Surface Roughness of Varnished Wood Pre-Treated Using Sanding and Thermal Compression

Forests

Nataliya Bekhta¹  Tomasz Krystofiak²  Barbara Lis²  Pavlo Bekhta³ 

[1] Department of Design, Ukrainian National Forestry University, 79057 Lviv, Ukraine;Department of Wood Science and Thermal Technics, Poznań University of Life Sciences, 60-627 Poznań, Poland;Department of Wood-Based Composites, Cellulose and Paper, Ukrainian National Forestry University, 79057 Lviv, Ukraine;

关键词: surface roughness;    sanding;    thermal compression;    varnish system;    wood veneer;   

DOI  :  10.3390/f13050777

来源: DOAJ

【 摘 要 】

Surface roughness is an important factor during the processes of wood gluing and finishing. This study proposed a new approach for the preparation of wood veneer surfaces before varnishing through the use of thermal compression instead of sanding. The quality of the pre-treated surface was examined using surface roughness measurements. In the experiment, a wood veneer of black alder and birch, before varnishing, was subjected to sanding with a sandpaper of 180 grit size, and thermal compression at temperatures of 180 and 210 °C. Three different types of commercially manufactured varnishes (water-based (WB), polyurethane (PUR) and UV-cured (UV)) were applied to the prepared veneer surfaces with various numbers of varnish layers. Seven roughness parameters such as R_a, R_z, R_q, R_p, R_v, R_sk, and R_ku were determined for the sanded and thermally densified unvarnished and varnished surfaces. The profile surface was recorded with a portable surface roughness tester along and across the wood fibers. It was found that there was no difference between the surface roughnesses of the surfaces that had been sanded and the surface roughnesses of those that had been thermally densified at a temperature of 210 °C. The research suggests that thermal compression at a temperature of 210 °C is enough to obtain smoother surfaces with a UV varnish system, and this process can be recommended as a replacement for sanding before varnishing as the most labor-intensive and expensive operations in woodworking industry. Applying two layers of varnish along with intermediate sanding was also sufficient to obtain a satisfactory finish.

【 授权许可】

Unknown