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以一个具有气辅成型典型结构的塑料制品为研究对象,通过物理实验和全三维数值模拟结合的方法,研究了不同延迟时间时的气辅成型中气体穿透行为,对结果进行了分析和探讨。结果表明,延迟时间对气体穿透长度、气指尺度和残余壁厚等衡量气辅成型质量的关键参数有较大的影响。 相似文献
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为了建立气辅控制系统的控制模型,系统研究了气辅注射工艺参数对气辅共注成型过程的影响规律。研究表明,保压时间和气体注射延迟时间对气辅共注成型的气体穿透有较大影响,而对芯层熔体的穿透影响不明显。随着保压时间的延长,气体的穿透深度和穿透宽度均增加,而随着气体注射延迟时间的延长,气体穿透深度增大,穿透宽度减小。延长气体注射延迟时间有利于气体的穿透,但易出现指进现象和气体穿透流动的不稳定。 相似文献
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气体辅助注射成型工艺凭借其特有的技术优势,近年来得到了广泛的研究及实际工程应用.并正成为塑料成型加工业中的新贵。本文探讨了气体辅助注射成型工艺流程。分析了气道中空效果对气辅件品质的影响。由于气道中空效果是气体穿透效果的直接反映。因此在文中较全面地论述了成型工艺对气体穿透效果的影响。通过运用有限元数值分析手段,预测气辅成型气体穿透效果。寻求最佳塑件中空效果的工艺参数。 相似文献
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基于纯水液压水辅助注射成型设备,将水辅成型技术与传统注塑行业结合起来,以自行车前叉为模具,成型自行车前叉制件.主要从制件水穿透长度,中空率及残余壁厚等方面对试验结果进行分析,结果表明,在适当注塑工艺参数条件下.水辅成型技术能应用于自行车前叉的成型. 相似文献
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气辅注射成型的影响因素有很多,选取四因素三水平正交表,通过正交试验法,利用CAE软件Moldflow分析了不同工艺参数对气体穿透的影响,用极差法分析了各因素对气体穿透的影响程度,最后对工艺参数进行了优化组合. 相似文献
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对先进的气辅共注成型工艺进行了系统的实验研究,研究了熔体注射温度、气体压力这两种工艺参数对气辅共注成型气体和芯层熔体穿透形貌的影响规律,并基于聚合物流变学和流体动力学揭示了这些工艺参数对成型过程的影响机理。结果表明,随着芯层熔体温度升高,芯层熔体的黏度会减小,流动阻力减小,使得气腔的穿透深度减小,而穿透宽度和穿透厚度则增大,但芯层熔体的穿透长度变化不明显;随着注气压力增大,气体的穿透深度、穿透宽度和穿透厚度均增大。 相似文献
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To understand the crystalline morphology of the parts molded by gas-assisted injection molding (GAIM), in this work, the hierarchical structures and the crystalline morphology of gas-assisted injection molded high-density polyethylene (HDPE) were investigated. According to the comparison between the results of the GAIM part and those of the conventional injection molded counterpart, it is found that gas penetration can remarkably enhance the shear rate during GAIM process and oriented lamellar structure, shish-kebab structure and common spherulites arise in the skin, subskin and gas channel region, respectively, owing to the different shear rate in these regions. Meanwhile, cooling rate also plays an important role in the formation of the oriented crystalline structure. 相似文献
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《塑料、橡胶和复合材料》2013,42(2-3):113-119
AbstractInvestigation of the characteristics of gas penetration in gas-assisted injection moulding (GAIM) of parts plays an important role in the successful application of gas-assisted injection moulding. Although these have been proposed by various investigators, quantitative rules based on well designed experiments on fibre-reinforced plastic materials have not been reported previously. Additions of glass-fibre bring about rather dramatic changes in material viscosity and heat conductivity, etc. In the present paper, spiral tube moulds with uniform diameters of 8 and 10 mm, respectively, and a plate mould of 3 mm thickness with gas channel design of semicircular crosssection were moulded using glass-fibre reinforced Nylon resin. The effects of fibre content, tube diameter, and processing parameters, including gas pressure, delay time, and injection stroke on gas penetration characteristics and mouldability for fibre-reinforced Nylon parts were investigated experimentally. It was found that the coating melt thickness decreases with increasing gas pressure, until the gas pressure reaches a critical value, when the coating melt thickness becomes relatively constant for the spiral tube. Meanwhile, using a longer delay time for gas injection will increase the skin melt thickness. The hollowed core ratio increases with increasing diameter of spiral tube. Alternatively, the hollowed core ratio of GAIM plate and spiral tube parts increases when the content of glass-fibre is increased. However, when the fibre content is over 10 wt-%, it shows less influence on the hollowed core ratio for plate parts. Furthermore, although the area of the moulding window decreases with increasing content of fibre, they all show good mouldability. From these results, one can provide an empirical formula to CAE simulation designers and part/mould designers for GAIM fibre-reinforced Nylon parts to achieve suitable mouldability and accurate CAE simulation. 相似文献
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运用MoldFlow软件对把手零件的气辅注塑成型过程进行CAE分析,结合气辅成型原理优化了浇口、进气口的位置,总结了气辅CAE的工作流程,分析了各工艺参数对产品壁厚、气道长度的影响,并调整参数,得到了满足设计要求的制品。 相似文献
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Guo‐Qiang Zheng Wei Yang Ming‐Bo Yang Jing‐Bo Chen Qian Li Chang‐Yu Shen 《Polymer Engineering and Science》2008,48(5):976-986
In this article, gas penetration‐induced skin‐core structure of isotactic polypropylene(iPP), which is molded by gas‐assisted injection molding at different gas pressures, was investigated. For comparison, the counterpart was also molded by conventional injection molding (CIM) using the same processing parameters but without gas penetration. They were characterized via PLM, DSC, and SEM. And the crystal morphology at different gas pressures was principally concerned. For the GAIM parts, highly oriented structure is formed in the skin zone, and much less oriented structure in the inner zone (near the gas channel surface). Furthermore, it is suggested that the naked shish structure can be developed in the skin zone of GAIM part, which is molded at higher gas pressures, and shish‐kebab structure is mainly formed in the skin zone of that, which is molded at lower gas pressure. However, for the CIM part, from the skin to the core zone, the dominant morphological feature is spherulite. In a word, the presence of gas penetration notably enhances the oriented structure formation and gives rise to the skin‐core structure. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers 相似文献