Performance evaluation of cryogenic liquid nitrogen as a coolant on the machining of tool steels in the milling process

Abstract

The challenges of modern machining industries is mainly focused on the achievement of high quality in terms of work piece dimensional accuracy surface finish high production rate less wear on the cutting tools economy of machining interms of cost saving and increase of the performance of the product with reduced environmental impact The major problems in achieving high productivity and quality are caused by the high cutting temperature developed during machining at high cutting velocity and feed rate particularly when the work material is difficult to machine like tool and die steels Such high temperature causes dimensional deviation and premature failure of cutting tools It also impairs the surface integrity of the product by inducing tensile residual stresses and surface and subsurface micro cracks in addition to rapid oxidation and corrosion The detrimental effect of high cutting temperature is generally controlled by applying flood coolant by soluble oil which could reduce the cutting temperature and improve tool life to some extent However conventional coolants generally cause environmental and health problems to the machine operators Cryogenic machining using LN2 as an environmentally safe coolant for the desirable control of cutting temperature and improve the machining performance