| 摘要 |
PURPOSE:To provide an injection mold which is capable of performing molding of high-accuracy optical parts, by preventing the generation of a defect based on shrinkage of molten resin by making a core forming a cavity advance during a gate sealing period of time. CONSTITUTION:Simultaneously with the time when a cavity 11 is filled with molten resin 27 and the cavity is turned into a gate sealing state a control signal SC is applied to a valve control mechanism 19 and hydraulic pressure source 17 from an electric control part 20. Then a control signal SV is applied to a valve mechanism 18 from the valve control mechanism 19. Then a valve is opened and a working fluid is fed to a pressurizing device 13 through an oil pipe 17a from the hydraulic pressure source 17. Consequently, the core 12 is kept moving forward until a ram part 15 is controlled in the direction of an arrow 2a through a stopper 16. An advancing quantity in this instance is adjusted so that it becomes compression allowance beforehand. As the titled mold is so constituted that a core 8 is made to advance to the cavity side by the compression allowance during a sealing period of time, generation of various defects such as a sink mark and warp due to shrinkage of the molten resin 27 can be prevented. |
