The partially-permeable molds, which were made of acrylic, were designed to observe the filling phenomena of water solution (viscosity was 30 cp., which was close to the true flowing of molten aluminum alloy ) in horizontal-gating systems. The hydraulic and air pressure measured by pressure transducer, while poured water solution was filling in the mold cavity. The back pressure of exhausted air was introduced by the moving water front that forced the air out of mold cavity. The magnitude of responded air pressure did a great effect on the flowing rate of filling water, especially when the water was approaching to the final stage of filling. The maximum air pressure in the mold cavity was found to be equal to hydrostatic pressure of water; that is, pressure head. The effects of top and bottom filling, pressure head, ingate area (or gating ratio), permeability of mold wall (or ratio of permeable area) on the filling velocity of water and accumulated air pressure in the mold cavity were fully investigated in this study.
Filling rate Air pressure