Making Better Fitting Facemasks With a Quick 3D Printed Frame

Protecting ourselves from COVID-19 has been a moving target since the start of the pandemic. Whether or not people want to wear facemasks, they remain one of the best ways to prevent the spread of the coronavirus. However, loose-fitting surgical masks mostly protect others, not the person wearing the mask. If we want to protect ourselves, we’d have to wear masks like N95 respirators, but those are not easily accessible as they are reserved for medical professionals in most places.

So, is there a way to protect ourselves with normal surgical masks? My research suggests yes!

Masks without nose wires leave gaps between the mask and the face on both sides of the nose. Surgical masks often have gaps on the sides of the cheeks when tightened to reduce gaps under the chin.

Fabric face masks are good at stopping droplets from spraying everywhere when someone sneezes or coughs, but they’re not very good at filtering out small particles like the COVID-19 virus that might be floating in the air. Certified surgical masks are very good at filtering out particles around the same size as COVID-19, but as they don’t fit tightly to the face, contaminated air can enter the mask through the gaps between the mask and the face (For more information on the importance of fit, you can check out this research article and this article from the CDC).

To help people protect themselves better from COVID-19, I scoured the internet for ideas on how to better protect the person wearing a mask from COVID-19 and found this mask frame, created by shiuan.

I used the same technology that hospitals use to fit test N95 respirators (PortaCount 8038) to test this frame and many other ideas (like wearing two masks) on myself and one of my colleagues. The preliminary results suggest that this frame worn over a certified surgical mask had results comparable to an N95 respirator!

The graph above shows the results of the tests with the PortaCount. You can see that the certified surgical mask worn with a properly fitted frame had a Face Fit Factor comparable to an N95 respirator. These results are still preliminary and need further testing, however you can see that the combination of a certified surgical mask with the frame is showing promising results.

This Instructable shows you:

1. How to download the 3D model of shiuan’s frame from thingiverse.com
2. How to choose a size that will best fit your face
3. How to prepare the model for 3D printing
4. How to prepare the printed mask frame for use

Thingiverse.com is a website dedicated to share user-created 3D designs. From replacement window handles to miniature models of your favorite movie character, Thingiverse pretty much has it all. Some models are posted by professionals with a lot of experience in 3D modeling and printing, and others by hobbyists wanting to share their passion. But what they all have in common is their willingness to share what they’ve developed.

The 3D model I am using in this Instructable is titled Covid-19 Mask - Face mask close to face. You can search for the model on thingiverse.com using this title or by simply clicking here.

Once you are on the model’s page, click Download All Files at the top-right of the webpage.

Once the folder has downloaded, open the folder and go to the folder called files. There you will find four 3D models of the frame in different sizes.

Note: Depending on the software you have on your computer, you may or may not be able to open these files. STL files are 3D models that need special software to read them, so if you do not have this software, the files will not open. Don’t worry, wherever you go to get these printed, they will have the software to open them.

We all have different face shapes and sizes. It is important that you choose a frame size that will most likely create a good seal between the mask frame and your face.

shiaun provides mask frame models in four sizes: 107mm, 112mm, 118mm, and 125mm. These model sizes correspond to the distance from the bridge of your nose to your chin. You will need to measure that distance (see the image above - the bidirectional arrow is the distance you need to measure).

Once you have the measurement, choose the size model that is closest to your measurement: 107mm, 112mm, 118mm, or 125mm.

Tip: If you have a narrow face, you can go to the closest size to your measurement, but if you have a fuller face, going one size up from the closest size to your measurement may be helpful. For example, I have a fuller face, so although the distance from my nose to my chin is 102mm, the frame that measures 112mm is a better fit for me.

*A part of the image above was derived from a photo released to the public domain by George Hodan.

Once you have selected the size of mask frame that you want to print, it’s time to 3D print it! If you don’t have a 3D printer at home, check with your local library. Many libraries have 3D printers that the public can use (you can’t usually borrow them, but you can use them onsite). Many community makerspaces also have 3D printers that the public can use. You can also find them at FabLabs.

Tip: Before you go to any library, makerspace or FabLab to 3D print a file, give them a call to ask about their service. They’re usually very helpful and can show you how to use the 3D printers. Don’t worry, they will stay with you and help you print it if you’ve never used a 3D printer before. I recommend printing at least 2 frames in case one breaks during the molding process or during use.

