MatterHackers Reusable 3D Printed Replacement Straps for N95 Face Masks

Huge thanks to Sarah Flora, 3D Lab Program Director at Geisinger Health System, for making these STLs available to the public.  When Sarah saw a need for replacement N95 straps in her hospital, she worked with MatterHackers' Applications Engineer Scott Cahoon to quickly design, test, and distribute these essential replacement components to her grateful COVID-19 front-line hospital staff. 

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Healthcare professionals all over the country are facing shortages in personal protective equipment (PPE). Currently, the use of N95 masks far outpaces the availability and manufacture output. Supply chains, at best, can promise an increased supply in weeks, but the essential need is right now. As a last resort, medical professionals are forced to reuse the masks they have on hand. To reduce the risks of reusing these masks as much as possible, N95s go through a sterilization process that makes them safer to use, but may also cause the mask's straps to fail.

To resolve this problem, Sarah Flora of Geisinger Health System has designed a temporary solution—3D printed clips and straps.

3D Printed Parts Required Per Mask

• Print with Nylon 3D Printer Filament
  • 2 x Merged Straps
  • 2 x Straight Straps
    • Straight Straps are extensions and might not be needed for everyone.
• Print with Tough PLA 3D Printer Filament
  • 2 x Female Buckles
    • FormLabs White Resin also works for Female Buckles
  • 2 x Male Buckles
  • 2 x Strap Connectors
    • Strap Connectors are to add the extensions to the merged straps

How to Assemble

• Step 1. Create a hole on each side of the fused part of the mask using a standard size hole punch.
  • If it’s a round mask, create the hole in between the two strap locations.

• Step 2. Attach a Merged Strap to the outside of the mask and use the clip to connect together
  • The shorter part goes lower, longer part goes in the direction of the crown of the head.
  • Depending on how big you need it, either attach a Strap Connector and a Straight Strap to extend, or part of the buckle if they don’t need more.
    • After adjusting cut off the majority of the excess and tape the ends of the strap so they don’t stick out or poke the person wearing it.

• Step 3. Add the other part of the buckle to the other side of the strap so that it can connect.

• Step 4. Tighten the straps until it properly fits the person.
  • Don’t forget to fit test! A mask is useless if it’s not sealed up. 
  • Look for air gaps, especially around the nose and bottom of the chin. Keep adjusting until those air gaps are gone. If you can't get rid of the gaps, you may need a different mask.