Laser processing head with a focus positions of adjustment unit as well as a system and a method for adjusting a focal position of a laser beam

摘要

The invention relates to a laser machining head (14) for machining a work piece by means of a laser beam (12), comprising a housing (16), through which a beam path for the laser beam (12) is conducted and which is provided with focusing optics (18) for focusing the laser beam (12) through a nozzle (20) on the work piece to be machined, an actuator (26), which is connected to the focusing optics (18) in order to adjust the focusing optics (18) in the beam direction and in a plane perpendicular to the beam path, at least one scattered light sensor (28), which is installed in the housing (16) in order to detect scattered light generated by scattering or reflection of the laser beam (12) on parts of the housing (16) or the nozzle (20), and a focal position adjustment unit (32), which is connected to the at least one scattered light sensor (28) in order to receive a scattered light intensity signal. The focal position adjustment unit (32) is designed to control the actuator (26) for the focusing optics (18) such that the scattered light intensity received from the at least one scattered light sensor (28) is minimal.