G Whiz—20-kW Laser Cutting Machine Promises Accelerated Throughput

October 4, 2021

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“Where Metal Becomes Beautiful.” That’s how Shrock Fabrication, Bird-in-Hand, PA, greets visitors to its website—a simple description of a difficult task: custom manufacturing and mass production of components and parts for architectural and other markets from steel, stainless steel, aluminum, bronze and nickel alloys.

To meet its high-volume needs in sheet metal fabrication, Shrock Fabrication, in a 37,000-sq.-ft. manufacturing operation with 35 employees, relies heavily on its laser cutting equipment and capabilities.

“We cut a lot of 16-, 12-, 11- and 7-gauge,” says Kendall Shrock, the company’s general manager, noting that prior to purchasing a 4-kW laser cutting machine three years ago, “we were outsourcing tractor-trailer loads worth of laser work at a time. We finally decided that it would pay to have inhouse laser cutting for our current projects, and then get into new work.”

More Power, Greater Acceleration

That decision has led to consistent growth, with Shrock Fabrication adding 6-kW then 15-kW capability, and, most recently, ordering a 20-kW Eagle laser cutting machine from Fairmont Machinery (which also supplied the 15-kW model). In its laser operations, “we are specializing only in high-volume contract work,” Shrock says, noting that the 20-kW machine, being installed at press time, will help immensely in this specialization.

Both the 15- and soon-to-be-installed 20-kW machines are part of the Eagle iNspire series, which offers a top traverse speed of nearly 14,000 in./min. and 6-g acceleration. Design attributes in this series include a polymer-granite base structure, carbon-fiber bridge, linear-drive motors on all axes and rapid optical encoder feedback, which help achieve the rapid acceleration and the ability to cut more than 9 holes/sec.

“Going high wattage doesn’t necessarily deliver any productivity gains unless a machine has the high g forces (acceleration) associated with a carbon-fiber gantry and linear-motor system,” Shrock explains. “Normally, at more than 10 kW of laser power in a typical machine you wouldn't see speed increases in the sheet metal that we process, but because we have twice the g forces, or even as much as six times the g forces in our Eagle machines, we see a significant cycle-time improvement as power increases. Some machines offer only 1-g motion systems, but in ours, with acceleration to 6 g, we can utilize all of our 20-kW capacity on material as thin as 7 gauge. Without the fast motion, we could only utilize 10 kW of power. It is a combination of laser power and acceleration—we really can’t use that much wattage if we're slowing down too much in every corner.”

Targeting High-Volume Cutting to 1-In.-Thick

3-Laser-Cutting-Eagle-Inspire Though the new 20-kW machine will cut 1-in. plate with pure nitrogen, Shrock reports that by using mix gases, “we can add a small amount of oxygen into the nitrogen, delivering a faster and cleaner cut. But again, with the 20-kW machine we can use pure nitrogen or a nitrogen/oxygen mix to cut all the way to 1-in. thicknesses—cooler and faster, potentially four to six times faster in some situations than with pure-oxygen cutting. With the ability for fast and clean cuts, right we now are pushing for high-volume production contract work on material between 7 gauge and 1 in. thick.”

With the new machine’s high laser power, rapid acceleration and the ability to cut cleanly in the above-mentioned material-thickness range, “we can do something that we believe no one else in the industry can,” Shrock offers. “We can pierce a 1⁄4-in.-dia. hole through 3⁄4-in. material, so clean and fast using nitrogen that we can tap without a secondary operation. Normally, fabricators have to cut 3⁄4-in.-thick material with oxygen, but that doesn’t deliver a hole diameter and shape precise enough to tap it—the tap would break off. Secondly, the hardened surface would break the tap just by itself. Our material remains soft because we cut so quickly and coolly that the carbon steel does not crystalize.”

Aiding in this capability, the 20-kW Eagle machine, like the 15-kW Eagle, offers cutting tolerances to 0.001 in., considerably better than other machines in the shop.

Less Downtime

For increased uptime, Shrock Fabrication’s 15-kW machine includes automated part handling. As for the 20-kW machine, “not right now, as we have sufficient time for two people to separate parts from the sheets and unload that machine,” Shrock says.

The 15- and 20-kW machines, reports Shrock, also offer a design characteristic that contributes greatly to uptime.

“I have never replaced the protective glass laser lens on the 15-kW machine (the lens closest to the cutting surface),” he says. “Some lasers require replacement of that lens almost daily, or weekly.”

Why no replacement? The protective lens sits nearly 14 in. above the cutting surface—higher than most other machines on the market, according to Shrock.

“Protective-glass-lens replacement takes 10-15 min., but every time that chamber is opened for replacement brings the risk of a microscopic piece of dust landing on the protective lens and requiring another replacement when that lens fails,” he says. “With the protective lens located so high above the cutting surface, spatter doesn’t travel up that high and burn onto the glass, so we have yet to replace it.”

Adding the 20-kW machine to its laser cutting stable, Shrock Fabrication hopes to add another 1 million lb. worth of laser cutting per month.
“That's my next goal: Grow with the 20-kW machine, gain some diversity and take on heavier-plate cutting,” Shrock says. “We cut close to 1 million lb. now, and I think we could double it if we added that heavy-plate cutting.” MF

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See also: Fairmont Machinery/Eagle Laser