New approach to beam shaping improves efficiency in 3D printing

The Fraunhofer Institute for Laser Technology ILT has developed a new platform to specifically optimize the Laser Powder Bed Fusion (LPBF) process. This innovative approach to beam shaping enables the process to be used more flexibly and efficiently. The system will be presented for the first time at Formnext in Frankfurt am Main from November 19 to 22, 2024.

Marvin Kippels, PhD student in the LPBF department at Fraunhofer ILT, is currently working on the development of a flexible LPBF system that can generate individual beam profiles using Spatial Light Modulators (SLMs). This technology is based on the targeted bending of the phase front of the laser beam by LCoS-SLMs (Liquid Crystal on Silicon). With a laser power of up to 2 kW, the system offers the possibility of investigating a wide range of beam profiles and optimizing the LPBF process for specific applications.

Standard Gaussian beams, which have been used in many LPBF processes to date, have considerable disadvantages. The high energy density in the center leads to local overheating, evaporation of the material and process instability, which can impair component quality. These effects limit the scalability of the process and often prevent the efficient use of higher laser powers.

“One way to speed up the process is to use several lasers and optical systems in parallel,” says Marvin Kippels. “However, the costs scale at least proportionally to the number of systems installed.”

The aim of the current research work is to increase the productivity of the single beam process, which could also be relevant for use in multi-laser systems. Initial studies have shown that even simple beam shapes such as rectangular or ring-shaped profiles can lead to better results. More complex beam shapes have hardly been investigated to date due to a lack of system technology – this is now changing with the new system.

Thanks to the new platform, the LPBF process can be specifically adapted to minimize material evaporation and spatter formation and increase efficiency. This offers industrial partners the opportunity to research application-specific solutions.

“We are still at the very beginning, but we can already see the enormous potential that beam shaping can offer for the LPBF process,” says Marvin Kippels. “There is no one perfect beam shape; every application has its own requirements. Thanks to our flexible beam shaping, we can find the ideal distribution for each process, the best process parameters for the task in question.”