Used Facemasks Turned Into Rapid Antigen Tests With Injection Molding

Here’s a little eye-opener for you: next time you’re taking a walk, cast your eyes to the ground for a bit and see how far you can go without spotting a carelessly discarded face mask. In our experience, it’s no more than a block or two, especially if you live near a school. Masks and other disposal artifacts of the COVID-19 pandemic have turned into a menace, and uncounted billions of the things will be clogging up landfills, waterways, and byways for decades to come.

Unless they can be recycled into something useful, of course, like the plastic cases used for rapid antigen tests. This comes to us by way of [Ric Real] from the Design and Manufacturing Futures lab at the University of Bristol in the UK. If any of this sounds or looks familiar, refer back to October when the same team presented a method for turning old masks into 3D printer filament. The current work is an extension of that, but feeds the polypropylene pellets recovered from the old masks into a desktop injection molding machine.

The injection molding machine is fitted with 3D-printed molds for the shells of lateral flow devices (LFD) used for COVID-19 rapid antigen testing. The mold tooling was designed in Fusion 360 and printed on an Elegoo Mars MSLA printer using a high-strength, temperature-resistant resin. The molds stood up to the manual injection molding process pretty well, making good-quality parts in the familiar blue and white colors of the starting material. It’s obviously a proof of concept, but it’s good to see someone putting some thought into what we can do with the megatonnes of plastic waste generated by the pandemic response.

15 thoughts on “Used Facemasks Turned Into Rapid Antigen Tests With Injection Molding

  1. When the filament extruders will be as common as 3D printers, maybe the recycling rate of plastic will ramp up. This is a great project that shows that we could make new things with garbage with a better success rate than specialized factories (As far as I am concerned, masks aren’t recyclable).

      1. Steam in the IMM barrel is always fun for all involved!

        There is a reason nobody sane even tries to recycle dirty plastic.

        The best way to recycle mixed or dirty plastic is to burn it for fuel (mixed with gas to get the burn temp high enough).

        It costs more energy to recycle than the difference in energy content between the hydrocarbons used to make the plastic and the plastic itself.

        Put simply: It’s greener to burn the plastic and make new, than to clean, sort and recycle it. Narrow exceptions for streams of some single chemistry plastics (e.g. two liter soda bottles).

        1. @HaHa, damn right. Plastic “recycling” is usually a greenwashing scam, with a few exceptions as you mention. It’s not as sexy or profitable, but the best way to “make a difference” for the environment is to simply Buy Less Stuff.

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