Mixed Aggregation by Comprehensive Normalization Technique–Based Parametric Optimization of Turning of Ti-6Al-4V Alloy in Minimum Quantity Lubrication Environment

<div>Although Ti-6Al-4V alloy offers high strength-to-weight ratio, corrosion resistance, and biocompatibility properties, its machining is challenging due to low thermal conductivity, high hardness, and chemical reactivity. This study examines turning of Ti-6Al-4V under minimum quantity lubrication (soybean oil). Cutting speed (CS), feed rate (FR), and depth of cut (DOC) are considered as the input parameters. On the other hand, material removal rate (MRR), tool wear rate (TWR), surface roughness (SR), and cutting force (Fc) are treated as the responses. Optimization of the said process is carried out using the mixed aggregation by comprehensive normalization technique (MACONT), a recently developed multi-criteria decision-making (MCDM) method. The optimal parameters are identified as CS = 72.26 m/min, FR = 0.022 mm/rev, and DOC = 0.2 mm, achieving high MRR with low TWR, SR, and Fc. The effects of different turning parameters on the responses are also investigated. Sensitivity analysis confirms robustness, and comparative evaluation with other MCDM tools validates accuracy of the adopted approach. The results demonstrate MACONT’s effectiveness in optimizing turning of hard-to-machine alloys, supporting greener and sustainable machining practices.</div>