Study on processing mechanism to reinforce weld line strength by advanced methods for micro injection molding

微注射成型作为一种新型的制造技术，受到了世界各国的广泛关注。焊接线是普通注射成型和微注射成型中常见而又不利的缺陷。因此，全面了解焊缝发育理论对提高注塑件质量具有重要意义。目前，在普通尺寸注射成型领域对焊缝现象的研究已经成熟，但在微尺寸注射成型领域，对焊缝现象的研究还不够集中。本课题将考虑冷焊缝和热焊缝，建立微尺度焊缝成形过程的模拟方法，以预测微注射成型过程中焊缝的强度和位置。此外，还研究了工艺参数、微通道截面形状和V形缺口等因素对微注射成型焊缝力学性能的影响。并对焊缝成形过程中的微流体行为和V形缺口的形成进行了全面的探讨。此外，还将检查不同材料的焊缝性能，如结晶聚合物、非晶聚合物、短纤维树脂和金属颗粒填充聚合物。此外，还将开发机械性能测试方法。

As a novel fabrication technology, micro injection molding is drawn much attention all over the worlds. Weld line is a usual but unfavorable flaw both in normal and in micro injection molding process. Therefore, it is important for improving the quality of injection molding parts that the weld line developing theory is understood completely. Nowadays, the weld line phenomena in normal size injection molding field has been studied maturely, but as for micro injection molding, the concentration is not enough adequate. In this project, the cold and the hot weld lines will be considered and the simulating method for micro scale weld lines forming process is intended to be built up for predicting the strength and position of the weld lines in micro injection molding. In addition the factors which influence the mechanical properties of weld lines in micro injection molding will be studied, like processing parameters, cross section shape of micro channels and V notch. The micro fluid behavior and the V notch formation during the weld line developing process will also be explored comprehensively. Furthermore, the weld line properties for different materials, like crystalline polymer, amorphous polymer, short fiber resin and metal particles filled polymer, are going to be checked up. As well as the mechanical property test methods will be developed.