Experimental and simulation studies on the mold replicability in the thermoforming process

Abstract

Abstract In the precision thermoforming process, one of the main drawbacks occurs in the profile deviation of the produced part. In this study, the effect of different thermoforming process parameters on the mold replicability of a high impact polystyrene container produced by vacuum forming and drape forming processes has been experimentally and numerically investigated. According to experimental results, in the drape forming process, when the initial sheet thickness increases, the part will have higher mold replicability, whereas in the vacuum forming process, by increasing the initial sheet thickness, the mold replicability increases and reaches its peak, then decreases. The results also indicate that both temperature and vacuum pressure exhibit the most significant effect on mold replicability of the part. Furthermore, the finite element method is utilized by the implementation of a fully thermomechanically coupled hyperviscoelastic constitutive model in ABAQUS 6.13. By using this material model, it is possible to compare the sensitivity of the output (mold replicability of the part) to the changes in the range of the process parameters. The simulation results verified by the experimental data and the hyperviscoelastic model showed to be an outstanding and stable platform for the process simulation.