Modelling stretch blow moulding of polymer containers using level set methods

Stretch blow moulding is a widely used technique e.g. for the production of PET bottles. In a stretch blow moulding process a hot preform of polymer is simultaneously stretched and blown into a mould shape. The process takes place at a fast rate and is characterised by large deformations and temperature gradients. In this paper a computer simulation model for stretch blow moulding is presented. The model is based on finite element methods and uses a level set method to track the interfaces between air, polymer and stretch rod. The PET behaviour is modelled as a non-newtonian, isothermal fluid flow, based on a viscoplastic material model. An application presented is the stretch blow moulding of a realistic PET water bottle. The model is validated by verifying volume conservation.