Reusable N95 cartridge and building filters via binder jet 3D printing informed by 3D characterization, modeling and simulation

Principal investigator: Markus Chmielus and Ian Nettleship

University: University of Pittsburgh

Industry partner: ExOne and ANSYS Inc.

Our team of two faculty at the University of Pittsburgh (Profs. Chmielus and Nettleship) and The ExOne Company began work on reusable, easily sterilizable N95 porous binder jet 3D printed cartridge filters for masks through the COVID Manufacturing PA challenge. In this follow-up project, we will increase the involvement of PA companies by adding filtration simulation and microstructure optimization modelling (with ANSYS Inc.) and broaden potential applications of the filters based on current progress and collected potential customer feedback. In this project, we will continue to work on cartridge-based N95 filters, but also investigate large scale N95 air filtration for building HVAC systems and room filtration. We will receive direct feedback from the University of Pittsburgh facilities department for HVAC testing (in addition to established connections with physicians and leadership from UPMC and AHN). At either size, our proposed copper or stainless steel cartridge filter inserts will be reusable after already-available autoclave sterilization. This not only aids in alleviating the current short-term supply crisis, but also decreases the escalating long-term biowaste issue. The proposed research to be performed by the graduate/undergraduate fellows will include further optimization of the binder jet 3D printing process parameters, 2D and 3D microstructural analysis, and mechanical strength, filtration and pressure drop tests of specific powder and process parameter combinations to better understand how powder, processing and design are influencing the filtration and mechanical properties of the filters. Simulation and analysis of tortuosity and pressure drop will be compared to test results to potentially predict how to optimize powder and processing for specific filtration requirements and usage cases. Furthermore, senior design student teams and senior research students will be involved in this project to assist with filter designs, modelling efforts and filtration test setups.