2023年全國(guó)碩士研究生考試考研英語(yǔ)一試題真題(含答案詳解+作文范文)_第1頁(yè)
已閱讀1頁(yè),還剩6頁(yè)未讀, 繼續(xù)免費(fèi)閱讀

下載本文檔

版權(quán)說(shuō)明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請(qǐng)進(jìn)行舉報(bào)或認(rèn)領(lǐng)

文檔簡(jiǎn)介

1、<p>  Modeling and Analysis of Process Parameters for Evaluating Shrinkage Problems During Plastic Injection Molding of a DVD-ROM Cover</p><p>  Plastic injection molding plays a key role in the product

2、ion of high-quality plastic parts. Shrinkage is one of the most signi?cant problems of a plastic part in terms of quality in the plastic injection molding. This article focuses on the study of the modeling and analysis o

3、f the effects of process parameters on the shrinkage by evaluating the quality of the plastic part of a DVD-ROM cover made with Acrylonitrile Butadiene Styrene(ABS) polymer material. An effective regression

4、 mo</p><p>  Keywords:plastic injection molding, regression modeling andANOVA,shrinkage</p><p>  1、Introduction</p><p>  Injection molding is one of the most ef?cient processes in m

5、ass production of manufactured plastic part with thin-shell features. The quality of the plastic part depends on the material characteristics, the mold design, and the process parameters, one of which is more important.

6、Several studies found that the injection molding process parameters have crucial effects on the quality of the plastic parts. They investigated the problems of the injection molding part such as the shrinkage,warpage, we

7、</p><p>  statistically a key role in determining the quality of the plastic part. On the other hand, in the studies above, it is not employed any molding simulation tool (Mold ?ow analysis) for comparing th

8、e experimental results.</p><p>  However, there are many articles investigating the simulation of the plastic injection molding which are in?uenced by the process parameters on the quality problems. One of t

9、he most signi?cant of these articles is successfully applied by Chen et al. This article deals with the application of computer-aided engineering integrating with statistical technique to reduce the warpage based on the

10、plastic injection parameters. For this purpose, a number of Mold?ow analyses dependent on the Taguchi orth</p><p>  2. Experimental Methodology</p><p>  2.1 Taguchi Orthogonal Array Design of Ex

11、periments</p><p>  The design of experiments utilizing the orthogonal arrays is, in most cases, efficient and easy to use when compared to the traditional experimental design methods. It is necessary to redu

12、ce and to control the number of experiments. Furthermore, a large number of experiments have to be performed when the number of process parameters increases. In this study, 27 FE analyses based on Taguchi (L27) orthogona

13、l arrays were run by utilizing plastic injection process parameters such as the mold tempera</p><p>  2.2 Mold Design and Manufacturing</p><p>  When producing a plastic part, the molds must be

14、designed and manufactured using various machines. In this study, the steps applied for manufacturing the plastic product of the DVD-ROM cover are described and shown in Fig. 1. </p><p>  In the plastic injec

15、tion molding, the CAD model of the plastic product of the DVD-ROM cover was designed in the Pro/Engineer Wildfire CAD/CAM program. Also, the mold designed for the DVD-ROM cover consisted of two clamping plates, a core pl

16、ates, and pins. In fabricating the mold components, some machines such as CNC milling, EDM machining, drilling, and grinding were employed. The material utilized for the mold components was selected as DIN 1.2738 (IMPAX)

17、 steel. This materials hardness was meas</p><p>  2.3 Finite Element (FE) Analysis and Molding Cycle</p><p>  2.3.1 FE Pre-Processing of the DVD-ROM Cover. </p><p>  The 3D model of

18、 the DVD-ROM cover part was imported into the Moldflow Plastic Insight 5.0 (MPI 5.0) . The DVD-ROM cover part has dimensions of 153, 45.17, and 7 mm. The polymer material (ABS) for the DVD-ROM cover part was composed of

19、CMOLD generic estimates, and its material properties are listed in Table 4. The ABS polymer material was also dried for 4 h using a drier before the molding cycle. The FE model of the DVD-ROM part was created by discrete

20、 geometry into the smaller simple elements. T</p><p>  2.3.2 Molding Cycle of the DVD-ROM Cover. </p><p>  The mold components were designed and manufactured to inject the plastic material of th

21、e DVD-ROM cover part, which is mounted on the front of a computer body to fix a DVD within a DVD-ROM. The plastic injection machine which is used in this study was a NETSTAL (600 H-110 60 tons 1.66 oz (25 mm)) made in Sw

22、itzerland. This plastic injection machine has the technical specifications of a maximum clamp force of 543 tons, a maximum injection pressure of 243 MPa, a maximum injection rate of 491 cm3/s ,</p><p>  DVD-

