• Schmidt, Fabrice M.
• Monteix, Serge
• Denis, Gérard
• Vigny, Murielle
• Maoult, Yannick Le

Abstract

The injection stretch-blow moulding process of thermoplastic bottles requires an heating step before forming. During this step, an amorphous preform is heated above the glass transition temperature using an infrared oven. This step is fundamental in order to determine the thickness distribution along the preform height and then insure high quality bottles. Basically, the infrared oven is constituted of a row of halogen lamps, a cooling device, different aluminium reflectors, a rotating support where the preform is fixed. These facts lead to manage various parameters such as lamps temperature, the shape of the lamps, the position of the lamps, the heat transfer coefficient between cooling air and the preform. Thus, the optimisation of the infrared oven based on trial and errors even becomes tedious and yields to develop numerical modelling. In this work, various experiments have been conducted in order to characterise the heat source and the semi-transparent properties of the P.E.T. Measurements of air temperature inside the infrared oven and air cooling speed have been processed. The surface temperature distribution of the preform has been measured using an infrared camera. The relevant parameters have been implemented in a software called PLASTIRAD based on the control volume method and developed to simulate the infrared heating of polymers. Different comparisons between experimental measurements and numerical simulations for rectangular sheets, fixed as well as rotating preforms, have been successfully achieved.

Topics

• impedance spectroscopy
• surface
• amorphous
• experiment
• simulation
• aluminium
• glass
• glass
• glass transition temperature
• forming
• thermoplastic