Experimental and Simulation Study of Thermoforming Using PC/PMMA Multilayer Films

This paper presents an experimental and simulation study on the thermoforming of PC/PMMA multilayer films. The thermoforming study was conducted using dome-shaped and cubic-shaped extruded molds. The thermoform-ing experiments were performed at various film heating temperatures under a constant vacuum pressure. The optimum thermoforming temperatures for the films were 165-175 ℃ for the dome shape and 175-185 ℃ for the cubic shape. The deformation characteristics were quantitatively analyzed by measuring the area stretch ratio and thickness distribution of the thermoformed films. In the thermoforming simulation, isotropic, orthotropic, and hyperelastic models were adopted as material models. The simulation results showed that the stress in the thermoformed product decreased while the strain tended to increase as the film heating temperature increased. The hyperelastic model showed the most similar tendency to the experimental results among the three material models. The experimental and simulation results obtained from this study are expected to provide useful guidelines for the thermoforming process optimization and product design for PC/ PMMA multilayer films.