METHOD OF MANUFACTURING A PLASTIC CAP

摘要

A plastic cap is made by introducing an upper plunger formed with a thread groove and a lower plunger into the cavity of a die, while compressing a molten plastic stock between the upper and lower plungers, with the upper plunger sliding along the inner peripheral surface of a holding pad which is held in contact with the upper surface of the die, whereby the skirt portion of the cap is formed by the material of the plastic stock flowing out from between the first and second plungers into between the first plunger and the inner peripheral surface of the die cavity.