Laser brazing weld surface defect detection method based on envelope line recognition

Abstract

The invention discloses a laser brazing weld surface defect detection method based on envelope line recognition, comprising the following steps: after weld surface contour data is obtained, real-timefitting is carried out on an actual contour curve by adopting a weighted cubic spline curve to obtain a standard contour, and the standard contour is respectively translated upwards and downwards fora fluctuation distance to obtain a weld qualified interval; the actual contour curve is compared with a reasonable weld interval: when the actual contour curves are completely located in the reasonable weld interval, the weld has no defects; when the actual contour curve is higher than an upper contour line or lower than a lower contour line and the area of the exceeding part is greater than or equal to a threshold value, the weld contour is unqualified; when the continuous appearing number of the unqualified weld contours reaches a weld defect critical dimension value, it is judged that the weld has defects; and on the basis, defect classification is carried out and a corresponding characteristic value is calculated. According to the weld surface defect detection method, weld defects canbe rapidly and accurately detected, and the weld surface defect detection method is insensitive to interference caused by the environment, sensors and the like.

Description

technical field [0001] The invention belongs to the technical field of weld seam defect detection, and more specifically relates to a laser brazing seam surface defect detection method based on envelope recognition. Background technique [0002] The quality of the weld seam determines whether the mechanical product is qualified and meets the requirements. The poor quality of the weld seam reduces the strength of the weldment, and it is prone to fracture during use, causing accidents and causing economic losses and threatening personal safety. Various inspections are carried out on the weld to make the weldment meet the use standard. Among them, the laser brazing seam has high requirements on the surface quality, especially in the processing of the outer surface of the parts in automobile manufacturing, the surface quality of the weld seam is directly related to the qualification of the parts. The complex splicing joint form of laser brazing has brought many challenges to th...

AI Technical Summary

Problems solved by technology

However, the accuracy of this detection method is strictly affected by the degree of color difference, and it is difficult to achieve a good trade-off between sensitivity and accuracy

Moreover, it is difficult to achieve good detection results in the strong noise environment of laser brazed joints

In addition, the types of defects detected in the above patents do not involve welding spatter, and as one of the defects that seriously affect the quality of the welding surface, this patent proposes a detection method for welding spatter

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