Patent ID: 7132069

Claim:
A mold clamping force correction method for a mold clamping apparatus in which variation in mold clamping force is detected during production operation, and the mold clamping force is corrected on the basis of the detected variation, the method comprising: providing a closure position detection mode for detecting an amount of movement of a movable platen, or a crosshead in the case where the mold clamping apparatus is of a toggle type, during closure of a mold, detecting a variation in a physical quantity because of closure of the mold, obtaining a rate of variation in the physical quantity to a predetermined amount of movement of the movable platen or the crosshead, and detecting, as a mold closure position, a position of the movable platen or the crosshead when the variation rate reaches a preset ratio; previously operating the mold clamping apparatus in the closure position detection mode so as to store, as a reference value, the mold closure position at which a target mold clamping force is obtained; operating, in the production operation, the mold clamping apparatus in the closure position detection mode so as to detect an actual mold closure position as a detection value; and correcting the mold clamping force on the basis of a deviation of the detection value from the reference value.