| 摘要 |
PURPOSE:To constitute the titled method so that sliding resistance of a core is extremely small and movement is performed smooth, by a method wherein at the time of formation of a cavity for secondary molding by moving the core backward the core is moved after stress of the inside of a mold has been mitigated by depressurizing mold clamping force. CONSTITUTION:A core 13 forming a secondary molding cavity 10 is provided on a mold cavity part advanceably and retreatably and primary injection is performed under a state wherein the core 13 has made to advance. Then at the time of performance of injection molding of a multi-color molded article composed of a primary molded article 30 and secondary molded article 31 by moving the core 13 backward under a mold clamping state caused by straight pressure and applying secondary injection to the cavity 10 generated there, mold clamping force at the time of backward movement of the core 13 is depressurized to secondary mold clamping pressure which is lower than primary mold clamping pressure, and then the secondary injection is performed by boosting up the mold clamping force to tertiary mold clamping pressure which is higher than the secondary mold clamping pressure. With this construction, as the backward movement of the core 13 under a mold clamping state is performed by depressurizing the mold clamping force, sliding resistance of the core 13 is reduced, movement of the core is performed smoothly and galling becomes hard to occur. |
