Effects of Built-Up Edge in Drilling

Experimental tests were performed to study the effects of built-up edge in drilling four different work materials with a twist drill, at different cutting speeds and feeds. The tests were made dry to facilitate observation. Chip-flow angles, normal rake angles, and web angles with built-up edge were measured and correlated with inclination angles and effective rake angles. Comparison of the angles with and without built-up edge showed that the built-up edge significantly affects the basic mechanics of drilling.