Study on the influence of tool electrode materials on electrode wear in hole machining in EDM

In the process of EDM, the wear of tool electrode has a great influence on machining accuracy. In order to analyze the wear phenomena of tool electrodes with different physical properties in hole machining, this study conducted hole machining experiments on 304 stainless steel using tool electrodes made of five different materials (copper, silver, tungsten, brass, and molybdenum). Experiments showed that when tungsten was used as the tool electrode material, the electrode relative wear was the lowest. And by observing the surface of the tool electrode, it was found that the main form of wear was fracture wear, with a small amount of melting wear existing at the same time. The wear forms of copper, silver and brass tool electrodes were mainly melting wear, but the wear of brass tool electrodes was the biggest. Meanwhile, it is concluded that the melting point of the tool electrode material has the greatest influence on wear, followed by specific heat capacity, thermal conductivity, and density. In order to make a more intuitive analysis, the electrode discharge of different tools was observed by high-speed camera. It was found that the splash direction of the tungsten tool electrode was mainly on the electrode side, while that of the brass tool electrode was mainly on the workpiece side. This effectively demonstrates the higher electrode relative wear of brass tool electrodes.