Injection molding apparatus with a melt channel in valve pin

An injection molding apparatus comprising:

• a manifold having a manifold melt channel;
• a nozzle coupled to said manifold and having a nozzle channel;
• a valve pin having a retracted position and being reciprocally axially movable through said nozzle channel of said nozzle to an extended position, wherein said valve pin includes a valve pin melt channel substantially including a longitudinal portion defined by and coaxial to said valve pin and an outer surface in close proximity to an inner surface of said nozzle channel, wherein an inlet of said valve pin melt channel selectively communicates with said manifold melt channel when said valve pin is in the retracted position and is restricted from communicating with said manifold channel when said valve pin is in the extended position;
• and
• a mold gate to a mold cavity, wherein said mold gate is open when said valve pin is in the retracted position and is closed by a valve pin tip of said valve pin when said valve pin is in the extended position,
• wherein said valve pin melt channel includes an outlet extending from said longitudinal portion of said valve pin melt channel to said outer surface of said valve pin, wherein said outlet is adjacent to said valve pin tip and is positioned such that said outlet is not blocked despite the position of said valve pin.

An injection molding apparatus comprising:

• a manifold having a manifold melt channel;
• a nozzle having a nozzle channel, wherein said nozzle is coupled to a valve pin bushing positioned between said manifold and said nozzle, wherein said valve pin bushing has a bushing melt channel with an inlet and an outlet, wherein said inlet communicates with said manifold melt channel;
• a valve pin having a retracted position and being reciprocally axially movable through said nozzle channel of said nozzle to an extended position, said valve pin including a valve pin melt channel defined by and substantially coaxial to said valve pin, wherein said valve pin melt channel selectively communicates with said outlet of said bushing melt channel when said valve pin is in the retracted position and is restricted from communicating with said outlet of said bushing melt channel when said valve pin is in the extended position;
• and
• a mold gate to a mold cavity, said mold gate being open when said valve pin is in the retracted position and being closed by a valve pin tip of said valve pin when said valve pin is in the extended position,
• wherein said valve pin melt channel includes an outlet extending from a longitudinal portion of said valve pin melt channel to said outer surface of said valve pin, wherein said outlet is adjacent to said valve pin tip and is positioned such that said outlet is not blocked despite the position of said valve pin.