tion, a smaller included angle is needed and hence less fi ller material.
Solid-State Lasers—Power and Multiplexing Hansen from ESAB noted that while solid-state
and fi ber lasers now run up to many 10’s of kW in power, the practical limit of what they would use in hybrid welding is around 12 kW. Beam quality in terms of beam parameter product (BPP) need not be fi ner than 10–12 mm-mrads, in most welding applications. In fact, for “high power” welding ap- plications, from hybrid to remote scanning, 75% or more of most applications require lasers that provide power between 4–6 kW, according to Hurley from Trumpf, with a BPP around 8 mm-mrad or better. For example, a common laser for welding is the Trumpf TruDisk 6002. It provides a near-IR beam at 6 kW with a BPP of 8 mm-mrad. Another plus is that some models deliver their energy through up to six individ- ual fi bers, enabling a single laser to power a number of independent workcells, reducing capital cost. As important as the advent of hybrid welding is, Hurley also noted that remote laser welding remains important. Remote welding uses the unique stand- off capability of lasers and scanning optics. Remote welding systems rapidly direct a laser beam over large parts like automotive doors and closures. They weld a number of spots and short seams separated by distance, saving time over traditional spot-welding methods. In many cases, it produces a better weld, according to Hurley. Remote welding started with far- IR beams from CO2 lasers delivered in fl ying optics. Today, he noted that solid-state lasers are now the choice. This means that laser heads mounted on com- mon six-axis articulated arm robots provide unprec- edented mobility, combining motion of the head with directed motion of the beam. With advancements like solid-state remote weld-
ing and hybrid welding, Hurley believes there is plenty of room for growth for laser welding, espe-
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cially in North America. “The Europeans are leaders in developing and deploying it,” he said. They are more comfortable with the technology, according to Hurley. “They are seeing the benefi ts,” he said. Those benefi ts will grow on manufacturers in North America, he believes.
The Foundation Elements for Growth “Laser cutting is like a divorce, but laser welding is like a marriage,” said Paul Denney, senior laser applications engineer of Lincoln Electric (Cleveland, OH). “For a cut getting separation cleanly and quickly is what you worry about. However, for a successful weld you do not only worry about getting things to ‘stick’ together but also what has to be done so that ‘union’ will last in the long term. For laser welds you have to be concerned about the chemistry of the base and weld metal, the resulting microstructure of the weld and the HAZ, and the size.” He sees laser-weld- ing growing, from remote welding to creating tailor- welded blanks. Lincoln Electric supplies laser-welding systems, hybrid laser systems that combine laser and GMAW, and hot wire cladding laser systems. The key, as Denney sees it, is to think of laser welding as a revolutionary, not an evolutionary, process, especially for the newer hybrid approaches. “You do not want to try and replace a resistance or
“For laser welds you have to be concerned about the chemistry of the base and weld metal, the resulting microstructure of the weld and the HAZ, and the size.”
arc-welding process one-for-one. For example, lasers want to give you a high aspect, deep penetration weld, but if you look at the drawings from most com-
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