Influence of coconut oil on tribological behavior of carbide cutting tool insert during turning operation

In manufacturing industries, machining is considered as one of the most significant and effective processes. During machining process, cutting zone experiences the higher temperature due to friction between the chip-tool and work-tool interfaces, which directly influences the tool wear, surface quality and dimensional accuracy of the work material. Even though cutting lubricants are extensively used for lubricating and cooling the tool-workpiece contact area, their application has several drastic effects on environment and the health of operators. Hence, there is a need to identify an environmental friendly and user-friendly alternative to conventional cutting lubricants. The main objective of this work is to evaluate the effect of cutting lubricants on tool wear, friction coefficient, surface quality and chip morphology during turning of AISI 1040 steel with tungsten carbide tool insert under dry, wet, coconut oil, minimum quantity lubrication (MQL) using water-miscible fluid and MQL using coconut oil cutting conditions. The wettability characteristic of coconut oil on a carbide tool insert results in good adsorption on tool and workpiece, which causes effective lubrication and reduction in friction. It was found that the wettability angle of coconut oil is 33.7°, which greatly enhanced the wettability characteristics compared to the conventional cutting fluids. The MQL method using coconut oil machining condition resulted in a significant decrease in tool wear, friction coefficient along with favorable chip morphology and better surface quality of the workpiece.