Development of EDM Electrode by Powder Metallurgy Process

Abstract

The EDM electrode is specially made of tungsten powder by powder metallurgy process. Negative or reverse polarity is used for better results of layer deposition of electrode material of tungsten powder and carbon particles within the dielectric liquid used for machining. The work piece is of low carbon steel or HSS. It is observed that tungsten carbide layer deposited on the work piece has better performance characteristics for application. In this work the powder used for electrode manufacturing consists of 75 % Tungsten, 25% copper by weight and 2% of it camphor is added as binder. Each electrode is made of 10 gm mixed powder of Tungsten and copper in the proportion. Three line pressures are applied on the powder placed in the die to get three different densities of the electrode formed. The pressed electrodes are then semi sintered at 800ºC in the resistance furnace. The formed electrodes have better properties for deposition of its material on work piece during electro discharge machining process.