A Preliminary Study exploring Dielectric Fluid Dynamics within the Inter-Electrode Gap in Micro-Electro-Discharge Milling

Understanding dielectric fluid dynamics within the inter-electrode gap (IEG) is essential for improving debris evacuation and process stability in micro-electro-discharge milling (μ-EDM). This study develops a two-dimensional laminar flow model using COMSOL Multiphysics to simulate fluid behavior and debris particle transport within lateral IEGs. Simulations are performed for rotational speeds of 400, 600, and 850 rpm and gap sizes of 20, 25, and 30 μm. Flow field analysis reveals that while the overall flow pattern remains consistent across conditions, narrower gaps exhibit steeper velocity gradients and stronger recirculation zones behind the rotating tool, which may hinder effective flushing. Steady-state velocity data at key monitoring points indicate that tool rotational speed significantly impacts fluid motion more than gap size. Particle tracing simulations further show that, under narrow-gap conditions, debris tends to accumulate in recirculation zones before gradually migrating toward the outlet. These findings emphasize the dominant role of rotational speed and localized flow features in debris transport, offering practical insights for improving dielectric performance in μ-EDM milling.