Evaluation of modified jatropha-based oil with hexagonal boron nitride particle as a biolubricant in orthogonal cutting process

Abstract

Crude jatropha oil (CJO) has been acknowledged as an environmentally benign metalworking fluid (MWF) in the machining industry. However, one drawback found in CJO is that it has poor thermal-oxidative stability that leads to poor lubrication behavior. Henceforth, the objective of this study was to evaluate the machining performances of the newly developed modified jatropha oil (MJO) as a lubricant-based oil. The CJO was improvised through transesterification process at various molar ratios of jatropha methyl ester (JME) to trimethylolpropane (TMP) (MJO1, MJO3, and MJO5) and through the addition of various concentrations of hexagonal boron nitride (hBN) particles, ranging between 0.05 and 0.5 wt.%. The newly developed MJO were compared to CJO and synthetic ester (SE) by considering both viscous and tribological behaviors. In addition, the orthogonal cutting process was carried out on AISI 1045 through minimum quantity lubrication (MQL) methods to evaluate the machining performances (i.e., cutting force, cutting temperature, chip thickness, tool chip contact length, and specific energy). Interestingly, kinematic viscosity and viscosity index were improved with the increase in JME/TMP molar ratio and concentration of hBN particles. MJO5 added with 0.05 wt.% of hBN particles (MJO5a) exhibited the best tribological behavior correlated with excellent machining performances by reducing the cutting force, cutting temperature, chip thickness, tool chip contact length, and specific energy. MJO5a exemplified its potential on the lubricant market place with regard to the environmental concern and energy saving.