Above: A 6kW fiber cutting ¼-in. mild steel with nitrogen at a speed of 200 IPM can take the place of two CO2 machines and make more parts for a fraction of the floor space, operations and electrical costs.

Maintaining laser beam quality in the face of expanded power levels

October 2016 - Albert Einstein said that “life is like riding a bicycle: To keep your balance, you must keep moving.” It’s a principle that Amada America Inc. understands. Since introducing its fiber laser technology in 2010, the Buena Park, California-based  manufacturer of metal processing machinery has pushed the power envelope while working to equalize edge quality and cost improvements over that of a CO₂ laser cutting system.

“When fiber first came out, it cut faster but there was a gap in edge quality when compared to CO₂,” says Jason Hillenbrand, general manager of blanking products for Amada. “Poor edge quality was most notable in materials 11 to 12 gauge and thicker. Six years later, there’s little a fiber [machine] can’t do that a CO₂ [machine] can. The industry has seen a big jump in edge quality; and 4kW, 5kW and 6kW fiber laser machines are now the norm.”

In 2015, fiber equipment outsold CO₂ systems for the first time. “Roughly 60 percent of industrial laser cutting was fiber,” says Hillenbrand. “I wouldn’t be surprised to see that number climb to 75 percent or better this year. There’s certainly more interest in higher wattage fiber lasers.”

In the U.S., he continues, “everyone wants the fastest cutting speeds they can get but they also want the best quality. It’s difficult to blend both characteristics in the same fiber machine but we’ve been able to find a good balance between the two.”

This Amada EG Series automated robotic bending system keeps pace with the output of a high-powered fiber laser.

The task at hand

Close monitoring of the rapidly evolving market and customer feedback have helped Amada focus its development efforts in several key areas. Initially the industry measured fiber speeds three to five times faster than a CO₂ cutting system, but being able to maintain beam quality and contain costs can be problematic for some users. Amada sought to accommodate increasing power levels going to the machine without compromising beam quality.

“Improved diode pump technology allowed us to increase output wattage for the fiber laser itself,” says Hillenbrand. “We can go from 4kW to 6kW without undermining beam quality. The laser is as bright and sharp on the 6kW as it is on the 4kW except that customers can cut faster with excellent edge quality.”

Higher-kilowatt systems have been possible for a long time, he notes. “What was lacking was pump source technology that could produce high output power while maintaining high beam quality.”

Measuring performance

A fiber laser’s beam quality is defined by Beam Parameter Product or BPP.  Beam radius and beam divergence measurements produce BPP, which is used to specify a laser’s beam quality. A higher beam value equals reduced beam quality. Low or smaller BPP means higher beam quality which results in improved cutting performance. 

Peripherals have also come of age because of fiber’s rapid evolution. “We offer a gas mixing unit that allows us to finitely mix oxygen and nitrogen for effective cutting of materials like aluminum,” Hillenbrand says. “Cutting aluminum on a CO₂ is an accepted, commonly used practice, but the alloy doesn’t readily absorb the machine’s wavelength, which raises the risk for reflection. Aluminum is also hard on consumables and shortens nozzle life. 

“Fiber’s shorter wavelength is more easily absorbed by aluminum,” he says. “Our mixer gives customers a more exact gas formula. The combination is producing edge quality and cutting speeds that we’ve never seen before. And in some cases, cutting jobs are running faster than those that just use gas or shop air,” he says.

At Fabtech 2015 Amada introduced a new high-powered fiber laser that incorporates the benefits of Clean Cut  for thicker materials. Historically, operations use oxygen to process midrange materials like 1⁄4 in. to 3⁄8 in. and thicker. A fabricator must typically reduce power output when using oxygen as an assist gas, which also means slower cutting speeds. 

An Automation Seminar at Amada’s Schaumburg, Illinois Solution Center.

Versatility improves

“When people think about faster cutting, they usually associate speed with thin materials,” explains Hillenbrand. “When you got above 1⁄4 in., you switched over to oxygen. Because we can now maintain a fiber laser’s critical beam qualities at higher kilowatts, we can use nitrogen on thicker materials and achieve incredible results.”

For example, he says, a 6kW CO₂ laser might cut 1⁄4-in. mild steel with nitrogen at 120 to 130 inches per minute (IPM). Today, a 6kW fiber will cut 1⁄4-in. mild steel with nitrogen at over 200 IPM. Therefore, “one fiber laser can now take the place of two CO₂ machines and produce more parts with a fraction of the floor space, maintenance, consumables and electrical costs.”

Associated tasks

Following Einstein’s logic, Amada maintains its forward momentum by anticipating what’s ahead. In addition to automating peripherals like nozzle changers, the equipment supplier has developed faster material load and unload systems. Amada is also helping customers answer a crucial question: “Now that I have a faster fiber laser, how do I handle downstream processes?”

The machinery builders’ engineers have been working on a faster material load/unload system, says Hillenbrand. “Some processes that can take up to 10 minutes on a CO₂ we’re doing in 2 minutes on our fiber lasers. Getting material on and off the machine has become increasingly important. It has also forced us to look at what needs to happen downstream.”

Amada developed an automated bending machine that can keep pace with its fiber laser and material handling solutions. “You can end up slowing your high-powered laser to a crawl if you don’t address your downstream processes,” Hillenbrand says. 

During a recent automated bending seminar at Amada’s  Solution Center, Mark Lindquist, operations manager for Rapid-Line Inc., Grand Rapids, Michigan, talked about how his company handled bending challenges with its Amada high-speed fiber laser.

The numbers don’t lie. With Amada’s automated bending solution, Lindquist reported that setup times fell by 88 and 92 percent. The machine’s auto tool changer allows Rapid-Line operators to achieve in 2 minutes what it would take an operator an average of 45 minutes to accomplish with conventional equipment. 

Lindquist was also able to raise production without expanding the machinery footprint and run lights out, eliminating the potential for human error and the need for skilled workers.

Hillenbrand doesn’t see the appetite for automation slowing. “People want to control everything with their smart phone. They want to push a button and see the system start up. If there is a problem, they want to know about it right away so they can address it immediately.” 

Amada is in the middle of this evolution. Using customer intelligence, “along with what we’re seeing in the industry and what our R&D facilities worldwide are telling us, and combine data to identify where we need to focus our energies and resources. The result is, we’re turning out new products every year to support the needs of a quickly changing market.” FFJ