Similar to the deep drawing of metal components, a method is used which allows to draw thermoplastic semifinished
parts to three-dimensional hollow bodies. This process is referred to as thermoforming. For example
described by Engelmann et al. (2012), or Schwarzmann and Illig (2001), in this case the ability of the thermoplastic
materials to be soft and formable at higher temperatures and to solidify during subsequent cooling again is used.
For the forming of pure thermoplastic semi-finished, this process is widespread, especially in the packaging
industry. However, when reinforcing the plastic with fibres it cannot be formed easily. The forming of pure
thermoplastic is based on the high stretch ability of the plastic. The fibres introduced cannot be stretched with the
plastic; therefor other forming mechanisms must take place. Friedrich et al. (1997) describes five mechanisms:
resin percolation, transverse flow of laminate layers, inter-ply slip, intra-ply shear and inter-laminar rotation.