Nissei Plastic Industrial Co., Ltd.

Yoshito Aruga

Takashi Hakoda

Fumio Shiozawa

Hidenobu Yoda

Leak of a metered resin by backflow in injection filling is prevented not depending on reverse rotation of a screw but by closing a ring valve by controlling a screw forward movement speed in injection filling. An injection filling speed and a valve closing operation speed are set to the screw forward movement speed. The valve closing operation speed is different from an initial speed of the injection filling speed, and the operation time thereof is set to the time necessary for moving the injection screw by a distance capable of performing the valve closing after the end of metering. The valve closing is performed with the set operation speed and the set operation time.

Method for preventing backflow of resin in injection apparatus

The value of a monitor item is detected in a monitor region predetermined in relation to a mold closing operation during the course of a mold clamping step. Emergency processing is performed when the detected value exceeds a threshold value. There are preset an anomalous-state mold opening velocity higher than a normal-state mold opening velocity on the basis of which mold opening control is performed in a normal state, and an anomalous-state-velocity end position at which mold opening control based on the anomalous-state mold opening velocity is ended. Mold opening control based on the anomalous-state mold opening velocity is performed in a portion of the monitor region ranging from a point corresponding to time when the detection value has exceeded the threshold value, to a point corresponding to the anomalous-state-velocity end position.

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Nagano-ken, Japan

Yoshito Aruga