Effects of spring gripper configuration and forming temperature on the thermo-stamping of a carbon-fiber woven-fabric/polyphenylene sulfide composite sheet

Although thermo-stamping is one of the fastest and most cost-effective processes in the production of fabric-reinforced thermoplastic composite parts used in aerospace and automotive industries, it is quite prone to result in many defects. In particular, wrinkling is a frequently encountered defect in the production of doubly curved parts and is very sensitive to process parameters. Finite element analysis is an effective tool for estimating defects that can occur during the thermo-stamping process. In this study, effects of spring configurations in spring-based holders and forming temperature on wrinkling and shear deformation are investigated experimentally and numerically by using two different spring configurations and three different forming temperatures. Non-isothermal and isothermal approaches used in thermo-stamping simulations are compared in terms of wrinkling estimation and shear angle distribution. The results reveal that while the wrinkle predictions obtained by the non-isothermal approach are in good agreement with the experimental results, the isothermal approach cannot predict any of the wrinkles obtained in the experiment. Furthermore, the obtained results confirm that spring gripper configurations and forming temperature have a significant effect on wrinkling and shear angle distribution.