WOOD RESEARCH Volume 61, Number 1, 2016
Milan Gaff, Monika Sarvašová Kvietková, Miroslav Gašparík, and Martin Slávik

Dependence of roughness change and crack formation on parameters of wood surface embossing

This paper deals with roughness change and crack formation after surface embossing of aspen wood. Embossing was carried out with three various shapes of embossing wedges (convex, concave and with 45° angle). The embossing was realized with two temperatures, 20 and 160°C. The surface roughness before and after embossing was evaluated on the basis of the arithmetical mean deviation of the roughness profile, Ra. Surface quality measurements were carried out in perpendicular (transversal) and parallel (longitudinal) direction in relation to wood fibers. Embossment area quality was evaluated by the mean of portion of cracks in embossment. This evaluation was based on digital image of embossed area and subsequently calculation of portion of cracks area in relation to total evaluated area. Elevated temperature has a positive effect on the quality of the surface, because of roughness decrease. However, the increase in temperature causes a growth in the proportion of cracks on the embossed surface.

WOOD RESEARCH Volume 62, Number 5, 2017
Milan Gaff, Miroslav Gašparík, and Monika Sarvašová Kvietková

Evaluation of the wood surface quality depending on the parameters of embossing

This paper deals with changes in roughness and crack formation after surface embossing of aspen wood. Embossing was based on pushing a wedge with 45° angle into three embossing depths, i.e. 2, 4 and 6 mm. The surface roughness before and after embossing was evaluated on the basis of the arithmetical mean deviation of the roughness profile, Ra. Surface quality measurements were carried out in perpendicular (transversal), parallel (parallel) and perpendicular/parallel to the wood grain. (Embossment area quality was evaluated by the mean of portion of cracks in embossment). This evaluation was based on a digital image of the embossed area and a subsequent calculation of the portion of the cracked area in relation to the total evaluated area. Increasing the embossing depth has a positive impact on the quality of the embossed surface, i.e. the highest quality was generally achieved with an embossing depth of 6 mm. The worst surface quality was achieved with the perpendicular orientation of the wedge regardless of the direction of the roughness measurement.

WOOD RESEARCH Volume 63, Number 4, 2018
Miroslav Sedlecký, Monika Sarvašová Kvietková, Richard Kminiak, and Lukáš Kaplan

Medium-density f iberboard and edge-glued panel after edge milling – surface waviness after machining with different parameters measured by contact and contactless method

This article deals with the quality of the milled surface of board edges. The quality is evaluated using the Wa (mean arithmetic deviation of the surface waviness). The Wa was measured by two methods (contact and contactless). Form Talysurf 50 Intra was used for the contact method, and the LEXT 3D measuring laser microscope OLS4100 was used for the contactless method. The variable factors whose effect on the resulting waviness was determined were the machined material, milling cutters, cutting speed and feed rate. The boards used were medium-density fiberboard, medium-density fiberboard with single-sided lamination and spruce edge-glued panel. Three different cutters were used for the milling, all of which were made of sintered carbide, and one of them was coated (CrTiN). The cutting speeds were 20, 30, 40 and 60 m.s-1, and the feed rates were 4, 8 and 11 m.min-1. All the above-mentioned factors as well as their mutual interaction had an effect on the waviness. There was no significant difference between the two methods for determining the waviness. In terms of waviness, both methods are interchangeable.