Accuracy of the radiometric determination of raw density gradients on wood-based composites

Precise knowledge about the raw density profile of wood-based composites is crucial for R&D, quality assurance, and process control. The capability of X-ray measuring devices is overestimated so far. A round robin test by means of currently applied systems provides non-identical results in comparison to each other. The results deviate, furthermore, from the assumed real raw density profile determined by gravimetric reference method. Maximum deviations are observed within the surface layer section, which is most relevant for numerous panel properties. The insufficiencies are caused by radiation physical effects occurring during the penetration of polychromatic ionising radiation through inhomogeneaus materials, which are not considered by gauge calibration up to now. Accuracy enhancement is achievable through an optimised X-ray measuring device with improved calibration and data evaluation mode.