Investigation into the influences of the power circuit on the micro-electrochemical discharge machining process

Abstract

The electrochemical discharge machining (ECDM) process has become a promising area in the field of non-conventional machining processes, as it has a great potential to machine electrically non-conducting materials such as glass and ceramics. However, when it is applied as a micromachining process, its performance characteristics are influenced by various control factors such as the applied voltage, electrolyte concentration, and interelectrode gap, the characteristics of the power circuit, etc., as a result of variation in the sparking intensity. The objective of the present research work is to find out the most suitable power circuit for the ECDM process during its application in the microdrilling of glass. The influences of various power circuit configurations on the material removal rate (MRR), the tool wear rate (TWR), the radial overcut (ROC), and the heat-affected zone (HAZ) have been investigated using an NaOH salt solution as electrolyte. The individual effects of the inductance L, resistance R, and capacitance C of the power circuit on machining performance have been studied experimentally in order to find their optimal values. Experiments have been carried out to search for the pairwise effect of power circuit variables by considering their optimal values according to a Taguchi L9 orthogonal array. Maximum MRR and minimum TWR can be achieved at LC/60V/20 wt %/20 mm and RL/50 V/30 wt %/40 mm respectively. Minimum ROC and minimum HAZ thickness have been obtained at RC/50 V/10 wt %/40 mm. Thus, from the point of view of the accuracy and quality of the machined hole, an RC circuit has been found to be most suitable for the micromachining of electrically non-conducting materials by the electrochemical discharge machining process.