Development of Effective Method for Detecting the Contact Conditions between Dies and Thermosetting Resin Compound and the Solidification Front in Transfer Molding Processes

超声波的反射取决于模具与材料之间的实际接触面积、界面材料的声阻抗以及界面的接触几何形状。在这个实验中，我们检查了在成型过程中从上下平面模具表面反射的最大波强度。反射波的相对强度定义为成型时的强度与成型前的强度之比。相对强度的变化敏感地对应于树脂在界面处的填充率或接触比、由于声阻抗的变化而引起的树脂凝固的发展以及由于成型材料的收缩而导致的树脂与模具表面的分离。研究还表明，相对强度与界面处总热阻有密切关系。因此，一种新开发的测量瞬态接触条件的方法为优化成形精确形状或良好性能的工艺条件提供了有效的工具。

The reflection of ultrasonic wave depends on a real contact area between die and material, acoustic impedance of interface materials, and a contact geometry of the interface. In this experiment we examined the maximum wave intensities reflected from upper and lower flat die surfaces during a molding process. The relative intensity of the reflecting wave was defined as ratio of the intensity during molding to that before molding. The change in the relative intensity has corresponded sensitively with a filling rate or a contact ratio of the resin at the interface, development of solidification of the resin because of the change in acoustic impedance and the separation of resin from the die surface due to the shrinkage of molded material. It has been also clarified that the relative intensity has the close relation with overall thermal resistance at the interface. Thus, a newly developed method measuring transient contact conditions provides the effective tool to optimize the process coditions for forming accurate shapes or good properties.