Using UV short-wavelength laser irradiation, the layer
of mechanically damaged cells on wooden surfaces can be removed.
Four excimer lasers (157 nm, 193 nm, 248 nm, 308 nm) were used to
compare the ablation of wooden surfaces by different UV
wavelengths. The ablation depth was measured by using optical
microscopy. LV-SEM was applied to determine the appearance and
quality of the laser ablation. In addition to the ablation process
the laser can be used also to influence the surface energy. As the
same effect can be achieved by plasma treatment of wooden
surfaces, both methods were compared. The comparison was made by
means of the water droplet test. The plasma treatment was carried
out at atmospheric pressure as a dielectric barrier discharge. Two
types of wood were determined: beech and thermowood beech.
Thermowood is a heat treated lumber product especially made for
outdoor applications. It was examined, whether the thermal
treatment of wood influences the characteristic changes of the
laser ablation and the plasma treatment. With the researched
wavelengths, homogeneous ablation is possible. The absorption time
can be reduced both with laser ablation and plasma treatment,
whereas plasma treatment causes a stronger effect. A combined
treatment improves the effect additionally.