Experimental Investigation of Particle Impact Damping On Machine Tools

Abstract

In machine structure, the boring operations are extensively used for enlarging an existing hole. For large sized workpieces, the overhang length of the boring tool increased, which disturbs the slenderness of the tool (length to diameter ratio) leading to high amplitude vibrations. The tool-workpiece interaction strains the shank and induces vibrations in the workpiece. These vibrations bring along a package of defects such as poor surface finish, dimensional inaccuracy, reduced material removal rate etc. In order to suppress the damping, small metal particles were used. Particle impact damping [6] is a method of achieving high structural damping by using a particle filled enclosure in the region of high displacements. A series of experiments were performed where the closure was attached to the tool at three different locations, the material as well as the size of the particle was changed for obtaining different experimental observations. Further, a particle effectiveness or packing ratio of 25%,50%and 75% was used for experiments. Using NI signal software and LabVIEW we were able to obtain the natural frequency with and without the damper, in an experiment the frequency of vibration was reduced about 15% with the damper