A Flexible 3D Printed Respirator Mask

As we described in our last blog post, we have been working on a 3D printed respirator mask to help meet the global shortage of face masks for healthcare workers. As a rare U.S. manufacturer, we know that in this time of need, our unique expertise not only in creating products that are “Healthy by Design,” but also in 3D printing, is critical.

OESH 3D Printed Respirator Mask

We have been working tirelessly with our factory neighbor LUNA, and after numerous prototypes, we’ve developed a flexible 3D printed respirator mask that has a tight seal around the edges.  Because of our expertise using a flexible and elastic material (that we use to make components for our shoes), we believed we could adapt that model to make a flexible face mask that can be used when there are no certified N95 masks available.

Indeed, we were able to create a design with soft edges that conforms to the face. While it is important to note that the mask we designed is not certified by NIOSH or the FDA (this would take months), we do believe we’ve created a mask that has a better seal than the typical off the shelf N95 face mask. The mask has two vents with removable caps such that filter material can be placed inside. The filter material can be anything from cut up surgical gowns or MERV HVAC filters to cotton make-up pads, depending on availability. Better than the usual disposable face mask, this mask can be washed (in a dishwasher, washing machine, or by hand) and re-used indefinitely with different filter material; it is even 100% recyclable.

We have heard from our local Charlottesville/Albemarle community that the highest need right now is for masks for our EMS first responders. Therefore, this week we will begin production and start manufacturing face masks in multiple sizes first for our EMS first responders. Once that need is met, we will move on to meeting the needs of other health care workers in the Charlottesville/Albemarle region. We will be 3D printing the masks, including the straps, and LUNA will assemble and distribute them.

How to make your own:

We encourage makers with 3D printers around the world to begin making these masks starting with your own local community. While our 3D printers were specially designed to 3D print from elastomeric pellets, it is easy to print the same design with flexible TPE filament using a standard filament fused 3D printer.

We’ve made an STL file ready to 3D print which you can download here (Updated 4-10-20):

Small     Medium     Large

Cap      Insert

You will need:

  • A 3D printed mask– in small, medium, or large depending on the end wearer
  • Two 3D printed “caps” – The caps are the same for all three sizes.
  • Two 3D printed “inserts”– The tamping piece, or insert, holds thin filter material in place, to prevent gaps.
  • A nose piece– We found 14 gauge copper wire to be a good, available option, but you could also use a thin strip of aluminum, a couple unbent paperclips, etc. This nose piece is very important for achieving a tight seal around the face.
  • Filter material– enough for both sides- In qualitative testing, we found that a  circle of MERV 14 air filter and a cotton pad is  breathable and that combination passed multiple qualitative fit tests, including irritant smoke and bitrex. One layer of Halyard wrap, from hospital setting, could also an effective filter in our mask, as it passed a qualitative fit test preformed at UVA hospital. We recommend special caution when using HEPA filters in masks because they sometimes contain fiberglass, which can cause lung damage  if inhaled.
  • Two elastic straps– Secure and adjustable straps are very important for for fit and functionality of the mask. We have been 3D printing elastic straps, and provided the files below.


  • Weld the nose and chin seams together to create an air-tight seal. We use a soldering iron on a low temp to melt the thin edges of the model together.
  • Push the nose piece through the loops and over the bumps on either side of the nose.
  • Tie the elastic bands to either side so that they wrap around the head.  Adjust to the wearer by knotting the elastic.
  • Pack the filters, pushing the insert and cap down until they snap securely in place. See diagram below.


OESH 3D printed respirator maskBecause elastic straps are also in short supply, here are 2 simple file options for printing your own:

2.6mm wide strap (12in x 3/8in build area) 

5mm wide strap (10in x 7/8in build area) 


OESH 3D printed respirator maskOESH 3D printed respirator mask

With continued support from our OESHer community, we will be donating every 3D printed respirator mask we make.

This mask is not certified. Functionality of the mask is dependent on print quality, construction, and fit on the end wearer. This mask is not for sale. Our initial model was inspired by NanoHack by Copper3D which uses hard plastic to create a cover that goes over a N95 mask.

Casey is also working with our manufacturing partners in China to connect State agencies and hospitals with respirators and facemasks. Access to these disposable respirators should increase the total supply of PPE in hospitals and health agencies and limit hospitals reusing N95 masks, to decrease the spread of the virus.