Development and Optimization of Vibration-Damped Tool Holders for High Length-to-Diameter Boring Operations

Abstract

AbstractWhen the length-to-diameter ratio of a boring bar becomes too high, the vibration problem becomes excessive. This paper discusses the design and optimization of tuned mass dampers (TMDs) for vibration-damped boring bars. A typical TMD for a boring bar consists of a high-density mass, rubber elements, and viscous damping fluid. The TMD is mounted as close to the free end of the boring bar as possible for maximizing the damping effect. The different tuning strategies are related to the different types of vibrations that are observed in machining operations. It is shown that the classical tuning with minimized magnitude of the frequency response function will give the shortest settling time for free vibrations, while tuning for maximized negative real part of the frequency response function will give the highest resistance to regenerative chatter. For suppressing regenerative chatters, the internal damping in the material in the boring bar body is of minor importance for boring bars with TMDs, but of high importance for conventional undamped boring bars. The paper presents design solutions for TMDs in boring bars.