A Multi-Criteria Framework for Sustainable Cooling Strategy Selection in Turning of Inconel 600 via MCDM Methods

Inconel 600 is widely used in the manufacturing industry due to its high-temperature resistance, excellent mechanical strength, and corrosion resistance. However, these same properties make it difficult to machine, resulting in high cutting forces, elevated temperatures, and poor surface quality. Optimizing cutting parameters alone is not sufficient; sustainable cooling strategies must also be considered. While previous studies have explored individual cooling techniques, there is a lack of comparative research on hybrid methods—particularly those combining high-pressure air and minimum quantity lubrication (MQL). This study examines the turning of Inconel 600 under eco-friendly cooling conditions: dry machining, high-pressure air (7 and 10 bar), MQL, and a hybrid method integrating compressed air and MQL. Machining performance was assessed based on cutting force, surface roughness, and temperature. A structured multi-criteria decision-making (MCDM) framework—employing TOPSIS, MOORA, PROMETHEE II, and COCOSO with three weighting schemes (equal, entropy, and critic)—was used to determine the optimal strategy. Final rankings were consolidated using Copeland and Borda count methods. Results indicate the hybrid method is the most effective, significantly reducing main cutting force (20.18%), feed force (31.79%), surface roughness (53.58%), and temperature (35.84%) compared to dry machining, demonstrating its potential for sustainable and high-performance machining.