Injection control method for an electric injection molding machine

(57) [Summary] To provide an injection pressure during injection even when an abnormal state occurs. Control so that the force does not exceed the limit pressure. SOLUTION: A screw 3 is advanced at a set speed, and a die is formed. The molten material is injected into the cavity. The injection is performed while constantly measuring the injection pressure P. Also, In the comparison unit 10c, the injection pressure P and the pressure increase ΔP Is the critical pressure P L Comparing for greater than You. P + ΔP ≧ P L Is satisfied, the controller 10 sends a rapid braking signal to the injection servomotor 8 to fire The output servomotor 8 is suddenly braked and the injection pressure P reaches the limit pressure. Force P L To prevent the pressure from rising beyond. After that, injection system Pressure control at the pressure limit Pa, and then Injection depends on whether screw 3 has reached the holding pressure switching position. Stop the machine or hold the pressure while maintaining the pressure limit Pa Execute any of the controls that shift to the process.