This design is influenced by the many Face Shield designs floating around. Specifically, I'd like to recognize the excellent designs from
3DVerkstan
Stratasys
Prusa Research

I was dissatisfied with these designs due to their BOM (most require elastic bands), the fitment of the clear shield (most are not secure), but mainly with the lack of batch-printability. All of the designs I've seen are not stackable, which means someone needs to babysit the machine and remove parts every few hours.

This design is first and foremost batchable:
If your printer has a support nozzle, add a single layer between parts, and stack them as high as you like. If not, just skip a layer (requires separation with a knife), or skip several and use breakaway Supports.

This design requires a transparent sheet of plastic (roughly 8.5x11), punched with a US standard 3-Hole Punch (4.25in on center). Ideally, use at least 10mil thick plastic - 100 packs of clear Binding Covers (/presentation covers) can be had cheap, just make sure they're optically clear (such as PVC; PP is hard to see through). Transparency film can work in a pinch.

Added Retention Clip to better secure the Clear Shield during rough handling.
Added Clear Shield DXF for those with access to CNC cutting equipment.
Added FaceShield_r1.1 - revised to eliminate the need for the retention clip (but still compatible, if desired).
Added Forehead - optional, adds some surface area to the forehead area for comfort if elastic is used in the back. Apply foam for extra comfort.

This design fits over glasses, and doesn't require a rubberband to stay on the head.

Please remember to wear proper PPE when assembling for others, to avoid contamination.