| 摘要 |
PROBLEM TO BE SOLVED: To enable injection molding of a ultra-low pressure, to mold a fine long hole precisely, and to produce an injection-molded article having the hole with burr generation controlled. SOLUTION: In a method for producing the injection-molded article in which the fine long hole is formed, a moving plate which moves along the inner wall of a cavity which forms a part having the hole inside while approaching the inner wall is penetrated by a small-diameter core pin is fitted freely slidably to the core pin, the tip of the core pin is held temporarily in relation to a mold by a clamp means, a minute clearance is formed between a small-diameter core pin tip receiving channel formed in one clamp piece of the clamp means and the core pin, the moving plate is moved from the starting point toward the end point of the cavity against the pressure of a molten resin packed in the cavity through a bias means for biasing the plate against the pressure of the resin, gas generated during the movement of the plate is extracted from the minute clearance. |
