Monitoring of industrial welding processes using high-speed uncooled MWIR imaging sensors

Abstract

The paper is focused on the application of uncooled MWIR imaging sensors for the monitoring of industrial welding processes: resistance spot welding, resistance seam welding and laser welding. During the last 40 years, there has been little advancement in sensor systems for inline quality control monitoring of the welding process. Most of the existing systems are oriented for current, voltage and welding force monitoring. However, the temperatures reached during the majority of the welding processes lead to infrared sensing as a powerful tool, and to the MWIR band in particular as the most useful spectral band for monitoring this type of industrial processes. Infrared image information is a powerful tool to study the energy distribution in the HAZ (Heat Affected Zone). The work presents some experimental results obtained with uncooled MWIR imaging sensors, by monitoring several welding processes. These results may be applied for real-time quality assurance of the process leading to better throughputs in industrial manufacturing. The high-speed capability of the sensors used helped also to characterize the dynamics of the welding process.