MOLD FOR MOLDING OPTICAL DISK SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To prevent the dripping or stringing of a resin from a nozzle to be generated by the insufficiency of the cooling of a sprue at the time of shortening of a molding cycle. SOLUTION: Immediately after injection and filling, a sprue ejecting pin 9 and a gate cutting punch 11 rise in connection with the driving of the ejection mechanism of a molding machine in a mold clamping state and the ejecting pin 9 comes into contact with the tip of the nozzle 2 of a semi-hot runner simultaneously with the cutting of a gate. By this constitution, the sealing of the gate is forcibly performed and the temp. of the gate causing dripping and stringing is lowered to accelerate the cooling and curing of a sprue 15.