Low-voltage micro-arc discharge-grinding process optimization for GH4169

To address deep erosion pits and recast layers in conventional arc machining of GH4169, this study proposes low-voltage micro-arc discharge-grinding hybrid machining (LV-MADG). High-speed imaging and discharge waveforms showed that discharge initiation changed from contact triggering to gap breakdown at 20–25 V. Compared with electric arc machining, LV-MADG suppressed sustained high-amplitude conduction and improved surface quality and groove accuracy while maintaining material removal capability. Quadratic models related feed rate, duty cycle, spindle speed, and voltage to material removal rate, relative electrode wear rate, areal arithmetical mean height, and recast layer thickness. Pareto-front analysis revealed a clear efficiency–surface-integrity trade-off. The model-selected solution was Pareto-nondominated, and the equipment-rounded condition of 1.0 mm/min, 62%, 920 r/min, and 19 V was experimentally validated, with relative deviations below 6.57% for all responses.