Abstract To achieve high removal rate and low electrode wear when roughing by the sinking electrical discharge machining process (EDM), appropriate average surface power density is required in the gap between the workpiece and the electrode, i.e. rough machining parameters have to be tuned to the machining surface. Since machining surface varies with the depth of machining, the rough machining parameters have to be selected on-line to obtain appropriate average surface power density in the gap. The systems for on-line selection of the rough machining parameters of EDM process presented in the literature either have hardly acceptable disadvantages or they are very complex. Thus, a simple solution could be a significant step towards better automation of the EDM rough machining and micro electrical discharge machining (MEDM). In this paper, a system for on-line selection of the machining parameters according to the given machining surface is presented. The selection of the machining parameters is based on the acquisition of only one process attribute, i.e. the percentage of short-circuit discharges, which is significant improvement comparing to known systems
