Behavior of coated carbide tools in high speed machining of a nickel base alloy

Multilayer TiN/TiCN/TiN and single-layer TAIN PVD coated carbide tools were used to machine a nickel base, C-263, alloy at high-speed conditions in order to investigate their performance ill terms of toot life, surface finish and component forces generated during machining. The test results show that the triple layer, TiN/TiCN/TiN coated inserts gave longer tool life when machining at higher speed and depth of cut conditions while the single layer, PAIN, coated inserts produced better surface finish, The feed forces recorded were generally higher than the cutting forces. This could perhaps he attributed to the adverse effect of burr formation and work hardening of the workpiece associated with prolonged machining. Analysis of the test results indicate that the difference in thermal properties and tribo-chemical behaviour of both the coating and substrate materials are the major factors influencing the tribo-contact at the tool-chip interface during machining. Wear mechanisms of the coating materials call also affect tool performance ill terms of tool life, surface finish and component forces.