23、ROM上蓋的建模和注塑成型工藝對(duì)收縮率影響的分析</p><p>  塑料注射成型在生產(chǎn)高品質(zhì)塑料零件中發(fā)揮著關(guān)鍵的作用。收縮是影響注塑成型零件質(zhì)量最重要的因素之一。本文通過(guò)評(píng)估丙烯腈-丁二烯-苯乙烯共聚物(ABS)材質(zhì)的DVD-ROM上蓋質(zhì)量著重研究建模和注塑成型工藝對(duì)收縮率的影響。通過(guò)數(shù)據(jù)分析確定工藝參數(shù)(模具溫度、熔點(diǎn)、注射壓力、注射時(shí)間和冷卻時(shí)間)與收縮率之間的數(shù)學(xué)關(guān)系開(kāi)發(fā)一個(gè)有效的回歸模型。有限元 (F

24、E) 分析 (L27)田口所設(shè)計(jì)Mold?ow仿真程序中運(yùn)行的正交數(shù)組。通過(guò)方差分析(ANOVA)校驗(yàn)回歸模型并確定工藝參數(shù)對(duì)收縮率的影響。通過(guò)Mold?ow仿真分析,可獲得有限元分析與控制的回歸模型的準(zhǔn)確性。結(jié)果顯示回歸模型與有限元分析實(shí)驗(yàn)的結(jié)果高度一致。由此可以得出結(jié)論這項(xiàng)建模的收縮問(wèn)題在我們的應(yīng)用程序中研究成功。</p><p>  關(guān)鍵詞:塑料注塑成型,回歸建模和方差分析,收縮。</p>&

25、lt;p><b>  1 前言</b></p><p>  注射成型是批量生產(chǎn)制造薄殼塑料零件常用的加工方法之一。塑料部件的質(zhì)量取決于材料的特性、 模具設(shè)計(jì)和最重要的工藝參數(shù)。幾項(xiàng)研究發(fā)現(xiàn),注射成型的工藝參數(shù)對(duì)塑料部件的質(zhì)量都有關(guān)鍵的影響。他們調(diào)查注射成型工藝在生產(chǎn)過(guò)程中零部件的收縮、 彎曲、 熔合紋、凹陷和殘余應(yīng)力等問(wèn)題。他們的研究還顯示影響塑料部件質(zhì)量的最重要參數(shù)是保壓、 熔化溫度

26、和模具溫度。然而,這些研究沒(méi)有充分考慮到其他包括注射時(shí)間和冷卻時(shí)間等工藝參數(shù)的影響。此外,德米雷爾有對(duì)收縮和翹曲變形導(dǎo)致部件質(zhì)量問(wèn)題的計(jì)算進(jìn)行實(shí)驗(yàn)研究。這項(xiàng)研究還表明了收縮和翹曲變形隨著溫度的升高和注射壓力的降低而增加。在這個(gè)研究中,雖然沒(méi)有考慮到主要影響工藝參數(shù)注射時(shí)間和冷卻時(shí)間,但是這些實(shí)驗(yàn)條件足夠得出寶貴的結(jié)論。許多發(fā)表的論文指出,在薄殼塑料部件的注射成型中,工藝參數(shù)和影響零塑件質(zhì)量問(wèn)題的收縮與彎曲可以建立物理關(guān)系。在以往的研究中

27、,進(jìn)行一系列的試驗(yàn)來(lái)測(cè)量收縮和翹曲變形下的工藝參數(shù)的值。通過(guò)數(shù)學(xué)模型利用測(cè)量的值確定最佳工藝參數(shù)。以類似的方式,利用回歸分析取得薄殼塑料零件注射成型工藝參數(shù)與通過(guò)實(shí)驗(yàn)獲得的收縮率之間的關(guān)系。通過(guò)工藝參數(shù)與收縮率的數(shù)學(xué)關(guān)系式創(chuàng)建二階廣</p><p>  其中一篇由Chen et al寫的文章具有典型代表性。這篇文章涉及到計(jì)算機(jī)輔助工程結(jié)合統(tǒng)計(jì)技術(shù)應(yīng)用,用以減少塑料注塑參數(shù)引起的翹曲變形。為此,一些依賴田口正交數(shù)組

28、的模塑仿真分析、回歸方程和方差分析(ANOVA) 可以結(jié)合預(yù)測(cè)各種注塑參數(shù)引起的翹曲變形。但是,這篇文章只是簡(jiǎn)單說(shuō)明了塑料注塑過(guò)程中的翹曲變形而未提到收縮。然而,由Chen等人寫的另一篇文章負(fù)責(zé)通過(guò)利用一系列模塑仿真分析研究注塑模制品收縮率變化有影響的有效參數(shù)。與上述研究結(jié)果不同的是,由阿爾坦做的一項(xiàng)研究使用田口方法、方差分析和模擬腦神經(jīng)網(wǎng)絡(luò)使注塑成型收縮減小。進(jìn)行了二十七次注射成型試驗(yàn)獲得的聚丙烯 (PP)、 聚苯乙烯 (PS) 兩種

