| 摘要 |
PURPOSE:To prevent the air inclusion into molten metal and run defect in the case of exhausting the air in the cavity and the gas from the molten metal in the vent path formed by an ejector pin insertion hole and an ejector pin, by increasing its opening area in an initial period and exhausting a large amount. CONSTITUTION:A cavity 4 is formed by an upper die 2 and a lower die 3, and a vent path A formed by an ejector pin insertionhole 8 and an ejector pin 7 is provided. Molten metal is poured into said cavity 4 from below the dies and the ejector pin 7 is moved upward until it contacts the detecting element 14a of molten metal detecting means 14, thence the ejector pin insertion hole 8 is moved to the large- diameter part 8b to increase the vent area of the vent path A and venting is performed. When the molten metal ascends and contacts the detecting element 14a, the ejector pin insertion hole 8 is lowered to the small-diameter part 8a to decrease the opening area of the vent path A, then the molten metal is filled and this completes pouring. |
