I'm a doctor in Connecticut making 3D printed masks. I heavily modified the one I found that had the largest filter box, as this allows more material to fit inside than any other I have found while still being breathable.

Youtube video: https://youtu.be/ySOCNycv-aA

I recommend trying the "Mask narrow (male) 2 loop upgrade" and the "Filter Narrow (male)" to go on it, downloadable at https://www.thingiverse.com/thing:4237783

I am going to make another video very soon suggesting spraying the mask down with sealant to make it easier to wipe to to solve the porosity problem if this is to be used longer than a week, how to sand the edges and options for rubber material that can be added for comfort or wear over surgical mask for comfort and to boost this from estimated 90% to n95%, and what kinds of elastics work best if you don't have access to IV tourniquets that I'm using for straps.

 

Newspaper:

https://www.theday.com/local-news/20200327/with-3d-printer-new-london-native-develops-alternative-to-n95-face-mask

https://www.courant.com/coronavirus/hc-news-coronavirus-3d-printed-face-mask-20200331-dqn67ouibfelrglwri77pvvmcm-story.html

 

Television:

https://www.wfsb.com/news/local-doctor-using-d-printer-to-print-masks-for-medical/article_de3a805a-72c6-11ea-887e-db303591745e.html

https://www.fox61.com/mobile/article/news/local/a-uconn-doctor-channels-his-medical-background-and-macgyver-skills/520-0c5248f7-f207-4234-80bd-a55b11394117