When using hot runner molding reinforced plastics or plastics with fast crystallization speed, if the hot runner gate adopts the method of local cold gate, and the hot runner gate is an open gate, then during the molding process, the opposite side of the hot runner gate often produces cold glue residue.

This is because the hot runner gate often has melt overflowing into the local cold gate and solidifying, and the overflowing cold glue will be pushed out by the melt when the next mold is molded. If the wall thickness of the plastic part is thin, it may be pushed away from the gate position, and a silver filament defect will appear at a certain distance from the gate.