The damping capacity improvement of machine tool structures by balls packing

Efficient manufacturing is achieved by the damping capacity improvement of machine tool structure. The purpose of this study is to clarify the parameters influencing the damping capacity of machine tool structures packed with balls. In structures closely packed with balls, various damping characteristics appear in correspondence with the ball size and other conditions. The effect of ball size is the most significant factor in these structures. Excitation of structure is necessary for close packing, however, this process is troublesome. Excitation of structure is required to achieve an optimum packing ratio where the maximum damping capacity is obtained. For a 50% packing ratio, this excitation process is not necessary to obtain a stable damping capacity. Therefore, the effects of magnitude of impulse, packed ball material, and structure size on the damping capacity are investigated at a 50% packing ratio. Finally, actual machine tool structure models are constructed, and the effectiveness of the balls packing for the damping capacity improvement is investigated. (C) 2004 Elsevier Ltd. All rights reserved.