Investigations on Hard Turning with Minimum Quantity Lubrication and its Automation Thereof

Abstract

Abstract-Minimal quantity lubrication (MQL) is a recenttechnique introduced in machining (in particular, in drilling) to obtain safe, environmental and economic benefits, reducing the use of coolant lubricant fluids in metal cutting. In MQL a very small lubricant flow (ml/h instead of l/min) is used. In this case, the lubricant is directly sprayed on the cutting area. It guarantees a good level of lubrication. The cost of coolant is approximately from 7 to 17% of the total machining cost. This cost continues to rise. So coolant in wet machining operations is a crucial economic issue. An alternative, machining with "minimum quantity lubricant," or MQL, is gaining acceptance as a cost-saving and environmentally friendly option in place of some wet machining processes. In the present work a specially formulated cutting fluid was applied as a high velocity, thin pulsed jet at the immediate cutting zones at an extremely low rate of 2 ml/min using a fluid application system developed for this purpose during turning of hardened steel. The performance of HTMF (Hard Turning -Minimum Fluid) is studied in comparison with that of conventional hard turning in wet and dry form in terms of cutting force, cutting temperature, surface roughness, average flank wear, etc.