The ABC Face Shield

Last crawled date: 2 years ago

Atlanta Beats Covid (ABC) has been working with Atlanta Shield Makers to come up with a face shield to protect healthcare workers. There are countless variants out there, but ours has been developed with a particular emphasis toward 3D printing a master mold, then using that to cast plastic parts. The goal was to come up with a design that was:
- Beginner friendly for new plastic casters
- Able to use a wide variety of three-hole-punched visor materials
- Optimized for minimal silicone usage
- Easy to demold
- Easy to scale up to larger production quantities

To meet these requirements, we present a remixed Prusa (US) that incorporates a browshield and a host of small geometry changes to make it molding-friendly. File _0_ is the Solidworks part file that contains all the geometry for each of the subsequent parts - this is where you should go to have the best results remixing.

It is possible to 3D print the ABC face shield frame directly, where you simply download and slice file _1_. We have had great results with a really coarse 0.35mm layer-height PLA print taking around 2 hours.

For molding and casting we provide two STL files ready to use. File _2_ is simply the frame geometry from _1_ but with an additional flat plinth that provides a crisp edge when molding. For the best results this file should be printed in a high-resolution printer such as SLA or Polyjet, or post-processed. We have had great success with SLA, Polyjet, and acetone-smoothed ABS. File _3_ is merely a mold box that provides a 0.5" border around the outside of the part to contain the silicone rubber. It fits snugly around the plinth, with hot glue or tape being used to create the final master pattern ready for pouring. We use Smooth-On MoldStar 16 for this (around 22floz per mold), but many other silicone rubber options exist.

The final part to be made is the strap clip which hooks over the rear-most pegs on the frame and incorporates a tension adjustment. File _4a_ provides the DXF of this part for laser cutting, where we use 0.100" acrylic with good success. File _4b_ is the 3D version of this part in case you wanted to 3D print it.

For the visor material, we have proven our frame with the following options:
- Overhead transparency acetate with three-hole-punched holes
- Binder covers with three-hole-punched holes
- 34mil PET sheet CNCed or laser cut according to the original Prusa geometry, found here: https://www.prusaprinters.org/prints/27950-prusa-face-shield-us-version

Finally, we finish the assembly with the following:
- 12mm self-adhesive foam cut into 9"x0.75" strips, such as what can be found at https://tntcosplaysupply.com/product/eva-foam-sheets/
- 0.5" knitted elastic such as what is found at https://tntcosplaysupply.com/product/eva-foam-sheets/

Note: It goes without saying that this design or variants similar to it are free to use. Please share it far and wide, and we'd love to hear your feedback or remixes.