Correlation between thermal contact resistance and filling behavior of a polymer melt into multiscale cavities in injection molding

The mechanism through which thermal contact resistance (TCR) is generated and how it changes at the interface between a polymer melt and mold wall during injection molding have not yet been clearly identified. In particular, despite the TCR significantly influencing the surface quality of the resulting part, few studies have reported on the injection molding of a part with microstructural features. In this study, we predict the TCR using a new approach. Through a molding process known as “short shot”, we indirectly measured the filling height of patterns as a function of time. In addition, to make these results consistent with filling analysis results, we calculated the TCR through recursive calculations. With this approach, not only changes in the TCR as a function of time but also changes by position were estimated. Furthermore, on the basis of the TCR determined in this manner, the filling behavior of micropatterns according to the change in TCR was examined. Finally, this study shows that artificial control of the roughness of a mold surface leads to control of the TCR, resulting in improved transcription of micropatterns.