Wavelength dependence of machining performance in UV-, VIS- and NIR-laser cutting of wood

Abstract

Cutting of wood using short-wavelength (266-, 355-, 532-, and 1064-nm) lasers was carried out and wavelength dependence in relation to machining performance and post-processing appearance was investigated. We found that a 355-nm-wavelength laser achieves the greatest machining performance. The variation in machining performance between different wavelengths was due to the different light absorptances of the woods: when we measured the spectral reflectance of the woods, we found that the greater the machining performance for a wavelength, the lower its reflection of light (and thus the greater its absorption). Assuming that the absorption of ultraviolet wavelength of 355 nm by wood is due to lignin, a lignin-free cellulose board was prepared for further investigation, and the same machining and measurements were conducted. The results showed that machining progresses well via the absorption of laser light by lignin at the ultraviolet wavelength of 355 nm. On the other hand, when this cellulose board was impregnated with phenolic resin, there was high absorption of light between the ultraviolet range and wavelengths near 600 nm, machining progressed well at wavelengths of 355 and 532 nm.

Infrared Laser Application to Wood Cutting

“…The same beam applied in conjunction with a converging lens with a focal length of 500 mm penetrated the sample over 129 s when focused on the sample A major advantage of Er:YAG lasers is that their radiation is absorbed by water [23]. The use of lasers with even shorter wavelengths has been suggested, and in particular 355 nm (wave number 28,169 cm −1 ) [24]. While the laser cutting of dry wood has been described by numerous authors [25], to date no reports have been published on the use of lasers for cutting fresh shoots or branches in orchards, plantations, or nurseries, e.g., to prune trees and shrubs.…”

“…The use of lasers with even shorter wavelengths has been suggested, and in particular 355 nm (wave number 28,169 cm −1 ) [ 24 ]. While the laser cutting of dry wood has been described by numerous authors [ 25 ], to date no reports have been published on the use of lasers for cutting fresh shoots or branches in orchards, plantations, or nurseries, e.g., to prune trees and shrubs.…”

Research Progress of Wood Cell Wall Modification and Functional Improvement: A Review

“…Fukuta et al studied and concluded the best wavelength for wood processing. For CO 2 laser modification, although the absorption coefficient of wood components is different, 355 nm is the best wavelength for modification [40]. Laser TM changes color and improves hydrophobicity of wood surface, the surface of the wood is carbonized, the roughness increases significantly, and enhances decay resistance of the wood [41].…”

Effects of different incising pretreatments in improving permeability in two refractory wood species

“…Nath et al (2020a) reported that wood anatomy and density had a major influence on the effect of CO2 laser incising when incised at the same CO2 laser power. In addition, denser woods are more difficult to ablate or incise (Fukuta et al 2016;Nath et al 2020b). Nath et al (2020b) reported the ablation to be greater in lower-density springwood than in latewood of CO2-TEA (Transverse Excitation Atmospheric) laser-incised pine.…”