| 摘要 |
PURPOSE:To enable the titled device to control generation of residual stress as low as possible, by a method wherein when the central part of a disk on the inside of an existing cavity is blanked by a punch, resisting force in the direction opposing to pressing force of the punch is applied to a sprue bushing at the time of a backward movement of the said sprue bushing. CONSTITUTION:When mirror surface plates 7, 47 on a stationary and movable sides close upon completing mold clamping, molten resin on the inside of a heating cylinder 18 is injected into a mold cavity. Although the central part of a molded disk is opened through blanking by a method wherein when injection is completed, a cylinder 32 is operated, a piston 33 is shifted leftward and a punch 50 is ejected leftward in this instance, a sprue bushing 12 begins a backward movement along with a forward movement of the punch 50. Along with the above matter a piston 61c is moved backward also, which results in flowing out of oil on the inside of a hydraulic cylinder 61 through an oil hole 63. As the oil flows in an oil tank 66 through an electromagnetic proportional control valve 69 resistance is generated and resisting force in the direction opposing to pressing force of the punch 50 is applied to the sprue bushing 12. This resisting force can adjust arbitrarily a preset value of the electromagnetic proportional pressure control valve 69 by varying the preset value. |
