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編號(hào)
無(wú)錫太湖學(xué)院
畢業(yè)設(shè)計(jì)（論文）
相關(guān)資料
題目：基于Pro/E的便攜式手機(jī)充電器
上蓋注塑模設(shè)計(jì)
信機(jī) 系 機(jī)械工程及其自動(dòng)化 專(zhuān)業(yè)
學(xué) 號(hào)： 0923225
學(xué)生姓名： 顧 亞 勵(lì)
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(jì)（論文）開(kāi)題報(bào)告
二、畢業(yè)設(shè)計(jì)（論文）外文資料翻譯及原文
三、學(xué)生“畢業(yè)論文（論文）計(jì)劃、進(jìn)度、檢查及落實(shí)表”
四、實(shí)習(xí)鑒定表
無(wú)錫太湖學(xué)院
畢業(yè)設(shè)計(jì)（論文）
開(kāi)題報(bào)告
題目：基于Pro/E的便攜式手機(jī)充電器
上蓋注塑模設(shè)計(jì)
信機(jī) 系 機(jī)械工程及自動(dòng)化 專(zhuān)業(yè)
學(xué) 號(hào)： 0923225
學(xué)生姓名： 顧 亞 勵(lì)
指導(dǎo)教師： 曹亞玲 （職稱：講師 ）
（職稱： ）
2012年11月25日
課題來(lái)源
本課題來(lái)源于生活生產(chǎn)實(shí)際。
科學(xué)依據(jù)（包括課題的科學(xué)意義；國(guó)內(nèi)外研究概況、水平和發(fā)展趨勢(shì)；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(jì)算機(jī)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(guò)程中，塑料模具的應(yīng)用及其廣泛，在各類(lèi)模具中的地位也越來(lái)越突出，成為各類(lèi)模具設(shè)計(jì)、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(dāng)今市場(chǎng)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(chǎng)需求量。所以我選充電器注塑模具設(shè)計(jì)作為我畢業(yè)設(shè)計(jì)的課題。
本課題應(yīng)用性強(qiáng)，涉及的知識(shí)面與知識(shí)點(diǎn)較多，如注塑成型、模具設(shè)計(jì)、三維造型、運(yùn)動(dòng)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(lái)我國(guó)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(jī)全套塑料模具以及汽車(chē)保險(xiǎn)杠和整體儀表板等塑料模具。機(jī)密塑料模具方面，已能生產(chǎn)照相機(jī)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(jī)構(gòu)的創(chuàng)新業(yè)取得了較大進(jìn)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(kāi)始推廣，有些單位還采用具有世界先進(jìn)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(gè)新臺(tái)階，一些企業(yè)引進(jìn)CAD/CAM系統(tǒng)，并能支持CAE技術(shù)對(duì)成形過(guò)程進(jìn)行分析。近年來(lái)我國(guó)自主開(kāi)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(kāi)發(fā)的CAXA系統(tǒng)、華中理工大學(xué)開(kāi)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(jì)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(biāo)準(zhǔn)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(duì)各類(lèi)模具型件所采用的高性能、易切削的專(zhuān)用材料，以提高模具使用性能；為適應(yīng)市場(chǎng)多樣化和個(gè)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(lái)5～20年注塑模具生產(chǎn)技術(shù)的總體發(fā)展趨勢(shì)，具體表現(xiàn)在以下幾個(gè)方面：
1.提高大型、精密、復(fù)雜、長(zhǎng)壽命模具的設(shè)計(jì)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(jì)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(jì)與成型過(guò)程的3D分析將在我國(guó)塑料模具工業(yè)中發(fā)揮越來(lái)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(xiàng)技術(shù)是塑料模具的一大變革。制訂熱流道元器件的國(guó)家標(biāo)準(zhǔn)，積極生產(chǎn)價(jià)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(jì)和控制的難度較大，因此，開(kāi)發(fā)氣體輔助成型流動(dòng)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(kāi)發(fā)高壓注射成型工藝與模具也非常重要。
4.開(kāi)發(fā)新的成型工藝和快速經(jīng)濟(jì)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(biāo)準(zhǔn)化水平和標(biāo)準(zhǔn)件的使用率。我國(guó)模具標(biāo)準(zhǔn)件水平和模具標(biāo)準(zhǔn)化程度仍較低，與國(guó)外差距甚大，在一定程度上制約著我國(guó)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(biāo)準(zhǔn)件的應(yīng)用要大力推廣。為此，首先要制訂統(tǒng)一的國(guó)家標(biāo)準(zhǔn)，并嚴(yán)格按標(biāo)準(zhǔn)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(biāo)準(zhǔn)件質(zhì)量、降低成本；再次是要進(jìn)一步增加標(biāo)準(zhǔn)件的規(guī)格品種。
