Tribological evaluation of duplex treatment of plasma nitriding/ oxidation applied to injection mold extraction system

Abstract

This work analyzes the application of surface treatment of plasma nitriding with post-oxidation applied to injection mold extractor pins to reduce the injection cycle's interruptions for mold lubrication. For that, a device that simulates the operation of the injection mold extraction system was created. Wear was evaluated by mass loss and dimensional variation of the extraction pins and their bushings. The samples were characterized by microhardness and X-ray diffraction (XRD). The wear mechanisms were identified by scanning electron microscopy (SEM) and the coefficient of friction was analyzed employing a ball-on-plate tribological test. The results showed that the proposed system with plasma nitriding and postoxidation meets the requirements with a lubrication interval twice as long as the current system.