Experimental investigation on application of emulsifier oil based nano cutting fluids in metal cutting process

Abstract

The purpose of cutting fluids in metal cutting process is to provide cooling and reduce the friction between tool and work piece at the shear zone. In dry cutting, the work piece is machined under dry conditions. The air surrounding the work piece acts as the cooling agent. Since air has low thermal conductivity it acts as a poor coolant. High temperatures at tool-work piece interface causes failure of cutting tools, formation of micro cracks and surface roughness of work piece is compromised. In wet cutting, the work piece is machined under wet conditions. Most cutting fluids constitute ninety five percent of water and five percent of cutting oil. Usage of cutting fluids have shown significant changes in thermal properties, tool wear, surface roughness and cutting forces on tool and work piece respectively.A study by few American institutes states that 60% companies are spending 20% more amount on their coolants/lubricants in a cutting operation than on cutting tool being used for machining. Uncontrolled microbial contamination of metal working fluids represents both economic and health risk. Minimum quantity lubrication (MQL) is alternative to this problem which uses minute amount of cutting fluids which is about three or four times less than that of the amount commonly used in a flood cooling condition.MQL requires a fluid with high heat carrying and lubricating properties. The present work investigates upon the usage of nano-graphite, nano -boric acid and nano-molybdenum disulphide in emulsifier oil based cutting fluids in MQL application. The primary work is to prepare a cutting fluid by including 0.3 wt% of nano particles and to check its stability, as dispersion of nano particles in base fluid is a challenging process. The prepared cutting fluids with nano inclusions are applied at a flow rate of 10ml per minute while performing turning operation under constant cutting conditions. Performance of cutting fluids are evaluated by measuring cutting forces, cutting temperature near chip –tool interface, tool wear and surface roughness for each turn. The results are compared with dry and MQL application with emulsifier oil without nanoinclusions.