Laser welding. Power laser beams

Along with power and speed or time, beam format at the focal point is the third parameter of a laser welding or cutting operation.

The characteristics of a laser beam derive directly from the electromagnetic phenomena that take place inside the resonator. A mathematical development of these phenomena, taking diffraction into account, leads to expressions for the field distribution and power density at the limits of the resonator, and their evolution during beam propagation, focusing or special treatment.

These expressions, which form the basis of any scientific approach, are complicated. They can be found in specialized books or in the articles listed below, which can be consulted if necessary. It's their conclusions, expressed simply and easily understandable, that interest us, so that we can draw the lessons we're looking for.

In the Génie Mécanique articles on welding processes in general, laser welding, which is also associated with electron beam (EB) welding in high-energy processes [BE 7 740] , is given only a cursory description. The same is true of the space devoted to power lasers in the general and theoretical articles [A 1 095] , [AF 3 270] , [AF 3 271] . These articles, to which reference should be made, deal only briefly with notions relating to the beams themselves, which are nevertheless of definite practical interest. The aim of this supplement is to supplement them on this point, against the backdrop of ISO 11146.