| 摘要 |
PURPOSE:To facilitate molding at a constant quality, by a method wherein viscosity of a plastic material is measured directly and program control of three terms such as injection pressure, an injection rate and injection time of an injection piston is performed based on the viscosity, in a prepuller type injection molding machine. CONSTITUTION:When a chamber 22 of an injection cylinder 18 is being filled with a pressurized medium, a plastic material flow into the injection cylinder against pressure in the direction of injection acting upon the injection cylinder and an injection piston 16 is moved in the directions of counterinjection. The temperature of the pressurized medium is made constant, constant pressure is applied to the injection piston 16 and viscosity of the plastic material is obtained through a quantity of movement of the injection piston opposing to the pressure. The above viscosity can be secured as a value measured directly. A control device 20 is provided with a speed detecting sensor 26 of the injection piston 16, a position detecting sensor 28 of the injection piston and a detecting sensor 30 of the pressure of the pressurized medium. As for an arithmetic circuit 32, as molding terms have been programmed beforehand in an optimum state to respective plastic materials including temperature terms, injection pressure, a speed and time compatible with the viscosity obtained by the sensor 26 are obtained and the pressure and a flow of hydraulic oil to the chamber 22 are controlled through a result of the operation. The title method can correspond easily and far correctly to a variation of the plastic material itself in this manner. |
