Numerical and experimental analysis of HIPS sheets in thermoforming process

  • Mohammad Ghobadnam
  • Peiman Mosaddegh
  • Masood Rezaei Rejani
  • Hosein Amirabadi
  • Abbas Ghaei


In this study, two different thermoforming molds, i.e., male and female, were prepared and used to conduct different tests at various heating times and evacuation powers. High impact polystyrene sheets of 0.5 mm thick were used to produce the cups with two vacuum and drape forming process. The experimental results showed that a more uniform thickness distribution could be obtained by increasing the heating time for the female mold. However, for the male mold, the heating time must be decreased in order to achieve a more uniform thickness distribution. Our findings showed that biaxial stretching was dominant in the vacuum forming, while uniaxial stretching was dominant in the drape forming. A finite element simulation of the vacuum forming process was also conducted to present a simple and accurate study of the forming process. In this work, a hyperviscoelastic constitutive model was used for modeling the high impact polystyrene behavior at forming temperature. The thickness distribution obtained by the finite element analysis is in a good agreement with the experimental results. In addition, the effect of friction coefficient was investigated by finite element analysis on the thickness distribution of the cup.


Thermoforming process Drape forming Vacuum forming Thickness distribution Finite element simulation Hyperviscoelastic material model 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    O’Connor CPJ, Menary G, Martin PJ, Mcconville E (2008) Finite element analysis of the thermoforming of polypropylene. Int J Mater Form 1:779–782CrossRefGoogle Scholar
  2. 2.
    Illig A (2001) Thermoforming: a practical guide. Hanser, MunichGoogle Scholar
  3. 3.
    Muralisrinivasan NS (2010) Update on troubleshooting in thermoforming. iSmithers Rapra, UKGoogle Scholar
  4. 4.
    Warby MK, Whiteman JR, Jiang WG, Warwick P, Wright T (2003) Finite element simulation of thermoforming processes for polymer sheets. Math Comps Simul 61:209–218CrossRefMATHMathSciNetGoogle Scholar
  5. 5.
    Stephenson MJ, Ryan ME (1997) Experimental study of the thermoforming of a blend of Styrene-Butadiene copolymer with polystyrene. Polym Eng Sci 37:450–459CrossRefGoogle Scholar
  6. 6.
    Akkerman R, Pronk R (1999) Vacuum forming of thermoplastic foam. Polym Eng Sci 39:2064–2074CrossRefGoogle Scholar
  7. 7.
    Lee JK, Virkler TL, Scott CE (2001) Effects of rheological properties and processing parameters on ABS thermoforming. Polym Eng Sci 41:240–261CrossRefGoogle Scholar
  8. 8.
    Lee JK, Virkler TL, Scott CE (2001) Influence of initial sheet temperature on ABS thermoforming. Polym Eng Sci 41:1830–1844CrossRefGoogle Scholar
  9. 9.
    Chen SC, Huang ST, Lin MC, Chien RD (2008) Study on the thermoforming of PC films used for in-mold decoration. Int Commun Heat Mass Transf 35:967–973CrossRefGoogle Scholar
  10. 10.
    Oksuz M, Alsac C, Ates M (2009) The effects of thermoform molding conditions on Polyvinylchloride and polyethylene double layer package materials. Polym Eng Sci 49:2234–2241CrossRefGoogle Scholar
  11. 11.
    O’Connor CPJ, Martin PJ, Sweeny J, Menary G, Caton-Rose P, Spenser PE (2013) Simulation of the plug-assisted thermoforming of polypropylene using a large strain thermally coupled constitutive model. J Mater Process Tech 213:1588–1600CrossRefGoogle Scholar
  12. 12.
    Hummel SR, Hossain K, Hayes GT (2001) Biaxial stress relaxation of high impact polystyrene (HIPS) above the glass transition temperature. Polym Eng Sci 41:566–574CrossRefGoogle Scholar
  13. 13.
    Erchiqui F, Kandil AN (2006) Neuronal networks application for characterization of softened polymers. J Reinf Plast Comp 25:463–473CrossRefGoogle Scholar

Copyright information

© Springer-Verlag London 2014

Authors and Affiliations

  • Mohammad Ghobadnam
    • 1
  • Peiman Mosaddegh
    • 1
  • Masood Rezaei Rejani
    • 2
  • Hosein Amirabadi
    • 3
  • Abbas Ghaei
    • 1
  1. 1.Department of Mechanical EngineeringIsfahan University of TechnologyIsfahanIran
  2. 2.Department of Mechanical EngineeringBirjand University of TechnologyBirjandIran
  3. 3.Department of Mechanical EngineeringUniversity of BirjandBirjandIran

Personalised recommendations