Particle Dampers for Workpiece Chatter Mitigation

Abstract

It is well known that the chatter stability of a machining process can be improved by increasing the structural damping of the system. To date this approach has been effectively used on various components of the machining system, for example boring bars, milling tools, and the machine structure itself. Various damping treatments have been proposed, including tuned vibration absorbers, active methods, and impact dampers. However, to date there has been little or no work to investigate the issue of particle dampers for this application. This special class of damper comprises a container of thousands of small granular particles which dissipate energy by friction and impact when the container vibrates. The resulting behaviour is highly nonlinear but can provide very high levels of damping across a wide frequency range. In the present study, particle dampers were applied to a workpiece to mitigate chatter during milling, and the limiting critical depth of cut was increased by an order of magnitude. This article gives an overview of the particle damper’s behaviour and key design parameters. Cutting trials employing the device are then described.