Effect of wood porosity on surface creation process by single-grit scratching method

This paper presents an investigation of the effect of wood porosity on surface creation by single-grit scratching method. Single grits with cone geometry were prepared to experimentally simulate wood sanding operation. Five wood species with different porosity ranging from about 30 to 80% were selected as samples. Besides, aluminum (Al 1060) samples were made as a contrast. The surface morphology was evaluated by ultra-depth 3D microscope and SEM observations, and the cross-sectional profiles of scratches were analyzed using a 3D profilometer. The results showed that much less plowed ridges or plastic upheaval occurred on both sides of the scratched grooves for wood samples than of Al 1060. With respect to cutting with grain, visible fibrils protrusion was found only for African sandalwood that had the lowest porosity among the five wood species. The deformation absorption capacity of wood was verified through microscopic evaluation. In the case of cutting across grain, fiber bundles of high-porosity wood species like balsa wood and black cherry were mainly faced with compressive crush while tensile rupture was the general pattern for low-porosity wood like sugar maple and African sandalwood. Corresponding force analysis for wood-grit interaction was made to account for the detailed material deformation and removal.