Laser processing machine, in particular laser cutting machine, and method for centering a laser beam, in particular a focused laser beam

Laser processing machines (LM), in particular laser cutting machines with long-wave laser radiation (in particular CO2 laser), including at least one laser processing head (1), having interior (2) and nozzle (3) with nozzle orifice (4) for allowing a primary beam (5), in particular a focused laser working beam, to pass through and onto a work piece (6) and to align a gas current enveloping the beam, and an alignment device (15) with several sensors (13) for centering the primary beam (5), in particular a focused laser working beam, and the nozzle orifice (4) relative to each other. At least one conversion unit (9), in particular a conversion edge, is provided in the area of the nozzle orifice (4) for converting the primary beam (5) contacting it or impacting on it into one or more secondary electromagnetic heat beams (10) along at least one propagation direction (10A) in direction of the sensors (13). The sensors (13) are configured as radiation sensors and arranged in the interior (2) of the laser processing head (1) or the nozzle (3).