Evaluation of performance of various coolant grades when turning Ti-6Al-4V alloy with uncoated carbide tools under high-pressure coolant supplies

This work presents the evaluation of three commercially available coolant grades (dicyclohexylamine-based coolant, a triethanolaminebased coolant, and an ester-based coolant) when machining Ti-6Al- 4V alloy with high-pressure coolant delivery. The evaluations were based on tool life, tool failure modes, surface integrity, and chip formation. The dicyclohexylamine-based coolant was the more effective coolant when machining at the highest pressure of 20.3MPa due to its stability at elevated temperature, whereas the triethanolaminebased coolant performed effectively at a pressure of 11MPa due to its low surface tension properties. Deterioration of the ester-based coolant was found in almost all coolant pressures due to its low resistance to oxidation. Surfaces generated when machining with all coolants grades were generally acceptable with negligible physical damage.