優(yōu)點(diǎn)。塑料已成為金屬的良好代用材料，出現(xiàn)了金屬材料塑料化的趨勢(shì)。注塑成型由于可以一次成型各種結(jié)構(gòu)復(fù)雜、尺寸精密和帶有金屬嵌件的制品且成型周期短，可以一模多腔，大批生產(chǎn)時(shí)成本低廉，易于實(shí)現(xiàn)自動(dòng)化生產(chǎn)，因此在塑料加工行業(yè)中占有非常重要的位置。與很多工業(yè)發(fā)達(dá)國(guó)家相比，我國(guó)的模具行業(yè)特別是注塑模具起步比較晚，技術(shù)設(shè)備、管理水都比較低。長(zhǎng)期以來(lái)，我國(guó)注塑模具的設(shè)計(jì)與制造很多依賴于國(guó)外的經(jīng)驗(yàn)。據(jù)統(tǒng)計(jì)，我國(guó)每年生產(chǎn)的模具只能滿足國(guó)內(nèi)需求的60％左右，很多精密復(fù)雜的模具需要進(jìn)口。
（一）國(guó)內(nèi)外注塑模具的發(fā)展現(xiàn)狀對(duì)比
隨著塑料制品廣泛應(yīng)用，模具技術(shù)已成為衡量一個(gè)國(guó)家制造業(yè)發(fā)展水平的重要標(biāo)志之一，標(biāo)準(zhǔn)化、智能化、網(wǎng)絡(luò)化成為了工業(yè)發(fā)達(dá)國(guó)家注塑模具制造業(yè)的基本特征。近些年來(lái)，隨著我國(guó)注塑行業(yè)的發(fā)展和先進(jìn)制造技術(shù)的研發(fā)與引進(jìn)，注塑模具的制造水平也得到了很大的提高。但是由于起步晚、基礎(chǔ)薄弱、技術(shù)設(shè)備、管理水平都比較低等問(wèn)題，我國(guó)的注塑模具總水平與國(guó)外依然存在10年以上的差距，注塑模的精度、熱流道模具使用率、模具的使用壽命、標(biāo)準(zhǔn)化程度等都有待于進(jìn)一步提高。工業(yè)發(fā)達(dá)國(guó)家，其模具工業(yè)年產(chǎn)值早已超過(guò)機(jī)床行業(yè)的年產(chǎn)值。在日本、韓國(guó)等國(guó)家，其生產(chǎn)塑料模與生產(chǎn)沖壓模的企業(yè)數(shù)量差不多相等；而在新加坡等國(guó)家，其生產(chǎn)塑料模的企業(yè)數(shù)量已大大超過(guò)生產(chǎn)沖壓模的企業(yè)。所以，我國(guó)應(yīng)加大技術(shù)投入，重視技術(shù)創(chuàng)新，使我國(guó)的注塑模具得到快速高效的發(fā)展。
（二）我國(guó)注塑模具的發(fā)展趨勢(shì)
當(dāng)前，隨著市場(chǎng)競(jìng)爭(zhēng)的加劇、人們需求的不斷提高，為了適應(yīng)市場(chǎng)需要，模具行業(yè)也需要不斷發(fā)展創(chuàng)新。從以上的分析中可以看出，我國(guó)在注塑模具的研究方面取得了重要的進(jìn)展，先進(jìn)制造技術(shù)的采用與新材料的應(yīng)用使我國(guó)的注塑模具朝著精密、高速、節(jié)能的方向發(fā)展 。具體發(fā)展方向表現(xiàn)在以下方面：
1）注塑模具設(shè)計(jì)中 CAD／CAM／CAE技術(shù)的廣泛應(yīng)用；
2）注塑模具中熱流道模具的比重逐漸提高；
3）專用和優(yōu)質(zhì)模具的材料不斷地推陳出新；
4）智能化、自動(dòng)化研磨拋光的應(yīng)用；
5）不斷提高模具標(biāo)準(zhǔn)化程度。
二、打印機(jī)上蓋模具零件的設(shè)計(jì)工序
（1）模具尺寸設(shè)計(jì)合理且并無(wú)明顯缺陷；
（2）繪制相關(guān)的裝配圖和零件圖；
（3）運(yùn)用三維軟件描述注塑的動(dòng)態(tài)過(guò)程。
三、 注塑模具的設(shè)計(jì)步驟
1、 設(shè)計(jì)前的準(zhǔn)備工作。其中包括設(shè)計(jì)任務(wù)書(shū)、確定塑件的成型工藝與注射劑的型號(hào)和規(guī)格。
2、 制訂成型工藝卡。其中包括描述制品概況、注射機(jī)的主要技術(shù)參數(shù)、壓力與行程、成型條件等。
3、 模具結(jié)構(gòu)設(shè)計(jì)。其中包括確定型腔數(shù)目、選擇分型面、制訂型腔分布方案、確定澆注系統(tǒng)、脫模方式和排氣方式等。
4、 確定注射模主要尺寸，選用標(biāo)準(zhǔn)模架。
5、 模具的繪制。其中包括模具的結(jié)構(gòu)草圖、校核模具與注射機(jī)的相關(guān)尺寸、注射機(jī)結(jié)構(gòu)的審查、模具裝配圖、零件圖及設(shè)計(jì)圖樣的復(fù)核。
6、 注射模具的審核。其中包括以下幾個(gè)方面：
（1） 基本結(jié)構(gòu)方面；
（2） 設(shè)計(jì)圖紙方面；
（3） 設(shè)計(jì)質(zhì)量方面；
（4） 裝拆方便方面。
參考文獻(xiàn)
[1] 馮剛，江平.《塑料工業(yè)》我國(guó)注塑模具關(guān)鍵技術(shù)的研究與應(yīng)用進(jìn)展[J].浙江：
浙江工業(yè)職業(yè)技術(shù)學(xué)院，2014,42（4）：16-19
[2] 唐仁奎，許艷英.《科技風(fēng)》注塑模具技術(shù)現(xiàn)狀與發(fā)展趨勢(shì)[J],2010(12)
[3] 屈華昌.塑料成型工藝與模具設(shè)計(jì).第2版.北京：高等教育出版社，2006.7
[4] 余曉容.注塑模優(yōu)化設(shè)計(jì)理論的研究與應(yīng)用[D].鄭州：鄭州大學(xué)，2004:1-2
[5] 姬雷雷.《典型注塑模結(jié)構(gòu)》多媒體系統(tǒng)軟件的研究[D].南京：南京航空航天大
學(xué)，2004：14-16
[3] 梁艷豐．注塑模結(jié)構(gòu)設(shè)計(jì)要點(diǎn)分析[J]．中國(guó)科技縱橫，2010(9)：21．
