| 摘要 |
PROBLEM TO BE SOLVED: To control the occurrence of flash due to mechanisms necessary for injection of an inert gas, such as nitrogen gas, into a cavity and ejection of it. SOLUTION: An injection molding apparatus includes a feed gas source for supplying a feed gas into the cavity of a mold, a clamping mechanism for moving a movable mold to a fixed mold to form an integral mold, and a gas injection mechanism arranged in the movable or fixed mold. The gas injection mechanism has, within the mold, a hole communicating with an opening formed in the inner wall surface of the cavity of the mold, and a pin slidingly moving in the hole and constituting an opening/closing tap opening and closing the opening formed in the inner wall surface of the cavity. The pin slidingly moves to the side of the cavity to protrude its tip into the cavity, which opens the opening/closing tap to inject the feed gas into the cavity, and slidingly moves to the opposite side of the cavity to level the tip of the pin with the inner wall surface of the cavity, which closes the opening/closing tap. COPYRIGHT: (C)2010,JPO&INPIT |
