Today, ExOne and the University of Pittsburgh, along with other important collaborators, are announcing a breakthrough development in the effort to assist frontline healthcare workers, including my own daughter, an ICU nurse in New York City, with personal protection equipment in the fight against COVID-19: a reusable 3D printed metal filter for respirators and other equipment.

Now in testing, this new filter — currently being 3D printed in copper and stainless steel — will offer reusable, sterilizable personal protection equipment for long term use. We can envision medical personnel, and even everyday individuals, simply owning their own reusable masks.

What's more, this sustainable, reusable solution can meet current safety needs while simultaneously addressing the growing challenge that disposable PPE is causing for the environment, with an increasing number of news stories about tons of medical waste now polluting our environment and challenging medical facilities.

From the beginning of the COVID-19 crisis, the ExOne team knew that we might have a special solution to offer in this crisis with our porous 3D printed metal filters. That's because we have customers who've been using our binder jet 3D printers to manufacture metal filters with very specific levels of porosity for years, usually for industrial use. 

While our R&D teams have largely been focused on 3D printing high-density metal parts without porosity, printing porous metal objects is something we've done since we first began binder jetting metal in the mid-1990s. It's how we got our start.

Binder jet 3D printing is uniquely suited to print porous metal that can filter out contaminants while allowing the level of airflow required.

Our technology uses an industrial printhead to selectively deposit a liquid binder onto a thin layer of finely powdered material, layer by layer, until a final object is formed. After 3D printing powdered metals, the object is then sintered in a furnace to dial in a specific level of porosity. While binder jetted metal is typically sintered to full or high density, some applications require a specific level of porosity, such as filters.

Our team is grateful for the engineering support of Dr. Markus Chmelius, Associate Professor of Mechanical Engineering and Materials Science and the University of Pittsburgh's Swanson School of Engineering, which owns an ExOne Innovent 3D printer, for his assistance optimizing and analyzing the microstructure and porosity of the filters. Additionally, Ansys, the global leader in engineering simulation, also based near Pittsburgh, is providing additional computer simulation to optimize performance of the filters.

ExOne is now partnering with several makers of plastic respirator masks, such as Open Health Solutions, an affiliate of digital dental provider Core3DCentres, on a completely sterilizable and reusable solution. Customers can scan their face with a free smart phone app, Bellus3D FaceApp, have a custom-designed face mask 3D printed in a biocompatible and autoclavable surgical resin. The mask will feature a reusable metal filter 3D printed by ExOne, which fits into a cartridge on the front of the mask and can also be sterilized and reused. 

The Open Health mask design has been submitted to the NIH for approval, and we are moving as quickly as possible with our collaboration partners to bring these solutions to market.

ExOne thanks all of the engineers and collaboration partners who've been working urgently behind the scenes to make this concept a reality, and if you're interested in a metal filter for a custom 3D printed mask, or your mask design, you can reach out to us for additional information at

Stay safe.

John F. Hartner

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