A study on the electrical discharge machining of conductive ceramics

In this work, a comparative study of the electrical discharge machining (EDM) of three different conductive ceramics has been carried out. The ceramics used in the experiments were cobalt-bonded tungsten carbide (WC-Co), hot-pressed boron carbide (B4C) and reaction-bonded silicon carbide (SiSiC). This study has been done only for the finishing stages and the selection of the above-mentioned conductive ceramics was motivated by their wide range of applications: machining and mining for WC-Co, thermal-neutron absorber and nozzles for B4C and wear parts and heat exchangers for SiSiC, among others. The comparative study has been carried out on the influence of the design factors of intensity (I), pulse time (t(i)) and duty cycle (eta) over response variables such as surface roughness (evaluated through the R-a parameter), volumetric electrode wear (EW) and material removal rate (MRR). This was accomplished through the technique of design of experiments (DOE), along with multiple linear regression techniques, which allowed us to carry out the analysis with only a small number of experiments. (C) 2004 Elsevier B.V. All rights reserved.