Precision milling of nickel-based single-crystal superalloy by TiAlN coated small diameter solid carbide end mill

Nickel-based superalloys pose cutting challenges due to their high strength, hot hardness, work hardening, and low thermal conductivity. Precision milling with small cutters is used for complex shapes and intricate profiles, but selecting appropriate machining parameters for these alloys is a challenging task. A set of machining conditions in slot milling with a TiAlN coated 1.5 mm diameter solid carbide end mills are investigated for dimensional accuracy, cutting forces, and specific energy. The dimensional accuracy in depth consists of within 10% of the depth of cut. The axial force and the feed force increase from 20 N to 106 N and from 17 N to 46 N, respectively with an increase in chip area from 0.8E-03 to 1.5E-03 mm2/rev. Tool rotation caused a gradual increase of cutting forces in up-milling and decreasing of cutting forces in down-milling. The specific energy increases from 393 to 865 J/mm2 steeply under higher chip areas.