ASTRO participant contributes to understanding of thermal processes in 3D printing
Rebecca Kurfess had an early introduction to engineering.
When she was a child, she visited her father, a mechanical engineering professor at the Georgia Institute of Technology, at the school’s machine shop. She remembers learning about the different machines and watching parts being made on the mills and lathes.
Perhaps it’s no surprise that science and mathematics came naturally to Kurfess. She was especially fond of physics, which allowed her to apply math to real-world situations.
Kurfess went on to attend the Massachusetts Institute of Technology (MIT), where she quickly gravitated toward mechanical engineering.
“I love being able to apply the fundamental theories of engineering to physical parts,” she said, “and my favorite classes were those where I could work with my mind and my hands to take concepts that I designed and make them a physical reality.”
After earning a bachelor’s degree in mechanical engineering, she entered graduate school at MIT to continue her studies in the same field.
Initially, her graduate studies centered on the modeling and control of power grid systems, but a fortuitous encounter prompted her to rethink her career path.
While attending a Society of Manufacturing Engineers (SME) event during her first semester as a graduate student, she met Lonnie Love, Ph.D., a Corporate Fellow at Oak Ridge National Laboratory (ORNL) and group leader of ORNL’s Manufacturing Systems Research Group in the Energy and Transportation Science Division.
“After just a few minutes of talking with Lonnie about manufacturing and (ORNL’s Manufacturing Demonstration Facility), I knew I wanted to change the focus of my graduate work,” she said.
Love encouraged her to apply for the Advanced Short-Term Research Opportunity (ASTRO) Program at ORNL. Once accepted, Kurfess joined ORNL’s Manufacturing Systems Research Group at the Manufacturing Demonstration Facility (MDF).
Under the mentorship of Love and Alex Roschli, an electrical engineer at the MDF, Kurfess investigated the 3D printing process known as extrusion, in which thermoplastic material is heated and pushed through a nozzle to create a bead of polymer. These beads are then deposited to form the layers that generate a 3D-printed object.
“During extrusion, when the next layer is extruded onto the previous layer, the previous layer must be within a certain temperature range in order for the next layer to properly adhere,” Kurfess explained. “If the previous layer is too cold, the next layer will peel away instead of adhering. If the previous layer is too hot, the next layer will melt into it, and the part will not retain the desired shape.”
As part of her ASTRO appointment, Kurfess modeled the relationship between the cooling rate of the extruded polymer and the bead width and material properties of that polymer. She then used an infrared camera to collect temperature data on the polymer as it cools to validate her models.
“By modeling the cooling rate of the extruded polymer, we can calculate the temperature of the bead at a given time and therefore the time range during which the next layer should be extruded on top of the previous layer,” Kurfess said.
Through her ASTRO appointment at the MDF, Kurfess gained valuable technical experience in 3D printing, infrared imaging and physical system modeling. Additionally, she honed her networking skills and experienced the value of a collaborative environment.
“Not only have I had the opportunity to gain access to equipment and facilities that I would never have been able to use had I not come to the MDF, but I have been able to interact with an incredible group of people who have expanded my knowledge of 3D printing, supported my research and advised me on everything from potential career paths to the best restaurants in town,” she said.
Kurfess will continue the research she began during her ASTRO appointment through her graduate studies at MIT. Once she receives her master’s and doctoral degrees, she intends to pursue a career in either academia or at a national laboratory, and focus on her research in the field of advanced manufacturing and 3D printing.
“I definitely recommend this program to others,” she said. “ASTRO is well-run and well-organized, and I’ve felt supported by the program staff throughout my internship. Both the technical experiences I’ve had and the people I’ve met have made this internship one of the best I’ve completed.”
The ASTRO program is administered by the Oak Ridge Institute for Science and Education (ORISE) for the U.S. Department of Energy.