Direct-diode laser technology advances to take on fiber lasers

Figure 1. Mazak’s 4-kW Optiplex 3015 DDL laser cutting machine was up and running for the company’s Technology Days on Aug. 8-9. This laser cutting cell featured automated material load and unload and a conveyor that delivered laser-cut sheets directly to the machine operator for immediate parts sorting.

Is direct-diode laser technology getting to the point where it may overshadow fiber laser cutting technology in the near future? In early August metal fabricators learned that it already has in some instances.

These fabricators were attending Mazak Optonics’ Technology Days in Elgin, Ill., where they were given an overview of just where direct-diode laser technology is and how it stands out from other solid-state cutting machinery. They also had the opportunity to see that and other laser cutting equipment in action with live equipment demonstrations.

Mazak Optonics first introduced direct-diode laser generators to the market four years ago. The 2-kW laser generator was included in the company’s VCL T-100 tube laser cutting machine.

So what makes direct-diode lasers different from other solid-state technologies that have grown to dominate the market in recent years? In short, it’s a different laser-generating method that produces a different type of beam.

Direct-diode lasers don’t require “fuel” as other laser-generating methods, said Geoff Laughlin, a Mazak regional sales manager. The diodes generate the laser light, which is fed through diffraction grating to an output coupler. There are no YAG-doped fiber optics used to generate the laser in fiber systems and no gases needed to make laser resonators work in CO2 systems. Because it’s a “direct” process, direct-diode lasers have a wall-plug efficiency between 40 to 50 percent.

The direct-diode laser’s beam slightly differs from the other laser technologies as well. CO₂ lasers have a wavelength of 10.6 microns, and fiber lasers have a wavelength that is 10 percent of that—1.06 microns. A direct-diode laser has a wavelength of 0.94 to 0.97 micron.

“Think that little change doesn’t mean much?” Laughlin asked the fabricators in attendance. “I’d say, ‘You’re wrong,’ if you thought it didn’t matter.”

That tighter wavelength means that the direct-diode is able to cut faster than other competing technologies, Laughlin said. The direct diode laser beam has a higher absorption rate than fiber laser technology, which means more energy is converted to heat, which results in metal being cut at delirious speeds. For example, Mazak officials contend that fabricators can cut up to 15 percent faster in different material types and thicknesses with the direct-diode laser when compared to fiber technology and, in some cases, 30 percent faster when cutting aluminum.

The technology also delivers “the best beam in the industry,” Laughlin said, referring to the direct-diode laser that is devoid of a cool center or cool outer edges. The heat distribution is fairly consistent throughout the beam. Laughlin added that the technology’s quality beam mode and Mazak’s beam manipulation advances help to produce a laser than can cut thick materials with fiber-like speed and with CO₂-like quality.

Attendees got to see the technology in action on Mazak’s 4-kW Optiplex 3015 DDL (see Figure 1). It also gave fabricators a chance to see the company’s new Preview G machine controls and 2G acceleration drive package on the machine.

Although no official announcement was made, Marc Lobit, Mazak’s general manager, sales support, said that fabricators could expect to see more direct diode laser advancements at FABTECH® in Atlanta, Nov. 6-8.

In addition to the direct diode laser technology, attendees also got a chance to learn about material automation options for laser cutting machines and Mazak’s iSMART Factory shop management software. In the showroom, they were able to witness Mazak’s Optiplex 8-kW fiber laser, 3-D Fabri Gear 400 III tube cutting machine, and the VCL Tube 100 tube cutting machine in action.