Dynamics of Multipoint Thread Turning—Part II: Application to Thin-Walled Oil Pipes

Abstract

This paper extends the general threading model developed in Part I to the case of thin-walled workpieces. Structural behavior of a cylindrical shell is dominated by the low-damped flexural modes. Due to the circumferential patterns of the shell modes, the cutting forces result in different instantaneous displacements around the circumference of the workpiece. The residual shell vibrations can affect the chip thickness when the corresponding point arrives at the cutting region. In this paper, the workpiece surface is discretized, and the instantaneous shell deformations due to the cutting forces are evaluated. The dynamic equation of motion for threading thin-walled workpieces is derived, and the stability and surface location errors are analyzed. The proposed threading model is validated experimentally on real-scale oil pipes for different pass numbers and infeed values. Sample approaches for chatter suppression are demonstrated experimentally.