The Light Fantastic
Increased use of fiber optic technology in lasers is making laser cutting equipment more productive and cost-effective.
By Myra Pinkham, Contributing Editor
Service centers and other metal processors are showing growing interest in fiber lasers—devices that use fiber optics rather than mirrors to focus the laser beam—which offer significant advantages over conventional CO2 lasers for some applications. While fiber lasers are not likely to supplant CO2 lasers any time soon, say the experts, they are likely to win market share over other cutting technologies and will no doubt expand the market for laser cutting equipment overall.
Fiber optic technology actually dates back to the late 1960s, but its commercialization for use in metal processing equipment extends back less than a decade. The first high-powered fiber laser used for cutting metal wasn’t introduced until 2008, according to William Brossard, president of Salvagnini America, Hamilton, Ohio.
Their power and utility have grown quickly, says Bill Shiner, vice president, industrial, for IPG Photonics, Oxford, Mass. Today, fiber laser models with up to 50 kilowatts of power are available, demonstrating both speed and depth of penetration never before achieved. He expects fiber lasers to eventually replace Nd-YAG lasers, used largely for welding applications, as well as a good portion of the CO2 laser market. Despite double-digit growth rates in the past few years, fiber lasers hold less than 2 percent of the global material cutting market, by some
Clearly, CO2 is still the leading laser technology for materials processing, including cutting and welding, says Stefan Schreiber, product manager for TruLaser products at Trumpf Inc., Farmington, Conn. Described in simple terms, such a gas laser uses radio waves or DC electricity to excite the electrons in a mixture of CO2, nitrogen and helium gases. As a result of the excitation, the CO2 molecules emit photons of light, which are amplified and collected in a resonator, forming the laser beam. The resonator contains turbines and a chiller to keep it from overheating. Mirrors are used to focus the beam into the cutting or welding head.
Fiber lasers take a whole different approach, explains Schreiber. A fiber laser is a solid state, diode-based technology with no moving parts. With solid-state lasers such as fiber and disk lasers, a ytterbium-doped YAG crystal is “pumped” with the light of a diode to excite the electrons and generate the photons of light. Fiber optic cables are used to transmit the light to the cutting head, with less heat and without the use of mirrors, which must be kept clean and properly aligned in a gas laser. The wavelength of the beam from the fiber laser is 1 micron, compared with the 10-micron wavelength of a CO2 laser beam. “As a result, its absorption capability is higher, which gives you higher cutting speeds in thin materials than with CO2 lasers. That helps you to cut faster with the same laser power in light-gauge material,” he adds.
Fiber lasers do well cutting steel sheet up to 3 millimeter thick—and can do so faster using the same power and without the nitrogen assist gas required by a CO2 laser. At greater thicknesses, however, the cutting speeds are comparable. Therefore, the cutting of thicker materials, at least at this time, is largely reserved for either plasma or CO2 laser cutting systems, Schreiber says.
Fiber lasers can cut certain reflective metals such as aluminum, copper, brass, silver and gold better than CO2 lasers, but cannot be used to cut plastics, wood or fabrics. Fiber lasers also cannot cut coated stainless steels or other plastic- coated metals in a safe way unless the coating is vaporized first, Schreiber notes.
Another consideration, fiber lasers present some serious eye safety issues, says Douglas Shuda, product marketing manager for Hypertherm Inc., Hanover, N.H. While a typical CO2 laser machine is rated at laser safety Class 4, a solid-state machine with a 1 micron wavelength should be placed in a laser safety Class 1 enclosure. Operators should wear safety goggles specifically designed for that wavelength. “The market is working right now to ensure that eye safety is appropriately addressed,” he adds.
Another big advantage of fiber lasers is efficiency, explains Markus Ruetering, product manager of laser sources for Rofin-Sinar Laser GmbH, Hamburg, Germany. While the CO2 laser has a maximum efficiency of 18-20 percent from the RF power fed into the gas in relation to the laser power generated, the fiber laser’s optical pumping energy vs. output power offers efficiencies of up to 82 percent. Given its “wall plug efficiency”—its efficiency as measured by the electrical power brought to the work piece and the amount of that power the laser consumes—fiber lasers could be considered a green technology, Ruetering adds.
