The objective of this work was to obtain, through a simple experimental assembly, the real influence of the friction and process conditions in the assisted thermoforming process. The use of simulation tools to optimize this process requires the knowledge of the sheet-plug system friction coefficient [μ], the used temperature and velocity conditions, and due to that, the software does not have a wide database. For this, the users suppose μ with the previous known difference between the simulated and the experimental data. For this reason, the obtaining of μ may allow to achieve more accurate simulations. In this work, a modified pendulous impact in Izod geometry was used to the measurements. The μ increased with the sheet temperature. On the other hand, it was not possible to detect a significant μ variations regarded with the plug material