Since the advent of ultra-high-power lasers, defined as 12 kW or higher, machine tool manufacturers continue to discover new benefits of this relatively new technology. At LVD, a recent discovery that is proving beneficial for heavy-duty applications is the use of ultra-high-power lasers when combined with large-format cutting tables.
The result is the Taurus XXL fiber laser cutting machine, which Stefan Colle, laser product sales manager at LVD, describes as having “tremendous flexibility and essentially no length or thickness limitations.” These characteristics give the machine the ability to rival plasma for large-scale cutting needs, which is why this type of equipment is sometimes referred to as a plate laser.
After its release, LVD gained critical market insight, propelling the company to explore further areas for product development, including the addition of bevel cutting capabilities as well as the expansion of table sizes for other pre-existing LVD laser cutting machines.
Plasma vs. laser
Prior to the release of these ultra-high-power lasers, plasma was the cutting process of choice based on its speed and ability to handle thicker materials. For the most part, plasma could do the job, but sometimes the cuts weren’t always straight. With fiber lasers, however, the kerf/curve width is much smaller, so the accuracy and straightness of the cut is inherently improved.
One of the other aspects of plasma cutting that previously gave it a leg up on laser cutting was the ability to do bevel cuts. Understanding that fabricators need to produce these types of cuts, LVD added an optional bevel head to the Taurus XXL that cuts up to 45 degrees. The reason these deep bevel cuts are so critical is that they offer an increased surface edge that provides a longer, wider area on which to weld.
“As a result, whatever is being welded becomes stronger,” Colle says. “These companies are making bulldozers, excavators and heavy-duty, off-road vehicle equipment. The more they can do to make them stronger, the better.”
Furthermore, when cutting with fiber laser instead of plasma, fabricators can avoid the all-too-common issue of cutting through the slats or cross members that support the material as it’s being cut. Based on the time and cost involved with replacing these slats on a regular basis, fiber lasers win out yet again.
Another common trait among plasma users that LVD took into consideration when developing the Taurus XXL was the use of manual material handling as well as overhead cranes that are equipped with magnets, suction cups or vacuum systems. Because these large plasma cutting tables are so long, material handling often happens on the table with workers standing on one end of the table while the machine cuts at the other end. Knowing this, the machine is equipped for this type of operation and, therefore, all of the necessary safety technology comes standard.
As an example, when the gantry is approaching, anyone standing on the table receives a warning signal. If someone is in a critical zone, the machine stops. The same thing is true if material is being moved nearby with an overhead crane. The gantry has technology onboard that can detect that material hanging in the air, reducing the potential for collisions to essentially zero.
Colle says LVD was prepared for these scenarios because it’s what happens in plasma cutting every day in the real world. “There are companies that have machines that accommodate three 40-ft. plates on one large table. When it’s cutting one plate at the front, the remaining plates can be loaded and unloaded. We took the design of these plasma systems into major consideration when designing the Taurus XXL.
“Because of these features and the improved accuracy and repeatability, we can focus on applications beyond something like a metal service center that just needs to cut large thin sheets every day,” Colle adds.
Prior to the development of ultra-high-power lasers, metal service centers were a primary market for large-format tables. And while that’s still the case, the application possibilities have greatly expanded. With fiber lasers becoming so powerful, not only can they cut faster than plasma, but sometimes, they can cut thicker. Ideally, the top thicknesses for 20-kW lasers are 1.5 in. for mild steel, 1.5 in. for aluminum and 1.25 in. for stainless.
Based on the high range of thicknesses that are possible, industries that perform heavy plate work – off-road, agricultural and shipbuilding – are all big markets. Potential users also include anyone that needs to minimize the amount of visible welding seams for aesthetic or performance purposes. Fire trucks, which use a lot of diamond plate material, are a good example. These vehicles require minimal welding seams, so the large table is incredibly helpful for cutting long parts out of long plate. The same goes for the production of military vehicles because of all the thick armored plate involved.
A quick list of those that might be interested in large-format fiber laser cutters, therefore, includes shipyards, heavy-duty fabricators, companies that fabricate a lot of stainless steel, off-road and agriculture, producers of truck trailers and basically any manufacturer that makes longer, aesthetically important parts that can’t have a seam. And that’s just the short list.
“Companies that work with stainless steel are especially interested in fiber laser technology because the wavelength absorbs into stainless better than previous lasers,” Colle says. “And that translates into cutting thick material beautifully and fast.”
