It can also vary the shape of the beam to include a flat-top profile, where the laser energy is spread out equally across the spot, and a doughnut profile, which concentrates the energy around the circumference of the beam. NLight’s Corona fibre laser can tune the spot size of the beam between 100µm and 300µm with a transition time of 30ms. ‘We observed many of the promised benefits in our study, but we also discovered that selecting the exact mode shape and power distribution for a specific response on a specific material was not a simple matter,’ he added.
Speaking to Laser Systems Europe, Ream said that these lasers with beam shaping capabilities offer promise for reducing porosity in laser welds, reducing spatter, giving higher travel speeds and smoother bead surfaces.
Stan Ream, EWI fellow, presented the initial findings pf the study at the Laser Institute’s (LIA’s) International Congress on Applications of Lasers and Electro Optics (ICALEO) in October. The performance of the lasers is being tested for bead-on-plate welding of 304 stainless steel, HSLA steel, 3003 aluminium, and copper. The BrightLine laser will be used to test welding at higher power, 3kW to 6kW, while the Corona laser will work between 1kW and 3kW. The study is not a direct comparison to find out which is the better laser, but rather it will give baseline laser welding behaviour for these mixed-mode laser beams. The EWI engineering consultancy in the USA is exploring the welding performance of two of these adjustable mode lasers, Trumpf’s BrightLine laser and NLight’s Corona laser. The push for higher power continues in laser processing, but over the past few years laser manufacturers have been developing lasers capable of making the most of that power without the need for complex external optical systems.Ĭoherent, NLight, Trumpf, SPI Lasers, IPG, and others have all released lasers with variable beam quality – the shape of the output beam can be adjusted – which has been shown to provide better cutting results across different materials and thicknesses, in addition to improved welding capabilities.