Several useful STL's available to download here.

Hong Kong was one of the first regions to get hit by the COVID-19 outbreak and also one of the first to effectively reduce the rate of contagion. 3dpbm reported early on about local firms 3D printing face shields for healthcare workers. Now a number of other maker projects (and videos) have emerged that can provide some valuable lessons for printing filtration adapters to use on standard 3M masks to protect against coronavirus. Disposable surgical masks had been in shortage since late January, so Hong Kong makers come up with various 3D printable designs to adapt a 3M half mask to extend the number of times it can be reused.

Re-usability and improved safety

The first project covered one of the two filter ports on a dual filter half-face piece. This led to a number of different evolutions. One was based on the fact that most of the surface area on a disposable surgical mask area is wasted during use. In this design, only a small part of the surgical mask is used as a filter that is placed inside a 3D printed adapter and screwed onto the durable 3M mask. Other types of filter material can also be used, improving both the re-usability and safety performance of a standard surgical mask.

Several makers further developed this idea. One of them is Carlos Tchiang. Carlos is a teacher, a YouTuber and a maker. He uploaded his first project, the design and printing process for a “mask ring” adapter for a 3M HF52 maks model in early February. He offered to give away the adapters for free and kept improving the design to also include covers for aerosol droplet protection for the 3M 3200 mask. In early March, he presented new designs for the 3M 6200 and the 3M 7502 models. He organized volunteers to print the designs and give them away to those who needed. You can also find and download the 3D printable adapters from Thingiverse.

10 free designs for mask filter adapters

Another maker, Neo Chan, redesigned an adapter to improve protection against aerosol droplets. He produced a detailed tutorial to show how-to print this adapter and gathered various makers’ designs into a dedicated webpage. Chan is the director of Mirai Productions, a professional video production team specialized in high-end 3D animation as well as CGI. He dedicated a page on the Mirai corporate website to collecting mask adapter designs designed by him and by a number of other makers. Ten STLs are available to download for free to use in the emergency, and commercial use is strictly prohibited.

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