| 摘要 |
PROBLEM TO BE SOLVED: To provide an injection mold assembly which has a simple structure, enables runnerless molding having a plurality of gates, reduces a production cost, while being easy in maintenance and suitable for multikind and small quantity process. SOLUTION: Resin flow channels such as a sprue (13), a main runner (14), a large number of branch runners (15) or the like are linearly formed to the injection mold assembly (10). An on-off valve (20) freely advancing and retreating in the direction traversing the resin flow channels are arranged to the main runner (14). The on-off valve (20) opens the main runner (14) at the time of injection to open the resin flow channels to fill a cavity (12) with a molten resin and closes the main runner (14) after a predetermined dwelling time is elapsed. Even if a mold is opened after the main runner (14) is closed, the molten resin stays in the resin flow channels while the resin flow channels are densely filled with the molten resin, and the stringing between a gate (16) and the cavity (12) is prevented. COPYRIGHT: (C)2003,JPO
|
