Study on machining characteristics and parameter optimization of titanium alloy using green argon-assisted near-dry electrical discharge milling

Near-dry electrical discharge milling (Near-dry EDMilling) technology is a variant of Near-dry electrical discharge machining (Near-dry EDM) technology, and it also employs a gas-liquid atomized medium as the discharge medium for milling. This study adopted green argon as the gas-phase medium Near-dry EDMilling of titanium alloy, conducting comparative experiments with air-medium Near-dry EDMilling (Air-N-EDMiling). Results showed Air-N-EDMiling formed high-melting titanium oxides on the surface, while argon-medium Near-dry EDMilling (Ar-N-EDMiling) reduced surface compounds. Compared to Air-N-EDMiling, Ar-N-EDMiling increased material removal rate (MRR) by 22.5%, decreased surface roughness (Ra) by 18.1%, thinned recast layer by 64.81% and reduced microcracks. Orthogonal experiments were analyzed via signal-to-noise ratio (S/N) and variance methods to explore Ar-N-EDMiling parameters’ effects on MRR, Ra and relative electrode wear rate (REWR), determining optimal single-objective parameters. Multi-objective optimization using grey correlation degree identified the best combination: current 15 A, pulse width 300 μs, pulse interval 100 μs, rotation speed 400 rpm.