0125-拉鉤的冷沖模設(shè)計(jì)【全套5張CAD圖+文獻(xiàn)翻譯+說明書】
0125-拉鉤的冷沖模設(shè)計(jì)【全套5張CAD圖+文獻(xiàn)翻譯+說明書】,全套5張CAD圖+文獻(xiàn)翻譯+說明書,拉鉤,沖模,設(shè)計(jì),全套,cad,文獻(xiàn),翻譯,說明書,仿單
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題 目： 拉鉤的冷沖模設(shè)計(jì)
一、課題意義
1、模具工業(yè)的分類
我國模具設(shè)計(jì)與制造技術(shù)的發(fā)展經(jīng)歷了手工作坊制造階段、工業(yè)化生產(chǎn)階段和現(xiàn)代化生產(chǎn)階段。伴隨著計(jì)算機(jī)技術(shù)的快速發(fā)展, 數(shù)字化、信息化CADCAE/CAM技術(shù)和數(shù)控加工機(jī)床已普遍采用, 模具產(chǎn)業(yè)正處于高速發(fā)展階段。
模具是制造業(yè)的重要基礎(chǔ)工藝裝備。模具總體上可分為兩大類: 金屬材料制件成形模具，如沖壓模具、鍛造模具、壓鑄模具、擠壓模具、拉絲模具、粉末冶金模具等; 非金屬材料制件成形模具, 如塑料注射模具、壓鑄模具、擠出模具, 橡膠制件、玻璃制件和陶瓷制件成形模具等。模具的具體分類方法很多, 如按模具結(jié)構(gòu)形式分, 沖壓模具可分為簡單模、連續(xù)模和復(fù)合模, 注塑模具可分為單分型面和雙分型面注塑模具等; 按工藝性質(zhì)分, 沖壓模具可分為沖孔模、落料模、拉深模、彎曲模，塑模具可分為壓塑模、傳遞模、注射模等。其中沖壓模具、塑料模具、鑄造模具、鍛壓模具、橡膠模具、粉末冶金模具、拉絲模具、無機(jī)材料成形模具等是最主要的八大類, 用于制造業(yè)中的幾乎所有產(chǎn)品的生產(chǎn)。[7]
2、模具工業(yè)的地位
隨著社會的發(fā)展和科技的進(jìn)步， 模具行業(yè)越來越被重視，模具技術(shù)在國民經(jīng)濟(jì)各個(gè)部門都得到廣泛的應(yīng)用，它不僅與整個(gè)機(jī)械行業(yè)密切相關(guān)，而且與人們的生活密切相關(guān)。模具工業(yè)是國民經(jīng)濟(jì)的基礎(chǔ)產(chǎn)業(yè)，模具工業(yè)的發(fā)展水平標(biāo)志著一個(gè)國家的工業(yè)水平及產(chǎn)品開發(fā)的能力。模具是生產(chǎn)各種工業(yè)產(chǎn)品的重要基礎(chǔ)工藝裝備，國民經(jīng)濟(jì)的五大支柱產(chǎn)業(yè)—機(jī)械、電子、汽車、石化、建筑等都要求模具工業(yè)的發(fā)展與之相適應(yīng)。
模具因其生產(chǎn)效率高、產(chǎn)品質(zhì)量好、材料消耗低、操作簡單、生產(chǎn)過程易于實(shí)現(xiàn)機(jī)械化與自動(dòng)化、生產(chǎn)成本低而獲得廣泛應(yīng)用，利用模具可以加工出薄壁、重量輕、剛性好、形狀復(fù)雜的零件；產(chǎn)品質(zhì)量有模具保證，具有一模一樣的的特點(diǎn)；這是其它加工制造業(yè)所無法完成的；模具是現(xiàn)代工業(yè)，特別是汽車、摩托車、航空、儀表、儀器、醫(yī)療器械、電子通信、兵器、家用電器、五金工具、日用品等工業(yè)必不可少的工藝裝備。據(jù)資料統(tǒng)計(jì)，利用模具制造的零件數(shù)量，在飛機(jī)、汽車、摩托車、拖拉機(jī)、電機(jī)、電器、儀器儀表等機(jī)電產(chǎn)品中占80%以上；在電腦、電視機(jī)、攝像機(jī)、照相機(jī)、錄像機(jī)等電子產(chǎn)品中占85%以上；在電冰箱、洗衣機(jī)、空調(diào)、電風(fēng)扇、自行車、手表等輕工業(yè)產(chǎn)品中占90%以上；在子彈、槍支等兵器產(chǎn)品中占95%以上；在日用金屬產(chǎn)品中占95%以上?？梢姡芯亢桶l(fā)展模具技術(shù)，對于促進(jìn)國民經(jīng)濟(jì)的發(fā)展具有特別重要的意義。目前，模具技術(shù)已成為衡量一個(gè)國家產(chǎn)品制造水平的重要標(biāo)志之一。[2]
