Effects of dual speed injection on quality and metal flow of plate shape die casting

The effects of injection speed on the cast properties were first investigated. High injection speeds were found to cause a high degree of air entrapment in the casting which reduced the casting quality, such as mechanical properties and density. Secondly, water model experiments using transparent molds were performed to clarify the relationship between the mold filling flow characteristics and the injection speed. A critical injection speed, below which no air entrapment occurred, was found to exist, and its value was 0.5m/s. Furthermore, pre-charge in a mold prior to high speed injection was found to be effective for preventing air entrapment. The relationship of the amount of pre-charge required and the injection speed was determined from a series of water model experiments.