Welding of aluminum: Challenge and chance for laser technology

Abstract

Increasing demand for light-weight structures leads to enlarged use of aluminum alloys. The application of these materials is handicapped by a lack of productivity and reliability of available joining techniques, however. Laser welding of aluminum, on the other hand, turned out to be markedly more difficult than the treatment of steel. Difficulties to overcome threshold for deep penetration welding, the occurence of material related defects and seam deficiencies such as cacities and blow holes discourage production engineers from making use of lasers.A theoretical analysis reveals requirements that have to be fulfilled by laser systems in order to obtain process stability. In comparison to steel better focussability and shorter wave-lengths are needed. An intensity distribution leading to a v-shaped key hole is beneficial, too. The results of this analysis are confirmed by welding results obtained with CO2 and Nd:YAG-Iasers. An increase in process stability is observed when dual beam technique or the shorter wave length laser is applied. In conclusion, welding of aluminum alloys with appropriate laser systems proved to be ready for industrial application, now.Increasing demand for light-weight structures leads to enlarged use of aluminum alloys. The application of these materials is handicapped by a lack of productivity and reliability of available joining techniques, however. Laser welding of aluminum, on the other hand, turned out to be markedly more difficult than the treatment of steel. Difficulties to overcome threshold for deep penetration welding, the occurence of material related defects and seam deficiencies such as cacities and blow holes discourage production engineers from making use of lasers.A theoretical analysis reveals requirements that have to be fulfilled by laser systems in order to obtain process stability. In comparison to steel better focussability and shorter wave-lengths are needed. An intensity distribution leading to a v-shaped key hole is beneficial, too. The results of this analysis are confirmed by welding results obtained with CO2 and Nd:YAG-Iasers. An increase in process stability is observed when dual beam technique or the shor...