Effect of Feed Speed and Wood Species on Roughness of Machined Surface

In this study, the surface roughness values of planed beech-wood (Fagus L.), oak-wood (Quercus L.) and fir-wood (Abies alba Mill.) specimens were examined. The samples of beech-wood were cut from steamed beech-wood and from thermally modified beech-wood (212oC). The specimens were machined by planing in radial directions with two knives at 6, 12, 18 and 24 m/min feed speed. The cutting depth of 2.0 mm was constant and knife rake angle was 15o. The machining experiments were carried out using a single cutter-block of a Weinig Powermat 400. The cutter-block with a diameter of Ø 125 mm rotated at 6000 revolutions per minute (RPM). Surface roughness was measured from the radial face of each sample according to DIN 4768 (1990) by using Mitutoyo SJ-201 stylus scanner. Comparison between the results of surface roughness of four species showed that surface roughness increases with the increase of feed rate. The surface quality of samples of planed beech-wood, oak-wood and fir-wood were significantly different. The samples of planed surface of oak-wood had the best quality and the samples of fir wood had the highest values of surface roughness. There were no significant differences in the surface quality of thermally modified and steamed beach-wood samples despite the significant difference in mechanical and physical properties of thermally modified and steamed wood.