Measurement control method of an injection molding machine

A measurement control method of an injection molding machine in which a measurement is performed by rotating a screw, and a measurement is ended when the screw retracts to a preset measurement ending position, comprising:

• a measurement control method of an injection molding machine in which an operation control of the screw rotation side where an ending target position in which a prescribed length is added to the measurement ending position, a rotation rate pattern for rotating a screw, a back pressure in relation to the screw as well as a hypothetical retraction rate pattern for the screw to retract are preset, and while a screw position is detected at a prescribed time interval at the time of the measurement, and the remaining rotation rate pattern for stopping the rotation of the screw at the ending target position from the detected screw position is predicted by calculation, and while the rotation of the screw is controlled by the predicted rotation rate pattern, and the rotation of the screw is controlled to stop when the screw reaches the measurement ending position;
• and in which an operation control of the screw retraction side where the retraction rate of the screw is detected at a prescribed time interval, and the remaining retraction rate pattern is predicted by calculation from the detected retraction rate, and while the limit value for the retraction rate is set, and while the retraction of the screw is controlled by selecting the smaller control amount of either a pressure control amount for performing the back pressure control or a position control amount for performing the position control to the measurement ending position at the time of prediction, and the retraction of the screw is controlled to stop when the screw reaches to the measurement ending position.