| 摘要 |
PROBLEM TO BE SOLVED: To produce a plastic thin-plate article with projection on its surface by compressing a plastic material in a molding cavity and molding the material between the first mold surface and the second mold surface. SOLUTION: When a prescribed amount of a molten or softened plastic material is injected into a molding cavity 10, the injection is stopped, a lower mold 7 is separated from an upper mold 6 for preliminary molding, and the injected material, which is being held in a recessed part 7a, is moved downward from a molding upper mold. Next, the lower mold 7 is moved upward and combined with an upper mold 8 to form a molding cavity 11a between them. By this operation, the material which was injected in the cavity 11a the volume of which is smaller than that of a cavity 11 for preliminary molding is compressed to be molded by the molding surfaces of recessed parts 7a, 6a. In this way, both the pyramidal projection of a diffusion plate and an opposite mat surface can be molded simultaneously. |
