Stretch blow molding (SBM) is widely employed for the production of PET containers, in particular in the food and beverage industry as well as in the pharmaceutical sector. SBM is a high volume process with costly tooling for both the preform and the container. This study presents an optimization strategy for the entire stretch blow molding process. The method combines structural and process numerical simulations in an optimization environment. The overall simulation technique provides with a rational means to assist the bottle design and the determination of the optimal process conditions. The first aim of the strategy is to target the best preform thickness distribution which guarantees the highest top load for the bottle. The method is based on coupling an optimization algorithm and finite element (FE) simulations carried out using LS-DYNA. FE simulations were validated using in situ tests and measurements performed on 10-liter PET bottles. The computed container thickness distribution constitutes the target of the optimization of the process conditions. It has been analyzed the stretch and inflation sequence for the preform into a complex-shaped mold cavity. An unsteady large deformation analysis of the preform inflation process was carried out using a three dimensional membrane FE for viscoelastic materials. A non-isothermal flow with free surfaces and viscoelastic properties was described by a K-BKZ integral constitutive equation. The preform geometry was mathematically parameterized. This model was combined to an optimization loop to automatically compute the thickness distribution by manipulating the geometry of the perform and the operating parameters subjected to process and design constraints. The numerical results were verified using experimental data of an industrial case study, in order to assess the validity and the robustness of the proposed strategy.

Optimization of Design and Process Condition for Stretch Blow Moulded Bottles

CARRARO, PIERTOMMASO;LUCCHETTA, GIOVANNI
2010

Abstract

Stretch blow molding (SBM) is widely employed for the production of PET containers, in particular in the food and beverage industry as well as in the pharmaceutical sector. SBM is a high volume process with costly tooling for both the preform and the container. This study presents an optimization strategy for the entire stretch blow molding process. The method combines structural and process numerical simulations in an optimization environment. The overall simulation technique provides with a rational means to assist the bottle design and the determination of the optimal process conditions. The first aim of the strategy is to target the best preform thickness distribution which guarantees the highest top load for the bottle. The method is based on coupling an optimization algorithm and finite element (FE) simulations carried out using LS-DYNA. FE simulations were validated using in situ tests and measurements performed on 10-liter PET bottles. The computed container thickness distribution constitutes the target of the optimization of the process conditions. It has been analyzed the stretch and inflation sequence for the preform into a complex-shaped mold cavity. An unsteady large deformation analysis of the preform inflation process was carried out using a three dimensional membrane FE for viscoelastic materials. A non-isothermal flow with free surfaces and viscoelastic properties was described by a K-BKZ integral constitutive equation. The preform geometry was mathematically parameterized. This model was combined to an optimization loop to automatically compute the thickness distribution by manipulating the geometry of the perform and the operating parameters subjected to process and design constraints. The numerical results were verified using experimental data of an industrial case study, in order to assess the validity and the robustness of the proposed strategy.
2010
Proceedings of the Polymer Processing Society 26th Annual Meeting - PPS-26
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2436692
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact