Above: nLIGHT’s Corona CFX-5000 is the first commercially available fiber laser with programmable beam shaping.

February 2019 - The proverb, “Good things come in small packages,” is an apt description for a line of fiber lasers nLIGHT Inc. introduced at EuroBlech and Fabtech 2018. The Vancouver, Washington-based company designed and built the machines to “deliver the highest power available in the smallest size,” says Michael Hepp, nLIGHT’s high power/Corona fiber laser product manager. The fiber lasers are available in 3kW to 10kW and they “set the stage for future power scaling in small form factors.”

The company also used the trade show platforms to introduce what they call disruptive technology that makes it possible for operators to change the size and shape of the fiber’s output beam without the cost or complexity associated with conventional designs. nLIGHT’s Corona CFX-5000 is the first commercially available fiber laser with programmable beam characteristics that combine the speed and cost of traditional equipment with a CO₂ laser’s ability to produce superior edge quality in thick plate.

Graphs compare 4kW fiber laser (top) with 4kW Corona fiber laser (bottom) in terms of cutting speed and measured edge roughness values.

Customer needs and market direction influenced the company’s research and development efforts. “I like to look back to put perspective on things,” Hepp says. In 2016,  a modest growth rate was forecast for fiber lasers. “Instead we found that fiber has all but replaced new CO₂ laser purchases.”

Road less traveled

Market analysis revealed several needs. To fill them, nLIGHT took a path somewhat different from that of other fiber laser manufacturers. Founded in 2000, the company produced high-power semiconductor lasers, pump diodes and specialty optical fibers. In March 2015, it launched its first fiber laser with power levels up to 3000W. By 2016, the company had shipped its 1,000th fiber laser machine with 6kW and 8kW models available.

“We noticed that field service was problematic,” says Hepp. “Job shops either had to wait weeks for help or, in some cases, ship the downed machine back to the manufacturer. We designed our equipment with a modular configuration so that it could be serviced in the field by tool integrators trained by nLIGHT.”

The company also “saw a lack of innovation. Advances tended to focus on increasing power,” Hepp continues. “But that’s a linear innovation. We chose to be disruptive by changing the shape of the beam inside the laser without the need for external components.”

The ability to rapidly tune the laser spot size allows the machine to accommodate all metals and thicknesses. Small spot size beams are best for cutting thin material and processing with nitrogen. Large donut-shaped beams cut thick material with the edge quality of a CO₂. Operators can switch back and forth from piercing to cutting plate with ease.

Beam diameters for a 4 kW Corona fiber laser with five Index settings; spatial profiles and BPP values.

With beam shaping, “you can cut multiple shapes without changing optics,” Hepp says. “This technology removes free-space optics, zoom process heads and external fiber-to-fiber couplers—all of which are complex, performance-limiting consumables.”

Part of the equation was building hardware into the laser capable of dissipating the heat from reflective light generated by such metals as aluminum and copper. Back-reflection protection allows fabricators to process the most reflective metals without damaging the laser.

Corona fiber lasers are available in 3kW, 4kW and 5kW. Beam spot sizes run from 100μm to 300μm with beam shapes from tophat to donut mode. Beam adjustments can be made in less than 30 milliseconds. Operators can make adjustments in real time to optimize processing without compromising power and speed.

“Prior to the development of the Corona, job shops struggled to find the most efficient way to laser cut material for diverse projects,” Hepp notes. “Now they have one tool that cuts everything.” Beam shaping itself isn’t unique to nLIGHT, but “we’re the first to do it inside the fiber itself and eliminate add-ons. It also reduces maintenance.”

A look ahead

nLIGHT fielded a lot of questions at the 2018 trade shows following its demonstrations. “There was a lot of excitement,” Hepp says. “Visitors were able to see the laser work in customer booths as well. We processed 1-in.-thick material. People almost couldn’t believe how good the edge quality was, compared to CO₂.”

A standard 4kW fiber laser cuts steel plate, leaving bottom edge slag and a concave shape (top). Steel cut by nLIGHT’s 4kW Corona fiber laser shows reduced roughness, better perpendicularity and a straighter edge.

Discussions also revealed that fabricators tend to think of two things—power and cost—when considering a fiber laser purchase. “I think we’ve introduced a third component to the dialogue,” Hepp says. “Now you have power, cost and edge roughness. It changes the decision-making process.” Companies must ask what kind of edge roughness they want with the power that’s required.

When asked about the future, Hepp points to Moore’s Law—coined more than five decades after George Moore deduced that “computing would dramatically increase in power and decrease in relative cost at an exponential rate.” Moore’s Law has become the golden rule for electronics and a platform for invention. It’s a concept nLIGHT embraces.

“We want to continue to improve fiber laser technology while reducing cost, increasing productivity and making changes easier,” says Hepp. “We’re going to continue to innovate.”

nLIGHT is already looking at welding applications for its Corona fiber laser line. Beam shaping offers the market space a flexible solution.

“Cutting is about 80 percent of the market,” says Hepp. “But what we found interesting was how excited welders are to have beam shaping at their fingertips.” FFJ