Development of the automatic method of detection and grouping of external welding imperfections

The non-destructive testing of welded joints is a key issue in welding technology and processes. It is especially crucial for estimation of product quality. Among others methods, visual testing is the most fundamental. In most cases, it is made manually, which can introduce some problems resulting from the lack of objectivity and fatigue of the controlling person. This paper is an attempt of changing a mode of visual inspection. The proposed system is based on image analysis of welded joints. The welding imperfections were correlated with quality levels according to the ISO 5817 standard. For the original inspection system, six the most fundamental imperfections have been selected. The main idea of this system is a detection of selected welding imperfections and, based on acceptance criteria, assigning welded joints for the appropriate quality level. In order to validate the correct operation of the proposed system, the same welded joints have been subjected to conventional manual visual inspection. The compliance of the results was more than 90%, and the speed of visual examinations was more than 10 times higher than in the manual method.