Veli Kujanpää and John C. Ion
The use of lasers for materials processing is on the rise in Nordic countries, demonstrated not only by an increasing number of installed high-power lasers, but also by a growing attendance at the biennial Conference on Laser Material Processing in the Nordic Countries.
The number of high-power lasers (greater than 500 W) in the region tripled during the 1990s, noted Veli Kujanpää, chairman of the conference hosted by Lappeenranta University of Technology.
The market potential for laser cutting is still large, said Flemming Olsen, a professor at the Technical University of Denmark. The industry is expected to expand in flatbed sheet and three-dimensional component applications.
Lasers offer advantages in manufacturing automobiles, according to Johnny Larsson of Volvo Car Corp. in Gothenburg, Sweden. He noted three applications: welding of high-strength steel structures in the Ultralight Steel Auto Body project; Nd:YAG laser welding of aluminum panels to extrusions in the Audi A12 compact car to be launched in 2000; and diode laser welding of a plastic remote door-locking control for Mercedes-Benz.
Other speakers confirmed that laser welding has a firm and expanding foothold in the automotive industry, where the emphasis now lies on the use of improved laser sources and new materials, notably aluminum and polymers. One presenter described the use of hybrid techniques involving a laser beam and an arc as particularly relevant to the shipbuilding industry, in which thick section plates must be welded with minimal distortion.
A panel discussion addressed the future of laser materials processing. Several noteworthy observations and predictions emerged:
• The CO2 laser will continue to be the source of choice for welding and cutting of long linear and rotationally symmetric parts.
• As higher-power Nd:YAG lasers become available, their use for processing complex three-dimensional parts, as well as welding sections greater than 5 mm thick, will provide a feasible replacement for robotic arc welding.
• Flashlamp pumping will be used for pulsed Nd:YAG lasers, but efficiency improvements provided by diode pumping will lead to increased use in continuous-wave Nd:YAGs.
• Improvements will be made in the beam quality available from multikilowatt diode lasers, enabling them to be used for penetration processing of complex geometries by direct mounting onto an industrial robot.
• Of the new laser sources, the development of a disc Yb:YAG laser will be a major step forward.