Q1. What is the motivation for creating 3D printed PPE?
Provide a stockpile of alternatives to certified PPE and protection that exceeds the CDC guidance of using a “homemade mask (e.g. bandana, scarf) for care of patients with COVID-19 as a last resort”, which have been reviewed by clinician for emergency use.

Q2. What is the purpose of PPE?
According to the Occupational Safety and Health Administration (OSHA) PPE is “specialized clothing or equipment, worn by an employee for protection against infectious materials.” Masks protect the mouth and nose, goggles the eyes, and face shields the face, mouth, nose, and eyes. Respirators protect the respiratory tract. When used properly, PPE forms a “barrier between infectious materials such as viral and bacterial contaminants and your skin, mouth, nose, or eyes (mucous membranes).” (ref)

Q3. What process did USC use to validate the designs?
The designs were iterated based on feedback and testing performed in conjunction with Keck’s Infection Prevention and Respiratory Support staff. After finishing modifications were added after 3D printing, masks had to pass a N95 fit test.

Q4. Why did USC create its own design?
We adapted designs to produce multiple sizes to fit more users. Face shields were modified to close the gap in other designs at the top of the headband to provide a complete barrier. The designs were also modified to minimize use of material while balancing production speed. Face shields need to sit far enough away from the face to accommodate glasses. Cloth masks need to be more form fitting so we had professionals redraft the pattern.

Q5. What is involved in producing a finished mask?
The masks must seal against the face to be effective. That seal should also be comfortable. The 3D printed masks are finished by adding weatherstripping and using hot glue to form an air-tight seal. The filter is a piece of HEPA filter. That filter can be removed and replaced so that the mask is reusable.

Q6. How are the assembled PPE being sterilized?
At the hospital, we are using hydrogen peroxide wipes followed by UV cleaning. Both are done by following the manufacturer’s direction for use.

Q7. What is the size of a coronavirus?
Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). An individual virus particle is about 60-140 nm in diameter (ref).

Q8. Is 3D printed PPE approved for use?
According to the Food and Drug Administration, if the PPE is intended for use as a medical device, it must follow FDA regulations and meet certain voluntary protection standards. Some PPE are reviewed by the FDA before being sold in the US. (ref) N95 respirators are regulatedby the FDA, Centers for Disease Control and Prevention (CDC) National Institute for Occupational Safety and Health (NIOSH), and Occupational Safety and Health Administration (OSHA). (ref) 3D printed PPE is not approved by any regulatory body and therefore used only as a last resort when other certified forms of PPE are no longer available.


Published on April 10th, 2020

Last updated on April 21st, 2020