Evaluation of surface roughness of Thai medium density fiberboard (MDF)

Wood composites contain irregularities on their surface due to the sanding process which play an important role when they are used as substrate for thin overlays. The objective of this study is to evaluate surface characteristics of commercially manufactured medium density fiberboard (MDF) panels in Thailand. A skid type profilometer with diamond stylus of 5 μm tip radius and 90° tip angle was employed for the experiment. Roughness average (Ra), average maximum height of the profile (Rz), and maximum roughness depth (Rmax) were used to evaluate quantitatively surface characteristics of the specimens. Roughness measurements were taken from both sides of the sanded specimens along and across the sandmarks over 15.2 mm tracing span. Panel type-C had the smoothest surface with average values of 2.39, 21.03, and 26.93 μm for Ra, Rz, and Rmax, respectively. It was found that no statistically (p<0.1) significant difference existed between the values of all three parameters taken in both sandmark directions of all types of panels. Also none of the panels considered in this study had superior surface quality over the other. In further studies, surface roughness of MDF samples exposed to various relative humidity levels could give a better understanding of their roughness behavior for different overlaying applications.