Method and device for monitoring the process for a welding seam formed by means of collision welding

Patent metadata

Field	Value
Publication number	US-2019202009-A1
Application number	US-201716333917-A
Country	US
Kind code	A1
Filing date	Sep 8, 2017
Priority date	Sep 16, 2016
Publication date	Jul 4, 2019
Grant date	—

Abstract

The present invention relates to a method and a device for monitoring the process for a welding seam formed by means of collision welding, in which a first joining partner (1) and a second joining partner (2) are moved toward one another by an introduction of energy and are welded to one another to form the welding seam. A light flash between the first joining partner (1) and the second joining partner (2) is detected during the welding by an optical capture unit (6), which measures in a time-resolved manner, having at least one detector (19, 20, 24) and an actual value of a beginning of the light flash, a duration of the light flash, an intensity of the light flash, and/or an intensity distribution over time of the light flash is determined by an analysis unit (16) and compared to a respective target value of the beginning of the light flash, the duration of the light flash, the intensity of the light flash, and/or the intensity distribution over time of the light flash. The weld seam is only classified as qualitatively adequate if a maximum deviation of the actual value from the target value is maintained.

First claim

1 . A method for monitoring the process for a welding seam formed by means of collision welding, in which
a first joining partner ( 1 ) and a second joining partner ( 2 ) are accelerated toward one another by an introduction of energy and are welded to one another to form a welding seam, wherein a light flash between the first joining partner ( 1 ) and the second joining partner ( 2 ) is detected during the welding by an optical capture unit ( 6 ), which measures in a time-resolved manner, having at least one detector ( 19 , 20 , 24 ), and an actual value of a beginning of the light flash, a duration of the light flash, an intensity of the light flash, and/or an intensity distribution over time of the light flash is/are determined by an analysis unit ( 16 ), and is/are compared to a respective target value of the beginning of the light flash, the duration of the light flash, the intensity of the light flash, and/or an intensity distribution over time of the light flash, wherein the weld seam is only classified as qualitatively adequate if a maximum deviation of the actual value from the target value is maintained.

2 . The method as claimed in claim 1 , characterized in that only components having a welding seam classified as qualitatively adequate are supplied to further processing by a sorting unit ( 17 ).

3 . The method as claimed in claim 1 , characterized in that magnetic pulse welding, explosion welding, waterjet spot welding, welding by joining partner acceleration by means of vaporizing foils and/or welding by joining partner acceleration by means of laser-induced shockwaves is carried out as the collision welding.

4 . The method as claimed in claim 1 , characterized in that the deviation of the actual value from the target value is predetermined or is established via a statistical measure, preferably via the standard deviation, on the basis of a plurality of welding processes which are carried out and qualitatively evaluated.

5 . The method as claimed in claim 1 , characterized in that the light flash is acquired by at least two detectors of the optical capture unit ( 6 ) from at least two different spatial positions, wherein the welding seam is only classified as qualitatively adequate if a maximum deviation of the actual value from the target value is maintained at all detectors.

6 . A device for monitoring the process for a welding seam formed by means of collision welding, having
a welding unit ( 5 ) for accelerating and welding a first joining partner ( 1 ) and a second joining partner ( 2 ) by an introduction of energy to form the welding seam, an optical capture unit ( 6 ), which measures in a time-resolved manner, having at least one detector ( 19 , 20 , 24 ) for detecting a light flash generated during the welding between the first joining partner ( 1 ) and the second joining partner ( 2 ), and an analysis unit ( 16 ) for determining an actual value of a beginning of the light flash, a duration of the light flash, an intensity of the light flash, and/or an intensity distribution over time of the light flash, and for comparing the respective determined actual value to a respective target value of the beginning of the light flash, the duration of the light flash, the intensity of the light flash, and/or an intensity distribution over time of the light flash, wherein the analysis unit ( 16 ) is configured to classify the weld seam as qualitatively adequate only if a maximum deviation of the actual value from the target value is maintained.

7 . The device as claimed in claim 6 , characterized in that a sorting unit ( 17 ) is provided, which is designed to supply only components having a welding seam classified as qualitatively adequate to further processing.

8 . The device as claimed in claim 6 , characterized in that the optical capture unit ( 6 ) is designed having an image recording frequency of at least 1 MHz.

9 . The device as claimed in claim 6 , characterized in that the optical capture unit ( 6 ) is designed as a photocell, a photomultiplier, a photodiode, a phototransistor, and/or a photoresistor.

10 . The device as claimed in claim 6 , characterized in that the optical capture unit ( 6 ) has at least two detectors, which are designed to acquire the light flash from at least two different spatial positions, wherein the analysis unit ( 16 ) is configured to classify the weld seam as qualitatively adequate only if a maximum deviation of the actual value from the target value is maintained at the majority, preferably all of the detectors.

Assignees

• Fraunhofer Ges Forschung
• Univ Dresden Tech

Inventors

• Bellmann Joerg

Classifications

• B23K26/032

  using optical means · CPC title

• B23K20/08

  Explosive welding · CPC title

• B23K26/0622

  by shaping pulses · CPC title

• B23K31/125 Primary

  Weld quality monitoring · CPC title