Fiber laser cutting: Beam Me Up
- April 29, 2018
Everything about fiber laser technology is fast, forcing the rest of production to keep pace
by Noelle Stapinsky
When fiber lasers made their first debut as a cutting technology for fabricators, the cutting quality wasn’t really there, and for the most part, they were only well suited for processing thinner materials.
But today, fiber laser technology is three to five times faster than C02, and the increased power opens the door to higher quality cuts and a larger range of material thicknesses, not to mention a better process for reflective materials.
“Going back seven years or so, I remember having meetings with other manufacturers in the industry about how the fiber laser wasn’t really going anywhere,” says Hank White, national product manager for Mitsubishi Lasers at MC Machinery Systems. “But now we’re seeing the opposite. I don’t want to use the word expediential, but it has grown a lot faster than any of us had expected.”
For Amada America, fiber laser sales were only five to 10 per cent in 2012. “As of 2017, our numbers are coming in at about 90 per cent,” says Dustin Diehl, Amada’s laser division product manager. “And we’re anticipating that almost all of our laser sales in 2018 are going to be fiber.”
For the past 30 years, the industry standard for C02 technology was 4,000 watts. There were higher wattages available, but Diehl says 4,000 watt was pretty much everybody’s benchmark. “As soon as we got to a 4,000 watt fiber laser, they were doing a lot more work than the equivalent wattage of a C02. And 6,000 watt fibers were doing two times the work of what that old benchmark was,” he says.
“Now we’re up in the eight, nine and 10,000 watt range. Those high wattage fibers are producing three to four times the amount of work of what people were used to producing.”
While increased power has allowed a broader range of material thicknesses, White says there are still some limitations. Anything over ¾- to one-inch, a plasma table or waterjet is best suited for achieving pristine cuts. “Processing thick plate on a laser or even a C02 is a little more difficult, and most machines are not rated for one-inch plate for any material type. But the potential is there [for fiber lasers]. Fiber lasers have taken a lot of guesswork out of processing. Older machines, like C02s took a little more finesse to operate and program.”
For fiber lasers, new technologies are in a constant state of development, making machines smarter. Operators and programmers have the ability to monitor the equipment, lens life and power output.
And since fiber lasers are solid state, maintenance is drastically reduced. “The technology is very stable,” adds White. “There’s really nothing that moves, so you don’t get that thermal distortion that you would see on a C02. With fibers, you don’t have any drastically degrading technologies, everything just works as it’s supposed to.”
Solid-state components also simplify the beam delivery, allowing fabricators to use fiber lasers to cut more reflective materials, such as brass, copper or titanium, which proved to be a risky process on C02 machines. “Using a one-micron beam you can cut reflective materials like copper because the beam is absorbed more efficiently,” says Brett Thompson, engineer for TRUMPF’s 2D laser cutting machines. “With a C02 laser, there was sometimes a worry about the kind of material or the quality of the materials. The one-micron beam gives us greater material flexibility.”
TRUMPF’s BrightLine has the ability to switch between two distinctly different beam ranges. The first produces a small beam for maximum cut speed and the second produces a beam larger than can be achieved with simple light collimation or focal length changes. “With BrightLine, people started to view the solid state as a universal choice. It’s not just a thin material machine, it can do thin, mid-thick and all the way up to the thickest materials without any worry about quality or process reliability,” he adds.
With the power ranges meeting the demand for speed, fiber laser suppliers are now shifting
their focus to processing and monitoring technologies, and addressing gas usage issues.
“One thing that we’re doing at Amada, is working on simplifying the fiber delivery system, meaning we’re coming out with higher power modules that allow us to use few components within the fiber engine source,” says Diehl. “What that means is a higher quality beam, a simpler delivery systems, lower cost of operation and less points of failure.”
Amada’s current fiber laser line up uses 3,000 watt modules, for example, that allow for fewer components and a lot less combining points. “Every time you combine modules, it’s a potential point of failure. So with larger, higher power modules, it simplifies that system.”
