- Previous Article
- Next Article
- Table of Contents
Journal of Polymer Science Part B: Polymer Physics, Vol.41, No.9, 859-872, 2003
Warpage prediction of optical media
The warpage of injection compression-molded optical media, such as compact discs and digital video discs, due to asymmetric cooling during production is predicted. Thermally induced stress is calculated with a nonisothermal compressible flow simulation with a viscoelastic constitutive model. A finite element analysis is formulated with axisymmetric plate elements based on Kirchhoff thin-plate theory to simulate the warpage of the disc due to the asymmetric thermal stress and gravity after demolding. Simulation results of warpage for compact-disc-recordable moldings are compared with experimental observations under different processing conditions, such as the melt temperature, mold temperature, and packing pressure, with an optical grade of polycarbonate. The comparison shows that the simulation well predicts the effects of various processing conditions. Both the simulation and experiment indicate that of the processing conditions, the mold temperature has the greatest effect on warpage. (C) 2003 Wiley Periodicals, Inc.
Keywords:warpage;optical media;polycarbonates;injection compression;residual stress;viscoelastic properties;compact disc molding;injection molding