A low-cost infrared sensing system for monitoring the MIG welding process

In this study, a low-cost infrared sensing system based on the analysis of the surface temperature distribution is proposed for monitoring the perturbations occurring during the aluminum alloy metal inert gas (MIG) welding process. A galvanometer scanner is employed in this real-time infrared sensing system to continually reflect the infrared energy to the point infrared sensor. By controlling the scanning mirror of the galvanometer scanner rotating in a high speed, the infrared energy at different points of the welding seam and the heat-affected zone on the surface of the plate will be continually captured by the point infrared sensor. Different conditions (changes in the welding speed, welding current, and joint gap width) of the welding process have been simulated to perturb the welding process. Three representative geometric defects such as undercut, humping, and lack of fusion were produced to validate our infrared sensing system. Experimental results showed that the sensing system is useful for monitoring perturbations that arise during the welding process and identifying welding defects.