Higher power fibers have also all but eliminated piercing times, and drastically reduced burr issues. “The ability to pierce is so fast because of the fiber wave length of laser and you’re removing so little material. High power machines can pierce in a second, where in the past it took 30 to 40 seconds to cleanly pierce a thick plate,” says White. “Pierces are a lot cleaner, there’s less heat and you don’t have spatter going everywhere.”
And when it comes to burr-free technologies, White points out that the ability to manipulate the beam size and mode shape has been one of the biggest breakthroughs in fiber cutting part quality. “From what I’ve seen, the more power you throw at it, the cleaner the parts are. Fibers like to cut fast and the faster you go, the better.”
White says that nozzle technology and gas consumption and utilization are the next big focus for fabricators. Fiber lasers do consume more nitrogen than C02 and as more job shops get onboard with these cutting systems, they’re seeing big raises in their gas bills. Some are looking into nitrogen generation systems, air cutting is growing in popularity, and some suppliers are starting to experiment with how gas is directed and different gas blends. “You’re going to see how we direct the gas, through nozzle technology, what gases we use, and you might see that different blends of gas that give you different results,” says White.
A good example of a gas blending technique is by introducing a bit of oxygen to the nitrogen when cutting aluminum, which typically required a secondary process due to burring. “By introducing a little bit of oxygen in the cut, it will help with the thermal process,” says Diehl. “In the C02 world, cutting aluminum wasn’t always a favourite. Fiber technology allows not only increased speeds, but with the gas mixing technology, it’s allowed us to take full benefit of the fiber delivery source and we do get a very nice burr-free process.”
Different mix ratios are something Mitsubishi is testing. “Every time you change the ration of different gases, you get a different result, a different speed and colour on your edge,” says White. “We have seen up to a 50 per cent reduction in consumption with these combined technologies on some materials.”
TRUMPF’s Highspeed Eco nozzle is designed to decrease gas consumption. “It creates a seal on the surface of the material. The cool thing about it is that it’s able to move with contours, so if you have a little bit of a tip up, warped sheet or surface debris, your nozzle moves with the surface so you don't have constant pauses in the program due to the machine detecting constant collisions. It forces the nitrogen through the kerf and uses a slight fraction of the original gas pressure,” says Thompson. “We see an increase in cut speeds of up to 100 per cent, and a decrease in gas utilization of as much as 70 per cent, meaning that part has become really inexpensive to cut.”
To lower gas consumption, Amada uses a double nozzle technique and manipulates the venturis inside the nozzle to mix the gas flow as it surrounds the beam.
There are also reliability technologies on the market that detect nozzle damage from a collision, for example, and will automatically swap it out if needed, as well as monitoring technology that senses the cleanliness of the protective glass.
Next Stop: Automation
As more job shops employ fiber laser technology, the move towards automation has become more critical for process flow. The blanking and cutting divisions have become so fast in terms of processing, that many job shops are seeing bottlenecks shifted downstream to press brakes and welding, etc. Loading, offloading, and sorting parts is still a manual process in many shops.
What Amada, Mitsubishi and TRUMPF have noticed is an increase in orders for material handling automation to accompany their cutting technology.
“You can invest in the fastest laser, but if you cannot manage the increased part flow, you create a bottleneck and lose what productivity you hoped to gain,” says White. “You have to have fast automation and more intelligent software that can understand all of the processes and downstream operations.”
Diehl advises that with the every changing technology of the core blanking machines and laser cutting systems, fabricators need very flexible automation that will grow with the technology. “With almost every fiber laser order is some type of material handling system. As these machines are producing three to four times the amount of work, it’s hard for operators to keep up,” says Diehl. “Being able to integrate existing automation and the ability to add a tower or part loading robots is important. But choose an automation that can keep up with the machine and allow flexibility for future growth.”
With the need for speed and powerful fiber laser cutting technology on point, the new focus for fabricators is on cost per part and process flow. Having a machine waiting on an operator to keep pace is not ideal, and suppliers are at the ready developing flexible automation to help keep job shops flowing as they grow. SMT