Experimental and numerical investigation of shrinkage and warpage of a U-shaped injection molded part

Stefan Kleindel, Roland Eder, Herwig Schretter, Christoph Hochenauer

Research output: Contribution to journalArticlepeer-review


Prediction of shrinkage and warpage of injection molded plastic parts is a key issue of injection molding simulation. In the present work a U-shaped part is investigated experimentally and by means of state of the art injection molding simulation software. The part has thick walls in the corner where inner defects such as voids and porous zones may appear. Experiments and simulations were performed with POM and glass fiber reinforced polyamide. Measurements of pressure in the cavities and temperature profiles around the cavities were used to validate the numerical model. In case of POM it was found that warpage predictions are way off when the void volume is high and in good agreement when the void volume is minimized. No such correlation was observed in case of fiber reinforced materials. Here, shrinkage and warpage are dominated by the fiber orientation state with minor influence of the processing conditions. Predicted warpage was found to be extremely dependent on the used closure approximation.

Original languageEnglish
Pages (from-to)68-81
Number of pages14
JournalInternational Polymer Processing
Issue number1
Publication statusPublished - 1 Mar 2016


  • shrinkage
  • warpage

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Polymers and Plastics
  • Industrial and Manufacturing Engineering
  • Materials Chemistry

Fields of Expertise

  • Mobility & Production

Treatment code (Nähere Zuordnung)

  • Theoretical
  • Experimental

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