ABSTRACT
Injection molds are assemblies of parts in which two blocks, namely the core and cavity blocks, form an impression or a molding [1]. The mold core forms the interior of the molded parts (molding), and the mold cavity forms the exterior faces of the molding. Among all the components, the core and cavity are the main working parts. The molding is formed in the impression between the core and cavity and is ejected after the core and cavity are opened. The pair of opposite directions along which the core and cavity are opened are called the parting direction. For a given molding, one group of its surfaces is molded by the core and its inserts, and the other group of surfaces by the cavity and its inserts. The parting lines are therefore the intersection boundary between the surfaces molded by the core, the cavity and their inserts. The parting surfaces are the mating surfaces of the core and cavity. In a molding, the convex and concave portions of the molding are considered as undercut features. If the undercut features cannot be molded in by the core and cavity and their inserts, they will be the real undercuts and would require the incorporation of side-cores, side-cavities, form pins, or split cores in the mold structure. The side-cores, side-cavities, form pins, and split cores are called local tools since they are used to mold the local features in the molding. These local tools must be withdrawn by a mechanism prior to the ejection of the molding. Side-cores and side-cavities are normally removed by the sliders/lifters mechanism.
