INJECTION MOLDING METHOD AND INJECTION MOLD

摘要

PROBLEM TO BE SOLVED: To prevent the outer wall part of a molded product molded into a box shape from warping inside. SOLUTION: In an injection mold injecting molten resin into the cavity part formed between a female mold 11 and a male mold 13 to mold a box-shaped molded product 14, an air introducing mechanism having the ejection port 16a turned toward the inner peripheral surface 11a of the female mold 11 and introducing air A into the gap between the male mold 13 and the outer wall part 14a of the molded product at a time of mold opening is provided to the male mold 13. The air A supplied from an air supply means is introduced into the gap between the male mold 13 and the outer wall part 14a of the molded product at a time of mold opening to allow internal pressure to act on the outer wall part 14a of the molded product 14. By this constitution, the outer wall part 14a of the molded product is prevented from warping inside.