Design and development of a modular machine tool for micro-ED drilling and ED milling

Electrical discharge machining (EDM) facilitates the fabrication of complex geometries in hard, high-temperature-resistant, and electrically conductive materials. At micro-scale dimensions, micro-ED drilling and ED milling impose stringent requirements on machine tool design with respect to electrode handling, positioning accuracy, and discharge energy control. Micro-ED drilling processes require the use of ultra-thin electrodes with diameters de ≤ 10 µ m to achieve borehole diameters dh < 50 µ m, whereas ED milling typically employs thin electrodes for generating micro-scale surface features. This study presents the design and development of a modular EDM machine tool architecture configured to address these distinct operational requirements through an integrated mechanical and electronic approach. The mechanical design employs a modular frame structure capable of accommodating high-precision linear stages, a one-axis piezoelectric actuator for fine electrode approach control, and a redesigned workpiece holder with dielectric containment. Finite element analyses and experimental modal testing were conducted to assess the static and dynamic stiffness of the assembly, with the objective of minimizing structural deflection and avoiding resonance frequencies within the operational bandwidth. The control and generator systems were comprehensively redesigned, employing an integrated microcontroller platform that consolidates motion control, working gap control, and process monitoring. The EDM generator is capable of delivering low-energy pulses with configurable pulse and interval durations in the nanosecond range, enabling stable machining with both ultra-thin and thin electrodes. Real-time gap sensing and feedback allow for adaptive control of the discharge process to maintain consistent machining conditions. The modular system architecture supports future integration of additional subsystems such as real-time process signal analysis or alternative electrode handling modules. Preliminary validation experiments indicate the system’s capability to perform micro-ED drilling with improved handling of ultra-thin electrodes while using low discharge energies suitable for research and precision manufacturing applications.