Fiber lasers make their mark on thin-gauge cutting

The eyes don't lie. Solid-state lasers can hum.

I've seen these fiber lasers running at EuroBlech 2010 in Hannover, Germany, and FABTECH 2010 in Atlanta. Most recently I witnessed another "fiber" laser at INTECH North America, TRUMPF's customer event at its headquarters in Farmington, Conn.

The machine tool manufacturer fired up two of its own "fiber" lasers, the TruLaser 5030 fiber with 3 kW of laser power and the TruLaser 1030 fiber with 2 kW of power, for those fabricators and trade press in attendance. The TRUMPF "fiber" lasers are slightly different from other fiber lasers on the market in the sense that they rely on the company's own diode-pumped laser technology that uses a crystal disc as the medium to convert the laser into metal-cutting light. The only fiber-optic cable in the mix delivers the laser from the generation source to the workpiece. The other fiber lasers on the market actually use fiber-optic cable as the lasing medium.

At the TRUMPF event, the TruLaser 5030 fiber was cutting 0.060-in. steel, using nitrogen as an assist gas, at about 1,000 inches per minute. Someone watching a video of the cutting process in action might wonder if it were doctored because the torch head jumps so quickly from one cut to the next. Meanwhile, other manufacturers suggest that they can reach 2,000 IPM on their own fiber lasers. It's almost unbelievable.

So the technology is fast, but what's the lifespan of these solid-state lasers when compared to traditional CO₂ technology? When the fiber laser technology hit the market several years ago, people were saying 200,000 hours of operational life without major maintenance was possible. That number has come down appreciably since then.

"If you are talking about diode life, it can get pretty confusing," said Georg Treusch, director of diode lasers, TRUMPF Photonics. "Not any of us have 50,000 hours of diode technology in use [in metal fabricating settings]."

That 50,000-hour mark has emerged as a sort of reasonable goal that the machine tool manufacturers can live with happily. And it's one more reason that metal fabricators continue to be interested in the cutting technology. Other reasons include the solid-state laser technology's energy efficiency when compared to traditional CO₂ laser cutting machines, ability to cut reflective materials, and small footprint.

But the technology really is only for those fabricators that rip through a ton of thin-gauge material. The solid-state lasers can do the job of cutting thicker materials, but not as fast as CO₂ lasers can. That highly focused laser simply doesn't carve out the kerf necessary to dispense molten material in an efficient manner.

In the end, the solid-state laser is just one more tool for the fabricator's toolbox. It's not for everyone, but it will make some shops incredibly more efficient.