Within a European network project, Fraunhofer Institute for Material and Beam Technology (IWS), Dresden, Germany, is, for the first time, investigating beam shaping for Additive Manufacturing together with Israeli laser manufacturer Civan Lasers, Jerusalem, and A. Kotliar Laser Welding Solutions, Haifa, under the project name ‘ShapeAM’.
The research is based on the Coherent Beam Combining (CBC) method, still a new technique, wherein a thirteen-kilowatt laser can generate different energy distribution patterns quickly during operation, thus processing demanding high-tech materials with great efficiency. The Fraunhofer researchers intend to make the laser technology available to companies worldwide in the near future, after their testing provides new application scenarios.
“This laser will push the limits of materials processing – for example, in medical technology and aerospace,” stated Dr Andreas Wetzig, head of the Cutting and Joining technology field at Fraunhofer IWS.
In CBC, a Dynamic Beam Laser from Civan Lasers combines tens of individual beams into a powerful, high-quality laser beam. Through small phase shifts of the wave troughs and peaks in the partial beams, the laser can quickly generate completely different energy distribution patterns in the resulting processing laser beam. While a classic laser releases most of its energy only in the centre of the beam, Civan’s system can generate energy patterns on the workpieces – for instance in the form of a ring, a figure eight or a horseshoe.
In principle, this was already possible in the past with beam-deflecting optics or fast oscillating mirror, but even the fastest oscillating mirrors still need milliseconds to realign the energy patterns in the beam. The Dynamic Beam Laser is reputed to accomplish this within microseconds, making it possible to use dynamic beam shaping for metal AM.
As part of ShapeAM, researchers are testing the Cuban system to achieve improved material properties. Specifically, the aim is the Additive Manufacturing of titanium and aluminium alloys, such as those needed for space components, implants and lightweight components for mobility. In doing so, the partners plan to use dynamic beam shaping to eliminate defects, thus achieving higher quality part results.
Dr Elena Lopez, department head of Additive Manufacturing at Fraunhofer IWS, added, “We plan to use novel beam shapes and control frequencies that are not achievable with other methods to overcome challenges in crack-sensitive materials.”
The joint project is expected to develop into a fruitful scientific and personnel exchange between Israel and Saxony, Germany: Fraunhofer IWS will forward the test results (and, temporarily, some of its scientists) to Jerusalem. In return, experts from Civan are expected to conduct its own tests in the laser laboratory in Dresden.
The tests at the Dresden institute are planned to determine the possibilities and limits of the Dynamic Beam Laser; basic tests with various beam profiles, materials and processes are initially planned. After that, the researchers will evaluate concrete applications, such as how well the system can cut, join or additively manufacture diverse workpieces from materials and material composites that are otherwise difficult to process.
It is already predicted that the new laser will allow faster and more precise control of the melt pool dynamics in many AM and joining processes – and not only across the surface, but also in depth. Fraunhofer IWS also expects advantages in laser cutting in terms of burr-free cuts with high edge quality, at twice the working speed compared to conventional fibre lasers.
The test phase in Dresden will show whether the new laser will meet its expectations in practice. In any case, the quality and speed advantages that are already becoming apparent make the technology highly interesting for use in metal-working industry, medical technology and electromobility, as well as in aerospace industry.
In a webinar scheduled on September 14, 2021, Fraunhofer IWS will present the Dynamic Beam Laser to interested partners from industry and research. It will subsequently be possible to test the use of the CBC fibre laser for their own applications at Fraunhofer IWS. The first findings from the test series will be presented to a broader audience at the combined online event Laser Symposium/ISAM 2021 in Dresden from December 7 to 9, 2021.