Investigations on Performance of Various Ceramic Tooling While Milling Nickel-Based Superalloy

One of the most cost-effective dimensionally accurate processes used in manufacturing today, that is capable of producing a superior surface finish, is machining. As tooling wears, however, the advantages of machining greatly diminish. In addition, the time lost changing out the tooling significantly affects the overall process efficiency. Therefore, methods that decrease the wear rate of tooling and, thereby, increase tool longevity is essential to improving the efficiency of machining. Optimizing the machining feeds and speeds is one method that has been demonstrated to significantly increase the wear resistance of traditional tooling materials such as HSS, tungsten carbide and advanced ceramic tooling. However, the effects of machining feeds and speeds are not well established for γ′–strengthened nickel-based superalloys. In addition, round geometry inserts were studied due to the rising popularity in industry, since there are an increased number of cutting edges. To help establish these effects, in this work, commercial grade SiAlON (Silicon Aluminium Oxynitride) and Si-WRA (Silicon Carbide Whiskers Reinforced Alumina) cutting inserts are compared. Milling tests were conducted on a γ′–strengthened nickel-based superalloy. More specifically, tool life, machining forces and power were analyzed to evaluate the performance improvements of ceramic tooling. This study found that the abrasive/adhesion flank wear was the main failure mechanism of the ceramic inserts.