| 摘要 |
PURPOSE:To stabilize molding conditions of each cavity by controlling an injection cylinder with predetermined pressures in the cavities within a range capable of obtaining good products, in an injection molding utilizing a metallic die having a plurality of cavities of different configurations. CONSTITUTION:A molding metallic die 13 is consisting of a plurality of cavities 1a-1c having remarkably different configurations in thicknesses, dimensions and the like. When molten resin is filled in each cavity by beginning injection, pressures of the molten resin are detected by sensors 3a-3c for pressures in each cavity through respective inside-pressure transmitting pins 2a-2c. When all of lower limit values 5a-5c of pressures, preset for respective cavities as pressures capable of obtaining good products, are satisfied, an injection cylinder is controlled from filling condition to pressure reserving condition through a controller 6 and a hydraulic pressure control valve 8. When one of pressures in the cavities exceeds a higher pressure limit for obtaining good products, the injection cylinder is controlled from filling condition to pressure reserving condition, thus, production of rejected products may be reduced. |
