Development of cutting fluid from transesterified coconut oil and evaluation of its tribological properties

Among vegetable oils, coconut oil is identified as a good base oil for lubricant formulation owing to its inherent tribological properties. One of the main disadvantages of using coconut oil as a lubricant in cutting fluid is its low pour point characteristics. It is seen that through esterification process the pour point of coconut oil can be improved from 26.8 ℃ to −4.5 ℃. In the present work, a cutting fluid has been developed from transesterified coconut oil with distinctive additives and surfactants at optimum concentrations. An oil-in-water emulsion of coconut oil methyl ester with additives was found to be stable at HLB 15.8 by adding Tween 80 and 20 surfactants. Coconut oil methyl ester along with additives and surfactants enhanced friction, wear, and thermal properties of the oil by 15.12%, 30.66%, and 14.4% respectively when compared to the commercial sample. Operating temperature range, corrosion resistance, and particle size of the newly formulated oil were found to be satisfactory. Performance study during machining operation was conducted through drilling experiment using HSS tool, SS 304 work piece and coconut oil methyl ester cutting fluid showed superior machining properties (tool wear, cutting torque, and thrust force) when compared to the commercial sample. Tribological studies conducted on oil samples exhibited similar competency between coconut oil methyl ester cutting oil and the commercial sample.