Abstract
Coating thickness is considered to be one of the most important characteristics of thermally sprayed coatings. Despite this, there is a lack of a measurement method that could evaluate in situ the coating thickness with a sufficient accuracy that could be used as a feedback signal for online, closed-loop control. Offline methods that produce spatially resolved coating thickness measurements by capturing the surface topography have already been demonstrated to provide results with a high accuracy, comparable to the standard reference microscopical measurement method. However, up to now, the approach has not been applied in situ. This paper presents a novel approach to in situ measure spatially resolved coating thickness. It is based on a differential distance measurement of sample thickness before and after applying the coating. A high-resolution 3D camera is used to capture the surface topography and include it in the thickness measurement. The technique provides a 3D view of the deposited coating thickness measured in situ and gives results with excellent accuracy when compared to the reference microscopical method.
