A molding system and a method for operation of the molding system are provided. The method includes flowing a molten polymeric material from an upstream device into an in-mold tuning chamber in a filling position where the in-mold tuning chamber is positioned at least partially within a mold cavity. The method also includes adjusting at least one of a temperature of and a pressure applied to the molten polymeric material in the in-mold tuning chamber to create a first tuned molten polymeric material and releasing the tuned molten polymeric material into the mold cavity from the in-mold tuning chamber.