Mitigation of chatter in thin-wall milling by using double-side support device

Abstract

This article develops a new method to mitigate chatter vibrations in the thin-wall milling of the structures with half-opened side walls through designing a supplementary device, which can provide double-side support to the weakly rigid positions between cutter and workpiece. It aims to improve the stiffness and damping responses of the side walls without the need to consider the limitation of the workpiece’s geometrical configuration. That is, it is suitable for both the flat and the curved shapes. The typical structural characteristic of the device lies in that as the cutting continues, the supporting positions can be easily adjusted up and down along the axial direction to meet the instantaneous chatter mitigation requirement. Dynamic models of both the curved thin-wall milling process and the workpiece with the supplementary support device are derived by integrating the milling mechanics with the receptance coupling substructure analysis. The in-process modal parameters of the workpiece with the support device, i.e., natural frequency and modal shape, are calculated by comprehensively considering the removal of material and the influence of the supporting position change. Finally, a method that combines the derived models with the dynamic response of the spindle-tool system is used to predict the stability lobe diagrams (SLDs), with which chatter vibrations can be well avoided by reasonably selecting the cutting parameters. A series of thin-wall milling experiments are carried out on typical curved plates to validate the effectiveness of the designed support device together with the proposed methods for mitigating chatter vibrations.