Papers by Keyword: Melt Front

Abstract: Computational Fluid Dynamic (CFD) was used to simulate the injection molding process of a tray. The study focuses on pressure distribution and velocity drop during the injection process. CFD simulation software ANSYS FLUENT 14 was utilized in this study. The melt front pressure in the mold cavity shows that it was affected by the shape of mold cavity and filling stage. The melt front pressure will decrease as the flow move further than the sprue but it will increase rapidly when the mold was about to be fully filled. The slight pressure drop was detected when the molten flow meets the rib of the tray. The velocity of higher injection pressure was greater than the lower injection pressure but the velocity rapidly dropped when the melt front fully filled the cavity. The current predicted flow profile was validated by the experimental results, which demonstrates the excellent capability of the simulation tool in solving injection-molding problems.

Abstract: This study investigates the flow characteristics of microinjection-molded lightguiding plates. This study also analyzes the position of melt fronts on lightguiding plates. Viscous heating, temperature and velocity distribution are utilized to analyze delay or advancement of the melt front experimentally and using three-dimensional (3D) numerical simulation. A slow injection speed reduces viscous heating. As viscous heating decreases, the temperature distribution decreases and plastic viscosity increases. A high plastic viscosity increases flow resistance and melt plastic velocity decreases. The advancing melt front of a lightguiding plate is delayed in this situation. The key of this research is that the plastic melt front can arrive the end position at the same time on filling stage of lightguiding plate for microinjection molding. In this research, the authors find increasing the injection speed can help the previous situation. Experimental results demonstrate that filling in the experiment is very close to that in 3D numerical simulation.