| 摘要 |
PURPOSE:To enhance the productivity of a ring-shaped molding by a method in which a synthetic resin material charged into a pot portion is pressed by a lower mold having a part mold and the pot portion as cavity and an upper mold having a projection to be fitted into the pot portion while keeping a closed tiered portion and clearance and packed into the part mold. CONSTITUTION:A given amount of a synthetic resin material 7 is weighted and charged into a pot portion 3, and an upper mold 4 and a lower mold 1 are matched with each other and close. The resin material 7 is overflowed into a part mold 2 from the pot portion 3 along the aperture 8 between the inner surface of the pot portion 3 and the outer surface of the projection 6. The overlow of the resin material 7 is completely interrupted and closed by contact of a closed tiered portion 5 provided on the projection of the upper mold 4 with the surface of the lower mold 1. The action of an indentation allowance 9 provided on the outside peripheral edge of the mold 2 eliminate the needs to cut and remove disc gate in the ring-shaped molding and forms a smoothened face requiring no finishing process on the inside and outside peripheral edges. |
