Simultaneous Control of Birefringence and Warpage for Thermoplastic Optical Lenses Fabricated Using Microinjection Molding

Achieving tight tolerances for multiple properties of a single product becomes a key issue. This study presents an investigation on birefringence and warpage of thermoplastic lenses prepared using microinjection molding, aiming to identify the significant factors, and simultaneously control both properties for optical applications. The birefringence along the flow changed more drastically than that in the cross-flow direction. Meanwhile, two warpage shapes of the lenses could be observed and their formation mechanisms were discussed. The simultaneous control of both properties was accomplished through multi-objective optimization using the desirability function approach. Finally, the optimal processing parameters were obtained and experimentally verified. GRAPHICAL ABSTRACT