Machining with AlCr-oxinitride PVD coated cutting tools

AlCrOxN1−x coatings were arc deposited onto HSS drills and WC-Co end mills at N2/O2 ratios of 0.9-0.75 using DC or 10 kHz pulse bias. Lower O2 content coatings had a hardness of 32.5 GPa. whereas 0.25 O2 ratio coatings were 24-25 GPa. AlCrOxN1−x coated 6.35 mm Dia. HSS jobber drills were tested by drilling 2.5D holes in AISI D2. 10 kHz 0.9 N2 0.1 O2 coatings drilled a mean of 17.6 holes/µm, similar to commercial AlCrN coated drills at 17.8 holes/µm, whereas DC 0.75 N2 0.25 O2 coatings drilled 9 holes/µm. AlCrOxN1−x coated WC-Co end mills had low steady state wear in milling AISI 316L (70 m/min, MQL) and cut >24 m whereas uncoated tools cut 6 m. In contrast to drilling DC 0.75 N2 0.25 O2 tools had the least corner wear and low adhesion on the rake face.