Comparative studies of metal cutting with high-power lasers

The most widely used high power industrial lasers are Nd:YAG and carbon-dioxide lasers. Chemical oxygen iodine laser (COIL), whose wavelength (1.315 micrometer) is between that of YAG (1.06 micrometer) and carbon-dioxide (10.6 micrometer) lasers, is another high power laser for industrial applications. The cutting capability of these lasers is investigated. The cut depth depends strongly on the absorptivity of materials, kerf width and cutting speed. Absorptivity is an unknown parameter for which experimental data at high temperatures are unavailable. Theoretical values of the absorptivities of various metals are obtained using Hagen-Ruben\u27s relation. It is found that the absorptivity of metals is linearly proportional to the square root of resistivity and inversely proportional to the square root of the wavelength. The absorptivities of COIL ad YAG lasers are 2.84 and 3.16 times larger than that of carbon-dioxide laser, respectively. Based on the theoretical values of absorptivity, the cut depth of metals are analyzed for various laser powers, cutting speeds for these lasers. Due to the wavelength dependence of absorptivity, the cut depths for COIL and YAG lasers are expected to be 2.84 and 3.16 times deeper than that for carbon-dioxide laser. ©2005 Copyright SPIE - The International Society for Optical Engineering