| 摘要 |
PURPOSE:To make a thermal shrinkage of a molded form constant and improve the dimensional accuracy of the form by a method wherein a cavity pressure is kept at a predetermined set pressure and after a difference between a runner pressure and the cavity set pressure is arrived at a preset value, the form is cooled for a predetermined period of time. CONSTITUTION:A mold temperature is measured by a mold temperature detector 15 until the resin is filled into a cavity 2, then, the cavity set pressure is operated based on the signal of the detector 15 and a set cooling period of time is operated in accordance with an operating formula predetermined so that the product will show a predetermined dimensions. After the resin is filled into the mold, the cavity pressure is controlled under a constant value control by regulating the hydraulic pressure of a hydraulic cylinder 9 so that the cavity pressure detected by a cavity pressure detector 17 will become the previously operated cavity set pressure while this constant value control is continued until the pressure at the runner section 4 and the above-described cavity set pressure will show a predetermined pressure difference, thereafter, the hydraulic pressure is lowered and the product is withdrawn therefrom after it is cooled for the predetermined period of time. |