29、不同的聚合物材料的收縮量。從這項(xiàng)研究可以看到通過(guò)綜合辦法可以獲得最佳工藝條件對(duì)應(yīng)的最小收縮量。與從上述論文不同的是,一些研究人員只研究電火花加工(EDM) 。總之,即使這些研究者工作在不同領(lǐng)域,但他們有采用和塑料注射成型類似的方法。從這項(xiàng)研究中,從模塑仿真分析模擬得到以有限元分析為基礎(chǔ)的有效回歸模型可獲得塑料注塑工藝參數(shù) (模具溫度、 熔化溫度、 注射壓力、 注射時(shí)間和冷卻時(shí)間) 和使用 ABS</p><p>

30、<b>  2.實(shí)驗(yàn)研究方法</b></p><p>  2.1田口正交數(shù)組設(shè)計(jì)實(shí)驗(yàn)</p><p>  利用正交數(shù)組的實(shí)驗(yàn)設(shè)計(jì)方法,在大多數(shù)情況下,高效方便的實(shí)驗(yàn)方法與傳統(tǒng)的試驗(yàn)設(shè)計(jì)方法相比,有必要減少和控制實(shí)驗(yàn)次數(shù)。此外,當(dāng)工藝參數(shù)增加時(shí),必須要進(jìn)行大量的實(shí)驗(yàn)。在此研究中,27 FE 分析基于田口正交數(shù)組(L27)對(duì)塑料注塑工藝參數(shù)的研究,包括:模具溫度 (T 模

31、),運(yùn)行熔融溫度 (T 熔體),注射壓力 (P 注射用),(I 時(shí)間),注射時(shí)間和冷卻時(shí)間 (C) 如表 1 所示。收縮參數(shù)值對(duì)應(yīng)回歸模型中的響應(yīng)值。在表 2 中提供了從模塑仿真分析軟件模擬有限元分析取得的收縮率結(jié)果。</p><p><b>  2.2模具設(shè)計(jì)制造</b></p><p>  當(dāng)生產(chǎn)一個(gè)塑料部件的時(shí)候,模具必須經(jīng)過(guò)各種機(jī)械設(shè)計(jì)和制造。在此研究中,適用

32、于制造DVD-ROM上蓋塑料產(chǎn)品的的步驟說(shuō)明如圖1所示。在塑料注射成型中,用Pro/Engineer CAD/CAM 程序設(shè)計(jì)DVD-ROM上蓋塑料制品的CAD模型。此外,DVD ROM上蓋模具設(shè)計(jì)包括了兩個(gè)夾緊板、核心板和針腳。在制作模具組件中,會(huì)用到一些機(jī)械設(shè)備,如數(shù)控銑床、電火花加工、鉆和磨。DIN 1.2738 (IMPAX) 鋼被選為模具元件的材料。用沃伯特英斯特朗儀器測(cè)量此材料的硬度達(dá)到31HRC,表3中列出了它的化學(xué)成分。

33、</p><p>  2.3 有限元 (FE) 分析和成型周期</p><p>  2.3.1 FE 的預(yù)先處理,DVD-ROM蓋。</p><p>  3D模型的DVD-ROM上蓋部分被導(dǎo)入到Moldflow Plastic Insight 5.0(MPI 5.0)塑料仿真模擬軟件。DVD-ROM上蓋的尺寸為153mm×45.17mm×7mm。

34、DVD-ROM上蓋的材料高分子聚合物(ABS)由模流分析類似的推測(cè)而來(lái),在表4中列出了其材料屬性。在成型之前需要用干燥機(jī)烘高分子材料ABS四個(gè)小時(shí)。DVD-ROM 部件的有限元模型是利用離散幾何由較小的簡(jiǎn)單元素創(chuàng)建的。有限元融合網(wǎng)格模型,如圖 2 所示由 2726年節(jié)點(diǎn)、69 梁元素和5318三角元素組成。</p><p>  2.3.2 DVD-ROM上蓋的成型周期。</p><p>

溫馨提示

  • 1. 本站所有資源如無(wú)特殊說(shuō)明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請(qǐng)下載最新的WinRAR軟件解壓。
  • 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請(qǐng)聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
  • 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁(yè)內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒(méi)有圖紙預(yù)覽就沒(méi)有圖紙。
  • 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
  • 5. 眾賞文庫(kù)僅提供信息存儲(chǔ)空間,僅對(duì)用戶上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對(duì)用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對(duì)任何下載內(nèi)容負(fù)責(zé)。
  • 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請(qǐng)與我們聯(lián)系,我們立即糾正。
  • 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶因使用這些下載資源對(duì)自己和他人造成任何形式的傷害或損失。

最新文檔

評(píng)論

0/150

提交評(píng)論