My NanoHack Re-Design

thingiverse

This is a reworked 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 visit here: https://www.fie.us/my-nanohack-redesign/. To be clear, this is not their v2.0 design; it's my re-design based on their 1.0 release. For the reasoning behind my desire to create a design change, see: https://www.fie.us/2020/03/22/a-look-at-nanohack-3d-printable-respirator-mask/. This version 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 air flow in and out of the chamber by roughly 100% while providing the filter more protection from the user's direct spray. 2) I removed their branding because I don't like wearing advertisements on my face and I don't want to suggest that people should be using the original design, as was/is. 3) I altered the piping 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 no longer uses the original mesh in any part of the design, so if you load it into FreeCAD or 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 to maximize flow in and out of that cylinder. This resulted in a design where one cylinder was sufficient for many filter materials, but some filter materials have much higher pressure drop across the surface. An easy way to increase surface (rather than redesign for pleated materials) is to add a second filter. So I've 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 in case anyone wants to modify it. I did most of the design work in PLA, but I also printed 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.