Researchers from Penn State’s College of Earth and Mineral Sciences and College of Engineering, located in University Park, Pennsylvania, USA, have been awarded a $180,000 grant to investigate comprehensive quality control methods for Additive Manufacturing of metals.
The grant is renewable for up to three years, for a total of $540,000, as part of a Penn State agreement with 3M earlier this year.
“3M is funding the grant but, more importantly, the company will be a close collaborator on this project,” stated Allison Beese, principal investigator and associate professor of materials science and engineering in the College of Earth and Mineral Sciences. “The Penn State researchers will ensure scientific rigour, while 3M — a leader in industrial Additive Manufacturing — will guide industry relevancy, continuing to build the strong partnership between 3M and Penn State.”
Using non-destructive evaluation (NDE), a method for examining or testing a part or system without causing harm, the researchers will assess additively manufactured parts, specifically investigating Binder Jetting.
Beese added, “We’re trying to develop a detailed scientific understanding of how to link the binder-jet process to the microstructure and the quality of the part. At the end of the day, someone should be able to use NDE to evaluate a part to determine if the part is suitable for use and know exactly what in its microstructure results in good or bad properties.”
Current evaluation processes often take place part by part. After a batch is made, a sample part’s properties are tested to determine whether the part — and therefore the batch — is sufficient and safe for use. Whether a part succeeds or fails, it is not evaluated further and no cause for the part’s failure or success is identified.
To assess AM parts more comprehensively, the researchers will investigate links between the processes used, microstructure of the parts and mechanical properties like hardness, tensile strength and ductility. Making connections between process, structure, property and performance (PSPP) will allow the researchers to understand why parts fail more thoroughly and infer improved methods of manufacturing.
According to Beese, ultrasonic NDE will assist in this process. Using this method, researchers send ultrasonic waves into a material and examine their movement to identify microscopic features and flaws in the structure of a part that in turn dictate the part’s mechanical performance.
The group explains that it can benefit from this information in two ways. Firstly, a thorough analysis of a part’s microstructure can assist researchers in predicting performance failures or successes before they happen — and when they do, they support the researchers’ inferences and allow them to draw conclusions. Secondly, understanding PSPP connections informs the researchers on redesign, providing them with insight on how changes to the manufacturing process and material will influence the final product. Models will reportedly serve as valuable tools for the team’s analysis process.
Andrea Arguelles, co-principal investigator and assistant professor of engineering science and mechanics, commented, “We aim to develop models that link ultrasonic measurements to microstructure and collaborate with Dr Beese to connect the microstructure analysis to mechanical properties.”
“Our ultimate goal is to develop an ultrasonic method and model that will provide manufacturers with a prediction for a part’s performance,” Arguelles added.
Arguelles and co-principal investigator Christopher Kube, assistant professor of engineering science and mechanics, will contribute their expertise of ultrasonic measurement and computational analysis to the research, while Beese will provide insights on how the identified and analysed features affect the mechanical properties and ultimate application potential of a part.
Kube added, “Ultrasound is a traditional tool to assess the quality of structural components that have already been fabricated. This project, however, is unique in that ultrasound is being used parallel to the material development process to accelerate toward high-quality structural components.”