| 摘要 |
PURPOSE:To prolong the service life of mold and at the same time reduce the energy required for mold clamping by a method wherein mold clamping pressures in primary molding and in secondary molding are respectively set to the pressures corresponding to the projected areas and effective injection forces of two cavities formed in the mold. CONSTITUTION:Multi-color molding is performed as follows: firstly, a core 13 s advanced hydraulically and shifted at high speed in order to clamp mold. After that, primary mold clamping pressure is applied to the mold. The set value of the primary mold clamping pressure is applied to the mold. The set value of the primary mold clamping pressure is developed by actuating a pressure control valve 25 based upon the primary mold clamping pressure selected by a set pressure switch 23. After the primary mold clamping pressure is applied to the mold 1 by a mold clamping cylinder 5, resin is injected from an injection cylinder 17 and filled in a cavity 9 in order to obtain a primary molded part. Next, the core 13 is retreated by actuating a hydraulic cylinder 14 so as to form a cavity at the center of the primary molded part. After that, the set pressure switch 23 changes over the mold clamping pressure from the primary mold clamping pressure to secondary mold clamping pressure and the mold clamping pressure is increased to the secondary mold clamping pressure through actuation of the pressure control valve 25. |
