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Volumetric effects in the injection molding of polymers
Author(s) -
Isayev A. I.,
Hariharan T.
Publication year - 1985
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.760250504
Subject(s) - shrinkage , materials science , thermal conduction , composite material , molding (decorative) , polystyrene , heat transfer , mold , transient (computer programming) , convection , polymer , thermodynamics , physics , computer science , operating system
Density and shrinkage measurements have been performed in quenched and molded slabs from polystyrene (PS) and poly (methylmethacrylate) (PMMA). Various processing conditions have been employed and their effect on density and shrinkage variation in the final parts, as well as volumetric aging vs . Elapsed time at room temperature, have been elucidated. A numerical simulation of the density variation in quenched parts and their aging has been performed by using first‐order rate theory for volumetric changes in conjunction with solving the transient one‐dimensional heat‐conduction equation with a convective heat‐transfer boundary condition at surface. A numerical simulation of the shrinkage in molded parts has been carried out by using the equation of state with a simultaneous solving of the governing equations for one‐dimensional mold filling during the cavity filling stage followed by transient one‐dimensional conduction during packing and cooling stages. Predicted results for density and shrinkage are compared with experimental data.