MACHINING PROPERTIES OF THERMALLY MODIFIED BEECH-WOOD COMPARED TO STEAMED BEECH-WOOD

The objective of this paper was to determine and compare machining properties of thermally modified and steamed beech-wood (Fagus silvatica L.). Analysis was made of the influence of feed speed, rake angle and wood treatment on chips properties (particle size distribution, bulk density and factor of looseness), machining power and noise emission. Research was carried out during planing of radial and semi-radial boards at four different feed speeds (v(f1) = 6 m/min, v(f2) = 12 m/min, v(f3) = 18 m/min and v(f4) = 24 m/min) and three rake angles (gamma(1) = 15 degrees, gamma(2) = 20 degrees and gamma(3) = 25 degrees). Under all processing conditions, more chipping was recorded of thermally modified beech-wood than of steamed beech-wood. In these researches, the influence of feed speed on particle size distribution of produced chips is not unambiguous and it depends on the rake angle. Higher influence of feed speed on the size of chipped particles was recorded in processing steam beech-wood than in processing thermally modified beech-wood. Due to higher share of smaller particles, bulk density of chips produced in processing thermally modified beech-wood was two to three times higher than the bulk density of chips produced in processing steam beech-wood. When planing thermally modified beech-wood, up to 40 % lower power requirements were measured than in planing steam beech-wood. The increase of rake angle affects significantly the decrease of power requirements. The level of noise emission changes proportionally with the change of power requirements.