When the product is taken out after the injection process, the surface of the product and the mold are attached and to separate them, it is necessary to consider the frictional force between the mold surface and the product surface. Therefore, to reduce the frictional force, a subtraction gradient for the rib shape is generally applied, and a lapping process is performed to improve the surface roughness of the rib shape surface of the processed mold. Therefore, research is needed to improve the surface roughness when processing the rib. In this study, slotting processing was applied to improve surface roughness when processing ribs. Slotting processing is a processing method that removes material through the feed motion of the tool, and processing is possible regardless of the aspect ratio of the processing shape. A slotting tool was developed for rib machining and a comparative experiment with electric discharge machining was performed. Also after processing, the surface roughness and processing time were compared and analyzed, and the improved surface roughness and fast processing time characteristics of the slotting processing compared to electric discharge processing were confirmed.

The ribs of the injection molded article are a necessary shape in order to maintain the rigidity without increasing the material cost. The ribs on the outside of the molded article in the form of a housing are located on the side of the cavity inside in the mold. This paper proposes slotting by machining side-ribs. The slotting was performed through CNC control along the edge profile of the rib width. The machining time and the roughness of the machined surface were compared to verify the machining efficiency and the practicality of the machining method as a side-rib machining method.