Advancements in Laser Gas Shielded Welding Technology

In laser gas shielded welding technology, along with the emission of the laser beam, two gas shielded welding arcs also act on the molten pool, with three welding nozzles integrated into an automatic welding head. The additional welding arc creates a fundamental difference between laser gas shielded welding technology and traditional laser hybrid welding technology. On one hand, there is fierce competition between laser welding technology and arc welding technology, while on the other hand, their combination has innovative effects. In the so-called laser gas shielded welding technology, the combination offers higher welding efficiency and cost savings. During the 2001 Welding and Cutting Professional Exhibition, Fronius Company showcased practical and economical laser gas shielded welding equipment for the first time. Since then, a total of 65 sets of such welding equipment have been put into industrial applications for mass production in the automotive industry. In automotive manufacturing, these laser gas shielded welding devices are used for welding structures such as axles, doors, and roof frames made of aluminum alloys and steel, with a maximum welding plate thickness of up to 4mm. Development of new laser gas shielded welding Fronius plans to launch welding and cutting equipment that combines laser and two protective welding electrodes in 2009. The series of equipment utilizes laser gas shielded welding technology, which integrates the advantages of both laser welding and gas shielded welding processes. Its diversity of applications and specific advantages stem from the coexistence of the laser and gas shielded welding nozzles in one automatic welding head, while the laser welding beam and two gas shielded welding arcs act together on the molten pool of the workpiece. The first welding experiments that combined laser welding and gas shielded welding can be traced back to the 1980s. However, for 20 years, this technology has remained in the laboratory and has not stepped out of the lab. In this hybrid welding process, the laser beam and protective welding arc act simultaneously on the weld seam of the workpiece. The laser beam melts deeply into the workpiece with extremely high energy; the MSG gas shielded welding system continuously supplies welding material while emitting the welding arc, forming a wide and flat surface weld. This hybrid welding technology combines the advantages of laser welding (high welding speed, small heat-affected zone, deep weld) with the advantages of gas shielded welding (good weld connection capability, high weld strength, and the ability to purposefully improve weld quality through the use of welding materials). Based on the application experience of laser gas shielded welding, users hope for more powerful functions in laser gas shielded welding equipment, focusing on solving the welding of thicker steel plates, with better melting methods and faster welding speeds. According to the process analysis and usage evaluation by Fronius technicians, the hybrid welding technology of laser plus two protective welding electrodes is considered the best solution. In this solution, the main issue is to integrate the laser welding nozzle with the two gas shielded welding nozzles into an automated welding head that is as small as possible, with the distance between the laser welding beam and the arc being minimized (as shown in Figure 1). In addition to the factors of welding technology, the size and motion performance of the welding head, as well as accessibility, are also technical issues that need to be addressed.