Flow Visualization of Filling Process during Micro-Injection Molding

This is the authors' abstract. We don't add key points for this paper.

Micro-injection molding has been under development for the mass manufacture of micro parts. This paper presents fundamental research on the filling characteristics during micro-injection molding. Flow visualization was employed to observe the fast filling process. A lab-made impact type micro-injection machine was developed and used in this study. Filling of 4 × 4 × 0.2 mm 3 and 2 × 2 × 1 mm 3 cavities in quartz glass molds was recorded with a high-speed video camera. The effects of the processing conditions on the filling behaviors are systematically studied. The processing parameters include air pressure, mold temperature, and melt temperature. Based on the analysis of flow patterns, it was found that the melt fronts advanced quickly and filled the cavity in less than 0.1 seconds. The filling process can be divided into impact-filling and pressure-filling stages. Mold temperature and air pressure are found to be the dominant processing parameters.