Does fountain flow influence molecular orientation in injection moulded parts?

Simulations of the isothermal and non-isothermal filling of a rectangular cavity were carried out for polystyrene using a Giesekus viscoelastic constitutive equation, whereby in the non-isothermal case the thermal resistance at the mould wall was modelled with different heat transfer coefficients to...

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Bibliographic Details
Published inPlastics, rubber & composites Vol. 35; no. 10; pp. 418 - 424
Main Authors Nguyen-Chung, T., Mennig, G.
Format Journal Article
LanguageEnglish
Published London, England Taylor & Francis 01.12.2006
SAGE Publications
Maney
Subjects
Applied sciences
Exact sciences and technology
FOUNTAIN FLOW
INJECTION MOULDING
Machinery and processing
MOLECULAR ORIENTATION
Moulding
Plastics
Polymer industry, paints, wood
SIMULATION
Technology of polymers
THERMOPLASTICS
FOUNTAIN FLOW
MOLECULAR ORIENTATION
SIMULATION
THERMOPLASTICS
INJECTION MOULDING
Non isothermal flow
Viscoelasticity
Rheological model
Fountain flow
Thermoplastics
Isothermal flow
Theoretical study
Modeling
Thermal stability
Thermal properties
Structure processing relationship
Injection moulding
Molecular orientation
Simulation
Injection molding
Numerical simulation
Styrene polymer
Mold filling
Heat transfer
Rheological properties
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Summary:Simulations of the isothermal and non-isothermal filling of a rectangular cavity were carried out for polystyrene using a Giesekus viscoelastic constitutive equation, whereby in the non-isothermal case the thermal resistance at the mould wall was modelled with different heat transfer coefficients to investigate the effect of the thermal resistance on the development of the molecular orientation. Results for stress development along the flow front and the cold wall were compared showing that the principal stress differences in the middle of the flow front are lower than those at the mould wall. In case of the non-isothermal filling, the latter one will increase further while the melt is gradually cooling down, which is especially true if the thermal resistance at the mould wall has been properly considered. Consequently, the high molecular orientation at the wall seems to be rather a result of the non-isothermal shear flow than of the extension at the advancing front as usually assumed.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
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ISSN:1465-8011
1743-2898
DOI:10.1179/174328906X149709