[4] 洪慎章．現(xiàn)代模具技術(shù)的現(xiàn)狀及發(fā)展趨勢(shì)[J]．航空制造技術(shù)，2006(6)：30—32．
[5] 周永泰．中國(guó)模具工業(yè)的現(xiàn)狀與發(fā)展[J]．電加工與模具，2005(4)：8—12．
[6] 楊守濱．淺談注塑模具先進(jìn)制造關(guān)鍵技術(shù)的發(fā)展[J]．科技創(chuàng)新導(dǎo)報(bào)，2008(2)：
78．
[7] 王昌，胡修鑫．注塑模具的先進(jìn)制造技術(shù)綜述[J]．機(jī)床與液壓，2012，40(14)：
123—125．
[8] 姜愛(ài)菊，吳宏武．微注射成型的最新進(jìn)展[J]．塑料工業(yè)，2008，31(8)：1—4.
[9] 文泊．熱流道技術(shù)是塑料注射成型工藝的一大變革[J]．國(guó)外塑料，2012(1)：55
—56．
[10] 江健．淺析注塑模具的發(fā)展[J]．廣西輕工業(yè)，2011(3)：5l一52．
[11] wILDER R v．Hot Runners[J]．Plast Technol，2003，49(9)：23．
[12] 梅啟武．注塑模熱流道輔助設(shè)計(jì)技術(shù)與應(yīng)用研究[D]．杭州：浙江大學(xué)，2004：
l一11．
[13] 李聰，李輝．淺談注塑模具中一些先進(jìn)技術(shù)[J]，電子世界，2011(9)：38—39．
[14] 許發(fā)鍵．模具標(biāo)準(zhǔn)化及其生產(chǎn)技術(shù)[J]．現(xiàn)代制造，2004(9)：46—48．
[15] 宋滿倉(cāng)．注塑模具設(shè)計(jì)與制造標(biāo)準(zhǔn)化體系的研究[D]．大連：大連理工大學(xué)，2004：
1一14．
[16] 阮雪榆，李志剛，武兵書(shū)，等．中國(guó)模具工業(yè)和技術(shù)的發(fā)展[J]．模具技術(shù)，
2001(2)：72—74．
[17] 李菲，方沂．CAD／CAE技術(shù)在現(xiàn)代注塑模具設(shè)計(jì)中的應(yīng)用[J]．價(jià)值工程，
2012,33(31)：36—37．
[18] 孫錫紅．我國(guó)塑料模具發(fā)展現(xiàn)狀及發(fā)展建議[J]．電加工與模具，2010(4)：31
—33．
[19] 宋滿倉(cāng)，趙丹陽(yáng)．注塑模具的綠色制造方法研究[J]．機(jī)械設(shè)計(jì)與制造工程，2002，
31(3)：15—16．
3、實(shí)施方案、進(jìn)度實(shí)施計(jì)劃及預(yù)期提交的畢業(yè)設(shè)計(jì)資料
一、2015年12月—2016年1月：根據(jù)課題內(nèi)容完成開(kāi)題報(bào)告。
二、2016年1月至2月：完成外文翻譯英文。
三、2016年2月至4月：完成開(kāi)題報(bào)告，繪制裝配圖。
四、2016年5月中旬：撰寫(xiě)畢業(yè)設(shè)計(jì)說(shuō)明書(shū)。
五、2016年5月至6月：整理打印畢業(yè)論文及相關(guān)資料，交指導(dǎo)老師評(píng)閱，準(zhǔn)備畢業(yè)答辯。
指導(dǎo)教師意見(jiàn)
指導(dǎo)教師（簽字）：
2016年3月 日
開(kāi)題小組意見(jiàn)
開(kāi)題小組組長(zhǎng)（簽字）：
2016年3 月 日
院（系、部）意見(jiàn)
主管院長(zhǎng)（系、部主任）簽字：
2016年3月 日
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畢業(yè)設(shè)計(jì)（論文）中期檢查表（指導(dǎo)教師）
指導(dǎo)教師姓名： 填表日期： 年 4 月 7 日
學(xué)生學(xué)號(hào)
學(xué)生姓名
題目名稱
打印機(jī)上蓋的注塑模設(shè)計(jì)
已完成內(nèi)容
完成開(kāi)題報(bào)告和外文翻譯，完成塑件的繪制，開(kāi)始撰寫(xiě)說(shuō)明書(shū)。
檢查日期：
完成情況
□全部完成
□按進(jìn)度完成
□滯后進(jìn)度安排
存在困難
在準(zhǔn)備三維建模中遇阻，之前對(duì)于SolidWorks掌握得并不是很好，所以建模過(guò)程并不順利。且塑件結(jié)構(gòu)尺寸比較多，在繪制三維圖時(shí)也比較耽誤時(shí)間。
解決辦法
借閱圖書(shū)館里有關(guān)于SolidWorks注塑模的設(shè)計(jì)的書(shū)籍，網(wǎng)上查找學(xué)習(xí)視頻。
預(yù)期成績(jī)
□優(yōu) 秀
□良 好
□中 等
□及 格
□不及格
建
議
教師簽名：
教務(wù)處實(shí)踐教學(xué)科制表
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畢業(yè)設(shè)計(jì)(論文)外文翻譯
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學(xué) 院： 機(jī)電工程學(xué)院
專 業(yè)： 機(jī)械設(shè)計(jì)制造及其自動(dòng)化
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年 3 月 20 日
Abstract
