High-efficiency machining of Ti–6Al–4V with an optimized tool in underwater arc cutting

To enhance the environmental sustainability and energy efficiency of electric arc machining, this paper proposes an immersed rotating disc electric arc cutting (EAC) method. Unlike conventional SEAM or mechanical machining processes, EAC establishes a new paradigm for efficient material removal by synergistically regulating pulsed discharge parameters (voltage, duty cycle) and mechanical motions (electrode rotation, feed rate). Using an orthogonal experimental approach, the influence weights of key process parameters on machining efficiency and surface quality were systematically evaluated, and the optimal parameter combinations for various performance indicators were determined. On this basis, a TiN coating was applied to the tool electrode and its groove structure was optimized. Experimental results demonstrate that the toothed coated composite electrode delivers the best overall performance, achieving the lowest surface roughness (111.78 μm) and a relatively low electrode wear rate (18.47%). This performance advantage primarily stems from the toothed structure's enhancement of debris removal and forced arc extinguishing capability, coupled with the thermal barrier effect and arc erosion resistance provided by the TiN coating. The synergistic interaction of these features significantly improves discharge stability and energy utilization efficiency.