Analysis and sensitivity analysis for polymer injection and compression molding

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.