Flash Pulse Thermography Measurements of Coat Thickness

Sammanfattning: The application of varnish, metal coats, and paint is a common practice for modifying or enhancing material properties. Metal coats are frequently used as protective layers against corrosion, heat, and wear, while also influencing characteristics like conductivity, weight, and production costs. Achieving the optimal thickness of the coating is critical, as a too-thin layer may not offer sufficient protection, while an overly thick layer adds unnecessary weight and increases expenses. Therefore, it is crucial to accurately measure the coating thickness without causing any damage. This project focuses on utilising flash pulse thermography, a non-invasive and non-destructive measuring technique, with three algorithms — Dynamical Thermal Tomography, Power Function, and Pulse Phase Thermography — to measure and differentiate between plates with known variations in the number of coating layers. The study also aims to identify the limiting factors associated with the experimental equipment and the characteristics of the thermography algorithms. The thickness calculations were performed both individually for each plate and simultaneously for multiple plates. The results demonstrate that Dynamical Thermal Tomography exhibits superior precision and strong linear correlation when measuring individual plates. On the other hand, the Power Function algorithm outperforms in effectively distinguishing between two plates simultaneously, while providing decent precision for individual plates. It is worth noting that the framerate of the camera significantly affects the performance and serves as the primary limiting factor in this specific experimental setup.Further investigations are necessary to obtain more conclusive results and determine the limitations of accuracy when measuring coating thickness.