Performance study of different EDM Electrode Materials for machining of honeycomb cavities of plastic injection molds

Abstract

Electro Discharge Machining (EDM) is an extremely prominent machining process among newly developed non - traditional machining techniques for “difficult to machine” conducting materials such as heat treated tool steels, composites etc. In EDM, the material removal of the electrode is achieved through high frequency sparks between the tool and the work-piece immersed into the dielectric. The Material Removal Rate (MRR), Tool Wear Rate (TWR) and surface integrity are some of the important performance attributes of the EDM process. This is widely used in machining intricate cavities in Aluminum HPDC Dies, Tyre mold manufacturing and Plastic Injection mold manufacturing. In Plastic injection mold manufacturing, especially for machining narrow cavities of honeycomb structures, the tool wears faster and machining becomes costly. This study compares performance of three materials viz. Copper, Graphite and Copper impregnated Graphite used as EDM electrodes and evaluates their performances based in lower Tool Wear Rates (TWR)