Surface integrity optimization in AZ31 milling using integrated NSGA-II and GRA methodology
摘要
This study presents an integrated optimization framework to improve the sustainability of AZ31 magnesium alloy milling by minimizing machining vibration and surface roughness while maximizing hardness. A Taguchi L25 orthogonal array was used to design experiments across five levels of three input parameters. Empirical models were developed using stepwise regression with a 15% confidence threshold, and NSGA-II was applied to generate 18 Pareto-optimal solutions. Grey Relational Analysis (GRA) ranked the solutions, identifying the most effective trade-off: vibration = 10.3 mm/s², roughness = 1.6 μm, and hardness = 233.23 HV at optimized settings (X1 = 1004.3 rpm, X2 = 1231.8 mm/min, X3 = 1.566 mm). Experimental validation showed close alignment with theoretical predictions, with deviations of 8% for vibration, 2% for roughness, and 0.7% for hardness. The results confirm the robustness of the proposed method and its effectiveness in achieving sustainable surface integrity in magnesium alloy machining.