【作者】 陈安锡；

【导师】 毛华杰；

【作者基本信息】 武汉理工大学 ， 材料加工工程， 2007， 硕士

【摘要】 气体辅助注射成型(简称气辅注射成型)技术是近年来发展起来的一项塑料成型新技术，具有注射压力低、制品翘曲变形小、表面质量好以及易于加工壁厚差异较大的制品等优点。与传统的注射成型工艺相比，气体辅助注射成型有更多的工艺参数需要确定和控制，因而对于制品设计、模具设计和成型过程的控制都有特殊的要求，而且难度很大。随着计算机硬件和软件技术的发展，使得CAE技术在气体辅助注射成型方面有了更大的应用空间。为了有效的使用这项新技术，一方面要在大量应用和实验研究的基础上，引入一些好的概率统计和优化的方法，使得加工过程中的人工经验量化；另一方面则应当重视气体辅助成型CAE软件的应用。本文总结了气道设计及布置的要求，气辅模具设计的要求以及气辅工艺参数对制品成型质量的影响。根据不对称结构制品设计的要求，建立了多个具有不同制品结构及气道结构尺寸的典型转角类和平板类气辅制件的CAD模型。利用目前比较成熟的塑料成型CAE软件MPI对上述模型进行了气体辅助注射成型过程的模拟。研究了相同成型工艺条件下，基板厚度和宽度的变化对气道穿透长度、气体薄壁穿透、气体穿透体积以及熔接痕长度等的影响规律，发现通过改变基板的厚度可以有效的控制熔体在型腔中的流动，能够有效的抑制气体向薄壁的穿透并使得熔接痕的长度变短，从而改善了制件的成型质量。根据模拟分析的结果，从质量合格的产品中提取相应的气辅工艺参数。以气道半径、气道长度、气道两侧板宽比及其相应的壁厚比作为自变量，分别以熔体预注射量、切换延迟时间、气体压力、气体注射保压时间作为因变量，运用Matlab软件对上述自变量和因变量进行多元线性回归分析，得出了转角结构和平板结构的气辅工艺参数回归方程。最后分别对转角结构和平板结构的气辅工艺参数回归方程进行了显著性检验，验证了气辅工艺参数与制件结构和气道结构参数之间具有明显的线性相关性。对任意给定的转角类和平板类气辅制件设计参数，利用气辅工艺参数回归方程预测出了气辅成型工艺参数及其相应的置信区间。更多还原

【Abstract】 Gas assisted injection molding (GAIM), developed quickly in recent years, is anew kind of polymer processing technology.It has many advantages such as lowerinjection pressure, less warpage, better surface quality and easily processing productwith different wall thickness etc. Compared with traditional injection molding, GAIMhas more process variables needed to be specified and controlled, and therefore hassome special demand in processing control, product and mould design. With thedevelopment of computer hardware and software, there will be more space for usingCAE teclmology in GAIM. For the purpose of using this technology effectively, onone hand, we should introduce some better probability statistics and optimizationmeans to make the artificial experience quantized based on plenty of applications andexperiments; on the other hand, we should pay attention to the applications of CAEsoftware for GAIM.In this article, the arrangement and size design of gas channel, mould design andGAIM processing parameters to product quality were summarized. According to thedesign demand for unsymmetrical structure, created several typical CAD models withdifferent product and gas channel dimensions for rotation angle and planar structure.Use MPI, the mature plastic processing software, to simulate the GAIM process ofthe above CAD models. Under the same processing conditions, the influence ofthickness and breadth of base plate to gas channel penetration length, finger effectand melting-joint imprint were studied. Found that the melt flow can be effectivelycontrolled, the gas penetration to thin wall can be evidently restrained and the lengthof melting-joint imprint can be decreased by changing the thickness of base plate. Sothe quality of the product was improved. According to the simulation results, extractthe corresponding GAIM process parameters from the qualified product.Make the radius of gas channel, length of gas channel, ratio of breadth oftwo-sided cardinal plates and ratio of thickness of two-sided cardinal plates asindependent variables. Also, make the short shot, delay time, gas pressure, gasinjection time as dependent variables. Do the multiple regression analysis of thedependent and independent variables respectively with Matlb, so the regressionequation of GAIM processing parameters for the rotation angle and planar structurewere obtained.Finally, by testing the significance of the regression equation of GAIMprocessing parameters, verified that there was conspicuous linear correlation betweenGAIM process parameters and product and gas channel structure parameters. For thedesign parameters of any rotation angle and planar structure, using the regressionequation of GAIM processing parameters to predict the GAIM process parametersand its confidence interval.更多还原