Abstract

The invention relates to a method for ascertaining translational deviations between the measuring coordinate system (15) of a measuring mirror scanner (13), which can be tilted about two axes (C, D) and deflects a measuring beam (12) in two dimensions, and the processing coordinate system (10) of a processing mirror scanner (7), which can be tilted about two axes (A, B) and deflects both the measuring beam (12) deflected by the measuring mirror scanner (13) and a processing beam (3) in two dimensions onto a workpiece (2). The measuring beam (12') reflected on the workpiece (2) travels back on the path of the incident measuring beam (12) and is captured by a high-resolution measuring sensor (17) in order to determine high-resolution information about the workpiece (2). In a zero position of the measuring mirror scanner (13), the reflected measuring beam (12') is imaged in the sensor image (18) of the measuring sensor (17) onto a previously known image position (19). The method comprises different method steps, so that an ascertainment of a translational deviation (??, ?y) between the processing coordinate system and the measuring coordinate system (10, 15) based on the deviation, present in the sensor image (18) of the measuring sensor (17), between the previously known image position (19) corresponding to the focus position of the processing beam (3) and the pinhole diaphragm center (20') determined from the height information is completed.

IPC Classes  ?

• B23K 26/03 - Observing, e.g. monitoring, the workpiece
• B23K 26/044 - Seam tracking
• B23K 26/082 - Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
• B23K 26/21 - Bonding by welding
• G01B 11/03 - Measuring arrangements characterised by the use of optical techniques for measuring length, width, or thickness by measuring coordinates of points
• G01B 11/14 - Measuring arrangements characterised by the use of optical techniques for measuring distance or clearance between spaced objects or spaced apertures
• G01B 11/24 - Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
• G01B 11/26 - Measuring arrangements characterised by the use of optical techniques for testing the alignment of axes
• G01C 1/00 - Measuring angles
• G01C 3/00 - Measuring distances in line of sight; Optical rangefinders

Abstract

The invention relates to a method for determining the quality of a weld (5) of a workpiece (1) welded by means of laser-beam welding along the weld (5), wherein at least a partial region of a molten pool (4) and/or of a surrounding area of the molten pool (4) is observed by means of a measuring system (8) during the laser-beam welding and the quality of the weld (5) of the welded workpiece (1) is determined on the basis of the observation result. Said method is characterized in that at least one characteristic value that correlates with molten pool oscillation of the molten pool (4) is observed during the laser-beam welding and a measure of an amplitude of the molten pool oscillation and/or a measure of a frequency of the molten pool oscillation is determined from the observed time curve of the characteristic value, and that a probability and/or a frequency for the occurrence of hot cracks (11) at the weld (5) of the workpiece (1) is inferred from the measure of the amplitude of the molten pool oscillation and/or the measure of the frequency of the molten pool oscillation. The invention provides a simplified method by means of which the quality of a weld can be inferred.

IPC Classes  ?

• B23K 26/03 - Observing, e.g. monitoring, the workpiece
• B23K 26/70 - Auxiliary operations or equipment
• B23K 26/24 - Seam welding
• B23K 31/12 - Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by any single one of main groups relating to investigating the properties, e.g. the weldability, of materials