Engineers have discovered a method to reduce three different types of defects in parts made using a widely used additive manufacturing technique known as laser powder bed fusion.
Engineers at the University of Wisconsin-Madison have found a new way to address three different defects simultaneously in parts created through a popular additive manufacturing process called laser powder bed fusion.
Under the guidance of Lianyi Chen, an associate professor of mechanical engineering at UW-Madison, the team has uncovered the mechanisms and identified the necessary processing conditions that lead to a remarkable decrease in defects. Their research findings were published on November 16, 2024, in the International Journal of Machine Tools and Manufacture.
“Most past studies have concentrated on fixing one type of defect, which often involves employing additional methods to address the others,” Chen explains. “With the mechanisms we’ve identified, we devised a method that can handle all types of defects—such as pores, rough surfaces, and large spatters—simultaneously. Moreover, this method allows for faster production without sacrificing quality.”
Various sectors, such as aerospace, healthcare, and energy, are increasingly keen on adopting additive manufacturing, or 3D printing, to create intricate metal components that are challenging or impossible to fabricate with traditional techniques.
However, a significant hurdle is that metal parts produced through additive manufacturing often come with defects—like pores or “voids,” uneven surfaces, and large spatters—that notably undermine the part’s reliability and longevity. Such quality issues limit the use of 3D-printed components in critical applications where failure is not acceptable.
The UW-Madison team’s advancement, which facilitates improvements in both part quality and production efficiency, could promote the broader use of laser powder bed fusion across industries.
This process involves using a powerful laser to melt and fuse thin layers of metal powder, constructing a component layer by layer from the base upwards. In their study, the team utilized an innovative ring-shaped laser beam, supplied by a top laser manufacturer called nLight, rather than the conventional Gaussian-shaped beam.
The introduction of the ring-shaped laser beam was crucial in achieving this development, along with essential “in-situ” experiments, according to Jiandong Yuan, the lead author of the paper and a PhD student in Chen’s research group.
To analyze the material’s behavior during the printing process, researchers visited the Advanced Photon Source, a highly advanced, high-energy synchrotron X-ray facility at Argonne National Laboratory. Through a combination of rapid synchrotron X-ray imaging, theoretical assessments, and numerical simulations, they unveiled the mechanisms that mitigate defects, addressing the instabilities inherent in the laser powder bed fusion process.
The team also showed that utilizing the ring-shaped beam allowed for deeper penetration into the material without introducing instabilities. This capability enabled the printing of thicker layers, which enhanced manufacturing efficiency. “By grasping the underlying mechanisms, we were able to swiftly determine the appropriate processing conditions for producing high-quality parts with the ring-shaped beam,” says Chen.
Lianyi Chen holds the position of Kuo K. & Cindy F. Wang Associate Professor of mechanical engineering.
Other collaborators from UW-Madison include Qilin Guo, Luis Escano, Ali Nabba, Minglei Qu, Junye Huang, Qingyuan Li, Allen Jonathan Román, and Professor Tim Osswald. Samuel Clark and Kamel Fezzaa from Argonne National Laboratory also contributed to this research.
This project received support from the National Science Foundation and the Wisconsin Alumni Research Foundation.
