Experimental investigations into electrochemical discharge machining (ECDM) of non-conductive ceramic materials

Electrochemical discharge machining (ECDM) has potential for the machining of non-conductive ceramic materials as compared with different existing conventional and also non-conventional machining methods. However, now many aspects of this machining technology still demand further extensive in-depth research and development. The present research paper includes the analysis of the basic material removal mechanism in the ECDM process for the effective machining of non-conducting ceramic materials with enhanced machining rate and higher machining accuracy. The ECDM process is influenced by various process parameters such as the applied voltage; the interelectrode gap, the temperature, concentration and type of electrolyte; the shape, size and material of the electrodes; and the nature of the power supply, etc. Keeping in view the influences of the various process parameters of ECDM, the present paper highlights the modular mechatronic feature of the indigenously designed and developed machining set-up for carrying out experimental investigations. Such experimental investigations, on the material removal rate and over-cut phenomena in the ECDM process, have been reported in this study for the machining of aluminium oxide ceramic workpieces under varying process parametric conditions such as applied voltage (70-90 V), and electrolyte concentration (20-30%). NaOH solution with varying concentration was taken as the electrolyte. A pulsed d.c electric supply had been utilised for the drilling operation of ceramic work-samples. In addition, an attempt has been made through these sets of investigations to explore the influence of a suitable and effective tool tip geometrical shape for greater machining rate and accuracy. Detailed analysis of various test results, supported by a large number of micrographs of the machined work-samples, has been conducted that will provide further insight into the fundamental mechanism of this machining process. The research findings will lead to the exploration of the most effective range of parametric combinations for enhancing the machining rate and the accuracy. (C) 1999 Elsevier Science S.A. All rights reserved.