Sensor system and method for characterizing stacks of wet paint layers

Abstract

A method of characterizing a wet paint layer stack of a painted body by individual parameters of the wet paint layers, based on fitting to a physical model, is provided. The method includes: emitting a THz radiation signal towards the painted body such that the THz radiation interacts with the wet paint layer stack; detecting a response signal being the detected THz radiation signal having interacted with the wet paint layer stack; determining model parameters of the physical model by optimizing the model parameters such that a predicted response signal of the physical model is fitted to the detected response signal, at least some of the model parameters being indicative of optical properties of the wet paint layers and of a wet paint layer thickness; and determining, from the determined model parameters, the individual paint layer parameters of at least one of the wet paint layers.

Description

technical field [0001] Aspects of the invention relate to methods for characterizing wet paint layer stacks of painted bodies, such as painted automotive parts, by means of THz radiation. More precisely, the method consists in analyzing detected THz radiation signals interacting with the wet paint layer stack. Further aspects of the invention relate to a corresponding method of painting a body, a corresponding sensor system and a corresponding painting device for painting a body. Background technique [0002] Applying polymeric coatings and in particular paints may be useful to increase the protection and aesthetics of the body or to prepare the body for further processing, such as applying further layers. In the following, the case where the polymer coating is a paint film is mainly discussed, but the discussion also applies to bodies coated with other polymer coatings. [0003] Despite the increasing automation of the painting industry through the use of painting robots,...

AI Technical Summary

Problems solved by technology

However, the robustness of the method leaves room for improvement

Also, the method is only reliable for a single layer of known paint with a known refractive index, however this is typically unknown

However, in industrial applications such as car bodies etc. as cited above, typically many layers of paint of various types are applied before previously applied layers have dried, which is not adequately addressed by known techniques

[0007] Thus, known techniques for paint characterization leave room for improvement

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