| 摘要 |
PURPOSE:To provide a titled device which permits suction and pouring under the reduced pressure in short time without intrusion of air into the molten metal in suction casting involving the evacuation of the inside of an air permeable casting mold by controlling the change of the evacuation for suction with time in a way as to attain the change to a prescribed curve by a regulating valve. CONSTITUTION:The inside of the air permeable casting mold 1 is evacuated to suck the molten metal 3 through the vacuum by a vacuum pump 8 of a vacuum chamber 2 and opening of a suction start valve 4 by a directional control valve 5. The molten metal is thus cast. An evacuation signal 11 for suction is fed to a controller 15 which controls a suction speed control valve 6 by a variable speed motor 12 via a motor amplifier 14 so as to coincide with a set evacuation-time curve 13. The evacuation for suction is made slow initially and finally to eliminate the intrusion of air into the molten metal in the mold 2 and the pouring is completed in short time, so that the good casting is efficiently manufactured. |
