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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2016, Vol. 37 ›› Issue (6): 1992-2002.doi: 10.7527/S1000-6893.2015.0241

• Material Engineering and Mechanical Manufacturing • Previous Articles     Next Articles

Optimization and damping performance of constrained damping boring bar

LIU Yang, LIU Zhanqiang, SONG Qinghua   

  1. Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Ministry of Education, School of Mechanical Engineering, Shandong University, Jinan 250061, China
  • Received:2015-07-17 Revised:2015-08-28 Online:2016-06-15 Published:2015-09-06
  • Supported by:

    National Natural Science Foundation of China (51425503, 51375272, U1201245);Major Science and Technology Program of High-end CNC Machine Tools and Basic Manufacturing Equipment (2015ZX04005008);Taishan Scholar Special (TS20130922)

Abstract:

The constrained damping boring bar can effectively reduce the cutting chatter affecting the surface quality and accuracy in hole machining, but the effect is not significant because the mechanism has not been fully found out. The theoretical and experimental research of the structure optimization, optimal material selection and vibration damping characteristic of the constrained damping boring bar is finished in this paper. Firstly, the dynamics model of the constrained damping boring bar is established through Kelvin-Voigt's viscoelastic mechanics model theory, and it is proved that the increase of static stiffness and loss factor of the boring bar can enhance the vibration damping performance to improve the quality of machining. Secondly, structure optimization and optimal material selection are completed based on the static stiffness and loss factor theory formula, and the result shows that there is an optimal size range that can reduce the vibration on the main working frequency domain, then it is shown that the elastic modulus of damping layer should be reduced while the elastic modulus of constraining layer and the material loss factor of damping layer should be increased. Finally, four constrained damping boring bars with different materials are designed and manufactured, and the modal experimental results of the static stiffness and loss factor have little difference with the theoretical calculation results. Further study of the influence of material and cutting parameters on the vibration damping performance in machining shows that constrained damping boring bars can effectively reduce the radial vibration to improve the surface quality. The radial vibration of constrained damping boring bars with different materials has great differences in cutting process, and the radial vibration acceleration of the optimized steel-PMMA-carbide boring bar is smaller and more stable at different cutting depths and spindle speeds.

Key words: constrained damping, loss factor, structure optimization, modal experiment, cutting stability

CLC Number: