Drilling burr formation in titanium alloy, Ti-6Al-4V

Titanium alloy (Ti-6Al-4V) plates were drilled to investigate the effects of tool geometry as well as process conditions on the drilling burr formation. Drilling was done with solid carbide tools with and without coolant and high speed cobalt drills without coolant. Four distinct burr types were observed. During dry cutting, a "rolled back" type burr was observed at high feed rates and cutting speeds and is believed to be due to thermal effects. A "ring" type burr was observed when drilling with coolant. While cutting conditions had little effect on the burr sizes formed, drill geometry (helix angle, split point vs, helical point, lip relief angle and point angle) affected burr thickness and height.