Spatial structure of focused beams in high-power fiber and CO₂lasers and peculiarities of their application in cutting

Abstract

The requirements for quality parameters in radiation of different wavelength (i.e. CO 2 lasers and fiber lasers) have been defined so as to perform efficient oxygen-free gas laser cutting of large-thickness samples.The main channels of consumption of radiation power in the cutting process have been considered. It is noted that focused beam divergence not only decreases the cutting speed, but also causes cutting quality deterioration.

Efficiency of laser beam utilization in gas laser cutting of materials

“…The limit of speed is achieved when the temperature of the melt surface becomes close to the boiling point. As follows from (1), (3), ( 7) and (10), the beam utilization factor and accordingly the GLC efficiency monotonically decrease as the cutting speed reduces.…”

“…As a consequence, for the chosen cutting speed at the specified beam power and known absorptance η a , the temperature of the melt surface heating is first found from (7). After that, the beam utilization factor is determined from (1) using ( 3) and (10). The value of the beam utilization factor equal to unity corresponds to the maximum cutting speed.…”

“…Allowing for (17), the beam utilization factor for cutting low-carbon steel is obtained from (1) with the use of ( 3), ( 7) and (10).…”

“…The effect of this factor on the energy balance is in many respects dependent on the ratio of the sample thickness to the focusing depth. This issue has been examined in [10] and will not be touched upon in the present paper.…”