Numerical Study of Stretch-blow Molding of PET Bottles

摘要

In this research work, numerical modeling of the stretch-blow molding (SBM) of polyethylene terephthalate (PET) bottles is studied by finite element method (FEM). In this paper, due to symmetry of part geometry, the bottle is considered as axisymmetric model. A hyperelastic constitutive material model was used in variant high temperatures and strain rates. Instead of blowing process, hydrostatic pressure with convention heat transfer has been used. Comparisons of experimental observations with numerical results can predict an overall trend of thickness distribution. In contrast, some differences can be seen in some regions. These results were used for an overall prediction of bottle properties such as final bottle thickness and a defect free production. Moreover, the parametric studies are conducted on the effect of friction condition, heat transfer coefficient and initial pre-blowing air entrance time delay on bottle thickness. It was concluded that the proposed model is applicable for simulating the stretch blow molding process of PET bottles. This model is capable to offer a helpful knowledge in design of optimum preform and production of bottles.