As the world adjusts to a supply shortage of N95 masks and personal protective equipment (PPE) from COVID-19, 3D printers around the world are working on two solutions: dysfunctional N95 masks that do not form a tight seal, and face shields that can serve as a protective barrier.
3D printers work by pushing filament through a heated extruder, laying layers of filament in lines across a print bed. These layers can contain air gaps during the print process if the filament does not bond perfectly with the layer underneath it. Even if the print works correctly, the resulting mask may not form a seal against the wearer’s face and could limit the surface area for the wearer to exhale carbon dioxide. While the mask may be worn for a short time, extended use and buildup of CO2 poses a risk for the wearer to pass out as usage continues. Cloth masks are able to adapt more readily to the wearer’s face, and have the support of US retailers such as Joann Fabrics, who supplies cloth and patterns.
Regarding 3D printed masks, prominent electronics expert Naomi Wu laments, "testing [the mask] without a CO2 sensor is also a good way to kill yourself." Wu continues to explain current masks' exhale valve and the value of long-term wear coupled with a sensor to ensure breathability. A separate CNN article on the faces of health workers shows bruises from the tightness of wearing tight N95 masks during long work hours. Wu also encourages enthusiasts who wear prototype 3D printed masks that tighten to have a friend available to remove the mask and learn the recovery position should they pass out and fall. Wu’s commentary applies to masks and may not apply to other 3D printed geometries.
Technology firm HP has dedicated resources from their 3D printers to assist with the worldwide supply chain. HP's effort includes alternative items, such as door openers, clasps, and mask adjusters. A specific callout is made for FFP3 masks, explaining that HP is validating several grades.
InfoQ spoke with Kurt Henningsen from 3D Systems, a US firm that creates parts and machines. Within their COVID-19 response, 3D Systems is engaging their own customer base who own machines to obtain additional production capacity. While the company is producing other parts for service bureaus and OEM customers, masks are not currently a target for 3D printing. The first question listed in 3D Systems’ frequently asked questions is, "Is it possible to 3D Print a N95 Face Mask or Respirator? Based on clinical research and technical feasibility it does not make sense to mass produce surgical masks or respirators using 3D printers." Another key difference of professional printers is the type of material, such as ones that meet medical-grade specifications and biocompatibility.
"We're not in the business of designing parts, nor making suggestions about said designs. We are however working with our customers and vendors alike to support the medical community during this time of need. Most of the geometries we are seeing are components for medical equipment. Anything from hospital bed parts, to components for diagnostic equipment. We are also seeing requests for parts that may be used to secure face-shielding and other kinds of PPE. I don’t expect to see 3D printing used for N95 masks as most of the processes yield structural parts, made of plastics or metals. Our systems are not used to generate filtration materials as would be used for an N95 mask. There are plenty of other needs right now, where our technologies can better be utilized."
Kurt Henningsen, 3D Systems
For 3D printing enthusiasts eager to help, 3D Systems, HP and Wu cite face shields as a helpful alternative. Columbia Surgery agrees on the value of printing limited-supply face shields as an effective measure. In a March 23 letter, Craig R. Sith, the chair of the department of surgery writes, "CU engineers have been working on 3D printing solutions to the scarcity of face shields." Columbia's letter does not mention 3D printed masks.
3D printing firm Prusa has published plans for face shields that can be created on standard printers such as the Prusa i3 or Mini. Prusa is currently producing shields at their factory after having tuned their factory to produce hand sanitizer.
Other groups, such as Isinnova, have created viable utilities in coordination with existing industry suppliers. In particular, Issinova has worked with snorkel provider Decathlon, to open files that retrofit their existing snorkel for use with ventilators. Issinova's products are currently in use at Italian hospitals.
Owners of consumer-grade 3D printers can evaluate the vetted plans from known industry leaders like Issinnova, Prusa, and 3D Systems as a way to help their local organizations.