Electrochemical discharge machining (ECDM) process is a recent non-traditional machining technique used for structuring insulating materials like glass and ceramic substrates. In this work, systematic experimental investigations have been carried out to study the electrical and 2-D machining characteristics of an ECDM process. The influence of various process parameters like electrolyte type, electrolytic concentration, tool travel rate (TTR) and applied voltage on the process characteristics have been studied. Two different electrolytes, i.e., KOH and NaOH with concentrations varying from 10 to 50 % have been used to study their effect on critical voltage (Vc) and critical current (Ic). A cylindrical tungsten carbide tool of diameter 0.4 mm with varying TTRs (ranging from 0.3 to 4 mm/min) and an applied voltage varying from Vc + 2 V to Vc + 5 V is used for realizing microchannels. The influence of these parameters on the quality factors such as geometric accuracy, surface smoothness and channel outlines are explored using the optical images of the machined channels. Experimental results demonstrate that precise channels with smooth surface, and regular channel edges can be obtained at an applied voltage of Vc + 4 V and TTRs between 1 and 2 mm/min. © 2016, Springer-Verlag Berlin Heidelberg.