Thermoforming of a Polystyrene Sheet with a Vibrating Male Mold

The objective of the study was to present the results of research on the thermoforming process using a patented, original male mold vibrating with the adequate frequency during the stretching of a polystyrene sheet. The research included determining the influence pertaining to the frequency of the mold vibration as well as other selected conditions of the thermoforming process, such as the temperature of the heater and heating time on the irregularity of the wall thickness of the formed product. The research was conducted using the DOE methods – central composite design. The thermoforming process was conducted using the vacuum stretching method with initial forming by high-pressure air. The analysis of the results obtained showed that the frequency of mold vibration has a significant statistic influence on the thickness of the walls of a finished product, both in the area of their bottom as well as the bottom’s edge. The thickness of the product wall on these areas is also significantly influenced by the other above-mentioned factors. No interaction, however, was detected between those and the frequency of the mold vibration. Using the vibrating mold in the presented process proved favourable, since the walls of the obtained finished products showed lesser irregularity in terms of the wall thickness than the products manufactured using a fixed mold.