Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical and Experimental Study for Improvement of Formability in Flexible Forming Process

가변성형공정에서 성형성 향상을 위한 해석 및 실험적 연구

  • 허성찬 (한국항공우주연구원 한국형발사체개발사업단 연소기팀) ;
  • 서영호 (부산대학교 항공우주공학과) ;
  • 강범수 (부산대학교 항공우주공학과) ;
  • 김정 (부산대학교 항공우주공학과)
  • Received : 2012.08.16
  • Accepted : 2012.10.22
  • Published : 2012.11.01
Download PDF
⟨ Previous Next ⟩

Abstract

In this article, the design of the flexible forming process considering die shape compensation using an iterative over-bending method based on numerical simulation was conducted. In this method, the springback shape obtained from the final step of the first forming simulation is compared with the desired objective shape, and a shape error is calculated as a vector norm with three-dimensional coordinates. The error vector is inversely added to the objective surface to compensate both the upper and lower flexible die configurations. The flexible die shapes are recalculated and the punch arrays are adjusted according to the over-bent forming surface. These iterative procedures are repeated until the shape error variation converges to a small value. In addition, experimental verification was conducted using a 2000-kN flexible forming apparatus for thick plates. Finally, the configuration of the prototype obtained from the experiment was compared with the numerical simulation results, which had springback compensation. It is confirmed that the proposed method for compensating for the forming error could be used in the design of flexible forming of thick-curved plates.

Keywords

References

  1. S. C. Heo, Y. H. Seo, T. W. Ku, J. Kim, B. S. Kang, 2009, Study on Application of Flexible Die to Sheet Metal Forming Process, Trans. Mater. Process., Vol. 18, No. 7, pp. 556-564. https://doi.org/10.5228/KSPP.2009.18.7.556
  2. S .C. Heo, Y. H. Seo, J. W. Park, T. W. Ku, J. Kim, B. S. Kang, 2008, Numerical and Experimental Study on Plate Forming Process using Flexible Die, Trans. Mater. Process., Vol. 17, No. 8, pp. 570-578. https://doi.org/10.5228/KSPP.2008.17.8.570
  3. Y. H. Seo, S. C. Heo, B. S. Kang, J. Kim, 2011, Statistical Study on Correlation Between Design Variable and Shape Error in Flexible Stretch Forming, Trans. Mater. Process., Vol. 20, No. 2, pp. 124-131. https://doi.org/10.5228/KSTP.2011.20.2.124
  4. Y. H. Seo, S. C. Heo, W. J. Song, J. Kim, B. S. Kang, 2010, Tendency Analysis of Shape Error According to Forming Parameter in Flexible Stretch Forming Process using Finite Element Method, Trans. Mater. Process., Vol. 19, No. 8, pp. 486-493. https://doi.org/10.5228/KSTP.2010.19.8.486
  5. Y. H. Seo, S. C. Heo, T. W. Ku, J. Kim, B. S. Kang, 2011, Design of Flexible Die Punch and Control System for Three-dimensional Curved Forming Surface, Trans. Mater. Process., Vol. 20, No. 3, pp. 204-211. https://doi.org/10.5228/KSTP.2011.20.3.206
  6. Y. H. Seo, S. C. Heo, J. W. Park, T. W. Ku, W. J. Song, J. Kim, B. S. Kang, 2010, Development of Stretch Forming Apparatus using Flexible Die, Trans. Mater. Process., Vol. 19, No. 1, pp. 17-24. https://doi.org/10.5228/KSPP.2010.19.1.017
  7. S. Oral, H. Darendeliler, 1997, The Optimum Die Profile for the Cylindrical Bending of Plates, J. Mater. Process. Technol., Vol. 70, No. 1-3, pp. 151-155. https://doi.org/10.1016/S0924-0136(97)80800-X
  8. J. S. Shu, C. Hung, 1996, Finite Element Analysis and Optimization of Springback Reduction : the "double-bend" Technique, Int. J. Mach. Tools Manuf., Vol. 36, No. 4, pp. 423-434. https://doi.org/10.1016/0890-6955(95)00072-0
  9. P. Xue, T. X. Yu, E. Chu, 2001, An Energy Approach for Predicting Springback of Metal Sheets after Double-curvature Forming, Part I : Axisymmetric Stamping, Int. J. Mech. Sci., Vol. 43, pp. 1893-1914. https://doi.org/10.1016/S0020-7403(01)00003-0
  10. M. Z. Li, Z. Y. Cai, Z. Sui, Q. G. Yan, 2002, Multi-point Forming Technology for Sheet Metal, J. Mater. Process. Technol., Vol. 129, No. 1-3, pp. 333-338. https://doi.org/10.1016/S0924-0136(02)00685-4
  11. A. P. Karafillis, M. C. Boyce, 1996, Tooling and Binder Design for Sheet Metal Forming Processes Compensating Springback Error, Int. J. Mach. Tools Manuf., Vol. 36, No. 4, pp. 503-526. https://doi.org/10.1016/0890-6955(95)00023-2
  12. W. Gan, R. H. Wagoner, 2004, Die Design Methods for Sheet Springback, Int. J. Mech. Sci., Vol. 46, No. 7, pp. 1097-1113. https://doi.org/10.1016/j.ijmecsci.2004.06.006
  13. Z. Y. Cai, S. H. Wang, X. D. Xu, M. Z. Li, 2009, Numerical Simulation for the Multi-point Stretch Forming Process of Sheet Metal, J. Mater. Process. Technol., Vol. 209, No. 1, pp. 396-407. https://doi.org/10.1016/j.jmatprotec.2008.02.010

Cited by

  1. Flexible roll forming process design for variable cross-section profile vol.16, pp.1, 2015, https://doi.org/10.1007/s12239-015-0009-2
  2. Development of Profile Design Method Based on Longitudinal Strain for Flexible Roll Forming Process vol.22, pp.7, 2013, https://doi.org/10.5228/KSTP.2013.22.7.401
  3. Flexible Roll Forming Technology for Multi-Curved Sheet Metal Forming vol.22, pp.5, 2013, https://doi.org/10.5228/KSTP.2013.22.5.243