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Abstract
In this research, the effect of different machining processes on wood surface roughness was studied. There were applied three main furniture manufacturing processes, respectively planning, routing and sanding. The sanding process was applied twice, respectively with 100 and 120 grit sandpapers. The study was focused on two main native wood species, beech (Fagus sylvatica L.) and fir (Abies alba Mill.). The specimen samples were sawn with dimensions 90·8·2 cm, with 11% moisture content. For each machine were processed two specimens from each species. Routing process was carried out after planning, as well as sanding. Sanding process with 120 grit paper was conducted after the 100 grit process, respecting so the processing line applied by manufacturing sector. For measurement of surface roughness was applied the direct contact method. This method reproduces the surface profile by means of contact stylus profilometer, making so possible the calculation of arithmetic mean deviation of the profile, maximum two point height of the profile, mean roughness depth and root-meansquare deviation of the profile. The measurements were performed in ten different clear wood points for each specimen. Results showed that fir wood gave the same class of roughness for all machining processes, respectively 8. Regarding to beech wood, planning and routing processes gave the same roughness class, equal with those of fir, while sanding gave a higher class for both numbers of sandpapers, respectively 9. The results obtained present useful information for furniture manufacturing sector, by the cost effective viewpoint.
Keywords: machinig, wood, furniture, surface, roughness class.
1.Introduction
The complexity of wood as a substrate appears to be a crucial element to guarantee the gluing quality. Studies have shown that rough veneer reduces the bond quality by as much as one-third comparing to the smooth one [3]. It is proved that the strength of adhesive joints is influenced by surface roughness [16]. The same situation appears to be related to wood finishing quality as well. For smoother surfaces the finishing performance is improved and the consume of the paint is lower [21].
The roughness of wood surface can be considered as result from combination of deformations caused by anatomical structure of wood with irregularities caused by machining process.
In the first category are included various factors such as wood anatomy...