High-speed helical milling for hole-making of Inconel 718 with ceramic endmills

This paper investigates the high-speed helical milling of Inconel 718 with solid ceramic endmills. Tool life tests were performed. Flank wear of the frontal cutting edges was the main wear type. Temperatures in the range of Inconel 718 melting point were observed, giving some evidence of thermal softening of the alloy. Cutting forces were very high before the achievement of such temperature levels, justifying the premature tool wear. In the machined surfaces, it was observed adhered chips, plowing, and crushed burrs. Adhesion of Inconel 718 in the worn flank of the frontal cutting edges was the main wear mechanism. Diffusion was prominent with the highest cutting speed. A linear rise of temperature with wear, vc , and machined hole was observed. Despite the superior material removal, helical milling with ceramic endmills presented limited productivity considering the number of holes achieved.