Patent ID: 7252796

Claim:
An ejecting load monitoring method for an injection molding machine which comprises a movable die having an ejector pin therein, a movable platen which holds the movable die, and an ejector unit having an actuator rod, the actuator rod is attached to the back side of the movable platen and is used to advance and/or retreat the ejector pin when ejecting a molded product from a die face, the monitoring method comprising: providing a plurality of advance monitoring sections in a movement area of the actuator rod for advance; providing one or more retreat monitoring sections in a movement area of the actuator rod for retreat after the actuator rod arrives at an advance limit; setting an upper limit value of a forward thrust load of the actuator rod for each monitoring section prior to monitoring the actuator rod in the movement area; setting an upper limit value of a thrust load of the actuator rod for each retreat monitoring section prior to monitoring the actuator rod in the movement area; issuing an alarm when the forward thrust load of the actuator rod reaches the upper limit value set for any of the advance monitoring sections during an advance operation; and issuing an alarm when the thrust load of the actuator rod reaches the upper limit value set for any of the retreat monitoring sections during a retreat operation.