METHOD FOR DESIGNING INJECTION MOLDING DIE AND DEVICE FOR MEASURING SHRINKAGE FACTOR OF MOLDINGS

PROBLEM TO BE SOLVED: To provide a method for designing an injection molding die by which a failure such as a scratch or a turning-up generated in moldings can be prevented from occurring without increasing the draft angle, for the moldings, which is set in the die, beyond the acceptable limits. SOLUTION: This method for designing the injection molding die is used for designing the draft angle or beveling shape of a cavity. That is, this method comprises the molding step to form moldings and the measurement step to unload the moldings formed in the molding step from the die and measure a change over time in the temperature and dimensions of the moldings. Further, the dimensional change of the moldings between a point of time when the moldings are unloaded and a point of time when the measurement of the temperature and dimensions of the moldings is started, based on a change over time in the temperature and dimensions of the moldings which are measured in the measurement step and thus the shrinkage factor of the dimensions right after the unloading of the moldings is determined.