Cutting-tool geometry effect on turning process dynamics

Abstract

Introduction. Many scientists in their research aimed at investigating the cutting process dynamics, the cutting system stability and forming various attracting sets of deformational displacements, consider the machine an autonomous system. In contrast to these works, this paper describes the dynamic properties of the cutting process depending on the dynamic linking parameters under cutting, and on the properties of the subsystems interacting with cutting, taking into account the external disturbances effect. Many of these properties depend on the cutting-tool geometry, and thus the dynamic properties of the treatment process change when the tool geometric characteristics change. In particular, changes in the tool geometric parameters alter the stability of the forming movement trajectories, and their variations can cause bifurcations of the attracting sets of deformation displacements. The forming motion patterns determine both the geometric topology of the workpiece, and the tool wear rate, which depend on the tool geometry. Materials and Methods. A mathematical model that characterizes the system dynamics disturbed by the spindle group wavering is presented. On its basis, a model that allows for digital experimental research is developed through the use of the software package Matlab. Research Results. The mathematical simulation results and examples of changes in the system properties depending on the cutting-tool geometry are presented. Discussion and Conclusions. The problem of matching the control (for example, from the CNC system) and the cutting process dynamics is discussed. One of the directions of this matching is connected with the selection of cutting-tool corners such as forming motion trajectories could remain steady under all variations of the process conditions.

Keywords

• turning
• tool geometry
• spindle wavering
• attractive sets
• surface geometric topology