Abstract: To improve the efficiency of electrical discharge machining (EDM) ablation, this paper uses a sintered diamond electrode as the machining electrode, making use of grinding action of diamond particles, to achieve machining combined with high efficiency ablation and mechanical grinding. In the study, through gathering mechanical grinding force during machining, a control method based on force signal is proposed to ensure diamond particles grinding. In order to maintain the stability of pressure in the process, three control methods are proposed: inverse proportional control, fuzzy control and PID control. In addition, we use high strength steel as the workpiece and conduct three groups of machining efficiency comparative experiments. From these three groups of experiments, we conclude that the machining depth can reach to 14.5mm and the force range is less than 1.0N by using PID control method. PID control method has advantages over the other two in machining efficiency and stability.

Key words: electrical discharge machining (EDM), ablation machining, sintered diamond, PID pressure control, machining efficiency