Shiner at IPG Photonics agrees, estimating that fiber lasers have greater than 30 percent wall plug efficiency, vs. 8-9 percent for CO2 lasers and only 2-3 percent for Nd-YAG lasers.
Maintenance costs for a fiber laser are considerably less than for a CO2 laser, as well, Shuda says. On average, a CO2 laser owner needs to spend $20,000 to $40,000 a year to maintain mirrors and beam bending devices to optimize the beam quality. Every five years, the turbines that create the laser’s gas flow and the resonator gas inside the optical engine must be replaced at a cost of $10,000 to $30,000. With no mirrors and no turbines, fiber lasers require no such maintenance.
Although fiber and other solid-state lasers clearly have the advantage in terms of energy and maintenance costs, that is only part of the equation, notes Schreiber at Trumpf. “The big advantage of the CO2 laser is that high laser power is cheaper to buy up front, and high laser power in fiber lasers currently is not readily available.”
Depending on its power and features, the initial cost of a 5-by-10 foot fiber laser for metal cutting applications can range from the high $300,000s up to $900,000, vs. the low $300,000s to $800,000 for a CO2 laser, according to leading vendors.
While it is true that CO2 lasers have a smaller price tag, fiber lasers come out ahead in terms of the total cost of ownership, Shuda says. The initial cost of the fiber laser represents 90 percent of the investment over a 10-year period. The other 10 percent is the cost of electricity and consumables (gas, replacement nozzles, etc.). In comparison, the initial cost of a CO2 laser represents just 60 percent of the life-cycle cost, leaving another 40 percent for ongoing maintenance.
While the life-cycle cost for the fiber laser is definitely lower than that of the CO2 laser, some users are more price sensitive than others, Ruetering notes. “If you want to sell a machine in Asia, three things are important—price, price and price. In Europe, people think a lot about life-cycle cost and are willing to spend more to get a good return on their investment. In America, thinking is split, varying company by company.”
The bottom line for laser users, Schreiber says, is the final cost per part. “If you take a relatively low power fiber laser compared with a medium power CO2 laser, your productivity is typically higher with the CO2 laser cutting most materials other than light gauge, and that has a big influence on the cost per part.”
One factor that favors the proliferation of fiber lasers is the flexibility they allow in the use of cutting tables, Shuda says. CO2 lasers must be mounted on a table specifically designed for their use, and the table can only measure about 1 meter square because the beam can only travel a short distance. Fiber lasers, on the other hand, have no table size restriction, and a fiber laser and a plasma cutter could be mounted on the same table. “This could lower the overall barrier of entry to companies that want to cut fine features with a laser, but couldn’t do it previously without going to two cutting tables,” he says.
Despite the fiber laser’s advantages, Ruetering believes the CO2 laser continues to have a bright future. “It will lose some of its market to fiber lasers, but fiber lasers won’t take over everything. The two technologies will co-exist,” he says, estimating that fiber technology will win 25 percent of the market in the next two or three years.
Job shops that cut all kinds of materials—thick and thin, coated and uncoated—see the current generation of fiber laser as a limited tool, Schreiber says. But R&D departments throughout the industry are working to expand the technology’s capabilities.
“You can’t cut thicker material free of dross with a fiber laser today. If this can be addressed, it will offer more opportunities for fiber lasers,” Ruetering says. “We will have to wait another year or two before we know if there is a possible solution.”
Whether fiber lasers can overcome this technological roadblock, their ease of integration, flexible operation and low maintenance give them great potential, at least for thin-sheet applications, Shuda says. “Not only do you have the benefit of the fine feature cut quality, but you also get greater productivity. With the flexibility of the fiber laser technology, I think you will see the market for those kinds of applications explode and push up to thicker materials.”
|TRUMPF TruLaser 1030 Line Includes Fiber Option
TRUMPF, Farmington, Conn. offers two new options within its TruLaser 1030 product line. Initially available with the TruCoax 2000 diffusion-cooled RF laser resonator, the TruLaser 1030 has expanded to include the TruLaser 1030 fiber with TruDisk 2001 featuring 2.0 kW of solid-state laser power, and the TruLaser 1030 with TruCoax 2500, featuring 2.5 kW of power.
