3D PRINTING OF A LOWELL MAKES MASK IN PLA

Abstract

Relevance: The new pandemic crisis caused by the Covid19 virus has led to a global shortage of personal protective equipment including FFP2 masks necessary for the exercise of professionals in direct contact with positive patients. Objective: 3D print a PLA mask similar to the FFP2 mask with the addition of an ULPA filter Methods. The designed mask is based on the general morphology of the FFP2 standard. This is how we downloaded the prototype of the «LOWELL MAKES». We have adapted this prototype to our craniofacial dimensions on the «Meshmixer» software, to finally export the prototype in STL format to print it by fused deposition modeling (FDM) via the 3D printer «XYZ Junior 1.0» equipped with a PLA (polylactic acid) filament. Results. The total duration of the printing of the full mask (the cover, the body of the mask, and the retentive filter grid) was around 4h30 min. Regarding the choice of the filter, we opted for two solutions, the first to cut an FFP2 mask and to use the parts obtained as being filters (doubled), the second being a commercial ULPA or HEPA filter. A ULPA (Ultra Low Penetration Air) filter can theoretically filter dust, pollen, and bacteria from the air with an efficiency of 99.999 % thanks to a size of 0.1 microns. Remember that the average size of the Covid-10 virus is around 0.1 µm and that the porosity of the FFP2 mask allows particles to be filtered with a diameter of around 0.6 µm at 94 %. In order to maximize the filtering effect while wearing this mask, we opted for the interposition of a ULPA filter covered by an FFP2 filter. We tested the tightness of this mask by checking for side leaks by maintaining a stabilized sheet on the outer cover by suction during inhalation. We have also added to the edges of the mask in contact with the face a peripheral silicone seal, polymerized on the face, to avoid any marks or scars after removal of this mask while increasing the comfort of the practitioner. The protocol that we chose by superimposing two filters (the first having a porosity of 0.6µm and the second of 0.1µm) allowed us to potentiate the filtration. This allowed the filter to be used for 40 hours. The total cost price of the mask is around 9 €. Conclusions. The «open source» community makes it possible to popularize 3D printing while making it easier for any 3D printer owner to appropriate their protective equipment at a reduced price, however, intellectual property remains a concern, in particular for medical parts that cannot be procured promptly during a pandemic crisis similar to that caused by the Covid-19 virus.