Chip temperature and its effects on chip morphology, cutting forces, and surface roughness in high-speed face milling of hardened steel

Experimental investigation and finite element simulation of face milling AISI H13 steel with CBN tool were conducted in order to acquire thorough understanding of the chip temperature and its effects on chip morphology, cutting forces, and surface roughness. Cutting speeds adopted in the tests and simulations were in the range of 800 to 1,600 m/min. Axial depth of cut and material removal rate were set to be invariable for each cutting speed. The cutting parameter zones where relatively high chip temperature (zone “H”), long helix chip (zone “L”), lower resultant cutting force (zone “R”), and lower surface roughness (zone “S”) arose were distinguished. The analysis results showed that the higher chip temperature in zone “H” led to higher ductility of the chip, resulting in the formation of long helix chip instead of short washer-shaped chip. The thermal softening effects induced by higher chip temperature in zone “H” led to lower cutting force and more stable cutting process which was beneficial for the better surface finish. Relatively high chip temperature, relatively low resultant cutting force, and relatively low surface roughness arose at the same time in cutting parameter zone “R”.