1998 Volume 48 Issue 4 Pages 195-198
This study involves a basic research to determine the optimum cutting condition with the main objective of revealing the breaking mechanism of the continuous cone-shaped helical chips produced during intermittently decelerated feed drilling. The friction torque due to chips flowing through the drill flute and the breaking torque of chips are determined experimentally and the breaking mechanism of chips in intermittently decelerated feed drilling is investigated. The following facts are ascertained from the obtained results. (1) Chips formed in intermittently decelerated feed drilling break at points where chip thickness changes. (2) Chip breakage occurs when the resulting friction torque between the hole wall and chip exceeds the breaking torque of chips. (3) Chip breakage depends solely on the length of the fast feed section or the total length of the fast and slow feed sections, and varies according to the breaking strength of chips.
