Modeling of the compressed-air flow impact for thermoforming simulations

Thermoforming is a process for the cheap mass-production of thin-walled plastic parts. A sheet of plastic is heated for increased deformability, and then deformed by overpressure into a mold with the end productâs shape. The main drawback is the inhomogeneous wall thickness distribution resulting from the common process. The authors believe that it is possible to improve these inhomogeneities by locally influencing the highly temperature-dependent material strength using directed jets of pressurized air for local cooling. As the high number of potentially influential parameters renders purely experimental parameter studies infeasible, a computational model that couples the flow of the pressurized air with the structural simulation of the deforming plastic is set up. With the combined results of experiments and simulations, a parameter study can be conducted, which allows for an optimization of air flow parameters for a more evenly distributed wall thickness.