A Consideration for Improving the Processing Efficiency of UV-Laser Incisions of Wood

A short-pulsed laser with an ultraviolet wavelength is used for laser micro incisions of wood. In order to solve the technical issue of processing efficiency, the laser oscillation conditions were investigated. The output of this pulsed laser is the product of the pulse energy and the pulse repetition rate, and the output is represented by their two-dimensional planes. For the purpose of understanding the characteristics of processing on wood by this laser, drilling was performed on wood under each condition of this two-dimensional plane. As a result, the hole depth showed an asymptotic tendency with respect to the output increase, and the heat effect and the hole diameter tended to increase. Therefore, it was presumed that both machining quality and its efficiency could be achieved by beam splitting that disperses the output of the beam. In an application example of drilling hundreds of holes per square centimeter at a depth of a few millimeters, it was predicted that the machining time would be halved by applying such a beam splitting device. Moreover, it was considered that the shortening rate could be increased as improving the output of the oscillator. On the other hand, further shortening of pulse width by using the pico-second laser was not considered to be beneficial in the processing of wood. In-process monitoring of the processing phenomenon was examined and the progress of laser drilling was observed.