| 摘要 |
PURPOSE:To prevent a pinhole defect and blowhole defect and to obtain a stable product by pressurizing the molten metal in a cavity after the molten metal in a sprue is solidified. CONSTITUTION:A crucible 2 is moved upward by a hydraulic cylinder 5 so that the front end 10' of a sprue 10 projecting from a stationary bottom mold 7 is dipped to a prescribed depth in molten aluminum 3. A reversible motor 23 is run forward to move upward a rod 19, then a plunger 17 slides in a sleeve 15. The inside of a pressure chamber 15' is evacuated and the molten metal 3 is sucked up into a runner 12 and is admitted into a cavity 11. The molten metal 3 stagnating at least in the top end part 10' of the runner 12 is solidified, then the crucible 2 is lowered to detach the sprue 10 from the melt surface of the molten metal 3 in the crucible 2. When the plunger 17 is then lowered by reversing the motor 23, the molten metal 3 is pressurized and after a prescribed pressure is applied, the molten metal in the cavity 11 is solidified. The casting formed as desired is removed by opening the molds. |
