Machining with AlCr-oxinitride PVD coated cutting tools

Abstract AlCrO x N 1− x coatings were arc deposited onto HSS drills and WC–Co end mills at N 2 /O 2 ratios of 0.9–0.75 using DC or 10 kHz pulse bias. Lower O 2 content coatings had a hardness of 32.5 GPa. whereas 0.25 O 2 ratio coatings were 24–25 GPa. AlCrO x N 1− x coated 6.35 mm Dia. HSS jobber drills were tested by drilling 2.5D holes in AISI D2. 10 kHz 0.9 N 2 0.1 O 2 coatings drilled a mean of 17.6 holes/µm, similar to commercial AlCrN coated drills at 17.8 holes/µm, whereas DC 0.75 N 2 0.25 O 2 coatings drilled 9 holes/µm. AlCrO x N 1− 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 N 2 0.25 O 2 tools had the least corner wear and low adhesion on the rake face.