Thermoforming process: Simulation of the heating phase

The works reported in this paper are related to a Research and Development program focused on the optimization of thermoforming process. Thermoforming process belongs to the five main polymer moulding processes which are the injection moulding, the extrusion moulding, the blow moulding, the thermoforming and the rotomoulding. During the last fifteen years, progresses of thermoforming technologies concern mainly the mechanical components: optimisation of vacuum forming, cutting out of sheet, etc. In the opposite, "thermal" components (heater panels) are viewed today by thermoformers as the weaked components of the thermoforming process. Thermoformers agree to say that rejected productions are often due to a bad control of plastic sheet heating conditions. The results, presented in this article, are the fruit of a R&D program which have been supported by the D.R.I.R.E and the region Rhone-Alpes, and which is keeping with the general pattern of Visioplasturgie (Second Regional Plan of Development of the Rhone-Alpes). The goals of this project were to study in-depth plastic sheet heating mechanisms with respect to thermoforming process characteristics. Research investigations have been managed with the goal to design, in near future, innovative heating panels for optimising thermoforming process.