3、我國模具工業(yè)的現(xiàn)狀
近年來，我國模具工業(yè)的迅速發(fā)展是大家有目共睹的，中國模具工業(yè)的現(xiàn)狀大致可以從以下3個(gè)方面來講：
（1）模具的產(chǎn)值與出口量增長明顯。從整體情況來看，我國已經(jīng)步入模具工業(yè)大國之列，但是距模具強(qiáng)國還有相當(dāng)差距。
（2）模具制造水平不斷提高。近幾年，以大型、精密、復(fù)雜、長壽命模具為代表的、技術(shù)含量較高的中高檔模具的比重進(jìn)一步提高，現(xiàn)在中高檔模具所占比重已經(jīng)達(dá)到35% 以上。模具的設(shè)計(jì)和制造水平也有了很大的發(fā)展，很多先進(jìn)的模具設(shè)計(jì)與制造技術(shù)在我國的模具企業(yè)中得到應(yīng)用，如CAD/CAE/CAM 等計(jì)算機(jī)輔助技術(shù)、高速加工技術(shù)、熱流道技術(shù)、氣輔技術(shù)、逆向工程等新技術(shù)得到廣泛應(yīng)用，E R P、P D M 等信息化管理技術(shù)正得到積極推廣，這些先進(jìn)技術(shù)的應(yīng)用和信息化管理的實(shí)施極大地提高了模具企業(yè)的生產(chǎn)效率，縮短了生產(chǎn)周期。
（3）我國模具行業(yè)已經(jīng)形成了自己的骨干隊(duì)伍。目前，我國約有模具生產(chǎn)廠點(diǎn)3 萬余家，從業(yè)人員100余萬人，在各個(gè)模具行業(yè)的骨干企業(yè)隊(duì)伍中也涌現(xiàn)出了本行業(yè)的龍頭企業(yè)。他們的生產(chǎn)裝備先進(jìn)，生產(chǎn)達(dá)到了一定規(guī)模，技術(shù)水平較高，而且產(chǎn)品具有自己的特點(diǎn)。[10]
目前，中國約有模具生產(chǎn)廠2萬余家，從業(yè)人員50多萬人，全年模具產(chǎn)值達(dá)450億元人民幣以上。近年來，模具行業(yè)結(jié)構(gòu)調(diào)整步伐加快，主要表現(xiàn)為大型、精密、復(fù)雜、長壽命模具和模具標(biāo)準(zhǔn)件發(fā)展速度高于行業(yè)的總體發(fā)展速度；塑料模和壓鑄模比例增大；面向市場的專業(yè)模具廠家數(shù)量及能力增加較快。隨著經(jīng)濟(jì)體制改革的不斷深入，“三資”及民營企業(yè)的發(fā)展很快。中國模具工業(yè)的發(fā)展在地域分布上存在不平衡性，東南沿海地區(qū)發(fā)展快于中西部地區(qū)，南方的發(fā)展快于北方。模具生產(chǎn)最集中的地區(qū)在珠江三角和長江三角地區(qū)，其模具產(chǎn)值約占全國產(chǎn)值的2/3以上。[5]
二、現(xiàn)代模具的發(fā)展前景
為了制造高精度、長壽命、高效的復(fù)雜腔結(jié)構(gòu)的現(xiàn)代模具，需解決以下３個(gè)方面的問題：
1、模具材料及其表面處理技術(shù)。模具工業(yè)要上水平，材料應(yīng)用是關(guān)鍵。因選材和用材不當(dāng)，致使模具過早失效，大約占失效模具的45%以上。在模具材料方面常用的冷作模具鋼有CrWMn、Cr12、Cr12MoV 和W6Mo5Cr4V2，新型冷作模具鋼有65Nb、O12Al、CG-2、LD、GD、GM等；常用新型熱作模具鋼有美國H 1 3、瑞典QRO 80M、QRO 90SUPREME 等；常用塑料模具用鋼有預(yù)硬鋼(P20、SM1 B30)、時(shí)效硬化型鋼(P21、PMS、SM2、日本NAK55等)、熱處理硬化型鋼(MnCrWV、日本S-STAR、瑞典－勝百S-136 等)、粉末模具鋼(日本DEX40 等);多工位精度沖模硬質(zhì)合金(YG20、YG25 等)以及鋼結(jié)構(gòu)硬質(zhì)合金( T L M W 5 0 、GW50 等)。