ExOne and Pittsburgh University produce additively manufactured metal filters for reusable respirators

April 28, 2020

ExOne has additively manufactured filters in copper, as well as stainless steel, to test different porosities, airflows and filtration capabilities (Courtesy The ExOne Company)

The ExOne Company, North Huntingdon, Pennsylvania, USA, has collaborated with the University of Pittsburgh, Pennsylvania, USA, to develop reusable porous metal additively manufactured filters that fit into a specially designed plastic respirator cartridge for sustainable, long-term protection against contaminants, such as coronavirus (COVID-19).

By utilising its Binder Jetting technology, ExOne states that it has additively manufactured respirator filters in two metals, copper and 316L stainless steel, and a range of porosity levels for use inside a unique cartridge designed by the Mechanical Engineering & Materials Science department in the Pitt Swanson School of Engineering, part of the University of Pittsburgh. Initial testing for airflow and filtration efficiency is believed to be currently underway, and the filters are being optimised with the goal of adhering to an N95 respirator standard.

“Our team has been working urgently to expedite this promising and reusable solution for medical personnel on the frontlines of fighting the COVID-19 pandemic,” stated John Hartner, ExOne CEO. “Our customers routinely print porous metal filters for a variety of purposes, and we are confident that we’ll have a solution soon that can enable medical personnel to sterilise metal filters for repeated reuse, eliminating waste. Once approved, we can print these filters in a variety of sizes for respirators, ventilators, anesthesia masks or other equipment.”

“The advantage of binder jet 3D printing over other Additive Manufacturing methods for this filter application is the ability to utilise the porosity of the printed part and then fine tune it during the high temperature densification or sintering process to achieve optimum filtering and airflow performance,” explained Markus Chmielus, Associate Professor of Mechanical Engineering and Materials Science at the Swanson School.

ExOne additively manufactured a reusable, sterilisable copper filter to fit inside a cartridge designed and additively manufactured by Pittsburgh University (Courtesy The ExOne Company)

ExOne’s Binder Jetting technology uses an industrial printhead to selectively deposit a liquid binder onto a thin layer of powdered material, layer by layer, until a final object is formed. After additively manufacturing 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 density, some applications require a specific level of porosity, such as filters.

To test filters in different metals and porosities, Dr Chmielus’ research group is using CT scanners to analyse the microstructure and porosity of the filters. Ansys, a global leader in engineering simulation, also based near Pittsburgh, is providing additional computer simulation support to analyse and optimise the performance of the filters.

ExOne explains that while copper and stainless steel filters are currently being tested, copper has been recognised for its antibacterial properties for some time. The first recorded instance of using copper to tackle germs was in the Edwin Smith Papyrus, said to be the oldest known medical document in history, according to the Smithsonian. The company goes on to say that many studies have also proven copper’s disinfectant powers. One landmark 2015 study, funded by the Department of Defense, revealed that copper alloys contributed to a 58% reduction in infections and COVID-19 research also suggests the virus dies faster on copper than on other surfaces.



In the latest issue of Metal AM magazine

Download PDF

Extensive AM industry news coverage, as well as the following exclusive deep-dive articles:

  • Kennametal: The story of the successful commercialisation of AM hardmetal and steel solutions
  • General Atomics Aeronautical on metal Additive Manufacturing’s place at the centre of the digital manufacturing revolution
  • Adrian Keppler on Additive Manufacturing: An insider’s assessment from the outside
  • Metal AM’s journey to industrialisation: Are we there yet? And what does the destination even look like?
  • A stronger future, layer by layer: How next-generation software will drive adoption of metal AM
  • Volkmann: Making the case for the complete automation of powder handling in AM
  • Metal AM on an industrial scale: GKN Additive draws on decades of sintering expertise to commercialise Binder Jetting
  • International Conference on Electron Beam Additive Manufacturing: Highlights from EBAM 2023

The world of metal AM to your inbox

Don't miss any new issue of Metal AM magazine, and get the latest industry news. Sign up to our twice weekly newsletter.

Sign up

Discover our magazine archive…

The free to access Metal Additive Manufacturing magazine archive offers unparalleled insight into the world of metal Additive Manufacturing from a commercial and technological perspective through:

  • Reports on visits to leading metal AM part manufacturers and industry suppliers
  • Articles on technology and application trends
  • Information on materials developments
  • Reviews of key technical presentations from the international conference circuit
  • International industry news

All past issues are available to download as free PDFs or view in your browser.

Browse the archive

Looking for AM machines, metal powders or part manufacturing services?

Discover suppliers of these and more in our comprehensive advertisers’ index and buyer’s guide, available in the back of Metal AM magazine.

  • AM machines
  • Process monitoring & calibration
  • Heat treatment & sintering
  • HIP systems & services
  • Pre- & post-processing technology
  • Powders, powder production and analysis
  • Part manufacturers
  • Consulting, training & market data
View online
Share via
Copy link
Powered by Social Snap