Pressure of gas in gas gap during Lost Foam Process

In the study, a model and some fundamental relationships describing changes of gas pressure in the gas gap during manufacture of castings by the Lost Foam process were described. The mathematical description uses the equation of gas state and the equation of Darcy's rate of filtration. The equations describing changes of gas pressure in the gas gap and the kinetics of melting of a foamed polystyrene pattern as well as the dynamics of the process of mould filling with molten alloy were used in analysis of the effect of selected technological parameters on changes of gas pressure in the gas gap. The effect of foamed polystyrene pattern density and permeability, and of the protective coating thickness on changes of pressure in the gas gap were discussed.