Researchers at the University of Wisconsin-Madison have made a significant breakthrough in the field of additive manufacturing, also known as 3D printing. They have developed a method that simultaneously reduces three common types of defects in parts produced using a popular 3D printing technique, known as laser powder bed fusion.
The research team, led by Lianyi Chen, an associate professor of mechanical engineering at the university, has discovered the factors and the necessary conditions that contribute to a significant reduction of these defects. Their findings, published in the International Journal of Machine Tools and Manufacture on November 16, 2024, offer a promising solution to the quality issues that have long plagued the 3D printing industry.
Chen explains that most existing research focused on reducing one type of defect at a time, requiring different techniques to address other types of defects. However, their newly developed method can mitigate all common defects—pores, rough surfaces, and large spatters—in a single step. Moreover, this approach allows for faster production without compromising the quality of the printed parts.
3D printing holds great potential for various industries, including aerospace, medical, and energy sectors, offering the possibility to create complex, custom-designed metal parts that are difficult to produce using traditional methods. However, the presence of defects in 3D-printed parts has been a significant hurdle, affecting their reliability and durability, and limiting their use in critical applications where failure cannot be tolerated.
The method developed by the UW-Madison team paves the way for improving both the quality and productivity of additive manufacturing, potentially encouraging wider industrial adoption of laser powder bed fusion.
This technique involves using a high-energy laser beam to melt and fuse thin layers of metal powder, gradually building the part from the bottom up. In this research, the team used a unique ring-shaped laser beam, provided by nLight, a leading laser company, in place of the standard Gaussian-shaped beam.
This ring-shaped laser beam, along with crucial in-situ experiments, was instrumental in achieving this breakthrough, says Jiandong Yuan, the lead author of the paper and a Ph.D. student in Chen’s group.
To understand how the material behaved during the printing process, the researchers used the Advanced Photon Source at the Argonne National Laboratory, a facility equipped with ultra-bright, high-energy synchrotron X-ray. By combining high-speed synchrotron X-ray imaging, theoretical analysis, and numerical simulation, the team was able to illuminate how defects could be minimized in the laser powder bed fusion process.
The team also demonstrated that they could use the ring-shaped beam to drill deeper into the material without disrupting the process, allowing them to print thicker layers and hence improve manufacturing productivity. “With a deep understanding of the underlying mechanisms, we were able to quickly identify the optimal processing conditions for producing high-quality parts using the ring-shaped beam,” Chen added.
This groundbreaking research was a collaborative effort involving several other researchers from UW-Madison, as well as Samuel Clark and Kamel Fezzaa from Argonne National Laboratory. The project was supported by the National Science Foundation and the Wisconsin Alumni Research Foundation.
