Numerical simulation of molten metal flow under vacuum condition in high pressure and low pressure die casting process

Abstract

The vacuum analysis algorithm was developed to simulate the total system of high pressure die casting process including vacuum vent, cavity and plunger area. The various vacuum degrees (760, 650, 500, 250 and 60 mmHg) were artificially applied in cavity. The filling behaviours of molten metal under the applied vacuum conditions were simulated and compared with those of experiment. The filling amount in cavity was increased with the increase of applied vacuum pressure during partial shot experiments. The simulated filling behaviours of molten metal were relatively well agreed with those of experiment. Through the results of fluid flow simulation, the relationship of filling length and filling velocity with the variation of vacuum pressure was analysed respectively. And it applied to a real die casting product and the internal gas quantity of product was significantly reduced by modification of vacuum gate system.