An experimental study of the water-assisted injection molding of glass fiber filled poly-butylene-terephthalate (PBT) composites
An experimental study of the water-assisted injection molding of glass fiber filled poly-butylene-terephthalate (PBT) composites
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DOI：
10.1016/j.compscitech.2006.09.016
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发表时间：
2007-06
影响因子：
9.1
通讯作者：
Shih-Jung Liu;M. Lin;Yi-Chuan Wu
中科院分区：
文献类型：
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作者：
Shih-Jung Liu;M. Lin;Yi-Chuan Wu
本文对聚对苯二甲酸丁二醇酯(PBT)复合材料的水辅助注射成型工艺进行了实验研究。实验在一台80吨重的注塑机上进行，该注塑机配备了实验室规模的注水系统，包括水泵、蓄压器、注水销、配备温度调节器的水箱和控制电路。材料包括纯PBT和15%玻璃纤维填充的PBT复合材料，采用中心带肋骨的平板空腔。考察了各种工艺参数对注塑件透水长度的影响，并对这些零件进行了力学性能测试。利用X射线衍射仪(X射线衍射仪)对材料和结构参数进行表征。最后，对水辅和气辅注塑制品进行了比较。研究发现，熔体充填压力、熔体温度和短丸尺寸是影响渗水行为的主要参数。结晶器侧的结晶度高于水侧的结晶度。气体成型的零件也比水成型的零件显示出更高的结晶度。此外，还发现靠近注塑件表面的玻璃纤维主要沿流动方向取向，但随着与蒙皮表面距离的增加，玻璃纤维基本上与流动方向垂直。
The purpose of this report was to experimentally study the water-assisted injection molding process of poly-butylene-terephthalate (PBT) composites. Experiments were carried out on an 80-ton injection-molding machine equipped with a lab scale water injection system, which included a water pump, a pressure accumulator, a water injection pin, a water tank equipped with a temperature regulator, and a control circuit. The materials included virgin PBT and a 15% glass fiber filled PBT composite, and a plate cavity with a rib across center was used. Various processing variables were examined in terms of their influence on the length of water penetration in molded parts, and mechanical property tests were performed on these parts. X-ray diffraction (XRD) was also used to identify the material and structural parameters. Finally, a comparison was made between water-assisted and gas-assisted injection molded parts. It was found that the melt fill pressure, melt temperature, and short shot size were the dominant parameters affecting water penetration behavior. Material at the mold-side exhibited a higher degree of crystallinity than that at the water-side. Parts molded by gas also showed a higher degree of crystallinity than those molded by water. Furthermore, the glass fibers near the surface of molded parts were found to be oriented mostly in the flow direction, but oriented substantially more perpendicular to the flow direction with increasing distance from the skin surface.