Effects of Reduced Pressure, Casting Design and Heat Transfer Resistance of Liquid Resin on Mold Filling in Expendable Pattern Casting Process of Aluminum Alloy

Effects of reduced pressure and casting design on changes in mold filling due to coat permeability in the expendable pattern casting process of aluminum alloy were investigated experimentally. The effect of coat permeability on the melt velocity of molten aluminum alloy in the expendable pattern casting process was investigated experimentally under the conditions of reduced pressure and top pouring. Aluminum alloy plates were cast under conditions of the reduced pressure and top pouring, using eight kinds of coats with different permeabilities. The melt velocity was measured and the results showed that the difference in the melt velocity was not large depending on the casting design. The application of the reduced pressure condition and use of high permeability coats led to higher melt velocities. However in the high coat permeability region, the melt velocity did not increase much, even when the coat permeability increased. The experimental values of the melt velocity were compared with the calculated values based on the mold filling model used in the previous study. When the coat permeability was low, the experimental values were in relatively good agreement with the calculated values. However in the high coat permeability region, the experimental values of the melt velocity were lower than the calculated values. By considering the heat transfer resistance of the liquid resin at the EPS surface to the mold filling model, even in the high coat permeability region, the experimental values of melt velocity showed more or less good correlation with the calculated values.