Page 48 - MetalForming Magazine February 2023 - Metal Forming for the Automotive Industry

Laser welding of battery frames in EV applications, as shown here, offers speed and cleanliness, with cleanliness without spatter a must to ensure performance of finicky electrical components.
LASER
WELDING
in a Shifting Automotive World
While changes in automotive designs, particularly related to EVs, disrupt traditional joining processes, laser welding is uniquely positioned to continue playing a critical role.
BY LOUIS A. KREN, SENIOR EDITOR
Similar to the oft-mentioned advantages of laser cutting, laser welding also boasts speed and cleanliness. So says Richard Davis, head of automotive sales for Trumpf Inc. Davis, along with Yama Fedai, Trumpf industry manager, talked with MetalForming about sheet metal laser welding, and why this technology provides an answer to joining challenges in the automotive- production realm.
“The transformation to electric vehi- cles (EVs) certainly has changed the landscape when it comes to laser weld- ing,” Fedai says.
Speedy and Clean
The speed and cleanliness offered by laser welding, as well as flexibility, position this joining process well given an alternative-fuel automotive universe where battery-compartment sealing needs; a smorgasbord of designs; and lower-volume high-mix production appear to be the norm. As to speed, laser welding performs orders of mag- nitude quicker than traditional meth- ods such as gas-metal-arc welding (GMAW ). The cleanliness also can’t be beat.
“Battery systems can’t have debris that may come from welding processes that expel a lot of material,” Davis explains. “Spatter can release into areas and compromise the battery structure, and laser welding operates inherently cleaner than GMAW. That’s important, as specifications place nearly a zero tolerance for weld splatter in battery
structures, and cleanliness is critical in applications involving electrical sys- tems and motors.”
Zero tolerance on spatter necessi- tates the cleanest welds possible, and keeps welding-equipment manufac- turers busy designing solutions. For its part, says Davis, Trumpf offers Bright- line Weld technology for its TruDisk and TruFiber laser welding lineup, enabling welding of materials such as mild or stainless steel, copper and alu- minum with almost no spatter. Key here is a laser-light cable featuring an inner and outer fiber core. Laser power flexibly distributes among the core and the application-specific optimum. An outer-ring beam creates an enlarged keyhole opening that allows escape of metal vapor while diverting the melt in the direction of the weld pool, thus minimizing or in some cases eliminat- ing spatter.
“The dual-core fiber operates almost as concentric spots focusing differently through the weld volume, and control- ling the heat distribution throughout the weld,” Davis says.
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