Fast Thermal Monitoring of Pulsed Laser Cleaning Processes

Current manual laser cleaning methods often require highly skilled operators to achieve fast and reliable cleaning. This study investigated the feasibility of measuring thermal processes during laser metal cleaning to support the development of an automated and intelligent laser cleaning system. The measurement system was based on fast infrared (IR) diagnostics and used a field programmable gate array (FPGA) for fast signal analysis. Experiments were conducted on steel substrates covered with paint, scale, or corrosion. Thermal response in real-time for every laser pulse was monitored. Paints showed no solidification plateau, while steel exhibited a clear plateau above the ablation threshold. The scaled surface showed longer time intervals and higher heat accumulation. A histogram of time intervals enabled statistical analysis of the process. Time-resolved temperature values revealed hidden processes. These findings demonstrated the potential of IR thermal diagnostics for evaluating surface conditions and providing real-time data to optimise, monitor, and control laser cleaning processes.