Spark Gap System of Electrical Discharge Machining (EDM)

EDM is a process of machining electrically conductive materials by precisely controlled electrical discharge through a small clearance gap that occur between an electrode and a workpiece in the presence of a dielectric fluid. Through EDM process, the material of workpiece are melted and gap distance will increase. In order to maintain a stable spark, the gap must be controlled. This paper presents control spark gap system of EDM using PID controller with voltage and position feedbacks. The results show Time Rise (Tr) of PID control with voltage feedback has a value about 75 seconds and Time Rise (Tr) of PID control with voltage and position feedbacks has a value about 18.6 seconds. The average error of gap distance in PID control with voltage feedback is 55.56 and the average error of gap distance in PID control with voltage and position feedbacks is 48.53. Addition of the position feedback is used to increase the rise time and stabilize distance the electrode and the workpiece.