IPG Photonics, operating from its three manufacturing plants in the U.S. and Europe, has begun to gain market share on its extensive line of industrial single-mode and multimode fiber lasers.
Single-mode lasers
Single-mode fiber lasers with their perfect beam characteristics, air-cooled operation, high efficiency, and compact size are continuing to gain market share worldwide. For example, IPG Photonics has installed more than 2,500 units worldwide through 2003. Customers for this technology come from the microelectronic, medical device, printing, and micromachining industries where they are used for applications that include high-speed printing, engraving, sintering, marking, controlled bending, spot welding, keyhole seam welding, annealing, soldering, ceramic scribing, silicon cutting, precision cutting, and high-speed drilling. In most cases the fiber laser's success has been a result of superior performance with companies that were already familiar with and currently utilizing laser technology.
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The beam from single-mode fiber lasers can be focused to small spot sizes with long focal length lenses with consistent beam properties independent of power level or pulse duration, advantages that improve the processing parameters compared to other lasers. For example, when cutting silicon, the continuous-mode fiber laser produces crack-free results with minimal remelts, which results in a substantial increase in the processing speed and a decrease in post processing compared to Q-switched lasers that are currently being utilized for this process. In the cutting of flexures and thin metal components, the fiber laser's ability to minimize the heat due to an increased processing speed and small spot diameter has been unlike any previous processing results. IPG, for example, has delivered 10W lasers that can produce the power density necessary to keyhole weld, a feat that has never been previously demonstrated consistently.
Ytterbium single-mode fiber lasers with an M2<1.1 have continually increased in output power to the current 600W level. These fiber lasers can be focused to 10- or 15-µm spot diameters with a perfect Gaussian distribution, producing power densities that had not been achieved on a commercial basis at the 1-µm wavelength. These lasers may be of interest to the two- and three-axis cutting markets where they could provide high-quality deep, narrow welds in materials requiring minimal heat distortion. Tests have shown that for high-speed cutting these lasers can effectively compete with CO2 and Nd:YAG lasers that require multi-kilowatts of power.
Marking lasers
Q-switched fiber lasers for marking applications have attained a leading position in market share in the demanding Asian market and are now making inroads into the European and U.S. markets. These lasers, like other fiber lasers, utilize the same technology that features a monolithic configuration, long diode life, compact size, and maintenance-free operation. Models from IPG are available with 0.5 mJ, 1 mJ, and 2 mJ per pulse with average power levels to 200 W and near single-mode quality. Pulse durations in the nanosecond region produce the high peak power necessary for high-quality marking. To date, more than 2,000-pulsed lasers have been installed in Asia, North America, and Europe.
The first beta kilowatt fiber laser units were installed in a variety of laboratories, select end users, and integrators as a means to gain experience relating to the issues of their operation. These installations provided invaluable feedback allowing major improvements in the robustness of the fiber delivery cables, the control interfaces, and safety. The process data provided for additional improvement in the beam quality and development of qualified vendors for the beam delivery components. Various data on a wide range of applications showed that the processing results in both welding and cutting matched, and in most cases exceeded the quality and speeds of conventional lasers operating at the 1µm region. The first 1kW fiber laser unit was introduced by IPG in May 2002 and was quickly followed with the 4kW introductions in November 2002. A 10kW laser was released in March 2003. As of December 2003, the company has shipped 24 multi-kilowatt units for production applications in the U.S., Europe, and Asia.
The majority of the systems are being utilized for welding applications in the automotive and shipbuilding industries, with several units also being employed for cutting and powder deposition applications. While the market for high-power lasers is exciting, significant time and effort must be employed in order to gain the acceptance and understanding of this new technology from potential users. Unlike the lower power applications, where dramatic change and rapid acceptance has occurred in the types of lasers that are being utilized, the high power market has been using the same types of lasers, Nd:YAG and CO2, for several decades.
A challenge facing suppliers of high-power fiber lasers is the preference by users for older, proven technology rather than their becoming pioneers of advanced technology. The wide spread adoption of kilowatt fiber lasers is, however, inevitable as engineers realize the performance advantages that this technology brings to the manufacturing floor. By eliminating the need for realignment, maintenance, and constant monitoring of beam quality, users will be able to ensure their quality objective is achieved and maintained.
Other wavelengths
Although the principal wavelength for industrial applications is currently in the 1060-1085 nm wavelengths range, a great deal of interest has been generated for lasers operating at other wavelengths. The beam from Thulium fiber lasers, operating from 1800-2100 nm, is highly absorbed by some distributed plastics, which are transparent to the Ytterbium emission, and they have been used for both marking and 3D stereolithography. This laser is available from IPG with single-mode outputs of up to 150 W. The company is also proactively investigating the performance of this wavelength on a wide range of materials to determine the advantages they may offer to material processing markets.
Erbium fiber lasers are available with single-mode power to 200 W and can also be combined to produce kilowatt levels. Operating with a central emission wavelength of 1540-1550 nm, Erbium has two major advantages for industrial applications. The first is its wavelength, which is beyond the absorption wavelength on the retina, making it orders of magnitude safer in an industrial environment. The second is that the transmission through a fiber is the highest at 1540 nm, and the loss, < 4 percent per kilometer, allows for kilowatts of power to be delivered great distances through fiber for remote and distributed applications.
New fiber lasers
The 1mJ, 80ns Q-switched marking laser features 20 W of average power.
IPG has recently introduced a single-mode visible fiber laser operating at 775 nm with 2-ns pulse duration and average power of 30 W. This device operates at a frequency to 10 MHz and is currently being evaluated for micromachining and micro-drilling applications. Mid-year, the company will be releasing for production an ultraviolet laser with 4 W of power from a single-mode fiber as well as the first industrial-grade 10 W green fiber lasers.
Other advances
The important beam product parameter has consistently improved in the kilowatt class lasers. The requirement for applications such as remote welding for the automotive industry has stimulated the improvement of beam quality. The latest 10kW laser from IPG is now available with a beam product of <10 for a 10kW laser and <6 for a 5kW laser. In the diode area, continued advancement in the output power available from a single diode, higher efficiency coupling of the diode energy and a smaller diode package size has resulted in reduced physical size, less number of diodes, and consequently less capital investment for fiber lasers. The power level for single-mode operation is currently at 600 W with an 800W unit soon scheduled for release.
Conclusions
The market for fiber lasers utilized for material processing has expanded rapidly over the past year. The fiber laser is a direct substitute for current Nd:YAG systems, offering better beam quality with the same, or in most cases, improved performance with the added benefits of the high wall plug efficiency, compact size, and maintenance-free operation. Applications and shipment volumes have favored units below 1 kW as that market size is larger and user acceptance of new technology is immediate. The kilowatt level will take longer to penetrate established markets, but the market will expand as laser users and integrators understand the benefits that fiber lasers will bring to the production floor.
Fiber lasers will expand the overall market for utilization of laser technology in material processing due to the additional wavelengths, portability, high transmission through fiber, and their unparalleled reliability.
Bill Shiner is sales manager, industrial products, at IPG Photonics Corp., Oxford, MA. For more information, visit www.ipgphotonics.com.