| 摘要 |
PURPOSE: To easily and assuredly discharge air in a cavity of a mold so as to prevent generation of flashes by forming vent holes which communicate with the cavity in the mold and movably arranging, in the holes, movable pins whose head ends are formed into shapes capable of blocking openings at the cavity side of the holes. CONSTITUTION: In between holding pins 4 of an upper mold 1a and a lower mold 1b, vent holes 11 are formed in an arrangement opposed to each other. Each vent hole 11 is formed such that an opening 12 communicating with a cavity 2 has a small cylindrical shape 13 and a side which opens to the outside has a large cylindrical shape 14. In the holes 11, movable pins 15 are arranged movably. The cavity 2 is filled with a molding material. Immediately before the material enters the holes 11, moving devices 18 actuate the pins 15 to move toward the cavity 2 by a signal from a control device 19. Head ends of small cylindrical sections 16 of the pins 15 proceed in between the ends of the openings so as to block the openings 12. |
