Additive manufacturing holds much promise for fields such as automotive and biomedical and U of T engineers are looking to advance the technology. PHOTO courtesy Ingersoll.
The University of Toronto’s first metal additive printing laboratory is working to advance the technology for automotive, energy and biomedical applications.
“We are working to uncover the fundamental physics behind the additive manufacturing process, as well as improving its robustness, and creating novel structural and functional materials through its applications,” Professor Yu Zou, who leads the U of T Engineering research team, is quoted in a story appearing in the university’s Engineering News.
Unlike traditional manufacturing, in which parts or components are made from bulk materials, the metal additve printing process enables microstructure and materials constitutions to be locally tailored — that is, they can exhibit distinct properties compared to those made by traditional manufacturing.
“For example, medical implants require human bone-like materials that are dense and hard on the outside, but porous on the inside,” says Xiao Shang, an MSE PhD candidate in Zou’s lab told Engineering News. “With traditional manufacturing, that’s really hard to accomplish, but metal printing gives you a lot more control and customized products.”
Zou’s metal additive printers are designed to specialize in both selective laser melting (SLM) and directed energy deposition (DED).
“Conventional manufacturing techniques are still well suited for large-scale industrial manufacturing,” Tianyi Lyu (MSE PhD candidate) told Engineering News. “But additive manufacturing has capabilities that go beyond what conventional techniques can do. These include the fabrication of complex geometries, rapid prototyping and customization of designs, and precise control of the material properties.”
For example, dental professionals can use SLM to create dentures or implants customized to specific patients, via a precise 3D model with dimensional accuracy that is within a few micrometres. Rapid prototyping also allows for easy adjustments of the denture design. And since implants can require different material properties at distinct locations, this can be achieved by simply changing the process parameters.
The team is also looking to gain a better understanding of the SLM and DED printing processes. Currently, their research is focused on advanced steels, nickel-based superalloys and high-entropy alloys, and they may expand to explore titanium and aluminum alloys in the future.
“One of the major bottlenecks in conventional alloy design today is the large processing times required to create and test new materials. This type of high-throughput design just isn’t possible for conventional fabrication methods,” Ajay Talbot (MSE MASc candidate) told Engineering News.
With AM techniques such as DED, the team is rapidly increasing the amount of alloy systems explored, altering the composition of materials during the printing process by adding or taking away certain elements.
“We are also working towards intelligent manufacturing. During the metal additive printing process, the interaction between a high-energy laser and the material only lasts for a few microseconds. However, within this limited timeframe, multi-scale, multi-physics phenomena take place,” Jiahui Zhang (MSE PhD candidate) told Engineering News. “Our main challenge is attaining data to capture these phenomena. In our research, we have successfully customized specific machine learning methods for different parts of the metal additive manufacturing lifecycle.”
