An objective method to measure and evaluate the quality of sanded wood surfaces

No agreed guidelines exist in wood surface metrology about how to objectively measure and evaluate the surface quality and existing general standard methods and corresponding software are not usually applicable to wood. This paper presents a review of a method developed for sanded wood surfaces, which covers the choice of instrument type, the measuring resolution, the minimum evaluation length, aspects of filtering and the separation of processing roughness from anatomical irregularities. Compared with previous studies in the literature, processing roughness parameters calculated in this study excluded the influence of wood anatomy and represent objective references for the quality of sanding.The method was tested on several sanding variables, but was used in this paper to evaluate the influence of grit size on the quality of European oak (Quercus robur L.) sanded with P120, P150, P180, P240 and P1000. Grit size measured with the method above had a clear influence on surface roughness, the finer were the grits the smoother was the surface. Roughness values were fairly close together with P120, P150 and P180 and much smaller with P240 and P1000. This indicates that for oak it is not economical to have a sequence of sanding operations in the domain of fine grit sizes. The method can further be used to evaluate roughness parameters for different combinations of sanding variables to optimise the sanding process.