Effect of compression wood on surface roughness and surface absorption of medium density fiberboard

Abstract

Compression wood is undoubtedly one of the most important raw material variables in wood based panel manufacturing. This study evaluated effect of compression wood on surface roughness and surface absorption (flow distance) of medium density fiberboards (MDF) manufactured from furnishes of pine (Pinus nigra Arnold var. pallasiana) containing compression wood. Panels were manufactured from two different portions of the furnish, one of the portions having a compression wood/normal wood ratio of 75/25, and the other having a ratio of 10/90. Surface absorption and surface roughness were determined according to (EN 382-1) and (ISO 4287), respectively. It was found that panels made from furnish with a 75/25 ratio had a significantly lower surface absorption value (255.78 mm) than panels made from furnish with a 10/90 ratio (317.95 mm). Surface roughness measurements based on three roughness parameters, average roughness (R-a), mean peak-to-valley height (R-z), and maximum peak-to-valley height (R-y) were considered to evaluate the surface characteristics of the panels and supported the above findings as the panels made from furnish with a 75/25 ratio had slightly rougher surface with average values of 4.15 mu m (R-a). From the tests performed, we conclude that increasing of the compression wood portion increased the surface roughness and decreased the surface absorption value.