Measurement of tribological properties of Cu and Ag blended coconut oil nanofluids for metal cutting

Abstract

Lubricants are used during the metal cutting process to remove the heat generated during the process and to reduce the Coefficient of friction (CoF). In this paper an attempt was made to synthesize an environment-friendly nano-lubricant using virgin coconut oil as base fluid by separately blending Copper (Cu) and Silver (Ag) nanoparticles in concentrations of 0.1%, 0.25%, 0.5% and 1% on the mass basis. The nanoparticles were blended in coconut oil by the means of ultrasonic shaking to obtain a uniform blend. The dependence of the Coefficient of friction of nanofluids and its performance on the concentration of the nanoparticles is well reported by researchers; therefore the optimal concentration of the nanoparticles was identified by Pin-on-Disk tribological testing. The following tests were conducted on the synthesised nano-lubricant such as Coefficient of friction (Pin-on-disk test), viscosity, flash & fire point and real time turning operation to determine the cutting force, and operating temperature. From the wear test results, it was inferred that copper added coconut nanofluids exhibited lower Coefficient of friction as compared to silver added coconut nanofluids. Further, it was identified that the lowest Coefficient of friction in the range was exhibited by copper added coconut nanofluids of 0.25% concentration. When these nanolubricants were tested in a real time turning operation using lathe tool dynamometer, it was found that 0.25% concentration of copper added coconut nanolubricant exhibited minimum cutting force and operating temperature indicating minimum coefficient of friction. Keywords: Nanolubricants, Cutting fluid, Cutting force, Cutting temperature, Coefficient of friction