Rapidly Manufacturable, Flexible-Media Respirator

A cheap respirator mask, rapidly made via vacuum-forming, for use with any filter media.

Public Chat
Similar projects worth following
While large scale manufacturing ramps up worldwide, respirators are in short supply throughout the globe. This project seeks to develop a design that can be easily manufactured in large quantity (~1000+ per week) by anyone with access to tools typically found in any well-equipped makerspace.

This respirator project is driven by the following top level requirements (with thoughts/consequences listed below):

  1. Producible in bulk by the smallest possible team:
    1. Focus on maker-level CNC machines and vacuum forming to make many parts quickly.
    2. Avoid 3D printing, which is too slow to be scalable.
    3. Avoid manual labor wherever possible, especially skilled labor.
  2. As cheap as possible:
    1. Doctors and nurses are busy, must be able to throw away masks rather than wash/reuse.
    2. I'm expecting to fund this out of my own pocket, must be affordable
  3. No off-the-shelf filter:
    1. As of the time of writing, effectively all filters (even those inadequate for filtering sub-micron virus particles) are out of stock.
    2. The mask must be flexible, to be used with whatever ad-hoc filter media is available on hand.

To satisfy these requirements, I'm pursuing a design based around a vacuum formed shell.   To form a tight fit against the face, a lasercut foam gasket is glued to the rim of the mask. 

The main 'trick' to this design is how it forms the filter: the mask has a conical section with holes on the end, which allows a matching conical shim to wedge inside, trapping a piece of fabric or other filter medium against the end of the mask.


First prototype of the mask. Still needs flanges for elastic bands.

sla - 2.50 MB - 03/25/2020 at 07:41



This ring locks the filter media into the snout of the mask.

sla - 210.04 kB - 03/25/2020 at 07:41



Laser cut from 1/4" crosslinked polyethylene foam (or equivalent), and glued to inside rim of the mask.

svg+xml - 4.70 kB - 03/25/2020 at 07:41


  • First Pass Through Development Cycle

    David Lesser03/28/2020 at 08:04 0 comments

    To make sure I'm happy with the overall geometry, I completed the design, including loops for elastic.  The fit is rather good on many adult faces (although I know I'll ultimately need different sizes).

    The next step is CNC routing an MDF mold for the vacuum former.  Since the part is 3.5" (~90 mm) tall, I needed to order some unusually-long end mills to avoid crashing the machine; I picked up a pair of extended 7/16" square-end mills and a pair of 1/4" ball-end mills (chosen largely based on what was cheap on ebay).  I'm still teaching myself 'proper' CAM in Fusion 360, but the resulting part came out pretty good:

    Next step was to our ancient vacuum former (whose manufacture was probably closer to the Spanish Flu than the current Coronavirus outbreak...), where I had fairly good results from 0.030" (0.75 mm) polystyrene. 

    I'm still fighting some annoying issues with seams.  It would appear that my most recent pass is my most successful, where I had the idea of reducing the heating time, making the plastic more viscous and less likely to pinch easily.  Another approach would be to change the angle of the nose cone section, from it's current 10 degrees (if I recall correctly) to something more aggressively chamfered.

    Last step was to the laser cutter, where my 4" (100mm) focal length lens was just barely long enough to cut the strap slots and outside profile of the mask, liberating in from the remainder of the sheet:

    Not too bad! Next step is to try to meet up with some researchers here in Tucson at the University of Arizona, who have a respirator efficiency testing rig, to determine how well it performs versus existing commercial designs.  Fingers crossed!

  • What's an effective filter medium?

    David Lesser03/25/2020 at 09:06 0 comments

    This project is based around the not-so-obvious premise that commonly available household materials are at least modestly effective at filtering particulates from the air.  A big part of what motivated me to do this project was stumbling across papers like these, which show fairly promising results using ad-hoc materials like cotton shirt fabric or tea towels.

  • Early success, refining the shape

    David Lesser03/25/2020 at 08:38 0 comments

    I'm new to modelling organic 3d shapes (I'm using Fusion 360's 'form' workflow), so I was happy to see my first 3d printed prototype masks are fairly good fits to my face.  I think the biggest difficulty of this project is designing a small number of different masks that will be both effective and comfortable for a large variety of people.

    Currently, I'm 3d printing shells roughly 0.050"/1.2mm in thickness to test the geometry, with an eye towards vacuum-forming using similar thickness of stock. 

    I've also done a first pass attempt at vacuum forming using my 3d printed prototype as a form (ultimately, I'll be CNC routing a 'proper' mold in MDF once I'm ready to commit to a design).  I don't have the right material on hand, and I don't have the best setup (as evidenced by the creases), but I've confirmed that the geometry should be moldable, as I intended.

    For the time being, I'm just drilling holes for the elastic bands in the rim.  Once I get a more certain feeling for where they should go, I'll design in some ears to keep the gasket un-disturbed.

View all 3 project logs

Enjoy this project?



izak last wrote 03/28/2020 at 21:44 point

I'd like to come and pitch in and I can pledge a donation for materials when you need it. Send me a paypal address or other means to donate. 

  Are you sure? yes | no

Dan Maloney wrote 03/27/2020 at 20:18 point

YES! 3D printing is fine for prototypes and very limited runs, but vacuum forming is where it's at for mass production. Or injection molding, of course, but the tooling costs there are prohibitive. Great thinking!

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates