Development of a Micro w-EDM Pulse Generator with Energy-Optimized Boost Effect for Study on High-Precision Machining of Silicon Carbide Microstructures

Silicon carbide (4 H-SiC) is widely used in green energy industries, such as in electric vehicle charging modules and renewable energy power switches. However, its high-resistance, -melting point, and -hardness demand significant energy for machining with conventional w-EDM, making high-precision processing difficult. To address this, a micro w-EDM pulse generator with an energy-optimized boost circuit is developed and presented in this study. In this system, magnetic energy briefly stored in an inductor is converted to electrical energy during pulse-on time and instantly superimposed onto the original input voltage. This discharge energy forms a pulsed current train with superimposed peak values, rapidly breaking the surface barrier of 4 H-SiC to enable efficient gap ignition and arc initiation. Cutting tests using a micro brass wire on 4 H-SiC show that commercial transistorized discharge circuits cause severe slot expansion, damaged layers, and welding-scars, indicating excessive energy consumption, thermal deformation, and failure to meet the precision needs of microstructure fabrication. In contrast, the energy-optimized boost circuit confines each discharge pulse to a narrow width with high-frequency, superimposed peaks, enabling rapid, trace-amount material removal with low energy consumption and minimal thermal shock. Two microstructural arrays—comb-like and curved-fin—are successfully machined, achieving thicknesses as thin as 13 μm, high uniformity, excellent flatness, and aspect ratios exceeding 1:30. The surface roughness remained below Ra 0.292 μm without thermal deformation, confirming the circuit’s effectiveness in preventing excess discharge energy. This advancement enables low-energy wire-cutting discharge machining, particularly suitable for materials with high melting points, hardness, and electrical resistance.