Laser welding of aluminum car bodies - From research to production

Abstract

Aluminum as a light weight material has become more and more important for car body construction in the past few years. The laser which has been very successfully applied to steel for many years can also be used for welding of aluminum. Nevertheless, the laser is rarely found as a tool for joining aluminum in series production, up to now. Among others this is due to the fact that the existing literature does not provide any hints concerning essential issues for series production by laser with respect to weldable tolerance zones and permissible limits, e.g. the maximum bridging of gaps or the welding out of position.The paper presents exemplary solutions to the problems mentioned above, resulting from the application of a 3 kW fiber-guided Nd:YAG-Laser. Taking the example of an aluminum car body, the possible combinations of aluminum alloys and joining geometries are shown. The tolerance zones referring to mismatch of the beam are pointed out for overlap and butt joint geometries - using a six thousand series alloy which is sensitive against hot cracks. Furthermore, it is demonstrated which size gaps can be bridged with filler wire and in which constrained positions a secure and stable process is possible. The experimental setup, especially the processing head which facilitates these experiments is presented.Aluminum as a light weight material has become more and more important for car body construction in the past few years. The laser which has been very successfully applied to steel for many years can also be used for welding of aluminum. Nevertheless, the laser is rarely found as a tool for joining aluminum in series production, up to now. Among others this is due to the fact that the existing literature does not provide any hints concerning essential issues for series production by laser with respect to weldable tolerance zones and permissible limits, e.g. the maximum bridging of gaps or the welding out of position.The paper presents exemplary solutions to the problems mentioned above, resulting from the application of a 3 kW fiber-guided Nd:YAG-Laser. Taking the example of an aluminum car body, the possible combinations of aluminum alloys and joining geometries are shown. The tolerance zones referring to mismatch of the beam are pointed out for overlap and butt joint geometries - using a six thousand ser...