Method of setting terminal position of forward motion of ejector pins of ejector mechanism

A method of setting a terminal position of a forward motion of ejector pins of an ejector mechanism in an injection molding machine, having means for moving the ejector pins forward to project into a mold, springs for generating an elastic force to return the ejector pins to a retracted position, and brake means for generating a retaining force to retain the ejector pins at the terminal position, said method comprising:

• moving the ejector pins forward from the retracted position in a state where no molded product is present in the mold;
• detecting the elastic force of the springs during the forward motion of the ejector pins;
• determining a criterial position of the ejector pins where the detected elastic force of the springs is equivalent to the retaining force of the brake means;
• and
• setting the terminal position of the forward motion of the ejector pins closer to the retracted position than the determined critical position.