Study on micro reciprocating multi-wire electrical discharge machining

This paper presents a high-efficiency and sustainable micro wire electrical discharge machining (micro-WEDM) method employing reciprocating multi-wire electrodes with 50 µm in diameter. To realize stable multi-channel discharge, two-roller, three-roller, and four-roller micro-wire winding configurations are investigated. A multi-degree-of-freedom vibration model is established to analyze the natural frequencies of the micro-wire traveling system, and the tension variation characteristics in the machining region are further examined for different winding modes. Based on these analyses, a multi-wire micro-WEDM method and a corresponding three-roller winding mechanism are developed and validated through machining experiments. The effects of the number of wire electrodes on machining efficiency and accuracy are first evaluated, indicating that micro double-wire EDM provides an effective balance between efficiency and precision. Subsequently, the influences of open-circuit voltage, discharge capacitance, and feed rate on machining performance are systematically investigated to determine suitable processing parameters. Finally, the proposed method is successfully applied to the sustainable fabrication of a micro relay, achieving high machining efficiency and dimensional accuracy, thereby demonstrating its feasibility and practical potential.