Simulation of stress distribution in the base of PET bottles under different processing conditions

Polyethylene terephthalate (PET) bottles, especially the ones with petaloid shaped base are the most widely used containers for carbonated soft drink (CSD) packaging. Occasionally, cracks develop in the base of the bottles due to the internal stresses generated by the carbonation pressure of the content. To eliminate the stress cracking problem, the process parameters as well as the bottle design need to be optimised. In this study, the effects of process parameters on the distribution of stresses in the bottle base will be studied. In particular, the timing of the stretch rod in relation to the blow pressure activation, the preform temperature and weight will be considered.