Experimental study and numerical simulation of preform or sheet exposed to infrared radiative heating

International conference on Advances in Materials and Processing Technology, DUBLIN, IRELAND, AUG 03-06, 1999International audienceThermoplastic processing like the injection stretch blow moulding and thermoforming processes provide the heating stage with infrared oven. This is a critical stage of the process, as the final part thickness is strongly dependent on the preform or sheet temperature distribution prior to forming. Optimisation of the infrared oven is therefore necessary. Experiments have been conducted in order to characterise the heat source of the infrared emitter and the interaction between the heaters and a semi-transparent PET sheet. An 880 LW AGEMA infrared camera has been used to determine the surface distribution of the transmitted heat flux by measuring the temperature distribution on the surface of the thermoplastic sheet. In addition, numerical simulations of the temperature distribution using control-volume method have been carried out and compared with experimental data

Experimental study and numerical simulation of preform infrared radiative heating

International audienceThe injection stretch-blow moulding process of thermoplastic bottles requires an heating step before forming. An amorphous preform is heated above the glass transition temperature (80°C for the P.E.T.) 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. Thus, the optimisation of the infrared oven is necessary. Various experiments have been conducted 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. These parameters have been implemented in control volume software that simulates the heating step. The surface temperature distribution of the preform has been measured using an infrared camera. Comparisons between experimental and numerical results for a rotating preform are presented