Increasing discharge energy of micro-EDM with electrostatic induction feeding method through resonance in circuit

• Controlled pulse train method allows multiple discharges to occur at the same spot.
• Resonance in circuit is utilized to increase discharge energy in micro-EDM.
• At resonant frequency, highest discharge energy can be achieved.
• Machining at resonant frequency results in highest MRR.

This paper describes the method to increase discharge energy in micro-EDM using electrostatic induction feeding as the pulse generator. In a previous study, controlled pulse train method was introduced to increase discharge energy and enlarge unit removal per discharge by allowing multiple discharges to occur at the same spot. During observation, it was found that the oscillation of discharge current is excited at higher amplitude even if the same capacitance is used. In this paper, the influence of frequency on discharge energy was investigated. It was found that higher discharge energy can be obtained when machining was done at the resonant frequency of the circuit. Influence of capacitance and inductance on resonant frequency was studied. Probability of discharge continuity at different frequencies was examined. The results confirmed that higher discharge continuity within the pre-determined pulse train duration can be achieved when machining is conducted at resonant frequency, leading to higher material removal rate (MRR).