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 para-meters using a standardisation template. The standardisation 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 predefined 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 mounted on 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 standardised 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 standardisation 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.
Fig. 1. Front insert (cavity) and back insert (core).
Fig. 2. A simple 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.
Fig. 3. (a) A single cavity mould. (b) A multi-cavity mould.
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.
Fig. 4. Short moulding in an unbalanced layout.
Fig. 5. Multi-cavity layouts.
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”.
Fig. 6. Mould assembly hierarchical design tree.
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 standardisation procedure for the “cavity layout design”: component assembly standardisation and cavity layout configuration standardisation.
Fig. 7. Interplay in the standardization procedure.
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 the second 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.
Fig. 8. Detailed “cavity layout design” hierarchical design tree.
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 non-standard. Figure 9 shows the standardisation procedure of the cavity layout configuration.
Fig. 9. Standardisation procedure of the cavity layout configuration.
A cavity layout design, can be undertaken either as a multi-cavity 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 multi-cavity 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 standardisation 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 layout design 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.
Fig. 10. The standardization template.
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.
Table 1. Sample of the configuration database.
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:
Fig. 11. The back mould plate with pocketing.
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.
Fig. 12. Single-cavity layout configuration and geometrical parameters.
Fig. 13. Eight-cavity layout configuration and geometrical parameters
without cavity rotation.
Fig. 14. Eight-cavity layout configuration and geometrical parameters
with cavity rotation.
4 System Implementation
A prototype of the parametric-controlled cavity layout design system for a plastic injection mould has been implemented using aIII PC-compatible as the hardware. This prototype system uses a commercial CAD system (SolidWorks 2001) and a commercial database system (Microsoft ) 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 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
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