Chip curl and the action of the groove type chip former

Abstract Previously published work on the mechanism of chip curl and on the performance of obstruction and groove type chip formers is examined and new explanations of chip curl and the action of the groove type former are proposed. Experimental evidence is presented which shows that, for a range of materials, when cutting orthogonally with a restricted contact length tool, a chip is formed with no curvature when the length of the zone of sticking friction is equal to the restricted contact length. The results of tests on groove type chip formers indicate that under conditions where the chip does not contact the bottom of the groove, the relationship between chip curl radius, groove geometry and chip thickness can be predicted.