Journal of the Korean Society for Precision Engineering (한국정밀공학회지)

Korean Society for Precision Engineering (한국정밀공학회)
권호 표지

Design of the Stiffened Punch for Stamping of Lead Frame by Buckling Analysis

좌굴해석을 이용한 리드프레임 타발용 펀치의 보강설계

  • 고대철 (부산대학교 동남권부품소재산학협력혁신연구소) ;
  • 이인수 (부산대학교 대학원 정밀기계공학과) ;
  • 안병환 ((주)삼우테크) ;
  • 김병민 (부산대학교 정밀정형 및 금형가공 연구소)
  • Published : 2006.09.01
Download PDF
⟨ Previous Next ⟩

Abstract

The lead frame manufactured by stamping process plays an important role in connecting semiconductor to PCB board. As a result of the miniaturization of semiconductor, its corresponding lead frame punch has been narrow. In case of the punch with high slenderness ratio such as lead frame punch, the punch can be broken suddenly due to buckling. To prevent the fracture of lead frame punch, some manufacturers have experientially attached stiffeners to weak parts of punch. The purpose of this study, therefore, is to suggest the guideline far design of stiffened punch. The optimal position and the number of stiffeners to be attached to punch are investigated by elastic buckling analysis. The elastic buckling analysis consists of the eigenvalue buckling analysis and nonlinear buckling analysis. The critical buckling load of elastic buckling analysis is compared with that of buckling test. Finally, the guideline far attaching stiffeners is suggested through analysis of cross section of lead frame punch such as moment of inertia and eccentricity.

Keywords

References

  1. Lim, S. H., Suh, E. K. and Shim, H. B., 'A Study on the Characteristics of the Precision Blanking of Lead Frame (1): Influences of Blanking Process Variables,' Transactions of Materials Processing, Vol.10, No.5, pp. 425-432, 2001
  2. Kim, Y. Y. and Lee, D. H., 'Local Buckling Analysis of the Punch in Stamping Die and Its Design Modification,' Journal of KSPE, Vol. 16, No.3, pp. 25-29, 1999
  3. Timoshenko, S. P. and Gere, J. M., 'Theory of Elastic Stability,' McGraw-Hil, New York, pp.212-250, 1988
  4. Todhunter, I. and Pearson, K., 'A History of the Theory of Elasticity and of Strength of Materials,' Cambridge Press, pp. 66-67, 1886
  5. Keller, J. B., 'The Shape of the Strongest Column,' Archive for Rational Mechanics and Analysis, Vol. 5, pp.275-285, 1960 https://doi.org/10.1007/BF00252909
  6. Tadjbakhsh, I. and Keller, J. B., 'Strongest Columns and Isoperimetric Inequalities for Eigenvalues,' Journal of Applied Mechanics, ASME, Vol. 29, pp. 159-164, 1962 https://doi.org/10.1115/1.3636448
  7. Niordson, F. I., 'On the Optimal Design of a Vibrating Beam,' Quarterly of Applied Mathematics, Vol. 23, pp. 47-53, 1965 https://doi.org/10.1090/qam/175392
  8. Taylor, J. E., 'The Strongest Column: An Energy Approach,' Journal of Applied Mechanics, ASME, Vol. 34, pp. 486-487,1967 https://doi.org/10.1115/1.3607710
  9. Wilson, J. F., Holloway, D. M. and Biggers, S. B., 'Stability Experiments on the Strongest Columns and Circular Arches,' Experimental Mechanics, Vol. 11, pp. 303-308, 1971 https://doi.org/10.1007/BF02320583
  10. Kamat, M. P. and Simites, G. J., 'Optimal Beam Frequencies by the Finite Element Displacement Method,' International Journal of Solids and Structures, Vol. 9, pp. 415-429, 1973 https://doi.org/10.1016/0020-7683(73)90089-9
  11. Plaut, R. H., Johnson, L. W. and Olhoff, N., 'Bimodal Optimization of Compressed Columns on Elastic Foundations,' Journal of Applied Mechanics, ASME, Vol. 53, pp. 130-134, 1986 https://doi.org/10.1115/1.3171699
  12. Gere, J. M., 'Mechanics of Materials,' 5th ed., Brooks/cole press, pp. 755-765, 2001
  13. Koo, C. H. and Lee, J. H., 'Buckling Characteristics of the KALIMER-150 Reactor Vessel Under Lateral Seismic Loads and the Experimental Verification Using Reduced Scale Cylindrical Shell Structures,' Korean Nuclear Society, Vol. 35, No. 6, pp. 537-546, 2003