| 摘要 |
PURPOSE:To prevent the intrusion of air into a molten metal and to produce a casting having no blowholes with good productivity by filling the molten metal into a plunger sleeve which injects the molten metal at a high speed from the beginning. CONSTITUTION:A cavity 20 is evacuated to a vacuum and at the same time gas is admitted therein through the orifice of a sensor mechanism 22 to evacuated the air in the cavity 20 and to purge the same when a moving die 13 advances to contact tightly with a stationary die 11. The orifice is closed and a pressure switch 25 is operated when the molten metal 17 forced into the plunger sleeve 11 by driving of an electromagnetic pump 15 is filled 100% therein and rises up to the level of the orifice. The signal of the switch 25 advances the plunger 18 to inject the molten metal 17 through a gate 19 into the cavity 20. There is no air in the cavity 20 and the gas having good quality is filled therein and therefore the product having good quality having no blowholes is obtd. |
