Numerical simulation of hot imprint process of periodical lamellar microstructure into polycarbonate

Abstract

Thermoplastic polymers are frequently used in the industry. They represent the most important group of polymeric materials. Most of all, injection molding, extrusion, spinning and hot embossing are used for plastic processing. Today polymers are used in precision systems. So it is necessary to create new powerful modeling and analyzing tools. A finite element model for hot imprint process of periodical microstructure into polycarbonate has been developed. In the finite element model polycarbonate is assumed to be a nonlinear elasto-plastic material. The model covers the main three steps of hot imprint process: polycarbonate heating, imprinting and demolding. Periodical lamellar microstructure was chosen as die in the hot imprint process, because it is common structure in the practice. The model is solved using the heat transfer and the solid stress-strain application modes with thermal contact problem between die and polycarbonate. This multiphysics polycarbonate hot imprint model includes the heat transport, structural mechanical stresses and deformations resulting from the temperature distribution. Finite-element simulation of the hot imprint process has been performed using COMSOL Multiphysics. Nonlinear elasto-plastic model was created. It allows evaluation of temperature distributions and stresses in the polycarbonate during hot imprint process. Obtained theoretical results were compared with experimental.