在模具表面處理方面，主要趨勢是：由滲入單一元素向多元素共滲、復(fù)合滲(如TD 法)發(fā)展；由一般擴(kuò)散向CVD 、P V D、P C V D、離入滲入、離子注入等方向發(fā)展;可采用的鍍膜有：TiC、TiN、TiCN、TiAN、CrN、Cr7C3、W2C 等，同時(shí)熱處理手段由大氣熱處理向真空熱處理發(fā)展。另外，激光強(qiáng)化、輝光離子氮化技術(shù)也日益受到重視。
2、提高設(shè)計(jì)制造技術(shù)水平。當(dāng)代模具的設(shè)計(jì)與制造已廣泛采用計(jì)算機(jī)輔助設(shè)計(jì)與制造( C A D /CAM)，設(shè)計(jì)過程程序化和自動(dòng)化，使用程序模擬成形過程，采用交互式設(shè)計(jì)方法，發(fā)揮人和計(jì)算機(jī)的各自特長。數(shù)據(jù)庫和計(jì)算機(jī)網(wǎng)絡(luò)技術(shù)使設(shè)計(jì)人員擁有大量資料和信息。設(shè)計(jì)與制造之間的直接信息傳輸便于設(shè)計(jì)的反復(fù)修改。
3、專業(yè)化生產(chǎn)及標(biāo)準(zhǔn)化。專業(yè)化生產(chǎn)是現(xiàn)代化工業(yè)生產(chǎn)的重要特征之一，工業(yè)先進(jìn)國家模具專業(yè)化生產(chǎn)已達(dá)到75% 以上。標(biāo)準(zhǔn)化是實(shí)現(xiàn)模具專業(yè)化生產(chǎn)的基本前提，也是系統(tǒng)提高整個(gè)模具行業(yè)技術(shù)水平和經(jīng)濟(jì)效益的重要手段，這是機(jī)械制造業(yè)向深層次發(fā)展的必由之路。國外企業(yè)都極為重視模具的標(biāo)準(zhǔn)化，我國的模具標(biāo)準(zhǔn)化程度不足30%，而且標(biāo)準(zhǔn)品種少、質(zhì)量低、交貨期長，嚴(yán)重阻礙了模具的合理流向和效能的發(fā)揮，需盡快制訂標(biāo)準(zhǔn)化規(guī)范Windows 用戶界面。[3]
目前, 國內(nèi)模具市場不斷擴(kuò)大, 國際上將模具制造逐漸向我國轉(zhuǎn)移的趨勢和跨國集團(tuán)到我國進(jìn)行模具國際采購的趨向十分明顯。因此,展望未來, 國際、國內(nèi)模具市場總體發(fā)展前景美好。我國模具工業(yè)將會有一個(gè)繼續(xù)高速發(fā)展的機(jī)遇期。只要我們把握這個(gè)機(jī)遇期, 中國模具工業(yè)不但會在量和質(zhì)的方面繼續(xù)有一個(gè)很大的提高, 而且一定會在行業(yè)結(jié)構(gòu)、產(chǎn)品水平、開發(fā)創(chuàng)新能力、企業(yè)的體制與機(jī)制的方方面面取得較大進(jìn)展。
模具技術(shù)集合了機(jī)械、電子、化學(xué)、光學(xué)、材料、計(jì)算機(jī)、精密檢測和信息網(wǎng)絡(luò)等諸多學(xué)科, 是一個(gè)綜合性多學(xué)科的系統(tǒng)工程。模具技術(shù)的發(fā)展趨勢主要是模具產(chǎn)品向著更大型、更精密、更復(fù)雜及更經(jīng)濟(jì)快速的方向發(fā)展, 模具產(chǎn)品的技術(shù)含量不斷提高, 模具制造周期不斷縮短, 模具生產(chǎn)朝著信息化、無圖化、精細(xì)化、自動(dòng)化的方向發(fā)展, 模具企業(yè)向著技術(shù)集成化、設(shè)備精良化、產(chǎn)品品牌化、管理信息化、經(jīng)營國際化的方向發(fā)展。[7]
三、課題研究方法與計(jì)劃
