Laser incision of woods: Effects on liquid penetration

Incision of timber is an important process within the wood processing industry for enhancing material flexibility and to significantly increase the penetration and distribution of preservative chemicals. On account of the importance of incision for wood materials, there has been an increased interest in the development of incision technologies. This paper details the use of CO2 (Infra-red) and Nd:YAG (ultra-violet) laser systems to produce laser incisions in wood (Southern yellow pine and Redwood). Through optical microscopy it was observed that the incisions ranged from 6 mm into the sample up to 15 mm into the sample, with hole diameters ranging from 0.80 mm to 1.20 mm into edge grain. Following the micron-scale laser incisions the extent of liquid penetration, as a result of the laser incisions, are studied and discussed showing how laser material processing can be used to modify the liquid penetration properties of the wood types studied. The qualitative effects of the laser incision on the woods studied are also discussed, highlighting the best laser type for incised hole quality, incised hole profile definition, in addition to the speed and accuracy of processing.