6.應(yīng)用優(yōu)質(zhì)材料和先進(jìn)的表面處理技術(shù)對(duì)于提高模具壽命和質(zhì)量顯得十分必要。
研究?jī)?nèi)容
本課題主要是針對(duì)顯示器后蓋的模具設(shè)計(jì),通過(guò)對(duì)塑件進(jìn)行工藝的分析和比較,最終設(shè)計(jì)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(guò)查閱相關(guān)資料，對(duì)塑件的材料進(jìn)行分析和選用，并且對(duì)塑件的結(jié)構(gòu)，成型工藝進(jìn)行分析和確定。
模具的設(shè)計(jì)需要對(duì)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(jī)的選擇及有關(guān)參數(shù)的校核、都有詳細(xì)的設(shè)計(jì)，同時(shí)并簡(jiǎn)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(jì)包括分型面的設(shè)計(jì)，澆注系統(tǒng)的設(shè)計(jì)，成型零件的工作尺寸和外形尺寸的設(shè)計(jì)
模架的設(shè)計(jì)包括模架的組成，相關(guān)零部件的尺寸設(shè)計(jì)，各零部件的用途，以及模擬模架的開(kāi)模，合模。
最后還要有對(duì)成型零件，模架的安裝尺寸，合模力，頂出力，開(kāi)模行程的校核，確保所設(shè)計(jì)的模具符合要求。
擬采取的研究方法、技術(shù)路線、實(shí)驗(yàn)方案及可行性分析
研究方法：通過(guò)閱讀有關(guān)資料，文獻(xiàn)，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(yùn)用所學(xué)理論知識(shí)研究論文課題。
方案設(shè)計(jì)：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(jì)：在方案設(shè)計(jì)的基礎(chǔ)上，進(jìn)一步設(shè)計(jì)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(jì)計(jì)算。注塑壓力、注射的塑件的體積，所需原來(lái)的體積，成型時(shí)間確定，確定各主要零件的外形尺寸，計(jì)算模具的閉合高度，確定所用注塑機(jī)。
4． 繪制注塑?？傃b圖
5．通過(guò)對(duì)論文課題的學(xué)習(xí)研究，達(dá)到鞏固，擴(kuò)大，深化已學(xué)理論知識(shí)，提高思考分析解決實(shí)際問(wèn)題等綜合素質(zhì)的目的。
研究計(jì)劃及預(yù)期成果
研究計(jì)劃：實(shí)習(xí)調(diào)研、開(kāi)題準(zhǔn)備、工藝設(shè)計(jì)和擬定、模具結(jié)構(gòu)設(shè)計(jì)、編寫(xiě)設(shè)計(jì)說(shuō)明書(shū)。
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(xiě)開(kāi)題報(bào)告書(shū)。
2012年12月30日-2013年1月20日：填寫(xiě)畢業(yè)實(shí)習(xí)報(bào)告。
2013年3月11日-2013年3月15日：學(xué)習(xí)模具設(shè)計(jì)以及相關(guān)知識(shí)，考慮設(shè)計(jì)。
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(jì)要求及批量，計(jì)算塑件的體積和質(zhì)量，注塑機(jī)的確定；模具成型零件的工作尺寸有關(guān)計(jì)算；圖表配圖設(shè)計(jì)及相關(guān)計(jì)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(xiě)和修改工作。
預(yù)期成果：
本課題旨在通過(guò)對(duì)顯示器外殼產(chǎn)品的模具設(shè)計(jì)，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(duì)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(jìn)行一般的塑件產(chǎn)品設(shè)計(jì)。掌握各類(lèi)塑料模具結(jié)構(gòu)特點(diǎn)，零部件設(shè)計(jì)與計(jì)算，具備獨(dú)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(shí)。培養(yǎng)分析問(wèn)題以及運(yùn)用所學(xué)知識(shí)解決實(shí)際工程問(wèn)題的綜合能力。
特色或創(chuàng)新之處
手機(jī)充電器是我們?nèi)粘Ｉ钪胁豢扇鄙俚碾娖?，各個(gè)廠商生產(chǎn)的便攜式手機(jī)充電器都不一樣，但是現(xiàn)在越來(lái)越多的消費(fèi)者注重了便攜式手機(jī)充電器的外觀、實(shí)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(fèi)者的喜愛(ài)，所以各個(gè)生產(chǎn)廠商努力設(shè)計(jì)生產(chǎn)出各種新穎時(shí)尚切安全使用的便攜式手機(jī)充電器吸引消費(fèi)者的眼球。
已具備的條件和尚需解決的問(wèn)題
已具備的條件：
已具備的條件：已學(xué)過(guò)的塑料成型加工工藝、注塑模具的設(shè)計(jì)，并結(jié)合日常生活中所積累的相關(guān)知識(shí)，詢問(wèn)老師和有工作經(jīng)驗(yàn)者，同時(shí)有部分可參考的同類(lèi)設(shè)計(jì)資料及圖紙。
尚需解決的問(wèn)題：缺乏實(shí)踐經(jīng)驗(yàn)，并需要老師在設(shè)計(jì)過(guò)程中加以指導(dǎo)
尚需解決的問(wèn)題：
理論與實(shí)踐有著不可避免的差距，由于沒(méi)有設(shè)計(jì)經(jīng)驗(yàn)，在實(shí)際設(shè)計(jì)時(shí)，會(huì)遇到許多問(wèn)題。而且平時(shí)沒(méi)把三維軟件學(xué)好，設(shè)計(jì)繪圖時(shí)耗費(fèi)很大精力和時(shí)間。自身設(shè)計(jì)能力需要實(shí)踐經(jīng)驗(yàn)進(jìn)一步加強(qiáng)鞏固。
指導(dǎo)教師意見(jiàn)
指導(dǎo)教師簽名：
年 月 日
教研室（學(xué)科組、研究所）意見(jiàn)
教研室主任簽名：
年 月 日
系意見(jiàn)
主管領(lǐng)導(dǎo)簽名：
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