The TruLaser 1030, designed and built in the United States, provides users with a cost-effective and productive laser cutting system in a small footprint, the company claims. It requires half of the floor space of a typical 5-by-10 foot machine.
The TruLaser 1030 fiber with a TruDisk 2001 solid-state laser offers 2kW of laser power for cutting thin- gauge sheet metal and reflective materials.
For more information, visit www.us.trumpf.com.
Messer Cutting’s New FiberBlade
Combines Plasma, Fiber Laser
Messer Cutting Systems Inc., Menomonee Falls, Wis., offers its new FiberBlade system, which combines plasma and fiber laser technologies in a single cutting machine.
The Plasma/FiberBlade process is designed to incorporate both types of cutting heads on an integrated shuttle table with dual cross-axis cutting gantry so plasma and laser parts can be processed on one machine.
The FiberBlade is said to have comparatively low energy consumption, with a cutting power of 2.4 kW giving it the cutting capacity of a 3 kW CO2 laser.
To change plates, the cutting table or pallet is moved into the changeover area and a new preloaded pallet is transferred back into the cutting area. The cutting area of the FiberBlade is 6-, 8- or 10-feet wide and 10-to-25 feet long. Operating safety during laser cutting is ensured by a complete metal housing. Two cameras enable monitoring of the cutting process.
For more information, visit www.messercutting.com.
Hypertherm Packages Fiber Laser Cutting System
Hypertherm, Hanover, N.H., has released a new fiber laser cutting system that includes all components in one complete package. Hypertherm’s HyIntensity Fiber Laser HFL015 system includes the power source, cutting head, gas supply, operator interface consoles, motion controls and software.
The company claims the HFL015 is the industry’s first complete fiber laser system specifically optimized for cutting applications. The system dramatically reduces the complexity and operating cost of laser, enabling more businesses to apply fine feature cutting to their work and making it easier to produce consistent laser quality across a full range of materials and thicknesses.
Hypertherm’s system uses a low-maintenance solid-state laser source to generate a laser beam that is delivered through a fiber optic cable to the laser cutting head. There are no mirrors to maintain and calibrate and no lasing gas to replace. This fiber optic technology enables more flexible table integration without the table size restrictions associated with CO2 laser systems and is three times more energy efficient than traditional lasers, the company claims.
For more information, visit www.hypertherm.com.
Bystronic’s BySprint Fiber 3015
Designed for Power, Flexibility
Bystronic, Hauppauge, N.Y., offers the BySprint Fiber 3015, the company’s first production series model of a laser cutting system that employs fiber-laser technology.
Equipped with a 2 kW Fiber 2000 fiber laser, the BySprint Fiber 3015 is powerful enough to cut steel, stainless steel, aluminum and nonferrous metals such as copper and brass with high process reliability and precision, the company claims.
The laser beam is transported to the cutting head through a passive fiber, as opposed to the deflection mirror systems employed by carbon dioxide lasers. The result is lower operating and maintenance costs, in addition to significant energy savings from the Fiber 2000 laser source.
BySprint Fiber 3015 users will also benefit from fast cutting speeds and flexibility. The specially designed cutting head is available in several configurations, with focal lengths of 100 mm and 150 mm. Both the laser source and the chiller are integrated into the equipment control console, eliminating the need for additional floor space.
For more information, visit www.bystronic.com.
ROFIN FL 040 Offers 4 kW Power
Germany’s Rofin-Sinar Laser GmbH offers its FL 040 line of highly brilliant fiber lasers with an average output power of 4,000 watts. The lasers are said to offer high application speeds in thin sheet metals and are easy to integrate into 3D systems such as 5-axis machines or robots.
For more information, visit www.rofin.com.
Salvagnini’s L1Xe Fiber Optic Laser Uses Less Power
Salvagnini America Inc., Hamilton, Ohio, offers its L1Xe fiber optic laser, which uses less than 50 percent of the power consumed by conventional CO2 lasers to cut thin blanks. The light beam travels along a fiber optic cable that eliminates the need for mirrors with their attendant maintenance and replacement costs. The beam’s high density is said to offer higher cutting and piercing speeds.
The L1Xe system can also be equipped with Salvagnini material-handling options to automatically store incoming material, sort and stack parts and remove the skeleton after laser cutting is complete.
For more information, visit www.salvagninigroup.com.