Optimization of Pouring Velocity for Aluminium Gravity Casting

In current casting factories, tilting type automatic pouring machines are often used to pour the molten metal into the mold, with the operator relying on experience, perception and repeated testing to manually determine the pouring velocity. However, seeking an optimum multistep pouring velocity through trial and error results in an enormous number of combinations and is very difficult. For this reason, it cannot be said that suitable casting that realizes a high-quality cast is being carried out, inviting a decline in the yield rate due to product defects. Furthermore, the extension of the production preparatory phase and increase in costs due to this kind of trial operation also become a significant problem. Until now, much research relating to product defects in aluminum gravity molding has been conducted (Yutaka et al., 2001)(Takuya, 2004). Meanwhile, research applying casting CAE for the purpose of improving the quality of castings and production efficiency is coming to attention (Itsuo, 2006). Furthermore, in recent years, optimization of the casting problem has begun to be carried out in accompaniment with developments in computers (Takuya et al., 2007)(Ken'ichi et al., 2008). However, these all target comparatively short calculation time die-casting and adoption of optimization technology in sand mold casting and gravity casting is lagging. Accordingly, in this research, the objective is to stabilize the fluid speed in the mold gate and derive an optimum pouring velocity to realize a mitigation of defects such as pin holes and blow holes in aluminum gravity casting through invoking a fluid behavior simulator, swiftly filling the sprue cup and controlling the liquid level at a fixed high level of liquid. For the automatic pouring machine, the multistep velocity input is designed for actual product of an intake manifold. The effectiveness of this research is shown by a fluid analysis simulation and an actual test.