Modelling the Heat During the Injection Stretch Blowing Moulding: Infrared Heating and Blowing Modelling

Abstract

Effects of temperature: initial heating conditions or self heating during the process, are very important during the injection stretch blow moulding (ISBM) process of PET bottles. The mechanical characteristics of the final products, which are mainly controlled by the final thickness and the orientation of the molecular chains, depend strongly on the process temperature. Modelling the heat transfer during the ISBM process is therefore necessary. In the first part of this paper, an experimental study is presented in order to measure the initial temperature distribution and to identify the thermal properties of the PET. An infrared camera has been used to determine the surface temperature distribution of the PET sheets which are heated by infrared (IR) lamps. The Monte Carlo method is used to identify the parameters best fit from the temperature evolution. In the second part, a thermo-viscohyperelastic model is used to predict the PET behaviour, taking into account the strain rate and temperature dependence. A finite element approach implemented in matlab is used to achieve the numerical simulation.