A Computer Simulation Model for the Stretch Blow Moulding Process of Polymer Containers

Abstract

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 the computer simulation model presented in is applied to the stretch blow process for the production of PET bottles. The model was previously developed by the authors for the simulation of 2D axial-symmetrical blow processes for the production of glass containers. The model is based on finite element methods and uses a level set method to track the interfaces between air and the material. The simulation model is modified in order to correctly describe the material behaviour of PET, take into account the stretch process and substitute the process parameters for stretch blow moulding. Furthermore, it is verified that the PET behaviour can be 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.