The DtM-v3.0 face shield PPE design has been reviewed and approved for use by the USA National Institutes of Health (NIH).
See also the design on the NIH website here:
https://3dprint.nih.gov/discover/3dpx-013359

Files on this post include two versions:
-- DtM-v3.0 for US and Canadian letter-size transparencies and three-hole punch
-- DtM-v3.0-A4 for A4-size transparencies and the ISO 838 (888) four-hole punch.

The USA Food and Drug Administration (FDA) has guidance on 3d-printed PPE here: https://www.fda.gov/medical-devices/3d-printing-medical-devices/faqs-3d-printing-medical-devices-accessories-components-and-parts-during-covid-19-pandemic

DtM-v3.0 Face Shield - Graphical Instructions for Use
https://drive.google.com/open?id=124-gOXaXDoSyl-VApn8imYEQTtP6LLYI2Z3Au1uhq3U

We were inspired by the Prusa RC2 design, which demonstrated incredible leadership in a crisis.

In the last week, we have assembled a team of over fifty experts in design, engineering and medicine with volunteers from Spark Health Design, Microsoft, and Boeing, and clinical experts from Mass General Brigham, the University of Washington Harborview Medical Center and the UW Medical Center at University campus.  Working nonstop in groups spread across the country, we have blasted through three very fast cycles of prototyping and clinical testing.  Our remix focuses on the need for improved protection for the wearer from aerosol and splatter from above, and improved washability and re-use.

The final design, DtM-v3.0, along with instructions for fabrication and assembly, has received US National Institute of Health (NIH) recommendation.  Find the latest reference files for the version with three transparency mounting pegs that fit a standard US three-hole-punch for US and Canadian letter-sized paper here: https://3dprint.nih.gov/discover/3dpx-013238   

The files posted here on Prusa Printers include DtM-v3.0-A4, the same DtM-v3.0 design, with the four-peg layout from the original Prusa RC2.  These pegs are compatible with an ISO 838 (888) style four-hole punch for A4 paper.

We have released this design under a public domain open license so you are all free to use, remix and build upon our work, which itself builds on the Prusa team's design.  Let's work together to protect frontline healthcare workers!

Supplemental Information for DtM-v3.0 Face Shield PPE 
"Instructions for Use" and "Quality Control Protocol"
https://drive.google.com/drive/folders/1ek1mNVNVhsNzNVN9hRwf_Qq_5meSHNll

Reference photos from our product development process here (note all photos are of the DtM-v3.0 design with three mounting pegs):
https://photos.google.com/share/AF1QipNqzH_PNDcE8m2xsQLBfHIA31jVX9LyL8PKJtzTSdsLLD0w2HpOqelaDgfMkZ6IYg?key=TUpkSEFXei1WeGo0NDh0V2tvbnNON3BScVNGNDJn

And here's a link to our background research on clinical requirements, with links to citations and guidelines:
https://docs.google.com/document/d/15k20PMe14_XQa-8kTA2G7nSIrF1bGSpc90_GM9H8yNI/edit

Design credit goes to the Design that Matters team, and volunteers Elizabeth Johansen from Spark Health Design, David Packman from Microsoft and Eric Moyer from Boeing. Project details and a full list of credits here: https://www.designthatmatters.org/covid-19

Print instructions

3d-printed headband in PLA, roughly 50g/1.75oz per part.

Outer envelope of 3d-printed headband is 191mm wide, 148.5mm long, and 52.5mm tall.

Print time is roughly 3h15m per part on a Prusa i3 MK2S and a Lulzbot Taz 6 at 0.25mm layers, 30% infill, no supports.

PREFERRED PRINT SETTINGS:
Nozzle Diameter: 0.4mm
Programmed Extrusion Width: 0.5mm
Layer Height: 0.3mm
Shells: 3 (which results in a 1.5mm wall)
Infill: 30%
Infill Type: Grid
Solid Bottom Layers: 3 (which results in a 0.9mm thick bottom)
Solid Top Layers: 3 (which results in a 0.9mm thick top)