Mechanical Engineer Awarded NSF CAREER Award

Imagine a 3D printer that can produce metal parts at the microscale or even nanoscale. Miniature robots could deliver drugs directly to cancer cells. Computer chips could include internal cooling channels, reducing energy use by data centers. Tiny flying robots, no bigger than a bee, could conduct surveillance. 

Wan Shou, an assistant professor of mechanical engineering at the U of A, received a prestigious five-year, $550,000 Early Career Award from the National Science Foundation to develop high-resolution, selective laser printing with inorganic nanoparticles such as metals that could lay the foundation for all these technological advances. 

"I am honored to be supported by the NSF CAREER program and excited to advance research in microscale and nanoscale 3D printing with inorganic nanoparticles," Shou said. "We hope to enable emerging microelectronic and microrobotic applications with the proposed affordable manufacturing technologies." 

Currently, 3D printing electronic components on a microscale or nanoscale uses polymers enhanced with nanomaterials (i.e., nanocomposites) for conductors. Similarly, nanocomposites are also used for other functional components, such as thermal conductors and magnetic actuators. These parts have poor performance. Components created with pure metal would be more efficient, allowing the creation of high-performance and smaller devices. 

The commercial metal 3D printers typically use microscale metal powders, which are spread in a layer across a bed. A laser draws a layer of the object, fusing the powder into a connected solid. The bed is then lowered, another layer of metal powder is spread across the surface, and the laser creates the next layer of the object. This additive manufacturing of metals can create detailed, intricate objects that would be difficult or impossible to make using casting or machining. The approach has been used to make airplane components and orthopedic implants. 

To print metal components at the microscale or nanoscale, Shou must develop a metal nanoparticle bed or film that can be coated with high precision and low porosity. He will also study how short-wavelength lasers, in the blue or ultraviolet spectrum, will enhance precision and energy efficiency for the inorganic nanoparticles, including metal nanoparticles, compared with the current longer-wavelength lasers. 

Shou believes he can lower the costs of microscale 3D metal printers from hundreds of thousands of dollars to no more than the average cost of a car. He has already established connections with industry partners including Nikon SLM, an additive manufacturing company, and Nokia Bell Labs, an industrial research and development company that develops communications and computing technologies. 

"We are very proud of Dr. Shou's accomplishment in receiving this transformative NSF CAREER Award. Recipients of this award represent outstanding potential for impactful research and application to their discipline, and his research will greatly advance manufacturing and elevate the visibility of the U of A in this field," said Steve Tung, department head of mechanical engineering. 

Beyond advancing fundamental science and manufacturing capabilities, the project integrates education and K-12 outreach to broaden participation in micro- and nano-manufacturing. 

Shou joined the Mechanical Engineering Department in 2021 after completing postdoctoral training at the Massachusetts Institute of Technology. He holds a doctoral degree in mechanical engineering from Missouri University of Science and Technology.