Method and apparatus for real time control of injection of structural foaming agents, colorants, and other additives

An injection molding apparatus, comprising:

• a mold including a plurality of mold cavities formed by a first mold side and a second mold side;
• an injection unit including a hopper, a barrel, and a reciprocating screw configured to advance molten material toward a nozzle which injects the molten material into the mold cavities via one or more gates in fluid communication with the mold cavities;
• an additive injection molding system including:
• one or more additive tanks, each having a supply of an additive fluid material that is different than the molten material;
• one or more additive injectors in fluid communication with the one or more additive tanks, each of the additive injectors configured to receive and inject the additive fluid material into each of the mold cavities, each of the one or more additive injectors being distinct from the nozzle and being positioned in a respective one of the mold cavities;
• a common manifold connecting each of the one or more additive tanks and the one or more additive injectors;
• and
• one or more additive pumps that pump the additive fluid through the one or more additive injectors;
• a controller configured to control operation of the mold, the injection unit and the additive injection molding system;
• and
• one or more sensors coupled to the additive injection molding system and in communication with the controller, wherein at least one of the one or more sensors is configured to measure at least one non-time dependent variable during an injection mold cycle.