Development of a High-Frequency Discharge Power Source with Non-Equal Energy Relaxation Oscillator Circuit Applied to β-Ga₂O₃ Microstructure Array Wire Electric Discharge Machining

A high-frequency discharge power source with non-equal energy relaxation oscillator circuit is proposed in this study. An experiment based on gallium oxide (Ga₂O₃) and an aluminum alloy microstructure array is devised to verify the machining performance of the power source. Signals are sent by a field-programmable gate array (FPGA) for the control of an N-MOSFET load switch, thus determining when the power source charged and discharged to generate a discharge waveform with narrow pule width and alternating high and low peaks. Compared to a conventional RC discharge circuit, the proposed design generated a pulse train with a regular and dense pattern and created high-density and tiny-energy high-temperature plasma. The experiment was performed with a high-frequency discharge energy pulse train designed with alternating high and low-peaks to examine the machining performance of the discharge source for pyrolytic Ga₂O₃ material including: the best-fit capacitance combination, feed-rate of wire-electrode, material removal rate, kerf width and spark erosion capability. The experiment’s results revealed that the design high-frequency relaxation oscillator circuit successfully generated surface microstructure arrays and pillared microstructure with outstanding dimensional accuracy and consistence. Clearly, the application of the proposed high-frequency power source proposed performed admirably in spark erosion in addition to its high-efficiency, -controllability, and -stability, and it prevented thermal damage to microstructures. The workpiece’s polarity, surface roughness, material removal mechanism, surface degenerating layer and discharging performance of metal and semiconductor are analyzed both quatitatively and qualitatively.