Journal of the Korean Society for Precision Engineering (한국정밀공학회지)

Korean Society for Precision Engineering (한국정밀공학회)
권호 표지

A Study on the Dynamic Response Characteristics of Lathe Boring Bar

선반용 보링바의 동적응답특성 변동에 관한 연구

  • Chun, Se-Ho (Department of Mechanical Engineering, Graduate School, Yeungnam Univ.) ;
  • Ko, Tae-Jo (Department of Mechanical Engineering, Yeungnam Univ.)
  • 천세호 (영남대학교 대학원 기계공학과) ;
  • 고태조 (영남대학교 기계공학부)
  • Received : 2010.03.15
  • Accepted : 2010.06.09
  • Published : 2010.08.01
Download PDF
⟨ Previous Next ⟩

Abstract

Internal lathe machining with a boring bar is weak with respect to vibration because the bar is long and slender. Therefore, it is important to study the dynamic characteristics of a boring bar. The purpose of this study was to identify the effects of overhang and cutting conditions on the dynamic response characteristics of a boring bar. For an efficient experiment, an $L_g(3^3)$ orthogonal array was applied and the results were quantitatively analyzed by ANOVA. Overhang, feed per revolution, and depth of cut were selected as independent variables. Meanwhile, dynamic stiffness, damping ratio, damping coefficient, and acceleration were chosen as dependent variables. The vibration signal was obtained from an accelerometer attached to the boring bar, followed by visualization by a signal analyzer. The effect of overhang was found to have a significant effect on the dynamic stiffness, damping ratio, and damping coefficient, but the other variables did not. As the length of the overhang increased, the dynamic stiffness decreased and the damping ratio increased. In addition, the damping coefficient increased until the length of the overhang was 4D (where D is the shank diameter), after which it remained constant. The acceleration decreased until the overhang length was 4D, and then increased sharply when the overhang was increased further. From these results, the behavioral trend of the damping characteristics changed when its overhang length was 4D. Consequently, there is a critical point that the dynamic characteristics of boring bar change.

Keywords

References

  1. Sandvik Coromant, "Modern Metal Cutting," 1994.
  2. Shaw, M. C., "Metal Cutting Principles," Oxford University Press, 1984.
  3. Lee, S. Y. and Kim, H. N., "Effects of Cutting Conditions on Surface Roughness in Turning," Journal of the Korean Society for Precision Engineering, Vol. 18, No. 8, pp. 139-149, 2001.
  4. Beauchamp, Y., Thomas, M., Youssef, Y. A. and Masounave, J., "Investigation of Cutting Parameter Effects on Surface Roughness in Lathe Boring Operation by Use of A full factorial Design," 18th International Conference on Computers and Industrial Engineering, Vol. 31, No. 3-4, pp. 645-651, 1996.
  5. Choudhury, I. A. and El-Baradie, M. A., "Surface roughness prediction in the turning of high-strength steel by factorial design of experiments," Journal of Materials Processing Technology, Vol. 67, No. 1-3, pp. 55-61, 1997. https://doi.org/10.1016/S0924-0136(96)02818-X
  6. Sahin, Y., Motorcu, A. R., "Surface roughness model for machining mild steel with coated carbide tool," Materials and Design, Vol. 26, No. 4, pp. 321-326, 2005. https://doi.org/10.1016/j.matdes.2004.06.015
  7. Jang, D. Y. and Seireg, A., "Dynamic simulation for predicting surface roughness in turning," ASME Machinery Dynamics-Applications and Vibration Control Problems, Vol. 18, No. 2, pp. 31-36, 1989.
  8. Rakhit, A. K., Osman, M. O. M. and Dankar, T. S., "Machine tool vibrations: its effect on manufactures surfaces," Proceedings of the Fourth Canadian Congress of Applied Mechanics, pp. 463-464, 1973.
  9. Abouelatta, O. B. and Madl, J., "Surface roughness prediction based on cutting parameters and tool vibrations in turning operations," Journal of Materials Processing Technology, Vol. 118, No. 1-3, pp. 269-277, 2001. https://doi.org/10.1016/S0924-0136(01)00959-1
  10. Choi, C. K., Lee, D. J. and Lee, W. Y., "A Study on the Efficiency Improvement of a Anti-Vibration Boring Bar," Research Institute of Industrial Technology, Vol. 13, No. 1, pp. 149-154, 1998.
  11. Kim, J. S., Kang, M. C. and Park, S. K., "Dynamic Behavior of Boring Bar with Continuous System Analysis," Journal of the Korean Society for Precision Engineering, Vol. 11, No. 4, pp. 38-46, 1994.
  12. Tobias, S. A., "Machine Tool Vibration," Blackie & Son, 1965.
  13. Hwang, C. C. and Fung, R. F., "Strong non-linear dynamics of cutting processes," Journal of Sound and Vibration, Vol. 203, No. 3, pp. 363-372, 1997. https://doi.org/10.1006/jsvi.1996.0923
  14. Lin, J. S. and Weng, C. I., "Non-linear dynamics of the cutting process," International Journal of Mechanical Sciences, Vol. 33, No. 8, pp. 645-657, 1991. https://doi.org/10.1016/0020-7403(91)90034-Z
  15. Song, D. S., Hong, J. H., Jeong, H. Y., Kang, D. H. and Kim, B. I., "A Study of the Boring Bar Vibration Measurement using Optical Fiber Sensor," Journal of the Korean Society for Precision Engineering, Vol. 26, No. 4, pp. 107-113, 2009.
  16. Chun, S. H. and Ko, T. J., "Study on the dynamic stiffness variation of boring bar by Taguchi Method," Journal of the Korean Society of Manufacturing Process Engineers, Vol. 8, No. 3, pp. 98-104, 2009.
  17. Thomas, M. and Beauchamp, Y., "Statistical investigation of modal parameters of cutting tools in dry turning," International Journal of Machine Tools & Manufacture, Vol. 43, No. 11, pp.1093-1106, 2003. https://doi.org/10.1016/S0890-6955(03)00131-7
  18. Park, S. H., "Design of Experiment," Minyoungsa, 2003.
  19. Kim, N. K., Kang, M. C. and Kim, B. R., "A Study on the Chatter Vibration-Mechanism with Two Degree of Freedom," J. Industrial Technology Res. Inst., Vol. 1, No. 1, pp. 11-25, 1994.
  20. Kim, J. D. and Kim, D. S., "Theoretical Analysis of Micro-Cutting Characteristics in Ultra-Precision Machining," Journal of Materials Processing Technology, Vol. 49, No. 3-4, pp. 387-398, 1995. https://doi.org/10.1016/0924-0136(94)01345-2
  21. Bert, C. W., "Material Damping : An introductory review of mathematical measures and experimental techniques," Journal of Sound and Vibration, Vol. 29, No. 2, pp. 179-153, 1973.
  22. Clarance, W. D. S., "Vibration Damping, Control, and Design," CRC Press, 2007.