Holo/OR has developed a diffractive optical element (DOE), now supplied by Laser Components, that significantly accelerates the laser brazing process for hot-dip galvanised metal sheets. It provides better melting performance and cleaner edges at the same time.
Providing connections with high mechanical stability and without impairing corrosion protection, laser brazing has become an important process in the automotive industry. Oxides and impurities in the zinc layer of the soldered seam can cause irregularities, for example splashes, pores and uneven surfaces.
This effect is now prevented by the new DOE, which is made of UV fused silica and has an efficiency of 90 per cent. It forms three beams with different diameters and power levels. Two smaller stripping beams ensure that the zinc coating is preheated, cleaned and preconditioned for brazing. The large centre beam then performs the actual brazing process, with its homogeneous energy distribution ensuring that the brazing material is melted evenly. So far, similar results could only be achieved with several lasers or complex optomechanical elements.