Dimensional and Geometric Deviations Induced by Milling of Annealed and Hardened AISI H13 Tool Steel

The principal goal of this paper was to investigate the influence of tool grade, cutting speed and feed rate on the dimensional (length, diameter and radius) and geometric (parallelism and angularity) deviations obtained after milling AISI H13 hot work die steel in both annealed and hardened conditions using three indexable insert grades: two coated tungsten carbides tools and one cermet tool. The results indicated that lower dimensional deviations were obtained for the external features when up-milling the softer material. Tool grade did not seem to drastically affect external dimensional errors. The dimensional deviations for the internal features were lower when up-milling the hardened steel. The cermet tool was re- sponsible for tighter tolerances when milling the annealed steel, whereas the PVD-coated tungsten carbide tool gave the best results when machining the hardened steel. The parallelism results indicated that tighter tolerances were obtained when milling with the PVD-coated carbide tool. Finally, the angular deviation was lower when down-milling the annealed material with the cermet tool.