Polymer process modeling, design sensitivity analysis, and numerical optimi
zation are combined to design processes for the manufacture of plastic comp
onents via the injection and compression molding processes. The Newton-Raph
son iteration is used to solve the nonlinear equations for the polymer melt
pressure field which are formed via the isothermal Hele-Shaw flow analysis
and Galerkin finite element method. To compute the fill time and filling p
attern, a moving boundary analysis is developed based on the volume-of-flui
d (VOF) technique. Design sensitivities for the transient coupled pressure
and volume fraction analyses are evaluated using the direct differentiation
method. The molding analysis and sensitivity analysis are combined with nu
merical optimization to design, not just analyze, the injection and compres
sion molding processes. Examples illustrate the polymer processing design m
ethodology where the injection molding process is designed to minimize mold
fill time and satisfy constraints on injection flow rate and mold clamp fo
rce. (C) 1998 Published by Elsevier Science S.A. All rights reserved.