Automatic Laser Welding Defect Detection and Classification using Sobel-Contour Shape Detection

This paper describes a detection of common defects in laser welding of structural aluminum alloy. To overcome these problems, a technique has been proposed to detect defects automatically and effectively using the image segmentation technique. Although, this technique has been well developed, it does suffer from several disadvantages of radiographic images taken to be poor in quality, as well as the microscopic size of the defects together with poor orientation relatively to the small size and thickness of the evaluated parts. Using image segmentation algorithm allows the defects to be automatically inspected and measured within the welded surface such as cracks, porosity and foreign inclusions, which may be weakening the welded parts. This paper proposes a system to automatically identifies and classifies the faults from the welding process by using the existing image segmentation algorithms. The output of the developed system produces a measured analysis which can be then used to describe the mechanical properties of welded part of the alloy such as its tensile and force. The benefits of this project will improve the welding process to reduce faults and defects for both constructing and manufacturing field

The effect of beam geometry on diode laser forming of sheet metals

Laser beam forming has emerged as a new and very promising technique to form sheet metal by thermal residual stresses. One of the advantages of laser beam forming compared to conventional flame bending is its ability to accurately control the size and geometry of the heat source. In the area of optics, many studies explain the methods and design approaches to produce a variety of beam shapes such as line, rectangular, star, D-shape, annular, cross, etc. The objectives of this work are to compare the orientation effect of the rectangular beam, and to compare circular and rectangular beam geometries, for laser bending of AISI 304 stainless steel sheets. To achieve this, a high power diode laser (HPDL) is used to obtain bending angle for sheets of various thicknesses. From the study of the orientation of the rectangular beam, it is found that a narrow beam orientation produces higher bending angle. This is due to higher temperatures generated because of longer beam-material interaction. Comparing the circular beam with the rectangular beam, for the same average beam intensity, the circular beam produces higher bending angle