Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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A Study of Friction in Microfoming Using Ring Compression Tests and Finite Element Analysis

링 압축시험과 유한요소해석을 이용한 미세성형 공정에서의 마찰특성에 관한 연구

  • Kim, Hong-Seok (Dept. of Mechanical Engineering, Seoul Nat'l Univ. of Technology) ;
  • Kim, Geung-Rok (Dept. of Mechanical Engineering, Seoul Nat'l Univ. of Technology)
  • 김홍석 (서울산업대학교 기계공학과) ;
  • 김긍록 (서울산업대학교 기계공학과)
  • Received : 2010.05.10
  • Accepted : 2010.05.20
  • Published : 2010.10.01
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Abstract

Microforming processes have recently attracted considerable attention from industry and academia since they enable the production of microscale parts using various materials at a high production rate, minimize material loss, and provide parts with excellent mechanical properties. However, for successful development and applications of the microforming process it is critical to take the tribological size effect into consideration because previous studies have shown that traditional friction models for macroscale forming generate significantly erroneous results in the case of microforming. In this paper, we performed scaled ring compression experiments to investigate the tribological size effect of aluminum and brass materials in microforming. The sensitivity of the interfacial friction to the deformation characteristics of the ring was quantitatively analyzed by the finite element analysis. In addition, a friction model based on slip line field and upper boundary techniques was used to theoretically explain the friction mechanism in microforming.

미세성형 공정은 마이크로 크기의 부품 생산에 있어 다양한 재료의 활용, 높은 생산성, 적은 재료의 손실, 고품질 생산을 실현할 수 있는 방법으로 최근 산업계와 학계의 많은 주목을 받고 있다. 하지만 매크로 성형에서 마찰거동을 묘사하기 위한 기존의 모델들은 미세성형에서 많은 오차를 유발하는 것으로 알려져 있다. 따라서 미세성형 공정의 성공적인 개발과 실용화를 위해서는 마찰거동의 크기효과에 대한 심도 있는 연구가 필요하다. 본 연구에서는 다양한 크기의 알루미늄 및 황동 재료를 대상으로 링 압축시험을 실시하여 소재의 크기에 대한 마찰거동의 크기효과를 고찰하였다. 유한요소해석을 이용하여 링 압축 시 접촉면의 마찰력이 링 시편의 변형특성에 미치는 영향을 정량적으로 분석하였다. 또한 미끄럼선장 모델링과 상계해석을 응용한 마찰모델을 활용하여 미세성형에서의 마찰거동 특성을 이론적으로 설명하였다.

Keywords

References

  1. Geiger, M., Kleiner, M., Eckstein, R., Tiesler, N. and Engel, U., 2001, “Microforming,” CIRP Ann., Vol. 50, pp. 445-462. https://doi.org/10.1016/S0007-8506(07)62991-6
  2. Male, A. T. and Cockroft, M. G., 1965, “A method for the Determination of the Coefficients of Friction of Metal Under Bulk Plastic Deformation,” Journal of the Institute of Metals, Vol. 93, pp 38-46.
  3. Engel, U., Messner, A. and Tiesler, N., 1998, “Cold Forging of Microparts-Effect of Miniaturization on Friction,” Proceedings of the 1st ESAFORM Conference on Materials Forming, Sohpia Antipolis, France, pp. 77-80.
  4. Buschhausen, A., Weinmann, K., Lee, J. Y. and Altan, T. T., 1992, “Evaluation of Lubrication and Friction in Cold Forging Using a Double Backward-Extrusion Process,” J. Mater. Process. Tech., Vol. 33, pp. 95-108. https://doi.org/10.1016/0924-0136(92)90313-H
  5. Tiesler, N., 2002, “Microforming-Size Effects in Friction and Their Influence on Extrusion Processes,” Wire, Vol. 52, pp. 34-38.
  6. Tiesler, N., Engel, U. and Geiger, M., 1999, “Forming of Microparts-Effect of Miniaturization on Friction,” Proceedings of the 6th ICTP, Vol. 2, pp. 889-894.
  7. Engel, U., 2006, “Tribology in Microforming,” Wear, Vol. 260, pp. 265-273. https://doi.org/10.1016/j.wear.2005.04.021
  8. Bay, N., 1987, “Friction Stress and Normal Stress in Bulk Metal Forming Processes,” Journal of Mechanical Working Technology, Vol. 14, pp. 203-223. https://doi.org/10.1016/0378-3804(87)90061-1
  9. Wanheim, T., Bay, N. and Petersen, A. S., 1974, “A Theoretically Determined Model for Friction in Metal Working Processes,” Wear, Vol. 28, pp. 251-288. https://doi.org/10.1016/0043-1648(74)90165-3
  10. Nellemann, T., Bay, N. and Wanheim, T., 1977, “Real Area of Contact and Friction Stress-the Role of Trapped Lubricant,” Wear, Vol. 43, pp. 45-53. https://doi.org/10.1016/0043-1648(77)90042-4
  11. Jeon, H. J. and Bramley, A. N., 2007, “A Friction Model for Microforming,” The International Journal of Advanced Manufacturing Technology, Vol. 33, pp. 125-129. https://doi.org/10.1007/s00170-006-0608-1
  12. Vollertsen, F. and Hu, Z., 2006, “Tribological Size Effects in Sheet Metal Forming Measured by a Strip Drawing Test,” CIRP Ann., Vol. 55, pp. 291-294. https://doi.org/10.1016/S0007-8506(07)60419-3
  13. Tan, X., 2002, “Comparison of Friction Models in Bulk Metal Forming,” Tribology International, Vol. 35, pp. 385-393. https://doi.org/10.1016/S0301-679X(02)00020-8

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  1. A Theoretical and Experimental Study on the Tribological Size Effect in Microforming Processes vol.22, pp.7, 2013, https://doi.org/10.5228/KSTP.2013.22.7.394