A mold stacking carrier (often referred to as a stack mold carrier system) is a specialized mechanical support structure used in high-volume injection molding.
In a standard mold, there is only one parting line (where the mold opens). In a stack mold, there are two or more levels of cavities stacked on top of each other. The “carrier” is the mechanical framework that supports, aligns, and synchronizes the movement of the middle section (the center block) during the molding cycle.