Fibers and Polymers

, Volume 2, Issue 4, pp 203–211 | Cite as

Prediction and measurement of residual stresses in injection molded parts

  • Young Il Kwon
  • Tae Jin Kang
  • Kwansoo Chung
  • Jae Ryoun Youn
Article

Abstract

Residual stresses were predicted by a flow analysis in the mold cavity and residual stress distribution in the injection molded product was measured. Flow field was analyzed by the hybrid FEM/FDM method, using the Hele Shaw approximation. The Modified Cross model was used to determine the dependence of the viscosity on the temperature and the shear rate. The specific volume of the polymer melt which varies with the pressure and temperature fields was calculated by the Tait’s state equation. Flow analysis results such as pressure, temperature, and the location of the liquid-solid interface were used as the input of the stress analysis. In order to calculate more accurate gap-wise temperature field, a coordinate transformation technique was used. The residual stress distribution in the gap-wise direction was predicted in two cases, the free quenching and the constrained quenching, under the assumption that the shrinkage of the injection molded product occurs within the mold cavity and that the solid polymer is elastic. Effects of the initial flow rate, packing pressure, and mold temperature on the residual stress distribution was discussed. Experimental results were also obtained by the layer removal method for molded polypropylene.

Keywords

Injection molding Residual stress Hybrid FEM/FDM scheme Layer removal method Stephan problem 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    G. D. Gilmore and R. S. Spencer,Modern Plastics,27(8), 143 (1950).Google Scholar
  2. 2.
    R. S. Spencer and G. D. Gilmore,J. Colloid Sci.,6, 1118 (1951).Google Scholar
  3. 3.
    C. A. Hieber and S. F. Shen,J. Non-Newt. Fluid Mech.,7, 1 (1980).CrossRefGoogle Scholar
  4. 4.
    H. H. Chiang, C. A. Hieber, and K. K. Wang,Polym. Eng. Sci.,31, 116 (1991).CrossRefGoogle Scholar
  5. 5.
    H. H. Chiang, C. A. Hieber, and K. K. Wang,Polym. Eng. Sci.,31, 125 (1991).CrossRefGoogle Scholar
  6. 6.
    W. F. Zoetelief, L. F. A. Douven, and A. J. Ingen Housz,Polym. Eng. Sci.,14, 1886 (1996).CrossRefGoogle Scholar
  7. 7.
    K. M. B. Jansen and G. Titomanlio,Polym. Eng. Sci.,36, 2029 (1996).CrossRefGoogle Scholar
  8. 8.
    K. M. B. Jansen and G. Titomanlio,Polym. Eng. Sci.,36, 2041 (1996).CrossRefGoogle Scholar
  9. 9.
    K. K. Kabanemi, H. Vaillancourt, H. Wang, and G. Salloum,Polym. Eng. Sci.,38, 21 (1998).CrossRefGoogle Scholar
  10. 10.
    R. G. Treuting and W. T. Read Jr.,J. Appl. Phys.,22(2), 130 (1951).CrossRefGoogle Scholar
  11. 11.
    C. H. V. Hastenberg, P. C. Wildervanck, A. J. H. Leenen, and G. G. J. Schennink,Polym. Eng. Sci.,32, 506 (1992).CrossRefGoogle Scholar
  12. 12.
    M. Akay and S. Ozden,J. Mat. Sci.,30, 3358 (1995).CrossRefGoogle Scholar
  13. 13.
    M. Akay and S. Ozden,Polym. Eng. Sci.,13, 1839 (1996).CrossRefGoogle Scholar
  14. 14.
    O. Denizart, M. Vincent, and J. F. Agassant,J. Mat. Sci.,30, 552 (1995).CrossRefGoogle Scholar
  15. 15.
    V. Leo and C. H. Cuvelliez,Polym. Eng. Sci.,15, 1961 (1996).CrossRefGoogle Scholar
  16. 16.
    C. S. Kwok, L. Tong, and J. R. White,Polym. Eng. Sci.,5, 65 (1996).Google Scholar
  17. 17.
    K. M. B. Jansen, J. J. Orij, C. Z. Meijer, and D. J. V. Dijk,Polym. Eng. Sci.,39, 10 (1999).CrossRefGoogle Scholar
  18. 18.
    A. I. Isayev, “Injection and Compression Molding Fundamentals”, Marcel Dekker, New York, 1987.Google Scholar
  19. 19.
    S. C. Lee and J. R. Youn,J. Reinf. Plas. Comp.,18, 186 (1999).Google Scholar
  20. 20.
    J. H. Jung, S. W. Lee, and J. R. Youn,Macromolecular Symposia,148, 263 (1999).Google Scholar
  21. 21.
    Y. I. Kwon, M. S. Thesis, Seoul National University, Seoul, 1999.Google Scholar
  22. 22.
    J. Crank, “Free and Moving Boundary Problems”, pp. 163–282, Clarendon Press, Oxford, 1987.Google Scholar
  23. 23.
    H. See,Korea-Australia Rheology J.,13, 67 (2001).Google Scholar

Copyright information

© The Korean Fiber Society 2001

Authors and Affiliations

  • Young Il Kwon
    • 1
  • Tae Jin Kang
    • 1
  • Kwansoo Chung
    • 1
  • Jae Ryoun Youn
    • 1
  1. 1.School of Materials Science and EngineeringSeoul National UniversitySeoulKorea

Personalised recommendations