A coinjection molding apparatus includes at least one manifold having a
first manifold melt channel and a second manifold melt channel. A hot
runner nozzle is located between the manifold and a mold gate. The nozzle
has melt channels communicating with the first manifold melt channel and
the second manifold melt channel. A valve has a movable valve member for
increasing and decreasing flow of melt in one of the melt channels of the
nozzle. The valve member receives a pressure force from the melt. An
actuator provides a control force to the valve member. The valve member
moves in response to a difference between the pressure force and the
control force.