Kinematic Characterization of Chip Lateral-Curl—The Third Pattern of Chip Curl in Machining

Abstract

Two patterns of chip curl, namely up- and side-curl, have been widely recognized in machining operations. This paper presents the third pattern of chip curl that is called lateral-curl. The rotating axis of chip lateral-curl is perpendicular to the rotating axes of up- and side-curl. The essential differences are illustrated between the chip lateral-curl concept and the “chip-twisting” concept presented in other related studies. Based on an analytical vector analysis, a new kinematic characterization is presented for the natural (or born) lateral-curl of the chip that is associated with flat-faced tool machining. It is demonstrated that chip forms (or shapes) can be determined by four governing variables: the chip up-, lateral-, and side-curl radii and the chip side-flow angle. A method to indirectly measure the chip lateral-curl radius is presented. The effect of chip lateral-curl on chip forms is investigated through cutting tests, theoretical analysis, and computer simulations.