A study on the influence of thermoforming process on the optical properties of polycarbonate films

This article deals with the thermoforming process, in which the plastic sheet is heated to a suitable temperature and stretched through a single-sided mould. This paper focuses on the study of thickness distribution along the final part through numerical simulation with T-SIM software and optical characterization of the practical process. PC LEXAN™ 8A13E films, with different initial thickness, were moulded by two types of moulding (positive and negative). It was intended to evaluate, characterize and correlate the effect of the process on the optical properties of the films. The findings of the study suggest that films formed with a negative mould exhibit more pronounced thickness variations compared to those formed with a positive mould, resulting in lower final thicknesses. Additionally, thicker films exhibit higher thickness variations after thermoforming, as supported by the experimental data. Regarding the optical characterization of the films, transmittance and reflectance tests were performed. In the case of transmittance, a significant increase in this property is observed after thermoforming, while a decrease in the reflectance values was observed. This paper is then focused on the study through numerical simulation and optical characterization of the thermoformed films, elucidating the dynamics inherent in the thermoforming process with transparent polycarbonate films, providing valuable insights for optimization and application across various industrial sectors.