Tribological Analysis of a Low-Cost, Environment Friendly Used Cooking Oil-Based Venturi Spray Lubrication System for Hard Turning Applications

Abstract Tool life in hard turning can be improved using proper lubrication methods. Hard turning can be made economical by employing used cooking oil (UCO) as an alternative lubricant for reducing friction in the cutting zone. Repurposing UCO for machining applications contributes toward sustainable development. A low-cost Venturi spray lubrication system that requires only compressed air is designed, developed, and tested. The oil properties that affect machining are studied and compared for three oils—used cooking oil, fresh cooking oil, and commercial minimum quantity lubrication (MQL) oil. The machining performance of the three oils under spray lubrication conditions is compared in turning of EN 31 hardened steel with coated ceramic inserts. Various parameters of machining like surface finish, temperature distribution, tool wear, and motor current drawn are monitored and analyzed. It is found that stable machining conditions are observed when using UCO as a lubricant as the values of surface roughness, temperature distribution, and tool wear are very consistent for three different cutting speeds. It is also found that UCO has better surface integrity and lower tool wear when compared to the other two oils.