Briefly describe CO2 laser and CO2 laser power supply

Carbon dioxide laser is a gas laser with CO2 gas as the main working substance (CO2: N2: He=1:7:20). The CO2 laser consists of a discharge tube, a resonator and an electrode. With the addition of a DC high voltage pump, the gas in the discharge tube emits light (the output wavelength is 10.6μm). Compared with other types of lasers, CO2 laser is more widely used in the field of industrial processing, especially in laser welding and laser cutting has unique advantages:

(1) Among all gas lasers, CO2 laser has a higher energy conversion efficiency, and its output power can reach hundreds of thousands of watts.

(2) The output band of CO2 laser is 10.6μm, the band transmission in the air loss is very small, almost not affected by environmental factors, can work all weather, compared with other laser output performance, CO2 laser is more in line with the requirements of industrial applications.

(3) Compared with other gas lasers, the output spectral line width of CO2 laser is wider.

The CO2 laser power supply is essentially a DC high-voltage switching power supply. The working characteristics of the CO2 laser determine the characteristics of its pump supply, which are mainly reflected in the following aspects:

(1) the light discharge conditions of the mixed gas in the laser discharge tube are very harsh, usually need to provide 20 50KV high voltage at both ends of the discharge tube (discharge tubes of different lengths and different inner diameters have different luminous voltage), the general linear voltage regulator power supply or switching power supply can not provide this voltage.

(2) When the laser tube starts to discharge, the glow voltage is large. With the gradual stability of the work, the voltage at both ends of the air cavity gradually decreases, and the glow discharge current gradually increases. Therefore, the laser power supply needs to have the adaptive output ability.

With the increasing maturity of laser processing manufacturing industry, CO2 laser is gradually widely used in traditional manual or other mechanical processing fields, such as laser welding, laser cutting, laser punching, etc., because it also puts forward higher requirements for CO2 laser and its power supply. It is mainly manifested in the following aspects:

(1) In industrial laser cutting systems, CO2 lasers usually need to have stable power output.

(2) In laser processing, especially in laser cutting, laser drilling and other fields, when cutting different materials with laser, because the material itself is 10.6μm, when cutting different materials, the laser output power also needs to be adjusted properly, that is, the laser output power needs to be stable and continuous adjustment.

(3) In specific applications, multiple CO2 lasers are required to work in parallel. For example, in the laser embroidery cutting machine system, many lasers need to work at the same pace at the same time, or the laser output needs to be focused together in the laser energy focusing system. Although the energy conversion efficiency of CO2 laser can reach 30% to 40%, if the efficiency of a single laser power supply is low, the other lasers will waste a lot of capacity. Therefore, the efficiency of a single laser power supply has a key influence on the overall energy efficiency of the laser cutting system.

In the context of industrial application, CO2 laser has put forward higher performance requirements for its pump supplement, mainly as follows:

High stability - requires the laser to produce a stable laser output;

High reliability -- the laser power supply is required to maintain reliability in a variety of complex environments;

High efficiency - high energy conversion efficiency of laser power supply;

Controllability - The laser power supply is required to have good controllability when controlling the laser power output.