My NanoHack Re-Design

thingiverse

This is a reverse engineered and redesigned version of the NanoHack Mask found here: https://copper3d.com/hackthepandemic/ For build tutorials and other information regarding my mask re-designs, you can look here: https://www.fie.us/my-nanohack-redesign/ To be absolutely clear, this is not their v2.0 design. This is my re-design based on their 1.0 release. For reasoning behind my desire to do a design change, see: https://www.fie.us/2020/03/22/a-look-at-nanohack-3d-printable-respirator-mask/ This is fairly similar to the original with some minor changes: 1) the user-side grille into the filter chamber has been reworked with a louvered approach. This increases the air flow in and out of the chamber by roughly 100% while also providing the filter more protection from the user's direct spray. Since the fins are thinner than the original design, I like to cover the filter chamber with some painters tape on both sides, while I thermo-form the mask. 2) I got rid of their silly branding because... I don't like wearing advertisments on my face and I don't want to suggest to people that they should be using the original design, as was/is. 3) I changed the piping a bit to better support the kinds of folds I make when fitting the mask. 4) I straightened the strap slots. Straight slots work better with thicker straps like webbing and ribbon. 5) My filter cylinder's threads print a lot better and the original filter cap fits a lot better with them. I currently use my redesigned cap: https://www.thingiverse.com/thing:4237543 6) It's no longer using the original mesh in any part of the design, so if you load it into FreeCAD or even convert it to some other CAD program, it's a lot nicer to work with than a heavy mesh. I have also added a version with two filter cylinders. The majority of the design work was done on a version with a single filter cylinder in order to maximize flow in and out of that cylinder. This resulted in a design where one cylinder was sufficient for many filter materials. However, some filter materials have much higher pressure drop across the surface. And an easy way to increase surface (rather than redesign for pleated materials) is to add a second filter. So I have added such a modified version, for convenience. The thread direction is the same, so you can just print a second cap. No need to mirror the cap. I've included the FreeCAD source files along with the STL just incase anyone wants to modify it. I did most of the design work in PLA. However, I did print out a PET-G version and it thermo-forms well with a heat gun. I am not a scientist, engineer or medical professional. I don't know if this design is functional or dangerous. But I'm providing it anyway in an emergency situation. This mask shell was built as my Mark II design but it also serves as the main piece of my Mark IV and Mark V mask designs. For the Mark II, I print it out and thermo-form it. I use adhesive backed craft foam to make a simple gasket. I use some heavy ribbon and buckle parts from elsewhere on thingiverse to craft a strap that I can tighten quite a bit. I use my re-designed cap: https://www.thingiverse.com/thing:4237543 and my cloth filter holder: https://www.thingiverse.com/thing:4237519 . This provides a good enough seal to use a 100% cotton or cotton blend filter as per this research paper: https://www.researchgate.net/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic For the Mark IV and Mark V I skip the craft foam and use my TPU face gaskets here: https://www.thingiverse.com/thing:4251145 With that gasket, two medium strength rubber bands and my modifications to the HP strap adjustor here: https://www.thingiverse.com/thing:4251082 suffice for a far better seal than the Mark II. The Mark III was defunct on arrival. We shall not speak of it.