Experimental and numerical study on the thermoforming process of amorphous thermoplastic polymers

Thickness distribution has an important impact on the quality of thermoformed products. It has significant effects not only on durability but also on the oxygen and gas transmission rate of thermoformed packaging products. In this study, acrylonitrile butadiene styrene and polystyrene sheets were thermoformed using a lab scale thermoforming machine. Three different mold shapes were considered: conical, spherical and cylindrical. The thickness distribution of thermoformed acrylonitrile butadiene styrene and polystyrene samples for each mold was investigated based on geometric element analysis (GEA) and finite element analysis (FEA). Finite element analysis yielded more accurate results than geometric element analysis. Process parameters such as temperature distribution on the sheets before molding, have a crucial effect on thickness distribution for all configurations.