Injection molding system with gas flow through valve gate.

摘要

A valve gated injection molding system for making hollow plastic products. A fixed pin (66) extends through an elongated hollow valve member (60) which is reciprocated between a retracted open position and a forward closed position in which the forward end (64) of the valve member (60) is seated in the gate (18). The fixed pin (66) has a hollow portion (90) for the flow of pressurized gas to a porous portion at the forward end (68) which is centrally located in the gate (18). In the open position, gas from the fixed pin flows into the hollow center (134) of a stream of melt (130) which flows into the cavity (20) around the forward end (68) of the fixed pin (66) to form a melt (136) bubble in the cavity (20).