Laser welding operates in two fundamentally different modes: conduction limited welding and keyhole welding. The mode in the laser beam will interact with the material it is welding will depend on the power density of the focused laser spot on the workpiece.
Scanner-based laser welding uses scan mirrors for positioning the beam precisely at the desired weld location. A key requirement is a high-quality beam.
A typical beam delivery system for such a setup consists of reflective optical components to direct the beam to the scan head for rapid deflection by the moving mirrors. The beam delivery system is somewhat fixed and requires the scan head to remain stationary, limiting the working volume.