Laser processing head for direction-independent build-up welding

Scientists at the Laser Zentrum Hannover have developed a welding head for laser-assisted or laser-based buildup welding with a coaxial arrangement of the weld deposit feed. Several individual beams are bundled in a focal point below the welding material supply. In general, all meltable materials (e.g. metals, glass or polymers) can be processed with this system.

Challenge

In current arrangements for laser welding, it is often necessary to use a lateral arrangement of laser and torch or laser and wire. This brings with it the limitation that the buildup welding process is directionally dependent. Furthermore, additional axes are necessary to create complex components. The complex process is therefore usually associated with complex programming.

Our solution

In the laser-assisted coaxial gas metal cladding method presented here, the torch of the welding source is arranged vertically. The laser beams are arranged coaxially around the torch and focused below it. Both the arrangement and the number of individual beams can be varied. The coaxial arrangement means that process control is independent of direction. Furthermore, it is possible to control the power of the individual beams depending on the welding situation by using the direct diode principle with six installation positions. If one beam source is omitted, it is possible to install measuring equipment in the free installation position (pyrometers, cameras). It is also possible to use the process without an arc or with a powder stream nozzle. Another advantage of the direct diode principle is the possibility of using laser diodes with different wavelengths. Furthermore, the system is designed to be flexible in terms of the choice of optical components (focusing lenses or optical fibers), so that quick changeovers can take place. Changing protective glasses, which protect the optical components from emissions such as welding fumes and spatter, is just as easy thanks to the modular design of the process head. Furthermore, the process head can be equipped with a tungsten inert gas welding torch, which further increases the range of applications. A beam splitter in the form of a reflectively coated pyramid is used for beam guidance. It splits the beam, guides it around the wire guide and brings it together below in a focal point.

CPA-2221-LZH-imagePrinciple of coaxial laser wire buildup welding with pyramidal beam splitter. (source: Laser Zentrum Hannover e.V.)

Advantages

  • Highly flexible use due to possible adaptations
  • Wavelength adjustable, optics interchangeable for each beam path
  • Coaxial beam guidance
  • Power of the beam paths separately adjustable
  • Installation of additional measurement technology possible

Applications

  • MIG buildup welding
  • Laser wire buildup welding
  • Laser powder buildup welding
  • Laser soldering (trifocal)
  • Buildup welding of generative structures and coatings
  • Joint welding

Development Status

Process successfully tested on different surfaces (glass, glass ceramic, plastic), current further development with regard to application in industry

Patent Status

Laser Zentrum Hannover e.V.
EP21178803.9 (filed)

References

 

Contact

Dr. Markus Muchow
Patent Manager Physics & Technology
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Tel.: +49 551 30724 159
Reference: CPA-2221-LZH

Tags: Laserphysik und Optik, Physik und Technik & Software

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