technical know-how
A range of options There are three primary types of laser welders used for the welding process: • Gas laser (CO2): A CO2 laser source is a mixture of gases with CO2 being the main component alongside nitrogen and helium. These lasers can operate in a continuous or pulsed mode at a low current and high voltage to excite the gas molecules. Carbon dioxide lasers are also used in special circumstances, such as in dual-beam laser welding, wherein two beams are produced and arranged either in tandem or side-by-side. • Solid-state laser: These lasers use Diode Pumped Solid State (DPSS) technology to pump ore such as ruby, glass or yttrium, aluminium, and garnet (YAG), with a laser diode to produce laser rays. They are operated in either continuous wave or pulsed beam mode. The pulsed mode produces joints similar to spot welds but with complete penetration. These lasers have their fair share of disadvantages when compared to modern fibre lasers, but still have excellent beam stability and quality along with high efficiency.
• Fibre laser: Fibre lasers are the newer type of solid- state lasers that offer more power, better quality, and safer operation. The laser beam is created when the fibre absorbs raw light from the pump laser diodes. To achieve this transformation, the optical fibre is doped with a rare-earth element. By using different elements, laser beams with a wide range of wavelengths can be created. This makes fibre lasers perfect for a variety of applications. It is worth noting that a standard laser cutting head cannot be used for welding and a laser welding head cannot meet the cutting speeds and quality demanded in most industrial applications. There are two types of laser beam welding, both with unique operating principles to suit specific applications. How the material interacts depends on the laser beam’s power density. • Heat Conduction Welding is where a focused laser beam is used to melt the surface of the base materials. When the joint solidifies, a precise and smooth weld seam is produced. Welds created using the head
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