On April 28, 2020, Antarctic Bear learned that ExOne, a manufacturer of adhesive jet 3D printers, and the University of Pittsburgh have jointly developed a reusable metal filter that can be fitted into a respirator filter element of a plastic respirator.
ExOne’s adhesive jet 3D printing process can be used to produce metal parts with specific porosity, which can effectively filter out pollutants while allowing air to flow. Using its technology, the company can develop reusable porous metal filters made of two metals: copper and 316L stainless steel. It is reported that this plastic respirator filter element was designed by the Department of Mechanical Engineering and Materials Science, swanson Institute of Engineering, University of Pittsburgh.
ExOne is currently conducting preliminary tests on airflow and filtration efficiency, and optimizing the filter. The goal is to adhere to N95 respirator standard. ExOne explained that the combination device is likely to provide sustainable and disinfectable personal protective equipment (PPE), which can be used for a long time to resist pollutants such as COVID-19(COVID-19 is a disease causing the current coronavirus pandemic).
ExOne CEO John Hartner said: “our team has been working hard to provide this reusable solution to frontline medical personnel fighting the COVID-19 pandemic. Our customers often print porous metal filters for various purposes, and we are confident that we will soon have a solution that enables medical personnel to disinfect and sterilize the metal filters, reuse them, and eliminate waste. “
“Once approved, we can print these filters into various sizes for use in respirators, respirators, anesthesia masks or other equipment.”
Create different porosity levels for different 3D printed metal filters
ExOne’s adhesive jet technology works by selectively depositing liquid adhesive layer by layer onto a thin layer of metal powder coating using a print head until the final object is formed. After printing is completed, it is generally necessary to sinter in a furnace.
Normally, metal parts sprayed with adhesive are sintered to full density. However, ExOne’s technology allows specific porosity to be established for related objects. Different metal materials have different porosity requirements for filters.
Therefore, in order to test filters with different metals and porosities, the research team led by Dr. Markus Chmielus, associate professor of mechanical engineering and materials science at Swanson college, is using CT scanners to analyze its microstructure and porosity. In order to help analyze and optimize the performance of the filter, the engineering simulation software developer Ansys is providing additional computer simulation support.
Dr. Chmielus explained: “compared with other rapid prototyping manufacturing methods, the application of adhesive jet 3D printing to this filter has the advantage of being able to utilize the porosity of the printed piece and then fine-tune it during high-temperature densification or sintering to achieve the best filtration and airflow performance.”
Although both copper and stainless steel filters are 3D printed by ExOne and are currently being tested by Pitt University, according to ExOne, copper itself has been antibacterial for a long time. The company explained that according to Smithsonian Institution data, the earliest recorded use of copper to kill bacteria was in Edwin Smith’s Papyrus, which is the oldest medical document known in history. In addition, many studies have proved the disinfection ability of copper, including a study funded by the U.S. Department of Defense in 2015, which showed that copper alloy helped reduce the infection rate by 58%.
ExOne’s Metal Adhesive Jet 3D Printing Technology
ExOne developed the first iteration of its adhesive jet technology in 1996 and has since applied it to sand and metal 3D printing systems. The metal 3D printer it has chosen includes Innovent+ NT+,an entry-level system designed for research and development and production of small parts. At the Formnext exhibition in 2018, the company introduced X1 25 PRO system, which aims to achieve a larger construction size and Innovent+ equivalent powder metallurgy capability.
About a year later, in November 2019, the company launched X1 160PRO. This is the company’s largest equipment to date and is developed for mass production of terminal parts and castings.
In addition, ExOne has also participated in a number of cooperation to develop its metal adhesive spraying technology. Last year, it announced cooperation with sandvik Zengyang Manufacturing Company to promote its adhesive jet 3D printing process. The two companies will be committed to optimizing the use of metal powder and binder jet 3D printing.
The company also cooperated with Oak Ridge National Laboratory (ORNL) to promote adhesive jet 3D printing technology to realize 3D processing of H13 tool steel.
Compiled by: 3 dprintinggindustry