Device for measuring the depth of a weld seam in real time

Abstract

The invention relates to a device for measuring the depth of a weld seam in real time in the case of the welding or joining of a workpiece by means of radiation, comprising: a measurement light source, the light of which is coupled into a reference arm (18) and into a measurement arm (19) by a beam splitter (17); a collimator module (21), which has at least one collimating lens (29) for collimating a measurement light beam (23), which is fed to the collimator module (21) by means of an optical waveguide (20) in the measurement arm (19), and for imaging the measurement light beam (23) reflected back by a workpiece to be processed onto an outlet / inlet surface (26) of the optical waveguide (20); an incoupling element (24) for coupling the measurement light beam (23) into the beam path of a processing beam (10); a focusing lens (25) for jointly focusing the measurement light beam (23) and the processing beam (10) onto the workpiece and for collimating the measurement light beam (23) reflected back; and an evaluating unit (15) for determining the depth of a weld seam, into which evaluating unit the measurement light reflected back by the workpiece is directed together with the superposed, reflected-back light from the reference arm (18). The collimator module (21) comprises means for setting the axial focus position of the measurement light beam (23), means for setting the lateral focus position of the measurement light beam (23), and a field lens (28), which is arranged between the outlet / inlet surface (26) of the optical waveguide (20) and the collimating lens (29) and which defines the beam expansion of the measurement light beam (23) and thus the focus diameter of the measurement light beam (23).

Description

technical field [0001] The invention relates to a device for measuring the depth of a weld seam in real time when welding or joining workpieces by means of a beam. Background technique [0002] Such as figure 1 As shown, during the deep laser welding process, vapor pores 11 are produced during the welding process along the beam axis of the processing laser beam 10 , which are also referred to as keyholes and are surrounded by liquid melt 12 . The depth Td of the vapor pores (hereinafter also referred to as keyhole depth) is related to the weld seam or welding depth Te. Seen in the feed direction V, the solidified melt 14 is located behind the liquid melt 12 . [0003] If the depth Td of the locking hole 11 is known, the welding depth Te can be determined by means of metallographic tests and a correction factor between the two parameters can be determined. Therefore, the weld depth Te can be measured in real time by measuring the keyhole depth Td and applying a correction ...

AI Technical Summary

Problems solved by technology

Furthermore, polarization-dependent coaxial observation of keyhole emissions enables inference of keyhole geometry, but does not provide true depth information

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