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Direct benefits

At Fabtech 2015, direct diode lasers were presented, proving their enhanced cutting speed and quality

The recent annual gathering in Chicago for Fabtech 2015 was considered a huge success by everyone involved, gathering an international list of exhibitors and attendees at North America’s largest metalforming, fabricating, welding and finishing event. Covering the latest advances in all of these fields, the recent shift toward laser processing of metals in particular was obvious from the increased number of exhibitors in that field.

Among those processes, high-power, high-brightness direct diode laser technology has been the holy grail – for those visiting Fabtech as well as those who did not attend the annual event. Offering higher efficiencies and reliability at a lower cost when compared to the current state-of-the-art disk and fiber laser, TeraDiode Inc., a company that presented its recent products based on direct diode laser systems for cutting and remote welding at Fabtech, has been the first and only company to commercialize direct diode technology.

TeraDiode offers powers as high as 4 kW and BPP less than 4 mm.mrad that have been successfully used for cutting of metals with results showing superior speeds and edge quality. The company’s innovations have also been applied to remote welding of metals on sectors such as the automotive industry.This has been in collaboration with Panasonic Welding System Co. Ltd.

Performance improvements

The introduction of direct diode lasers into the cutting and remote welding application space, which was pioneered by Teradiode using patented technology from MIT Lincoln Labs, came with many benefits. These improvements in cutting performance over the existing fiber and disk lasers were highlighted by the benchmarking of cutting speed and quality presented by Teradiode at Fabtech. 

In the company’s Fabtech presentation, titled “High Brightness Multi-kilowatt Direct Diode Laser Applications Using Wavelength Beam Combining Technology,” the latest results using
2- and 4-kW TeraBlade direct diode laser for metal processing applications were presented, comparing them against other conventional near infrared lasers.

An example of the improvement in cutting speed is shown in Figure 1 on the following page where the speed of cutting aluminum using a 1-kW direct diode laser at 970 nm is compared with an industry standard fiber laser with similar beam quality (BPP~2.5mm.mrad). Clearly, the increase in cutting speed associated with the DDL (twice as fast at a thickness of 1mm) can be seen and is associated with the optimized laser wavelength for this material. Other materials show improvements in cutting speed although not as dramatic as the case of aluminum, where a 1-kW direct diode is cutting as fast as a 2-kW fiber.

Direct diode laser cutting of aluminum can double the process speed compared with typical fiber laser performance.

Improvements in cutting quality for thicker materials is also noted by many users of direct diode lasers and additional features incorporated into the direct diode laser, such as continuously variable BPP, further enhance these improvements in cut quality particularly for the thicker cross sections of materials such as mild steel.

An example of the cutting speed optimization obtained by varying the BPP is shown in Figure 2 on the following page, where a 50 percent increase in cutting speed for stainless steel (6- and 8-mm) is obtained by optimizing the BPP from the laser source, a 2-kW direct diode laser in this case. Variable BPP from the same laser, allows faster cutting speed of thin cross sections to be combined with the process optimization needed for thick materials.

With power levels covering the range 500 to 8-kW, direct diode laser technology is now poised to meet many of the key market segments currently covered by fiber and disk and offer an alternative to these technologies. Together, with higher wall plug efficiency and back-reflection insensitivity (making processing of reflective materials easier), the process improvements highlighted should further encourage migration to the latest industrial laser technology.

By optimizing the BPP for the process, improvements of 50 percent in cutting speed can be obtained.This tunable BPP option is available on standard Teradiode high power lasers.

Competitive edge

“Other advantages to direct diode lasers abound,” says Francisco Villarreal, Ph.D., senior director of laser application developments at TeraDiode. “They are unaffected by back reflections and include a pluggable fiber optic and field replaceable laser power modules. Ease of integration also comes as a standard on the TeraBlade laser systems together with a very competitive pricing schemes, all together making our laser an attractive choice to machine integrators and end users that are looking for a distinctive competitive edge, high performance product for their systems.”

At Fabtech, TeraDiode released the extended catalog of products that include the 6- and 8-kW direct diode systems with a BPP in the range of 6 mm.mrad using 120-micron fiber delivery cable. The company also released 1- and 2-kW laser systems with a BPP of 2.5 mm.mrad using a 50-micron fiber. All lasers are offering power conversion efficiencies of 45 percent. 

At the same venue, TeraDiode also released the continuously variable BPP (CVBPP) optional feature to its lasers. That allows the end user to fine tune the BPP delivered on the workpiece to further enhance the edge quality and thickness range for a given laser power. 

TeraDiode Inc. presented its recent products based on direct diode laser systems for cutting and remote welding at Fabtech and has been the first and only company to commercialize direct diode technology.

Teradiode was formed in 2009 and has been delivering high-power direct diode laser systems into the industrial laser market for the last three years, including 4-kW direct diode systems to Panasonic welding systems in Japan for incorporation into the LAPRISS remote welding system, most commonly deployed in automotive part manufacturing. In addition to Panasonic, other customers were also exhibiting cutting systems using high-power direct diode laser technology at the Fabtech event in Chicago this year.

Like many of the exhibitors at Fabtech, TeraDiode is a leader in its space. It has been since its conception of its laser innovation and will continue with this trend as many technological advances go through the company’s pipeline. On the scope of things to come, TeraDiode engineers plan to extend the technology to other wavelengths and to further increase power and beam quality. 

TeraDiode Inc.