Examination of Tool Shank Structure for the Purpose of Restraint of Chatter Vibration (2nd Report)

―Chatter Vibration Suppression Effect by Parallel Leaf Spring Structure Shank―

Abstract

This paper discusses chatter vibration in turning of a low-rigidity workpiece with parallel leaf spring structure shanks. Because the chatter vibration is suppressed by control of the tool vibration direction, the parallel leaf spring structure shank that reduces the stiffness artificially in the tool height direction is studied to design the tool shank in the 1^st report. In this report, the vibration directions of the workpiece and the dynamic component in the cutting force were characterized in cutting with the chatter vibration. The compliances of the workpiece were measured to identify the principal direction of the vibration. Because the measured cutting force includes vibration, the steady (average) and the dynamic components are decomposed to specify their applied direction. In turning with the parallel leaf spring structure shank, a large difference in the direction of dynamic component is confirmed from that of the workpiece vibration. A model considering the direction of dynamic components is presented to verify the effect of the difference of the vibration directions on control of the chatter vibration.