| 摘要 |
PURPOSE:To enable high efficiency casting with a low power casting device by attaching a pressure increasing piston to a liquid pressure cylinder for injecting a molten metal of a die casting device and increasing the injection pressure of the molten metal by the pressure increasing piston in the stage of high speed injection. CONSTITUTION:A pressure increasing piston 12 as the 2nd piston is additionally provided to a fluid pressure cylinder 8 of an ordinary die casting device. Die casting is accomplished by driving first a piston 9 at a low speed, then driving the piston at a high speed to feed a molten metal 2 of an Al alloy, etc. through a sprue 5 into the casting cavity 7 of dies 6, thereby casting the molten metal under pressure. The piston 12 is driven to increase further the high-speed injection pressure in the stage of performing casting with the injection pressure increased by the high speed injection so that the casting with higher power with the die casting machine of low power is made possible. The driving of the pressure increasing piston in the high injection region is accomplished in such a way that when the piston 12 attains the limit of the driving stroke, the driving of the piston 12 is once released and is again driven to increase the pressure, thereby increasing the die casting power by the high speed injection. |
