A Study on Welding Quality Inspection System for Shell-Tube Heat Exchanger Based on Machine Vision

摘要

An automated based-vision quality inspection system for Shell-Tube welding is presented in this paper in order to achieve nondestructive weld defect detection. The vision sensor is developed on the basis of the principle of laser triangulation. First, the composition and working principle of the vision-based quality inspection system are introduced, and meanwhile various defects may occur are described in detail. Then the image processing algorithm, as the most important part of online quality inspection system, is also represented. The image processing algorithm includes two parts: preprocessing and defect detection. In defect detection section, a novel method for determining and describing the position of undercut, which is based on the parameter equation of the circle to represent the position of the undercut, is presented. Last, two experiments are carried out for Shell-Tube heat exchanger and the experiments show that the image algorithm has high precision, strong robustness and can detect the defect accurately.