| 摘要 |
<p>This invention relates to a movel core ring gated injection molding system. Pressurized melt from a molding machine flows through the system and into a cavity. A gate (32) leading to the cavity (34) and a bore (14) in the movable mold platen (36) are in alignment and of the same size to receive the head portion of the valve pin (16) which extends from a reduced neck portion (92). Actuating mechanism drives the valve pin between a retracted closed position to an open position in which the reduced neck portion (92) extends into the cavity (34). In the closed position, the head portion (90) of the valve pin extends a considerable distance into the bore (84) in the mold platen (78) to provide sufficient cooling to rapidly cool the melt in the cavity adjacent the pin. In one embodiment, the valve pin has a hollow portion adjacent the neck portion to provide the valve pin with thermal separation between the hot melt and the cool mold platen. In another embodiment, the valve pin has a copper portion between the hollow portion and the tip end to promote cooling of the melt in the cavity.</p> |
