Special Section on Analog Circuit and Device Technologies

A material injection assembly (10) of the type for injecting a resin material into a mold cavity including a body member (12) defining a nozzle (13) for injecting material into a mold (14) and including at least one central channel (16) for conveying a first material through the nozzle (13). The assembly is characterized by an internal purging mechanism for closing the nozzle (13) to the mold (14) while allowing the flow of purging material between the channel (18) supplying resin material to the control channel (16) and a debris channel (22). The purging mechanism further allows flow of purging material between a separate purging material channel (20) and the debris channel (22) to perform a post-purge function. A cooling system is also disclosed which provides a coolant supply channel (70) which bifurcates into two channels (75, 77) about the central channel (16) proximal to the nozzle (13) to provide maximum cooling at the portion of the assembly (13) closest to the mold (14).