Effects of plasma treatment and sanding process on surface roughness of wood veneers

Abstract

An ideal veneer surface is crucial for good panel properties in plywood manufacturing. The aim of this study was to compare plasma treatments and sanding (mechanical) processes with respect to the surface roughness of veneers. Rotary-cut veneers with a thickness of 2 mm from Scots pine (Pinus sylvestris) logs were used as material. After rotary peeling, veneer sheets were dried at 110 °C in a veneer dryer. Veneer sheets were divided into 4 main groups. The surfaces of the control veneer sheets were left untreated. Two different grits of sandpaper, 80 and 180, were used for sanding the surfaces of veneers. Plasma treatment was applied to the last veneer group with 3 different gases (oxygen, nitrogen, and ammonia) and 3 different plasma times (1 min, 5 min, and 15 min). The Mitutoyo Surftest SJ-301 instrument was used to determine surface roughness of samples. Average roughness (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax) parameters were measured to evaluate the surface roughness of the samples based on DIN 4768. It was found that the smoothest veneer surfaces were obtained with the sanding processes. Surface roughness values (Rz) of veneer sheets sanded with 180 grit sandpaper were lower than those of veneers sanded with 80 grit sandpaper. Compared with the plasma treatment in terms of surface roughness, plasma-treated veneers had higher Rz values. It was also determined that Rz values were the lowest in the veneers treated with nitrogen plasma. Additionally, the surface roughness values of Scots pine veneers treated with ammonia plasma were a little higher than those of veneer sheets treated with oxygen plasma. The effect of plasma treatment time on surface roughness was not found to be statistically significant.

Glossiness Evaluation of Coated Wood Surfaces as Function of Varnish Type and Exposure to Different Conditions

“…A reflection structure image of high-gloss composite products was developed as an alternative method to describe the visual human perception of gloss [3]. However, recent studies have shown off the comfortable feelings given by both the coated and uncoated surfaces of wood products [4,5]. A model based on the value generation of wooden furniture has been validated by these qualitative, innovative, and ecological products.…”

Effects of plasma surface treatment on bending strength and modulus of elasticity of beech and poplar plywood

“…In recent years, the plasma modification process has been used to modify the surfaces of wood and wood based materials in order to enhance surface properties of the wood component and mechanical strength of the wood based materials (Aydin and Demirkir 2010, Acda et al 2012, Demirkir et al 2014.Plasma treatment is used to improve bonding properties of many materials such as wood based products by altering the surface properties and chemical structure of the wooden components. Bond quality as one of the most important parameters in wood based panels depends on the intermolecular attraction between the adhesive and the wood components.…”

Gozd in les: 70 let

“…Obdelava lesa in lesnih kompozitov s plazmo predstavlja enega od načinov za spremembo lastnosti površin (Wolkenhauer et al, 2008;Demirkir et al, 2014), na katere lahko z namenom povečanja površinske zaščite materiala nanesemo različne premaze (Riedl et al 2014). Do sedaj je bilo veliko raziskav izvedenih na temo obnašanja tekočin na tako modificiranih površinah, v smislu merjenja kontaktnih kotov in določanja proste površinske energije s plazmo obdelanih površin lesa Wolkenhauer et al, 2015).…”