Sensing welding circumstances during welding is essential for seam-tracking and in-process controls of automatic arc welding. Among many types of sensing, visual sensing is influenced to a less extent by the change in welding conditions and provides much more information than other sensing. However, miss-operation in processing of visual sensing may take place due to noises caused by arc light and others, and visual sensing devices are costly. From these reasons, the use of visual sensors have been less popular than arc sensors. The authors have developed a system of image measuring of a weld molten pool. The newly developed system has enabled to avoid the external interference such as arc light fluctuation and spattering during welding. This development has been achieved by, 1) reduction of relative intensity of arc light through improved optical processing; 2) detection of the location of the electrode wire through processing images by the camera with a trigger high-speed shutter; 3) averaging images by integration and stabilization of data processing through an algorithm using a weighting function. A control of the shape of a back-bead reinforcement in one-side narrow gap welding is important. This image processing has accomplished not only preferable seam-tacking but also the improvement of quality of deposited weld metal through a control of the surface shape of a molten pool. The in-line control system with this image processing is to be applied for one-side GMAW narrow gap welding in which a control of the shape of a back-bead reinforcement is significantly important.
展开▼
