Burrs produced by drilling

Component parts of small precision mechanisms typically require nearly sharp edges to assure reliable operation. A burr-free condition also is needed to minimize a possible jamming of the mechanism because of burrs breaking loose. Small burrs are easily removed by many deburring processes. Increasing the feedrate resulted in longer exit burrs from 303Se stainless steel and 1018 steel. Drill geometry, workpiece materials, and workpiece thickness also affected the exit-burr length. Radial-lip drills produced shorter exit burrs at fast feedrates in 303Se stainless steel than did the other drills, and they produced thinner exit burrs at all feedrates. Little difference was observed in the results from different drill points used in other materials. Burr size varied with the number of holes drilled in a typical wear-life pattern. Exit-burr thickness was a linear function of exit-burr length for the stainless steel specimens. No relationship between these properties was observed for either 1018 steel or 6061-T6 aluminum. The use of a backup material having a hole equal in diameter to that of the drill resulted in significantly shorter and thinner exit burrs than did any other drilling method studied.