Effects of powder characteristics on electrodischarge machining efficiency

This paper presents the effects of various powder characteristics on the efficiency of electrodischarge machining (EDM) SKD-11. The additives examined include aluminum (Al), chromium (Cr), copper (Cu), and silicon carbide (SiC) powders that have significant differences in their thermophysical properties. The machining mechanism with the addition of the foreign particles, the tool wear rate (TWR), and the material removal rate (MRR) have been investigated. It was found experimentally that the particle concentration, the particle size, the particle density, the electrical resistivity, and the thermal conductivity of powders were important characteristics that significantly affected the machining performance in the EDM process. Proper addition of powders to the dielectric fluid increased the MRR and, thus, decreased the TWR. Under the same particle concentration experiments, the smallest suspended particle size led to the greatest MRR and, thus, the lowest TWR. Of the additives investigated, chromium powder produced the greatest MRR and the lowest TWR whereas the process without foreign particles has the converse effects. The addition of copper powder to the dielectric fluid wa found to make almost no difference to the pure kerosene EDM system.