3M respirator compatible cartridge filter housing

Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4219678.

#DISCLAIMER WARNING! USE AT YOUR OWN RISK. THIS IS NOT A SUBSTITUTE FOR A PROPER COMMERCIAL CARTRIDGE FILTER. THE DESIGN IS ONLY A FILTER HOUSING. YOU MUST SUPPLY YOUR OWN FILTER. I AM NOT RESPONSIBLE FOR YOUR USE OR MISUSE OF THIS DESIGN. CONSULT A MEDICAL AND/OR OCCUPATIONAL HEALTH/SAFETY PROFESSIONAL FOR GUIDANCE.

###Background I remixed the design from Webbi001 with the goal of reducing print time, supports required, and material usage. It is a work in progress as I iterate the design, but am posting here now because it is functional. Designs might change at any time! If you download an updated part, download ALL parts in case there is an version incompatibility. I am making no attempt to keep parts backward/forward compatible.

SolidWorks files are included for ease of remixing.

###Description This housing fits the standard bayonet fitting on 3M masks and requires you to use your own filter material. See post-printing section for assembly instructions.

###File Explanations

• housing.STL - main component, which attaches to the bayonet connector on the mask.
• cap.STL - cap for the housing, which holds the filter in place
• housing_support.STL - helper mesh to specifiy support placement for your slicer (optional - see print settings)
• cap_cover.STL - cover that fits over cap to keep it clean when not in use (optional)
• bayonet_cap.STL - cover for the bayonet fitting that protects and seals the mask when no filter is attached (optional)
• *.SLDPRT and *.SLDASM files - Solidworks versions of the parts
• *.ZIP files - archives of past versions

###What filter should I use? This was designed to use whatever filter material is available to you. I am using a pleated HEPA filter designed for use in a household air purifier unit, flattening and cutting the material to fit in these housings. For reference, that material is ~0.4 mm thick.

###WIP/TODO

• Filter covers/plugs for protection when not attached to mask/in use
• Cover for mask fitting for protection when no filter attached/allow the use of a single filter
• Modifier mesh for supports
• Template for filter cutting
• Try PETG
• Publish estimated filament usage per part/configuration

###Updates 2020-03-13 - Make slots in cap larger, adjust chamfer on bayonet fitting to make filter easier to remove. 2020-03-14 - Sides of housing now extend higher than the rest of the part so inserting a filter is easier when it is cut to the right size. This changes makes it much more difficult to print in the "upside down" orientation, but i think the extra material usage is worth ensuring the filter is installed correctly. I also created a modifier mesh to print as support that lowers the support required compared to letting the slicer create them. Old files now provided in ZIP archive. 2020-03-14 - Confirmed functional print using PETG. 2020-03-15 - Adjust bayonet fitting to give a tighter seal when installed 2020-03-16 - Add mask bayonet fitting cover to allow use of single filters or otherwise protect the mask. Add TPU filter cover to protect filters when not in use.