| 摘要 |
PCT No. PCT/SE89/00331 Sec. 371 Date Dec. 12, 1990 Sec. 102(e) Date Dec. 12, 1990 PCT Filed Jun. 12, 1989 PCT Pub. No. WO89/12518 PCT Pub. Date Dec. 28, 1989.A method and apparatus for die casting comprising a stationary lower machine table (5) provided with a stationary lower mold part (24) which cooperates with a vertically moveable upper mold part (22) mounted on an upper machine table (10) and displaceable by hydraulic cylinders (7). The upper machine table (10) and the upper mold part are provided with a filling chamber (20) for receiving a measured quantity of a molten metal which is to be pressed into the mold by an upper piston (18). A lower piston (43) is moved to a variable position relative to the filling chamber, prior to the molten metal filling, and thereafter the upper piston (18) is moved into contact with a top surface of molten metal, without any air-entrapment or with only a minor entrapment of air. After this has occurred, the upper piston and the lower piston are displaced jointly downward until the lower piston is in a casting position in the lower mold part, whereupon the upper piston is displaced further downward to feed the molten metal and maintain pressure of the molten metal until the casting operation is completed. The cylinder casing (38) of the lower piston is rigidly connected to a mechanism (29-37) designed to eject the casting produced. |
