Kiel joint project optimizes 3D printing with titanium

Titanium is relatively light, extremely stable and can withstand high temperatures. This is why it is used in the aerospace and shipping industries as well as in medical technology. In order to produce small quantities or complex geometries economically, manufacturers are now increasingly printing titanium components using the 3D printing process. However, little research has been conducted into how these components behave under dynamic stress. A transdisciplinary research project from Kiel is providing new insights. Together with Element 22 GmbH and scuddy GmbH & Co. KG., scientists at Kiel UAS have analyzed and optimized the additive manufacturing of titanium components.

3D printing offers the possibility of producing complex components in small quantities. The Kiel-based company scuddy makes use of this advantage. It has been printing selected components for its electric scooters for years – mostly from plastic, but also from aluminum for prototypes. The engineers at scuddy are using the “FATiG” research project to test new materials. “We wanted to find out whether we could also use the process for 3D printing titanium components in the long term,” says Jörn Jacobi, co-founder of scuddy. The challenge: to date, there is little knowledge about how 3D-printed titanium behaves under dynamic stress. The Kiel-based company opted for a titanium toothed belt wheel for the load tests. This component drives the rear wheel of the electric scooter and is exposed to constant shocks and impacts.

The second industrial partner, Element 22 GmbH, was responsible for 3D printing the timing belt pulley. Dr. Johannes G. Schaper used “Cold Metal Fusion” technology to manufacture the timing belt pulley. In this process, a 3D printer applies a mixture of metal powder and binder in thin layers. A laser melts the binder and gives the metal powder its initial strength. After the printing process, the still brittle toothed belt wheel is placed in a sintering oven, where the metal particles combine under heat and vacuum to form a stable mass. The company looks back positively on the joint research project: “We were able to implement cold metal fusion in our company and now supply our customers with components made using this technology,” says Johannes Schaper. The company has also acquired new knowledge in the field of sintering and can now offer innovative component geometries.

At Kiel University of Applied Sciences, Deborah Kaschube subjected the 3D-printed components to various stress tests as part of her doctorate, until the first spoke broke.

“In science, we can test the load-bearing capacity of individual components intensively and for a long time, but this is obviously not economically viable for industry. They need reliable calculation software to put their products through their paces and ultimately predict their service life,” explains Kaschube.

To make this possible, the doctoral student and project manager Prof. Dr. Berend Bohlmann combined the results of the load tests and the material data collected in the process in software they developed themselves. Combined with a “finite element analysis” for modeling physical phenomena, she was able to predict the service life of the component. In future, it will therefore be possible to calculate the service life of components manufactured using cold metal fusion.