This file is from the Ga Tech PWP website. It is an open source STL file of a face shield that is being 3D printed by many, many public and private 3D printer operators. For the Face Shield Frame the polycarbonate (or analogous material) frame is 3/16″ thick. It is acceptable to go down to 1/8″, but 1/4″ is not ideal. Note that the frame size is 7.201” x 8.634”.