Role of minimum quantity lubricant in turning hardended AISI 1040 steel by uncoated carbide insert

Abstract

The generation of huge amount of heat in high production machining at high cutting velocity and feed rate shortens the tool life and deteriorates the job quality. The conventional cutting fluids are not that effective in such high production machining particularly in continuous cutting of materials like steels. Because of these some alternatives has been sought to minimize or even avoid the use of cutting fluid in machining operations. One of these alternatives is machining with minimum quantity lubricant (MQL). It is a mixture of impinging of least amount of cutting fluid along with highly compressed air through a small nozzle results in reducing the heat produced during metal cutting. The main objective of the present work is to make an experimental investigation on the role of MQL in turning hardened steel by uncoated carbide insert (SNMG 120408) in respects of chip formation, chip-tool interface temperature, tool wear and surface roughness. The result indicated that the machining with MQL performed much better than dry machining mainly due to reduction in cutting zone temperature enabling favorable chip-tool interaction. This also facilitated the reduction in tool wear in leading to enhance tool life and surface finish.