| 摘要 |
PURPOSE:To cast easily a casting having good quality with a low degree of pressure reduction by bringing the sprue apertures provided to the bottom surface of a sand mold into contact with a molten metal surface and lifting the molten metal surface by the reduced pressure acted on the top of the casting mold to fill the molten metal into the casting mold. CONSTITUTION:A sand mold 1 consisting of a bottom mold 3 having sprue apertures 20, 20a on the bottom surface and a top mold 2 is held by a mold holding means 4, and the bottom surface of the mold 1 is brought into contact with the surface of the molten metal 15 in a molten metal holding furnace 14. The reduced pressure is acted on the top of the mold 1 by the pressure reducing chamber 5 of the means 4 and a vacuum device (not shown) connecting thereto via a pipe 10 communicating therewith. The pressurizing chamber 19 in a working cylinder 16 for lifting the molten metal surface is connected via a pipe 18 to a pressure air source (not shown) to lift the molten metal surface thereby filling the molten metal 15 through the sprues 20, 20a into a cavity 21. The mold 1 is detached from the molten metal surface at the point of the time when the molten metal 15 begins to solidify in the sprues 20, 20a. |
