DIY Particle Filter Mask Assembly System

https://www.instructables.com/id/DIY-Particle-Filter-Mask-Assembly-System/

4/5/2020: Instructable to be updated soon

Summary:

Due to the COVID-19 crisis, many healthcare workers are facing a shortage of personal protective equipment (PPE). The DIY community has responded by developing many helpful solutions ranging from hand-sewn cloth surgical masks to 3D-printable face shields.

I’ve developed a simple, repeatable system for making disposable particle filter masks. These masks are made from 2+ layers of material taken from commonly available HVAC filters. The specific material I chose comes from 3M MPR 2200 (MERV 13) pleated electrostatic filters. One filter yields several feet of material from which to make the masks. The masks contain a thin metal wire embedded in the base that can be bent to help them conform to difference face shapes.

The Mask Assembly System involves two 3D printed tools: an assembly jig and a flat pattern cutting template. These can be made on most hobby-grade 3D printers with sufficient build volume. I used a Prusa i3 MK3S. The STL files will be made available for anyone interested in making masks with this system. I printed the Jig with PLA at 10% infill and 4 perimeters. I printed the Flat Pattern with PLA at 10% infill and 2 perimeters. The Flat Pattern may need to be split into two halves for printing on smaller machines, then rejoined with CA adhesive. It can be printed as-is on the Prusa i3 MK3S.

Simply use the Flat Pattern to cut pieces of suitable filter material. Wrap one layer around the Jig and use LOW TEMP hot glue to seal all the seams. Apply two loops of .025″ or similar size steel wire around the first layer using the integrated groove and tension it using the wire posts. Glue all around the wire with hot glue and trim off excess. Apply another layer of filter material for a minimum of 2 layers. Then, trim the excess filter material below the wire loops. Finally, glue on straps using the guide slots at the locations you prefer.

Disclaimer:

I make no claims about the filtration performance nor the efficacy of these masks against infection from SAR-CoV2 or any disease. 3M and other manufacturers do not endorse this use of their HVAC filter products.

This project is intended to create emergency PPE like the cloth masks or PET bottle face shields made by others in the community – it is not certified or regulated in any way. Use at your own risk.