Processing optimization of Fresnel lenses manufacturing in the injection molding considering birefringence effect

The Taguchi robust design method is used to examine the effects of the processing conditions on the birefringence properties of a Fresnel lens fabricated using a plastic injection molding technique. The Computer Aided Engineering (CAE) simulation results show that the residual stress within the lens is determined (in descending order of influence) by the melt temperature, the filling time, the packing time and the mold temperature. In addition, it is shown that given an appropriate setting of the processing parameters, the average residual stress can be reduced by 75.1%; resulting in a reduction of 74.7% in the average birefringence. In general, the results presented in this study confirm the effectiveness of the integrated Taguchi/CAE approach in optimizing the performance of plastic Fresnel lenses for a variety of focusing applications.