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Numerical simulation of blow molding—Viscoelastic flow analysis of parison formation
Author(s) -
Tanoue Shuichi,
Kuwano Yoshifumi,
Kajiwara Toshihisa,
Funatsu Kazumori,
Terada Kousuke,
Yamabe Masashi
Publication year - 1995
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760351908
Subject(s) - blow molding , die swell , materials science , swell , mechanics , die (integrated circuit) , stress (linguistics) , flow (mathematics) , extrusion , weissenberg number , composite material , viscoelasticity , thermodynamics , mold , physics , linguistics , philosophy , nanotechnology
The simulation of the parison formation process in blow molding has been studied. The flow field was divided into two regions, namely, the extrudate swell region near the die lip and the parison formation region after the exit swell. In the swell region, we predicted the swelling ratio and residual stress distribution for high Weissenberg numbers for steady planar well using the 1‐mode Giesekus model. In the parison formation region, the flow is assumed to be an unsteady unaxial elongational flow including drawdown and recoverable swell and is modeled using the 10‐mode Giesekus model. We calculated the time course of parison length and thickness distribution, and compare the calculation results of parison length with experimental data. It was found that the predicted values agreed rather well with the experimental values. The calculation results could especially predict the shrink‐back, which is the phenomenon where the parison length becomes shorter after the cessation of extrusion, and it was found tat this was caused by the recoverable swell of the parison, which depends on the tensile stress generation in the die. Various flow rates and die geometries were studied and confirmed the reliability and usefulness of the method.