P 402 - Longer wavelength structure components in thin sheet surfaces and their influence on the painting result

The investigations were based on thin sheets from various steel companies as well as paint finishes in laboratories of the paint and automotive industry and paint finishes in five paint lines of the participating automotive companies. The labelling of the elongation waviness was examined, its cause investigated and its effect evaluated. Among the parameters that are currently regarded as determining factors for the lengthening waviness in the thin sheet surface, those with the best significance for achieving a high-quality paint finish were identified. Factors that are particularly effective when skin-passing the thin sheets, essentially the type of texturing of the rollers and, to a lesser extent, the roller grinding and the degree of skin-passing, were identified as the causes of elongation waviness. In contrast, there was no recognisable influence from the condition of the uncoated strip. For the parameters with the best significance, areas were identified in which the longitudinal waviness in the thin sheet surface is low and only has a subordinate influence on the formation of the top coat levelling structure. With suitable measures, it will now be possible to further optimise the thin sheet surface with regard to the reduction of longer wavelength structure components for subsequent painting operations The research results will contribute to further improving the visual impression of painted surfaces, e.g. of cars, but also of household goods. STUDIENGESELLSCHAFT STAHLANWENDUNG e.V.