Manufacturing aircraft components, battery materials, cutting tools, biomedical implants and other precision-engineered parts often involves metals in powder form.
When these powders become mixed or cross-contaminated during material changes, handling, recovery or multimaterial 3D printing, they may no longer meet the strict requirements for reuse. Leftover powders, contaminated feedstock and material from failed production attempts may then be discarded even when they contain valuable metals.
A University of Maine research team has developed a process that could help recover these materials for reuse in 3D printing, sintering and other powder-based manufacturing processes.
The method, called shear-assisted particle entrapment (SHAPE), separates microscopic metal particles and captures them in a polymer film. In a new study published in , researchers tested the process using aluminum and copper powders mixed in a liquid and placed in a spinning machine.
鈥淲e鈥檙e trying to solve a significant materials-loss problem that occurs during the production of high-value components and products across critical sectors, such as aerospace, energy storage, tooling, biomedical devices and electronics,鈥 said lead researcher Bashir Khoda. 鈥淚t is also an ongoing challenge for strengthening 鈥楳ade in USA鈥 manufacturing, where uncertainty in the supply chain for critical minerals can affect cost, availability, and production resilience.鈥
Khoda, a 91福利 associate professor of mechanical engineering, said his team’s findings could be particularly relevant to 3D printing and other powder-based additive manufacturing processes, in which metal powders can become mixed.
Khoda said recovering the particles without melting and completely reprocessing them could eventually reduce material waste, energy-intensive reprocessing and demand for new raw materials.
鈥淥ur longer-term objective is not simply to separate particles in the laboratory, but to develop a scalable and AI-driven manufacturing system that could recover cross-contaminated powders and return usable material to the additive manufacturing supply chain and beyond,鈥 said Khoda, also an associate faculty member with the Advanced Structures and Composites Center (ASCC).
Khoda devised the particle entrapment method in collaboration with William Gramlich, associate professor of chemistry and associate faculty member with the ASCC; Khalid Jawed, an associate professor of mechanical engineering at the University of California, Los Angeles; and graduate student researchers Ibrahim Khalil, Adeeb Alam and Md. Akibul Islam.
Researchers tested aluminum and copper microparticles between 0 and 25 micrometers in diameter. The particles were mixed in a liquid carrier and subjected to rotational speeds ranging from 200 to 1,500 revolutions per minute (rpm).
The team found that fine-tuning process parameters resulted in different particles being captured. At approximately 200 rpm, about 87% of the particles captured on the substrate were aluminum. As rotational speed increased, copper became increasingly dominant. At 1,500 rpm, about 90% of the entrapped particles were copper.
鈥淲hat makes this interesting for separation is that different particles respond differently to the same flow conditions,鈥 Khoda said.
Although the researchers achieved high particle-level selectivity, the overall amount of material captured from the starting mixture remained relatively low under laboratory conditions.
鈥淭he current study demonstrates the selectivity of the mechanism, rather than an industrially ready recovery process,鈥 Khoda said. 鈥淭he next challenge is to maintain this selectivity while substantially increasing the amount of material that can be processed and recovered.鈥
Future research will examine ways to increase the amount of material processed while maintaining selective separation. Researchers are investigating substrate size and geometry, the use of multiple substrates, particle loading, polymer concentration, processing time and continuous or multistage operation.
The team also plans to further study the physics behind particle transport and retention and test additional material combinations. Ultimately, the goal is to determine whether recovered powders retain the chemistry, morphology, flowability and manufacturing performance necessary for reuse.
The study was partially supported by a grant from the National Science Foundation.
Story by William Bickford, graduate student writer
Contact: Marcus Wolf, 207.581.3721; marcus.wolf@maine.edu
