The PhD project "Multi beam fiber laser welding" is a study into multi beam fiber laser welding by high impact single mode (SM) fiber lasers with the purpose of developing optimal welding configurations in industry. In order to achieve an improved welding quality, work will be done to increase the stability of the melt during laser welding by using several laser beams. The possibilities of welding dissimilar materials will also be investigated, e.g. by using Diffractive Optical Elements (DOE). A DOE is an artificial hologram which reshapes the wavefront of the incoming laser beam by means of phase shift.

The core of the project is by means of multi laser beam welding with single mode fiber lasers to form a number of very small keyholes in a chosen workpiece in order to utilize at least one of the following characteristics:

• Expansion of the width and stabilisation of the geometry of the welds by using several primary keyholes placed in a pattern, primarily across the welding direction.
• Extension of the melting bath by placing one or more secondary keyholes behind the primary keyhole(s).
• Stabilisation of the melting flow behind the primary keyhole(s) by placing a number of secondary keyholes across the welding direction making them work like a strainer stabilising the melting flow.
• Increased stability of the process in which phenomena like humping beads are avoided, and the process window is increased.

The project is done in cooperation between IPU and the Faculty of Engineering and Science at Aalborg University. PhD candidate is Klaus Schütt Hansen who has been employed at IPU Technology Development since 2008. Klaus counsels in laser processes and welding technology, so the PhD project will be in natural continuation hereof. Supervisors of the project is Senior Engineer Flemming Ove Olsen from IPU and Professor Ole Madsen from Aalborg University. The project is supported by the companies Danfoss and Grundfos who foresee several possible applications of this new technology in their productions.
 

For further information contact Senior Engineer  - +45 45 25 47 51 or  - +45 45 25 47 06.