課題的主要內(nèi)容是沖壓模具的設(shè)計(jì)，所以我首先應(yīng)該深入學(xué)習(xí)機(jī)械設(shè)計(jì)、機(jī)械CAD/CAM、冷沖壓技術(shù)等相關(guān)知識。沖壓模具是模具類別中應(yīng)用最廣泛的一種，通過模具對金屬的直接加壓使其產(chǎn)生塑性變形，從而金屬材料分離，以此來獲得一定尺寸和性能的金屬零件。模具的設(shè)計(jì)過程是和實(shí)際生產(chǎn)分不開的。我們應(yīng)該充分研究設(shè)計(jì)任務(wù)書，了解產(chǎn)品用途，并進(jìn)行沖壓件的工藝性及尺寸公差等級分析，對于一些沖壓件結(jié)構(gòu)不合理或工藝性不好的，必須征詢指導(dǎo)教師的意見后進(jìn)行改進(jìn)。在初步明確設(shè)計(jì)要求的基礎(chǔ)上，可按以下步驟進(jìn)行沖壓總體方案的論證。
1、主要任務(wù)與目標(biāo)
圖1為某電器元件—拉鉤。該零件的制造方法為冷沖壓成型，本課題要求分析封蓋沖壓件的成形工藝，設(shè)計(jì)模具，畫出模具裝配圖及所有零部件的工程圖，寫出畢業(yè)論文。
圖1 掛鉤
2、主要內(nèi)容與基本要求
（1）分析墊片的沖壓成形工藝。
（2）模具設(shè)計(jì)。此零件厚度小，形狀簡單，要求設(shè)計(jì)的模具具有高精度和高成型效率。
（3）打印圖紙，寫出畢業(yè)論文。
（4）要求學(xué)生熟悉冷沖模具設(shè)計(jì)工藝，具有較強(qiáng)的機(jī)械設(shè)計(jì)能力。設(shè)計(jì)圖紙的正確與否是評定本次設(shè)計(jì)水平的關(guān)鍵。
四、參考文獻(xiàn)
[1]劉國勝.黃石理工學(xué)院學(xué)報(bào). Journal of Huangshi Institute of Technology，2007，01
[2]蔣桂芝.模具技術(shù)在國民經(jīng)濟(jì)中的地位[J].機(jī)電產(chǎn)品開發(fā)與創(chuàng)新，2009，05
[3]洪慎章.現(xiàn)代模具技術(shù)的現(xiàn)狀及發(fā)展趨勢[J].航空制造技術(shù)，2006，06
[4]袁崇磷.模具標(biāo)準(zhǔn)件的發(fā)展趨勢及需要解決的問題[J].模具制造，2006,06
[5]曹延安.中國模具工業(yè)現(xiàn)狀[J].現(xiàn)代零部件，2009，03
[6]洪慎章.現(xiàn)代模具技術(shù)的現(xiàn)狀及發(fā)展趨勢[J].航空制造技術(shù), 2006，06
[7]周永泰.中國模具工業(yè)的現(xiàn)狀與發(fā)展[J].行業(yè)展望，2007，12
[8]機(jī)械工程師[J].Mechanical Engineer, 2006，11
[9]林承全.論沖壓模具設(shè)計(jì)制造與模具壽命的關(guān)系[J].模具制造，2008，06
[10] 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.
[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.
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外文文獻(xiàn)翻譯譯文
題 目： 拉鉤的冷沖模設(shè)計(jì)
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 for this hand phone cover. After the creation of the main insert subassembly, the mould designer loads a layout configu
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