A novel hybrid particle damping in boring bar for effective machining and chatter suppression

Particle damping is a promising passive damping technique to attenuate the chatter in the boring process. Till now, researchers have considered the particle damping approaches with single-type particles and a mixture of particles. In this work, a novel hybrid particle approach is reported to improve the effectiveness of particle damping in a boring bar. For this purpose, an unmodified boring bar, single-unit, multiunit horizontal, and multiunit vertical particle damped boring bars were considered. Modal analysis, dynamic characteristics, logarithmic decrement, damping ratio, and resonance gap were assessed as the performance benchmarks. In addition, the surface roughness, tool-insert temperature and boring bar displacement during the machining of mild steel were also investigated. The comparative study revealed that the particle-damped boring bars had better damping and machining performance than the unmodified boring bars. Among the investigated boring bars (modified and unmodified), the multiunit vertical type particle damped boring bar showed a higher resonance gap (1282.14 Hz), lower displacement (0.69 mm), minimum surface roughness (0.84 μm), and minimum temperature (252 °C) during the boring process.