Satisfies Need for Speed

The technology also delivers speed.

“With such focus shaping, the main advantage relates to feed rates,” Flamm says. “In contrast to a standard multi-kilowatt cutting process, strongly depending on part shapes and a bit on sheet thickness, this shaping allows an increase in feed rates from 20 to 50%, and has been well-developed for hot-formed materials used in the automotive industry.”

When cutting 3D parts, inclination angles of the optics greatly affect productivity. Beam shaping pays big dividends here, according to Flamm.

“An optical head can be moved in three dimensions, so the beam focus shape must be moved over a curved workpiece,” he explains. “But due to process robustness, such as that with Trumpf’s BrightLine Speed process, the maximum inclination angle that can be applied to the workpiece increases by 20%.”

This translates to greater speed and higher cut quality. Overall, effective beam shaping not only involves focusing the working beam in a tighter area, but includes a higher-quality beam source and proper beam positioning.

“Beam shaping is much more than producing a small beam on the workpiece,” Flamm says. “The technology produces a surrounding beam from the outer core that guides the significant power produced in the inner-core beam into a central spot that tailors the cutting curve—tailoring the thermal footprint of the radiation on the workpiece. This is the key to obtaining an optimized energy deposition not only on the surface but also inside of the beam volume.”

Beam shaping can occur automatically, with parameters offered for various material types and thicknesses. No need for fabricators to learn all the details of laser focusing—that knowledge is baked into the laser system. By working from suggested parameters, fabricators can ascertain reliably the correct and most productive settings for their applications.

Benefits in Laser Welding

As mentioned, beam shaping offers dividends in laser welding as well as cutting. With the ability to modify beam shape, size and the distribution of its intensity, users can optimize laser welding of various material types and joint configurations, optimizing penetration depth and width, and minimizing spatter and porosity.

Beam shaping has produced real-world welding results. An example: the Benteler Automotive Division, which applies Trumpf’s BrightLine Weld technology and its MultiFocus optics to yield high-speed, low-spatter laser welding of aluminum cooling plates.

The Benteler R&D team developed an aluminum cooling plate, for an electric-vehicle battery pack, that requires reliable gas-tight welds. To meet this challenge, Trumpf’s industry-management team supported the effort to develop new laser-optics technology for series production, combining BrightLineWeld with its newly developed MultiFocus optics. Together, the two technologies stabilize the weld keyhole and prevent it from collapsing. The novel approach increases process efficiency, enables greater welding depths and improves weld-seam quality. 

Using MultiFocus technology, Benteler recognizes an increase in the keyhole area and an enlarged melt pool, a reduction in weld spatter and improved uniformity of the weld geometry (verified by microsections), and reliable gas-tight cooling-plate welds. 

Summarizing the benefits realized by Benteler:

• Spatially tailored laser-energy distribution enables keyhole stabilization and mitigation of pore formation for aluminum welding.
• Utilization of stabilized keyhole welding processes via the MultiFocus optics enables gas-tight welding for cooling plates.
• Welding speeds exceeding 10 m/min.

“The fast process speed requires a tailored input of thermal energy—this is the only way to ensure a stable capillary during welding,” explains Mauritz Möller, Trumpf’s head of global business development. “Pores can form. The MultiFocus optic prevents exactly that.” MF

See also: TRUMPF Inc.

Technologies: Cutting

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