S. Kang et al., OPTIMUM DESIGN OF PROCESS CONDITIONS TO MINIMIZE RESIDUAL-STRESSES ININJECTION-MOLDED PARTS, Journal of thermal stresses, 21(2), 1998, pp. 141-155
An Inverse design method has been developed to obtain an optimum mold-
wall-temperature history that produces an injection-molded part with m
inimum residual-stress distribution. Optimization has been formulated
within the framework of nonlinear least squares and a modified Gauss-N
ewton method with a zeroth-order regularization technique. The transie
nt temperature field has been generated based upon a purely viscous fo
rmulation of the filling and post-filling stages, and the cooling-indu
ced residual stresses have been calculated employing a thermo-rheologi
cally simple, linear viscoelastic model. The present study shows that,
with an optimum cooling history, maximum residual-stress levels can b
e reduced significantly for both unconstrained and constrained vitrifi
cation with holding pressure.