Recognizing the broad range of applications, LVD will release a new more economic Taurus XXL later this year, opening the doors to even more potential users. Currently, LVD offers five models, but these standard machines can be customized in a variety of ways.
Models and sizes
While there are several standard models to choose from – the 10-m Taurus 8, 14-m Taurus 12, 18-m Taurus 16, 22-m Taurus 20 and 26-m Taurus 24 – the Taurus XXL machines are modular, meaning the tables can range in size from about 30 ft. in length to about 140 ft. To accommodate customers’ custom table length requirements, LVD builds two base frames that are 20 ft. long and 14 ft. long that have lengths that can be extended by adding additional frames to the base.
Regardless of the size, whenever LVD is commissioned to build a new machine, the first order of business is to test the gantry. Once the efficiency of the gantry across the table length is verified, the machine can ship and is completely set up at the customer site. The only caveat is that the 20-kW option isn’t available on the Taurus 24 and longer LVD Taurus machines.
“The fiber that’s attached to the laser source can’t carry 20 kW of power all the way to the end of the 140-ft.-long machine,” Colle says. “This is dictated by the manufacturer of the laser source, which currently states that 20 kW is only effective up to 22 m, which is possible on the Taurus 20 model. Above that length, you have to come down in power to 12 kW, 10 kW or 8 kW, but we can do beautiful work with that amount of power.”
Tech to expect
In addition to releasing the more economic Taurus XXL later this year, LVD has also added larger tables to its Phoenix line of fiber laser cutting machines.
“We had no idea what the bevel head would mean to us in terms of opportunities, but what we discovered is that there are people that don’t need an extra-large table but do need to bevel cut on a larger-than-normal table,” Colle explains. “They also need to quickly switch out materials on a regular basis, which is possible on the Phoenix thanks to its shuttle table.”
Previously, the largest Phoenix was the 20-ft.-long-by-6.5-ft.-wide 6020, but today, it’s now offered with a 22-ft.-long-by-8-ft.-wide table along with the bevel head and shuttle table options. “Without any added automation, just the shuttle table time, fabricators can drastically reduce their idle times,” Colle adds.
Of course, any advanced technologies that can reduce the need for skilled labor are in high demand in today’s challenging workforce. The Phoenix comes stacked with advanced automation and so does the Taurus XXL, which features a fully automated nozzle changer as well as beam modification capabilities up to 12 kW.
Unsurprisingly, it features a larger-than-normal nozzle carousel with 30 pockets. For comparison, the standard Phoenix has 17. The difference is that the Taurus XXL has the optional bevel head, which requires conical nozzles.
“When cutting a bevel at 45 degrees, we don’t want the nozzle to touch the material, so it has to be machined into a cone shape,” Colle says. “That means the nozzle changer includes all of the bevel nozzles as well as the standard nozzles for straight cutting.”
With the automatic nozzle changer, both types of nozzles are constantly monitored by a camera to ensure the alignment is correct and the nozzle isn’t contaminated. The technology also monitors the lifespan of the nozzle. If the nozzle is out of alignment, contaminated or is simply near the end of its lifespan, the nozzle changer will automatically replace the old nozzle with a new one.
In terms of beam modification, Colle explains that the 12-kW limitation is ultimately dictated by the manufacturer of the cutting head. To a certain degree, it is also dictated by physics.
“A 20-kW laser is a different animal,” he says. “Its focal length needs to be longer than lower power lasers. In a nutshell, the focal length is what reduces the beam of the laser into a small focal point for cutting, and that involves some optics – a lens and a window.
“The lens is protected from back spatter by the window, which is expensive and time consuming to change out,” he continues. “With the 20 kW, there’s a lot of molten material that could hit the window, which would increase the amount of times that you would have to change out those windows.”
After excessive testing with a variety of focal lengths, LVD landed on the sweet spot of 250 mm (10 in.) – enough to perform well with thick and thin materials and enough to keep the window away from possible contamination. The issue, however, is that this length doesn’t accommodate the sophisticated beam modifications that are available on a 12 kW.
“Fortunately, the 20 kW does provide automatic focus, and often, that’s all that these types of fabricators need,” Colle says. “Often times, the main priority is edge quality. With the 250-mm lens, you have a curve width that is more than sufficient to evacuate the molten material without having to force it.”
As machine manufacturers like LVD deepen their experience with ultra-high-power lasers, the industry will continue to benefit. After all, it wasn’t that long ago when the speed of these lasers was the only benefit being discussed.