Abstract
Beam oscillation in laser material processing makes it possible to influence process behavior in terms of energy distribution, stability, melt pool dynamics and solidification. Within the setup presented here, the beam is oscillated transverse to the welding direction, and the filler wire is fed to the melt pool of a butt joint with an air gap. One advantage of this setup is the large gap bridging ability. Certain parameter sets lead to the so-called buttonhole welding method, which allows laser welding of smooth and nearly ripple-free seams. Observations showed a transition area between conventional keyhole and buttonhole welding in which the process is destabilized. Welds made with parameter sets from this area contain critical seam defects. Welding experiments with high-speed video recording and a simplified analytical model about the wire-beam interaction have helped to elucidate the mechanisms behind this. EN AW-6082 sheet material in 1.5 mm thickness and ML 4043 filler wire with 1.2 mm diameter were used. The investigations lead to the conclusion that partially melted wire segments result at certain parameter relations which hinder the formation of a buttonhole. If these segments are prevented, buttonhole welding occurs. In the transition area, these segments are very small and can lead to the detachment of a buttonhole, resulting in the named seam defects.
Highlights
Aluminum is a key material which is increasingly being used for lightweight structures, especially in transport industries [1]
Within the setup presented here, the beam is oscillated transverse to the welding direction, and the filler wire is fed to the melt pool of a butt joint with an air gap
They showed that precise positioning between the laser beam, the filler wire and the air gap is the key factor for a stable process [14]
Summary
Aluminum is a key material which is increasingly being used for lightweight structures, especially in transport industries [1]. Aalderink et al [12] investigated the gap bridging ability of solid-state lasers for different process combinations (one beam, double beam, laser MIG-hybrid (MIG—metal inert gas), with and without wire feed) They welded aluminum sheets in a butt joint configuration and revealed that the addition of filler wire increases the ability of gap bridging from 0.2 mm to 0.6 mm in case of one-beam processes. Investigations in terms of laser beam welding with filler wire are given by Binroth [15] His analytical model describes the heat transfer from the laser beam to the wire and enables the prediction of wire feed rates in which a continuous wire melting occurs and a smooth material transfer into the melt pool is achieved. He classified the melting conditions in periodical droplet formation (too much heat input), continuously melting (good heat input) and insufficient melting (insufficient heat input) [15]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
