WOOD RESEARCH Volume 62, Number 6, 2017
Zsolt Molnár, GÁBOR NÉMETH, Sándor Héjja, Endre Magoss, and Sándor Tatai

The effect of the position of 2D roughness measurement on the roughness parameters by natural wood material

There are notable differences between the 2-D standardized surface roughness parameters depending on the position of the profil of the surface roughness eavluation of natural wood.Therefore it is fundamental to determine which parameters are the least dependent on the position of the measured profil. The dependence of the standardized roughness parameters on the different measuring positions varies. We observed the smallest average dependence at the arithmetic average roughness (Pa) parameter of the P-premary profile, and at the Mr1 (threshold as the minimal Asperities’ height distribution AHD )and Mr2 (threshold as the maximal AHD) parameters and “reduced” height peak amplitude (Ppk) was more dependent. The greatest deviation occurs in the mean roughness depth (Pz), maximum height of the profile (Pt), and the maximum roughness depth (Pmax) values. These three parameters whoed the highest differences in function of the measuring positiions.

WOOD RESEARCH Volume 65, Number 4, 2020
Endre Magoss, Sándor Tatai, Zsolt Molnár, and Ingrid Fuchs

A calibration method of the laser triangular measuring system to evaluate wood surface roughness

Due to the fact that wood roughness measurement results measured with stylus and optical methods are not always comparable a new calibration method was proposed. In order to compare the surface roughness parameters of the stylus tactile 2D roughness parameters and the optical 3D roughness parameters a systematic experiment has been carried out on fourteen wood species. The essence of this calibration method is the use of metal calibration etalons for Rz = 20 μm and Rz = 30 μm and the filter option of the optical measuring apparatus. After the calibration process, the roughness profiles taken with the optical and stylus units were much closer each to other decreasing the difference in the measurement results of the two systems. Our study prove that the laser triangular method is less usable for the planed wood surfaces.

WOOD RESEARCH Volume 64, Number 3, 2019
Endre Magoss, Zsolt Molnár, Veronika Suri, and Ingrid Fuchs

Evaluating of wetting-induced effects on the surface stability of sanded wood

A sanding is a common woodworking operation to smooth the surface prior to apply surface finish or coating materials. All cutting processes damage the upper layer of wood surface and sanding also creates a deformation zone. This deformation zone is sensitive to artificial or environmental actions, especially to wetting. In order to determine the effect of wetting on the surface properties, to get insight into the dynamics of surface movement as a function of time during the wetting, special 3D surface roughness measurements were carried out and evaluated. For sanding of samples the most common grit sizes were selected and P100 and P180 sand papers were used. Measuring the weight of the samples the dynamics of evaporation of the applied water was also determined. The surface modification after wetting is caused by moisture gradients in the upper layer associated with swelling and shrinkage resulting in permanent deformations. For this layer the most characteristic roughness parameters are the average roughness Sa and the Abbott parameters Spk, Sk and Svk. The extent of roughness variation due to wetting is characterised by the ratio of roughness after wetting to the initial roughness value. The measurement results have shown that the simultaneous infiltration and evaporation rate has a definite influence on the surface roughness modification. The most stable wood species with the least modification were the ring-porous species, following by the diffuse-porous and conifers species. The evaporation rate measured followed the same sequence for wood species investigated.