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No‐flow temperature in injection molding simulation
Author(s) -
Mannella G. A.,
La Carrubba V.,
Brucato V.,
Zoetelief W.,
Haagh G.
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.32987
Subject(s) - molding (decorative) , shrinkage , materials science , crystallinity , composite material , flow (mathematics) , amorphous solid , polymer , mechanics , physics , chemistry , organic chemistry
Abstract Most injection molding simulation packages use the no‐flow temperature (NFT) as a means of determining whether the polymer flows or is solid. The NFT is not well defined, and a standard method for measuring it does not exist. A sensitivity analysis of the filling stage has been carried out with two different packages [VISI Flow (Vero Software Limited, Gloucestershire, UK) and Moldflow (Autodesk, Inc., San Rafael, CA)] to estimate the influence of the NFT on the main processing parameters. The NFT has a large influence on the thickness of the frozen layer, but it does not appreciably affect the filling pressure. Because the NFT affects the frozen layer, an effect on the estimation of shrinkage and warpage is expected. Software packages have also been compared, and similar simulations have been found to produce contrasting results. A simple correlation for NFT estimation, derived from the Cross–Williams–Landel–Ferry equation, is proposed for both amorphous and semicrystalline polymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011