3M reusable respirators are widely used during the COVID-19 epidemic. However P100 cartridges are in short supply and are not available in some places like my country. I have designed these cartridges which use commercially available HEPA filters used in air purifies. Due to the close design the filter is not exposed and the cartridges can be easily cleaned with alcohol wipes on the outside to prevent contamination.

The left and right sides are different to align the final fit of the cartridge on the mask.

Print the lower portion with support, the upper portion should be printed face down without any support. You can use PLA or ABS.

The HEPA filter should be cut according to size and put inside the lower part. I recommend sealing the edges of the filter wit hot glue to prevent air leakage.

Once you are satisfied with the filter placement, click on the top part. I recommend gluing together the two parts using superglue