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Title: Thermo-mechanical simulation of liquid-supported stretch blow molding

Abstract

Stretch blow molding is the well-established plastics forming method to produce Polyehtylene therephtalate (PET) bottles. An injection molded preform is heated up above the PET glass transition temperature (Tg∼85°C) and subsequently inflated by pressurized air into a closed cavity. In the follow-up filling process, the resulting bottle is filled with the final product. A recently developed modification of the process combines the blowing and filling stages by directly using the final liquid product to inflate the preform. In a previously published paper, a mechanical simulation and successful evaluation of this liquid-driven stretch blow molding process was presented. In this way, a realistic process parameter dependent simulation of the preform deformation throughout the forming process was enabled, whereas the preform temperature evolution during forming was neglected. However, the formability of the preform is highly reduced when the temperature sinks below Tg during forming. Experimental investigations show temperature-induced failure cases due to the fast heat transfer between hot preform and cold liquid. Therefore, in this paper, a process dependent simulation of the temperature evolution during processing to avoid preform failure is presented. For this purpose, the previously developed mechanical model is used to extract the time dependent thickness evolution. This information servesmore » as input for the heat transfer simulation. The required material parameters are calibrated from preform cooling experiments recorded with an infrared-camera. Furthermore, the high deformation ratios during processing lead to strain induced crystallization. This exothermal reaction is included into the simulation by extracting data from preform measurements at different stages of deformation via Differential Scanning Calorimetry (DSC). Finally, the thermal simulation model is evaluated by free forming experiments, recorded by a high-speed infrared camera.« less

Authors:
;  [1]
  1. Chair of Polymer Materials, Saarland University, Saarbruecken, Germany, – j.zimmer@mx.uni-saarland.de (Germany)
Publication Date:
OSTI Identifier:
22391850
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1664; Journal Issue: 1; Conference: PPS-30: 30. International Conference of the Polymer Processing Society, Cleveland, OH (United States), 6-12 Jun 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CALORIMETRY; CRYSTALLIZATION; DEFORMATION; DIFFERENTIAL THERMAL ANALYSIS; FAILURES; GLASS; HEAT TRANSFER; LIQUIDS; MOLDING; PLASTICS; POLYESTERS; PROCESSING; SIMULATION; STRAINS; TIME DEPENDENCE; TRANSITION TEMPERATURE

Citation Formats

Zimmer, J., and Stommel, M. Thermo-mechanical simulation of liquid-supported stretch blow molding. United States: N. p., 2015. Web. doi:10.1063/1.4918406.
Zimmer, J., & Stommel, M. Thermo-mechanical simulation of liquid-supported stretch blow molding. United States. doi:10.1063/1.4918406.
Zimmer, J., and Stommel, M. Fri . "Thermo-mechanical simulation of liquid-supported stretch blow molding". United States. doi:10.1063/1.4918406.
@article{osti_22391850,
title = {Thermo-mechanical simulation of liquid-supported stretch blow molding},
author = {Zimmer, J. and Stommel, M.},
abstractNote = {Stretch blow molding is the well-established plastics forming method to produce Polyehtylene therephtalate (PET) bottles. An injection molded preform is heated up above the PET glass transition temperature (Tg∼85°C) and subsequently inflated by pressurized air into a closed cavity. In the follow-up filling process, the resulting bottle is filled with the final product. A recently developed modification of the process combines the blowing and filling stages by directly using the final liquid product to inflate the preform. In a previously published paper, a mechanical simulation and successful evaluation of this liquid-driven stretch blow molding process was presented. In this way, a realistic process parameter dependent simulation of the preform deformation throughout the forming process was enabled, whereas the preform temperature evolution during forming was neglected. However, the formability of the preform is highly reduced when the temperature sinks below Tg during forming. Experimental investigations show temperature-induced failure cases due to the fast heat transfer between hot preform and cold liquid. Therefore, in this paper, a process dependent simulation of the temperature evolution during processing to avoid preform failure is presented. For this purpose, the previously developed mechanical model is used to extract the time dependent thickness evolution. This information serves as input for the heat transfer simulation. The required material parameters are calibrated from preform cooling experiments recorded with an infrared-camera. Furthermore, the high deformation ratios during processing lead to strain induced crystallization. This exothermal reaction is included into the simulation by extracting data from preform measurements at different stages of deformation via Differential Scanning Calorimetry (DSC). Finally, the thermal simulation model is evaluated by free forming experiments, recorded by a high-speed infrared camera.},
doi = {10.1063/1.4918406},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1664,
place = {United States},
year = {2015},
month = {5}
}