Observation of Air Entrapment during Mold Filling of Die Casting Using Water Model Experiment for Mold Filling Simulation

Abstract

The mold filling simulation in the casting CAE is used to investigate the filling pattern of molten metal and to predict the casting defect. However, the prediction method of defects caused by unsuitable flow has not been established because the verification of analysis accuracy is insufficient. Especially, the air entrapment during mold filling is very important problem to obtain the sound casting. In this study, the direct observation of mold filling behavior using a water model equipment is carried out. The movement of free surface and the volume change of water are measured from observed filling behavior. The air entrapment is analyzed by quantification method using image processing. It is clear the location of thickness direction and entrainment timing of air varied with the experimental conditions. Further, the mold filling simulation is done using the casting CAE software TopCAST, which has the two-phase flow analysis MARS method. As a result of the analysis, the mold filling behavior of water and the volume of air entrapped almost agreed with experimental result. Although the calculated results have almost the same tendency with experiment, it has some unsuitable results. Therefore, it is necessary to make simulation closer to the real phenomenon by the validation of calculation conditions, and by introducing new algorithm of air movement.