Method and device for detecting and adjusting the focus of a laser beam when laser machining workpieces

摘要

The invention relates to a method for detecting and adjusting the focus (F) of a laser beam when laser machining workpieces, having the following steps: a.) guiding and focusing a laser beam of a machining laser (1) emitted from a machining head (48) into a machining point (26) on or with respect to the surface (49) of a workpiece to be machined, wherein the focusing takes place by means of an optical focusing element (2); b.) guiding and focusing the radiation (28, 31) emitted by at least one first adjusting light source (22) and one second adjusting light source (23) onto the surface (49) of the workpiece to be machined, wherein the wavelengths of the radiation emitted by the adjusting light sources (22, 23) are different; c.) uncoupling the electromagnetic radiation arising about the machining point (26) due to scattering and/or reflecting the laser beam (1) of the machining laser at the surface (49) of the workpiece to be machined, by means of an optical system (2, 4) having chromatic aberration, and detecting the intensity thereof by means of a first detector (5); d.) uncoupling the radiation (34, 36) of the adjusting light sources (22, 23) reflected back from the surface of the workpiece to be machined by means of the optical system (2, 4) having chromatic aberration and separate detecting of the intensities of the reflected radiation (34, 36) of the adjusting light sources (22, 23) by means of at least one second detector (20); e.) determining the location of the focus (F) of the laser beam (1) of the machining laser using the intensities captured in the steps c.) and d.); and f.) adjusting the focus (F) of the laser beam (1) of the machining laser to a desired machining point (26) with respect to the surface (49) of the workpiece to be machined.

主权项

1. A method for detecting and adjusting the focus (F) of a laser beam in the laser machining of workpieces having the following steps:
a) delivery and focusing of a laser beam of a machining laser (1) emitted from a machining head (48) into a machining point (26) on or with respect to the surface (49) of a workpiece to be machined, where the focusing takes place by means of an optical focusing element (2), b) delivery and focusing of the radiation (28, 31) emitted by at least one first adjusting light source (22) and a second adjusting light source (23) onto the surface (49) of the workpiece to be machined, where the wavelengths of the radiation admitted by the adjusting light sources (22, 23) are different, c) uncoupling the electromagnetic radiation arising around the machining point (26) due to scattering and/or reflection of the laser beam (1) of the machining laser at the surface (49) of the workpiece to be machined, by means of an optical system (2, 4) having chromatic aberration and detecting their intensity by means of a first detector (5), d) uncoupling the radiation (34, 36) of the adjusting light sources (22, 23) back-reflected from the surface of the workpiece to be machined by means of the optical system (2, 4) having chromatic aberration and separate detection of the intensities of the reflected radiation (34, 36) of the adjusting light sources (22, 23) by means of at least one second detector (20), e) determining the position of the focus (F) of the laser beam (1) of the machining laser using the intensities detected in steps (c) and (d), f) adjusting the focus (F) of the laser beam (1) of the machining laser onto a desired machining point (26) with respect to the surface (49) of the workpiece to be machined.