Welding of aluminum: A challenging opportunity for laser technology

Abstract

The increasing demand for lightweight structures has led to a greater industrial use of aluminum alloys. The application of these materials is handicapped by a lack of productivity and reliability in the joining techniques currently available. The laser welding of aluminum is markedly more difficult than for steel. The difficulties to be solved include the threshold for deep penetration welding, the occurrence of material related defects and seam deficiencies such as cavities and blowholes that discourage production engineers from making greater use of lasers. A theoretical analysis reveals the requirements that have to be fulfilled by laser systems in order to obtain process stability. In comparison to steel greater focusability and shorter wavelengths are needed. An intensity distribution leading to a V-shaped keyhole is also beneficial. The results of this analysis are confirmed by welding results obtained with CO2 and Nd:YAG lasers. An increase in process stability is observed when a dual beam technique or a shorter wavelength laser is applied. In conclusion, the industrial welding of aluminum alloys with appropriate laser systems is a viable option.

Inherent instability investigation for low speed laser welding of aluminum using a single-mode fiber laser

“…However, the focus has mostly been on high power and high speed laser welding which helps improve productivity speed and weld quality. Dausinger et al (1996) report that with a 2.2 kW Nd:YAG laser, weld depths of up to 3.7 mm in AA 6082 have been obtained at approximately 16.7 mm/s, at a power density of 3 MW/cm 2 . Also, Yoshikawa et al (1995), report that successful butt welds of 3 mm thick 5 and 6 series aluminum alloys can be obtained.…”

Fatigue crack fusion in thin-sheet aluminum alloys AA7075-T6 using low-speed fiber laser welding

“…However, the focus has mostly been on high power and high-speed laser welding which helps improve production speeds and weld quality. Dausinger et al (1996) report that with a 2.2 kW Nd:YAG laser, weld depths of up to 3.7 mm in AA 6082 have been obtained at approximately 16.7 mm/s, at a power density of 3 MW/cm 2 . Also, Yoshikawa et al (1995), report that successful butt welds of 3 mm thick 5 and 6 series aluminum alloys can be obtained.…”

Low Speed Laser Welding of Aluminium Alloys Using Single-Mode Fiber Lasers

“…The interactions between the large number of process variables involved are also not fully understood (Ion, et al, 2001). Dausinger, et al, (1996) reported that with a 2.2 kW Nd:YAG laser, weld depths of up to 3.7 mm in AA 6082 have been obtained at approximately 16.7 mm/s, at a power density of 3 MW/cm 2 . Also, Yoshikawa, et al (1995), report that successful butt welds of 3 mm thick 5 and 6 series aluminium alloys can be obtained.…”