covid faceshield US holepunch

This is similar to other faceshields with the following advantages:
1) mount clear plastic using standard US hole punch (4.25 inch spacing, 3 ring binder)
2) This design minimizes plastic usage due to cutouts in shield. Quicker printing, costs less.

To print, I recommend PETG, setting at .35 layer for speed, perimeter = 6 for strength. Print 3 pushpins with one facemask. Assemble by punching plastic sheet with 3 hole punch, and secure to facemask with pushpins.

Prints on my Prusa Mk2 in about 95 minutes, including the 3 pushpins.

Attach with elastic band or fabric strip.

Also added a lightweight version that prints in about 83 minutes. It's about 20% thinner. Your choice if you want the lightweight version or the regular one.

4/7/20 Added stackable versions 2, 4, and 6 high so I can run the printer all night.