Note: If you will print your mask frame at a library, makerspace or FabLab you will need to be able to access the STL file for the frame that you want to print. In most cases, you can bring the file on a USB key or download it onsite from an email account or cloud storage.

These are the settings that I used to print the frames. If you’ve never used 3D printers before, show these settings to the people helping you. Depending on the type of printer being used, the print time per frame will vary from 20 and 40 minutes.

• Material: PLA
• Print Quality: Standard (0.2mm layer height for 0.4mm nozzle)
• Shell thickness: 0.8mm
• Nozzle temperature: 205°C
• Print bed temperature: 50°C
• Infill: 15%
• Build plate adhesion: None
• Build support: None

CAUTION: This step involves using boiling water to warm up the mask frame. Adult supervision is advised. Read all of the instructions for this step before starting!

The mask frame is printed flat, so once printed, you will have to mold it to the shape of your face so that it creates a good seal between the mask and your face. The plastic filament (PLA or polylactic acid) used to print becomes malleable at about 60°C (140°F), so you will need to warm it up. The easiest way to do this is to boil some water and let the frame warm up in the hot water for about 5 to 10 seconds.

I recommend using a kettle to boil the water and pouring the hot water into a flat-bottomed heat-resistant container. This should ensure that the water is hot enough to warm up the plastic frame, but cool enough to reduce the risk of burns to your skin.

WARNING: DO NOT PLACE THE HOT FRAME DIRECTLY AGAINST YOUR SKIN! The frame becomes hot enough that it could burn the sensitive skin on your face. Put on a disposable surgical mask and mold the mask frame over the mask. Be sure to also use tongs when submerging and removing the mask frame from the hot water to avoid burns.

I recommend you watch this video created by shiuan. She shows you how she molds the frame to her face.

Note: In the video, shiuan uses a heat gun to warm up the mask. However, I do not recommend this approach as it is difficult to control the temperature the frame is heated to, which could result in burns to your face or the overheating of the plastic.

Tips for molding the mask frame to your face:

• Begin by molding the nose section and then push the rest of the mask frame against your face. You can reheat the entire mask reframe or sections of it by resubmerging it in the hot water for 5 to 10 seconds at a time.
• Molding your mask frame to your face can be a bit tricky, so it may take you multiple attempts before getting it right.
  • WARNING: To avoid burning yourself: If the mask that you are wearing become very moist after multiple attempts, change it for a dry one because heat conducts through water quickly.
• You may find it easier to mold the mask frame to your face if the elastics are already attached (see Step 7). This way it can hold the mask frame to your face and you can use both hands to mold the frame to your face.

If you haven’t already done so in Step 6, you can now attach elastic straps to the frame.

The straps can either go all the way around your head or around your ears. The frame should be relatively tight to create a good seal. I recommend wearing the frame with the elastics going around your head so that your ears don’t become painful after lengthy use.

Make sure the knot is facing outwards when you tie the elastics to the frame (see the images above). This will improve comfort and will prevent creating gap between the frame and the mask. You can also sew the elastics on for a more streamlined look.

Make sure that there are no gaps between the frame and the mask!

If there are gaps at the nose, cheeks or chin the frame may not be molded well or it may be too large. If there are gaps, try remolding the mask frame to your face or try a smaller size.

It’s important to wash your mask frame regularly to keep it clean. I recommend using dish soap or hand soap to wash the frame and elastics. Make sure to wash them well or let them soak for a short time in lukewarm soapy water (don’t soak it in hot water or it might lose its shape!). Do not put the frame in the dishwasher as it will break and/or lose its shape. Also, be sure to replace the surgical mask after each use. These masks are only meant for single use, especially when using something like a mask frame which can compromise the integrity of the material when you put the frame on, move and talk while wearing it, and when you remove it.

This research was conducted as part of a Mitacs internship at Concordia University in Montreal, Canada in collaboration with IRSST (Institut de recherche Robert-Sauvé en santé et en sécurité du travail) under the supervision of Dr. Ann-Louise Davidson (Associate professor, Concordia University), Dr Ali Bahloul (Researcher, IRSST), Barbara Layne (Professor, Concordia University), and in consultation with Dr. Clothilde Brochot (Research associate, Concordia University).

If you have comments or questions, don’t hesitate to contact me: nathalie.duponsel@concordia.ca

For more information on the DIY projects my team and I are doing, check out our website at www.educationmakers.ca

The mask frame created by shiuan is licensed under the Creative Commons - Attribution - Non-Commercial - No Derivatives license. All rights are reserved for the data shared in this Instructable.