A fiber laser operating with shop air is producing high-quality cuts for Kendall Howard

May 2011 - Kendall Howard keeps growing. In 2010, while many businesses continued to struggle, The Chisago City, Minn.-based company grew by 55 percent. Randy Herreid, company president and CEO, knows to keep up with growth and maintain product quality, he must continue investing in the latest machinery.

"You have to always be almost a half a decade ahead of yourself or you won't be able to keep up with the insane growth," he says. Roughly two years ago, Herreid knew a laser would be the next equipment purchase for his company. "One of the big intermediate goals was to go from raw steel to a painted, ready-to-assemble part without a human being touching anything, so I started looking at the different brands of lasers,"" he says.

Kendall Howard manufactures IT furniture, server racks and rack accessories using press brakes, turrets, saws and robotic welders. The company focuses on automation and uses a 140 ft. long conveyor that runs the length of the assembly area. "There is only a handful of manual processes that happen in our shop. Almost everything is automated," says Herreid. "If I could foreseeably do it, I would automate the process from raw steel to in-the-box without a human being touching a thing."

Any laser system Herreid purchased would need to not only fit in with the automation on the shop floor but also meet additional requirements, including cutting with shop air. He also considered operating costs, maintenance needs, cut quality and consumables before choosing the L1Xe fiber optic laser cutter from Salvagnini America Inc., Hamilton, Ohio. The system features fiber optic technology from IPG Photonics Corp., Oxford, Mass.

"After he input the overall operating costs, the lack of maintenance you have on a fiber laser compared to a CO2 laser, the faster cutting speeds and higher productivity," Herreid chose the L1Xe, says Mike Flanagan, an owner with Advanced Machinery Inc., Plymouth, Minn., a distributor of Salvagnini products.

The fiber laser fit with the company's requirements, notes Herreid. "The cut of a fiber laser [and] the beam integrity is completely different than CO2. It's a totally different wavelength. It reacts with the metal differently,"" he says. "A CO2 does not bode well with shop air."

Quality cuts, low maintenance
Shop air posed a challenge for many of the lasers Herreid considered before choosing the L1Xe. For CO2 lasers, "one of the big problems when you don't cut with nitrogen is you get a coating on the edge of your parts. Typically with oxygen, it's the worst," he says. Most companies that cut with oxygen must manually remove the unwanted coating, a step that would be in opposition with Kendall Howard's emphasis on automation.

Herreid was "pretty specific about the expectations he had about machine performance," says Bill Bossard, president of Salvagnini. "The shop air requirement was one of the more challenging technical issues involved." Companies like to cut with shop air because it is less expensive than nitrogen, and it doesn't generate as much oxide as oxygen does, he says.

The fiber laser using shop air "actually bonds the burn material to the material itself so it can't flake off," says Herreid. His team tested everything cut with the fiber laser vigorously. The company powdercoats most of its products and it needed to ensure the paint would not flake off the metal near the cut edges. "The side effect of using shop air was that this carbon depositing bonds into the steel and can't be removed," he says. "We tried everything we could do to try and get the paint to come off, and it wouldn't."

Herreid mostly is cutting mild cold-rolled steel and some hot rolled with the laser. "We cut with perfect quality on 060 and almost no residue whatsoever with shop air, and we're hitting the same speeds they say we can do with nitrogen," he says.

Indeed, Kendall Howard is cutting faster than expected with the L1Xe system, says Flanagan. The cut quality, feed rates and tolerance of the machine all are exceeding expectations.

In addition to delivering high-quality cuts, the laser is operating without need for maintenance, notes Herreid. "The IPG laser has never been opened, maintained or anything because it's all solid state. There's nothing to do. There's no blowers to replace. There's no resonators to tune," he says. "You buy it and it never stops working because everything is solid state."

Overall, a laser is a very simple machine to maintain if one removes the issues with mirrors and beam paths associated with CO2 lasers, says Bossard. Fiber laser owners typically only will need to perform some small routine maintenance, such as changing filters.

"We have a very stable beam platform,"" says Mike Klos, general manager of IPG's Midwest operations. The spacial mode beam profile will not change over the life of a laser. ""If the temperature of the shop floor is 55 degrees in the morning and 100 degrees in the afternoon, that beam does not change. The laser itself is immune to vibration," he says.

Additionally, the cost of operation for a fiber laser is lower than a CO2 laser, says Klos. CO2 lasers can achieve roughly 10 percent wall plug efficiency, while the IPG fiber laser reaches roughly 30 percent.

Efficient material handling
Kendall Howard is using a Salvagnini load/unload system to deliver raw material to and remove cut parts from the L1Xe laser system. Herreid at first struggled with the decision to add the material-handling system or not. The company could pay a worker to pull the sheets on and off, which may be less costly than the system, "but when you factor in the fact that it never stops, it doesn't take breaks and every sheet is ready to go 22 seconds after the next one," the investment is worthwhile, he says.

Ultimately, the load/unload system enables the machine to run with far fewer interruptions than with manual labor, notes Bossard. The company is running the machine 24 hours a day, some of which is unattended.

"The automation is wonderful," says Herreid. "Because I load about 20,000 lbs. of steel into one end of the machine and the parts come out the other side, we don't touch anything." Kendall Howard arranged the material-handling system so it has multiple in-feed and out-feed tables so workers can remove jobs and add more material without the laser stopping.

The laser has enabled the company to quote and design products it never was able to manufacture before, says Herreid. "The jump in designs going from a turret to a laser is astronomical," he says. ""We can do things now we never would have even dreamed of with the turret." FFJ

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