They should only be used as a last resort. That is what we would like to say to health professionals that might not be fully aware of what the technology is capable off. With this post we would like to outline the risks of using 3D printed respirator masks, both for the general public, the 3D printing community, and the medical community that might not fully understand what is being pushed by a panicked, but anxious to help, 3D printing community.
A couple of the many 3D printed masks that we have printed and tested at Slant 3D (Slant 3D)
Contamination
If you are using crowd-sourced masks. That is, masks that are made by local individuals with garage 3D Printers. Then you essentially have hundreds of individuals handling your masks in their homes. Those people may not be tested for Covid-19. so they could be infecting the masks that they are supplying. This means that they could potentially be directly infecting you staff if you utilize these masks. Amateur manufacturing means amateur facilities and handling.
Sanitation
Due to the layer lines in DIY 3D printed parts these masks can't be reliably sanitized. Therefore even though they will be relatively expensive to manufacture (2-5 dollars each). They would have to be disposable, if they can reliably be used in the first place.
Don't Fit
The vast majority of masks printed are being printed from the baseline design in rigid materials. They do not compensate for male or female. This means that they do not fit most faces. In fact most of these masks fit little better than the oxygen mask in an airplane. The only option to make them fit is to heat them up in boiling water or in a microwave and then press the softened plastic onto the face of the individual using the mask. The problem is that these masks are not reusable. They cannot be sterilized. So a worker has to potentially scald their face each time they put on a disposable mask. And the seal is still not viable. Because the mask would lose its seal as soon as the healthcare worker moves their jaw. The poor fit essentially makes the mask useless except as a splatter guard.
Don't Seal
Again, due to the rigid materials, and DIY designs. Most of these masks do not seal around the face. Admittedly many paper masks don't perfectly seal either. But they also do not force air to move through the few crevasses that exist. And again the only way to get a reasonable fit (other than a plastic part in front of your mouth) is to heat the plastic and form it to your face. Due to this problem healthcare professionals would almost be as protected if they simply tied a dishtowel in front of their face. Maybe better protected. (Read the full study about these materials effectiveness)
Limited Supply
At Slant 3D we have tested every publicly available 3D Printed face mask. The one that prints the fastest is complete in 2 hours. That means that a single printer could produce 12 a day. There are only about 1.5-2 million 3D printers worldwide. That means that only 24 million masks could be manufactured per day if every printer was working on it 24/7. China has the capability to manufacture 116 million N95 masks per day right now. And then it takes 2-5 days to ship those out. The US is expected to only need 3.5 billion masks to address coronavirus for a year. That is basically 1 month of production. 3D printing is not necessary and is not viable to address the supply shortages. Supply shortages that do not yet exist. They are only projected based on worst case scenarios. Please everyone calm down and allow the supply chains a few days to catch up.
In Summary
It is truly great to see the 3D Printing community stepping up to help with local manufacturing. But respirators are not the item to manufacture. There is not yet a need, and when there is, 3D printing is not a viable solution. Please believe us we do mass manufacturing with 3D Printing for a living. Time would be much better spent on face shields, potentially ventilator parts, and general everyday aides. To the medical community. If you have a drastic need for facemasks please use your knowledge to make a call. At this point there is no magical antibacterial 3D printing material that makes 3D printed masks much better than a torn tshirt tied across your mouth.Use your own judgement. It is possible that 3D Printed masks can help to limit the spread from covid-positive patients. But again, tshirt. Please feel free to reach out to us here at Slant 3D if you have any questions or need to have some other part manufactured. We are standing by and reserving capacity when viable solutions become apparent.