TITLE: 3D Printing Of Personal Protective Equipment And Repurposing Of Common Household Air Filters
AUTHORS: Giana Schena, Emma Murray

[DESCRIPTION]
<div class = "text-blocks"><div class = "text-block"><span>During the height of the COVID-19 outbreak, personal protective ​</span><a href="Https://time.com/5785223/medical-masks-coronavirus-covid-19/" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">equipment shortages</span></a><span>​ are felt around the world, in spite of the fact that traditional face masks are not even sufficient to fully </span><a href="https://www.crosstex.com/sites/default/files/public/educational-resources/products-literature/guide20to20face20mask20selection20and20use20-202017.pdf" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">protect against the 0.125 micron​</span></a><span> ​</span><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4369385/" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">SARS-CoV-2</span></a><span>​ virus.​ Medical personnel, more than any other sector, are being hit hardest by this shortage, given their close contact with infected persons. During this time of crisis and shortage, alternative and atypical solutions are necessary to ensure the protection of those who are on the front lines against this disease. One solution is the creation of reusable 3D-printed personal protective equipment (PPE) in conjunction with appropriate disposable filtration.</span></div><div class = "text-block"><span>3D-printed face masks are available on a variety of different open source 3D-printing online platforms. Unfortunately, the general public remains largely unaware of these potential solutions and can also be intimidated by the lack of information available regarding how to integrate scientifically appropriate filters. The intention of this white paper is to make available the information needed for simple construction of effective 3D-printed masks. We recommend a 3D printed ​</span><a href="https://creality.com/info/makers-guide-3d-printed-face-mask-no-worries-on-mask-shortage-and-virus-infection-i00248i1.html" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">face mask​</span></a><span> design made available by ​</span><a href="https://creality.com/" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">CREALITY</span></a><span>​, a leader in 3D-printing machines. By using CREALITY’s open source designs and easily obtainable air filters, cut to a desired size, we can increase our ability to protect medical workers against this disease. Additionally, CREALITY offers designs for a 3D-printed ​</span><a href="https://creality.com/info/makers-guide-3d-printed-face-mask-no-worries-on-mask-shortage-and-virus-infection-i00248i1.html" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">eye mask​</span></a><span> that can be used with plexiglass to protect eyes against airborne droplets. In practice, CREALITY’s 3D model object STL files can be uploaded into any available ​</span><a href="https://all3dp.com/1/cura-tutorial-software-slicer-cura-3d/" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">slicer software</span></a><span>​ allowing for creation of specific commands for 3D printers. Within the slicer, face mask and eye mask models can be scaled to small, medium, or large to fit a variety of face sizes. We have also included ​</span><a href="https://www.thingiverse.com/thing:1777669" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">strap adjustment clip</span></a><span>​ models for use with facemasks and a ​</span><a href="https://www.thingiverse.com/thing:4233193" style = "text-decoration:underline;color:blue;cursor:pointer;"><span style = ":;">face shield​</span></a><span> to extend the life of traditional facemasks.</span></div><div class = "text-block">We also propose a plan to coordinate large-scale construction of crowd-sourced 3D printed masks with collection and delivery of said masks to at-risk businesses, in particular hospitals and care facilities.</div></div>

[STEPS]
?. [Two Piece Face Mask Printing and Assembly]
Open the​ facemask_filter_guard.stl f​ile (currently on scale with the face unit, would also need to be scaled up).         a. Support is not necessary         b. Guard is in shape of a trapezoid: the face of the guard is 2.5 inches tall with 2.75 inch base length and 1.6 inch top length
?. [Two Piece Face Mask Printing and Assembly]
Open ​facemask_clip.stl​ file and print two copies.
Set XYZ percentages to 54%.
?. [Two Piece Face Mask Printing and Assembly]
Ensure the following settings are on in your printer (Exact wordage for Ultimaker Cura but similar settings available on all slicers):         a. Infill density = 30%         b. Generate Support = Checked                 i. Support Placement = Touching Buildplate                 ii. Support Overhang Angle = 45 degrees
?. [Two Piece Face Mask Printing and Assembly]
Slice file and print.
?. [Two Piece Face Mask Printing and Assembly]
Soak the unit and guard in Clorox bleach for . Rinse well and air dry.
?. [Two Piece Face Mask Printing and Assembly]
Choose filter material:         a. For general face mask replacement: ​option 1        b. For higher levels of protection:​ o​ption 1​ or ​option 2        c. Peel filter off of metal webbing, discard metal webbing and keep filter material:
?. [Two Piece Face Mask Printing and Assembly]
Cut filter to fit within the guard:
?. [Two Piece Face Mask Printing and Assembly]
Place filter between the guard and the face unit and snap together.
The facemask_filter_guard.stl f​its very tightly on the ​facemask_face_unit.stl b​ut can still be removed for reuse by pressing against the guard from inside the face unit.
?. [Two Piece Face Mask Printing and Assembly]
Thread elastic band through clips:
?. [Two Piece Face Mask Printing and Assembly]
Attach elastic band to holes on either side of the face unit:
?. [Two Piece Face Mask Printing and Assembly]
If desired, padding can be taped or glued around the outside edges of the facemask.
?. [Two Piece Face Mask Printing and Assembly]
Open the​ facemask_face_unit.stl f​ile (size= currently ~female size, would need to be scaled up).         a. Ensure that support is on
?. [One Piece Face Mask Printing]
Print the facemask_single_unit.stl​ file.
File should be printed with support enabled.
?. [Three Piece Face Goggles Printing]
Print eye goggles using the ​eyemask_thick.stl,​ eyemask_thin.stl​ and eyemask_hook.stl​ files.
?. [One Piece Face Shield, No Screws Printing]
Create a face shield using the ​faceshield_one_unit.stl ​file, originally found on Thingiverse and made by ​HanochH​.
This face shield is ideal because no screws or clamps are required. The model's design uses tension to keep any acrylic sheets firmly in place.
?. [Three Piece Face Goggles Printing]
Cut and glue plexiglass or A4 acrylic sheets in between the eyemask_thick.stl​ (outer piece) and ​eyemask_thin.stl​ (inner piece) prints.
?. [Three Piece Face Goggles Printing]
Foam-adhesive weather stripping can be attached to the inside of the eyemask_thin.stl​ print for a more comfortable and secure fit on the face.
?. [Three Piece Face Goggles Printing]
Clip the ​eyemask_hook.stl​ print to the ​eyemask_thick.stl​ print and attach maximum width of 1⁄2” elastic banding for strapping the mask to the face.
?. [One Piece Face Mask Printing]
Two clips can be printed using the ​facemask_clip.stl​ file with XYZ percentages set to 54%.
?. [One Piece Face Mask Printing]
Air filtration material should be cut to fit inside the single unit.
?. [One Piece Face Mask Printing]
Adhesive foam weather stripping and elastic banding can then be added to create a snug fit on the face.
?. [One Piece Face Mask Printing]
Print two clips using the ​facemask_clip.stl​ file with XYZ percentages set to 54%.
?. [One Piece Face Mask Printing]
Cut air filtration material to fit inside the single unit.
?. [One Piece Face Mask Printing]
Adhesive foam weather stripping and elastic banding can then be added to create a snug fit on the face.
?. [One Piece Face Shield, No Screws Printing]
Cut a sheet of acrylic to run along the diameter of the opening.
This design is made to fit A4 sheets and the original makers tested to confirm this design works with 0.10mm and 0.24mm thickness sheets. A video of the mask in use can be seen on the makers ​thingiverse​.