Cutting forces, tool life, and size effect of passivated cutters in milling of Inconel 718

An experimental study is conducted to research the passivation effects of cutters on cutting forces, tool life, and size effect in milling of Inconel 718. Cutting forces and tool life of passivated cutters with different cutting edge radiuses are measured and compared in plunge milling. The results show that, with the increase of the cutting edge radius, cutting forces keep increasing while tool life increases first and then decreases. When the cutting edge radius is 7.9 μm the tool life of passivated cutter reaches its maximum under experimental conditions. The unit cutting force per cutting area on the tool edge is adopted to evaluate the size effect of passivated cutters in end milling. The results show the effect size of tool edge is obvious when the cutting depth is less than the cutting edge radius. This effect is more significant with the decrease of the cutting depth.