A REVIEW OF MINIMUM QUANTITY LUBRICANT ON MACHINING PERFORMANCE

ABSTRACT This paper reviews the effect of minimum quantity lubricant (MQL) on machiningperformance. Minimum quantity of lubrication in machining is an establishedalternative to completely dry or flood lubricating system from the viewpoint of cost,ecology and human health issues. The effect of MQL, dry cutting and flooded coolantwere reviewed with respect to cutting forces, surface roughness of the machined workpiece and tool wear. Results from literatures indicated that the MQL leads to lowercutting forces, reduced surface roughness and tool wear. Therefore, it appears thatMQL, if properly employed not only provides environment friendliness but alsoimprove the machinability characteristics. Keywords : minimum quantity lubricant, cutting forces, surface roughness, tool wear INTRODUCTION In recent years, energy consumption, air pollution and industrial waste have been thefocus of special attention on the part of public authorities. The environment has becomeone of the most important subjects within the context of modern life, for its degradationdirectly impacts humanity. Driven by pressure from environmental agencies, politicianshave drawn up increasingly strict legislation aimed at protecting the environment andpreserving natural energy resources. These combined factors have led the industrialsector, research centers and universities to seek alternative production processes,creating technologies that minimize or avoid the production of environmentallyaggressive residues. In high speed machining, conventional cutting fluid applicationfails to penetrate into chip-tool interface and thus cannot remove heat effectively (Dharet al., 2000). Addition of extreme pressure additives in the cutting fluids does not ensurepenetration of coolant at the chip-tool interface to provide lubrication and cooling(Boothroyed and Cassin, 1965). However, high pressure jet of soluble oil, when appliedat the chip-tool interface, could reduce cutting temperature and improve tool life tosome extent (Kubala et al., 1989). Due to several negative effects, a lot has been done inrecent past to minimize or even completely avoid the use of cutting fluids (Sokovic andMijanovic, 2001). Dry machining is now of great interest and actually, they meet withsuccess in the field of environmentally friendly manufacturing (Klocke and Eisenblatter,1997, 1999). In reality, however, they are sometimes less effective when highermachining efficiency, better surface finish quality and severe cutting conditions are