Abstract: A method for monitoring a laser welding process for welding workpieces by a welding laser beam is provided. The method includes, during the laser welding process, directing a measuring beam of an optical coherence tomograph onto an interaction area in which the welding laser beam interacts with the workpieces. The measuring beam penetrates the workpieces in the interaction area in a through weld of the workpieces. The measuring beam penetrating the workpieces is incident on a reference element. The method further includes acquiring measured values using the measuring beam, defining a first measured value range corresponding to detection of a material of the workpieces, defining a second measured value range corresponding to detection of the reference element, and determine a ratio of a number of measured values lying in the first measured value range and a number of measured values lying in the second measured value range.

Abstract: A method determines translational and/or rotational deviations between the measurement coordinate system of a measurement mirror scanner and the processing coordinate system of a processing mirror scanner. A measurement beam reflected at a workpiece returns on a path of an incident measurement beam and is captured by a spatially resolving measurement sensor to ascertain spatially resolving information of the workpiece. The reflected measurement beam, in a sensor image of the measurement sensor, is imaged onto a previously known image position. This is accomplished by ascertaining a focal position deviation of the processing beam by scanning with the processing beam, evaluating a laser power detected at grid points, fixing the processing mirror scanner, capturing spatially resolving height information of the pinhole diaphragm by the measurement sensor, and determining a translational deviation between the processing and measurement coordinate systems based on the deviation.

Abstract: A method for producing a bipolar plate includes providing a first plate element and a second plate element. The first plate element has at least one bead with a longitudinal extent. The method further includes forming a welded connection between the first plate element and the second plate element along the longitudinal extent by using a laser processing beam. The formation of the welded connection includes detecting a geometric feature of the at least one bead located in a transverse direction. The geometric feature is a deepest point or a point of defined depth of the at least one bead. The formation of the welded connection further includes readjusting the laser processing beam in the transverse direction to a position of the detected geometric feature, and welding the first plate element and the second plate element together at the position of the geometric feature.

Abstract: A method for determining an optimized parameter set having a plurality of measurement parameters to carry out a measurement is provided. The method includes: C) carrying out and storing n measurements of a measuring element, n being an integer greater than one. Each measurement has one parameter set. Each measurement has a multiplicity of measuring points. The method further includes: D) evaluating the n measurements with an evaluation function and storing the evaluation, E) generating new parameter sets from the parameter sets used in step C), F) carrying out steps C) to E) multiple times, and J) outputting at least one parameter set that is evaluated as good.

Abstract: A calibration apparatus for a processing system with a plurality of optical tools is provided. The calibration apparatus includes a housing with a stop aperture, a sensor arrangement for capturing light that is incident through the stop aperture, and a light source arrangement for emitting light through the stop aperture.

Abstract: A method for processing a workpiece includes the steps of arranging the workpiece in a work space and guiding an OCT measurement beam of an optical coherence tomograph using a processing head so as to scan the workpiece, wherein the pose of the processing head in the work space and also the pose of the OCT measurement beam relative to the processing head are known. Distance measurement values of the optical coherence tomograph are determined during the scanning, which are used to determine at least one of the pose of the workpiece in the workspace, the presence of a workpiece in the workspace, the identity of the workpiece in the workspace, and the presence of a processing feature of the workpiece that was carried out on the workpiece in a previous processing step.

Abstract: A method for monitoring a curved solidified weld seam during the welding of a workpiece includes carrying out distance measurements using a measurement beam of an optical coherence tomograph both at one or more pre-measurement points situated upstream of a present welding position, and at one or more post-measurement points situated downstream of the present welding position, and monitoring the curved, solidified weld seam on the basis of the distance measurements. In the case of a plurality of post-measurement points, a post-measurement line is formed from the plurality of post-measurement points and positioned to be offset relative to a pre-measurement line in the direction of the pre-measurement line toward the curved, solidified weld seam and/or is rotated relative to the pre-measurement line. In the case of a single post-measurement point, spacing the single post-measurement point from a line passing through the present welding position in the welding direction.

Abstract: An OCT system includes an optical coherence tomograph for recording a height profile of a workpiece surface by optical scanning of the workpiece surface. The OCT system includes a camera for recording an image of the workpiece surface and a display for the joint, in particular superimposed, display of the recorded image and the recorded height profile of the workpiece surface. A method for displaying an optically scanned region of a workpiece surface is also provided.

Abstract: A method for distance measurement includes: (a) measuring a focus distance between a z-focus position of a processing laser beam and a reference surface, and measuring a reference distance between a reference arm mirror of a coherence tomography apparatus and the reference surface using a measurement beam. The processing laser beam is directed onto the reference surface via a laser processing optical unit. The measurement beam is directed onto a same point of the reference surface as the processing beam or onto a point of the reference surface next to an impingement point of the processing beam. The method further includes (b) measuring a workpiece distance between the reference arm mirror and a workpiece surface using the measurement beam directed onto the workpiece surface, and (c) determining the distance between workpiece surface and the z-focus position based on the reference distance and the workpiece distance and the focus distance.

Abstract: A method determines translational and/or rotational deviations between the measurement coordinate system of a measurement mirror scanner and the processing coordinate system of a processing mirror scanner. A measurement beam reflected at a workpiece returns on a path of an incident measurement beam and is captured by a spatially resolving measurement sensor to ascertain spatially resolving information of the workpiece. The reflected measurement beam, in a sensor image of the measurement sensor, is imaged onto a previously known image position. This is accomplished by ascertaining a focal position deviation of the processing beam by scanning with the processing beam, evaluating a laser power detected at grid points, fixing the processing mirror scanner, capturing spatially resolving height information of the pinhole diaphragm by the measurement sensor, and determining a translational deviation between the processing and measurement coordinate systems based on the deviation.

Abstract: A spray nozzle for atmospheric plasma spraying is provided. The nozzle includes an attachment at an axial end of the spray nozzle from which a protective gas may be discharged in the outflow direction. By means of a plasma spray nozzle that enables atmospheric plasma spraying using protective gas, it is also possible to deposit oxidation-sensitive metal coatings in atmosphere.