Numerical prediction and experimental validation of transient temperature profiles during reheating preform in stretch blow molding

Reheating of the preform represents an important stage in the two-stage stretch blow molding (SBM) process. This work aimed at developing a temperature acquisition system with an emphasis on the design of both thermocouples and brush mechanism, which leads the acquisition system to be used to measure in real time the transient temperature profiles within the wall of the reheated preform as it rotates. The measured temperature distributions both through the thickness of the preform and along its length were then compared with numerical results predicted by solving a thermal model for the preform reheating in the SBM. Both the radiative and convective heat transfers were considered in the simulation. After being verified by experimental dada, the thermal model was used to predict the transient temperature profiles within reheated preform under different conditions, such as preform thickness, air convection coefficient, and reheating time. This work helps to better deepen the understanding of the preform reheating in the two-stage SBM process.