Cutting performance of different coated twist drills

Abstract

The cutting performance of HSS twist drills with various coatings was experimentally investigated in this study. The experiments were conducted to investigate and compare the cutting force responses and drill life of these coated drills in the drilling of JIS SS 400 carbon steels. The experimental results indicate that the thrust forces and torque generated during the drilling process vary within a narrow range for these coated twist drills under some drilling conditions. However, the average values of trust forces and torque increase with increase in the feed rates for all of the coated twist drills, whilst the average values of thrust forces and torque decrease within a narrow range as the spindle speeds up to 725 rpm, in the current experiments. The wear widths developed on the flank surface were also examined, showing that the TiCN-surface multilayer coated drill has the least wear rate amongst these coated twist drills.