Emergency First Responders COVID 19 face mask / respirator. Extends use of N95 masks

I’ve taken the liberty of improving the open-source design released by Dr. Zaugg recently for 3D printing a mask that uses a 2″x2″ piece of filter material (they’re saying they can use a single N95 mask to make 4+ filters for the reusable 3D printed parts. Designed to use a relatively wide variety of filter materials (sandwich plate has an energy concentrator to provide a concentrated sealing ring).

Dr. Zaugg’s website for reference: https://longliveyoursmile.com/3d-printable-mask-for-covid-19/

The original design did not lend itself to a few things: 1) Push a square block thru a square hole makes it difficult to have the correct thickness of material and no a guaranteed seal. 2) strap attachments too close to edge to allow for putting a slit piece of tubing on or rubber seal.3) No terribly good way to know how to scale for your specific face.

I’m working with Dr. Zaugg’s office to try and get these files post as well.

I’ve also included a printable scale ruler to measure your face (see a photo of my favorite theoretical physicist how to measure). Simply measure from bridge of nose to point of chin, and read off the scale readout. This is how much you need to scale all the 3d printed parts. Since we’re on lock down I could only use myself and my wife to create the scale of what fits so hopefully it works for you.

If you have a pair of calipers or fine metric ruler on hand you can also find scale by this formula: y(x)% = 0.6061 * x + 26.364 where x is mm measurement of face.

Being printed in ridged material makes it hard to make a mask that fits everyone’s face. If the mask fits your nose and chin area correctly you can use a hair dryer to thermo-form the ill fitting areas to your specific face profile (why i’d suggest printing in PLA).

Thumb screw’s threaded area is the only part that need to be printed at a finer layer height (I’m printing with variable layer height at 0.07mm via PrusaSlicer).

UPDATE: I had an issue with the male screw thread working when switching materials, I found reducing the screw’s scale by 2 to 3% made them work perfectly.

Other then the 3d printed parts the assembly will need:

Qty. 1, 2″x2″ flat(ish) filter media (this piece gets sandwiched between the mask and the sandwich plate and clamped with the 4 3d printed thumb screws)

Qty. 2, 6-8″ elastic bands (I was thinking reusing the elastic from N95 or surgeon masks, rubber bands in a pinch).