| High power radio-frequency (RF) slab CO2laser is a very important type of industrial CO2laser. It becomes one of the main industrial laser sources, and an important trend for laser welding and cutting. To investigate the discharging behavior in the RF slab CO2laser in this paper, the RF excited gas discharge characteristics, the RF high power supply and the transmission matching, the discharge plate electrodes with large area, the laser power control and the anti-jamming measures are analyzed theoretically and experimentally. The main contents include the following aspects:(1) According to the theoretical model of RF discharge gas, it points out that the RF-excited slab laser needs to work in the a-discharge mode. A one-dimensional RF discharge model is given. Experimental researches mainly discuss the effects of excited frequency to the discharging quality. It contains the relationship between the breakdown voltage and the excited frequency, and the effect of exited frequency to the property of plasma in the discharge area. Furthermore, several rules for selecting the excited frequency are obtained. Through a series of experiments, the optimal scheme to choose the air mixture and the atmospheric pressure are obtained.(2) RF power sources for high power RF slab CO2laser requirements is designed based on high-power self-excited RF power which include amplifier circuit including the DC high voltage circuit, the filament heating circuit, the gate modulation circuit and a RF power oscillation. Oscillation and amplifier circuit section has calculated the tube model and component parameters. Determine the RF power and dc discharge load impedance matching, and calculate the matching parameters. Pressure longitudinal parallel resonant inductor, when the electrode vertical and horizontal, respectively, for intermediate feed and side feed into, by calculating the electrode side inductance asymmetric distribution, get the entire electrode two-dimensional pressure model and verified through experiments.(3) According to the structure and thermal environment of the electrode, the heat exchanger for the electrodes has been calculated and analyzed. The finite element theory of temperature field is discussed. By designing different flowing channels, a series of discharging and lasing experiments have been taken. When improving the serpentine waterways at high duty cycle, the laser power gain saturation phenomenon will not appear. It proves that the flowing channel design meets the cooling gas temperature requirements at the maximum RF power injection.(4) RF slab CO2laser power control, power sampling unit sampling based on the transmittance of0.5%of the spherical mirror and thermocouple heap, changing the pulse width adjustment of the injected RF power, taking into account generate PWM wave stability and the requirements of real-time feedback, the design of a dedicated power control circuit board, through the host computer, PLC and lower machine CPLD communication, the optimized laser power feedback control, to improve the stability of the laser power, the power fluctuations<±1.5%.(5) The simple point measure on the slab laser electromagnetic radiation detection, shielding and grounding the whole electromagnetic radiation is reduced to0.04W/m2. According to the conductive interference paths of anode high voltage power supply circuit, the filament current supply circuit and gate pulse modulation signal drive circuit, LC low-pass filter for attenuation of suppression ratio up to55dB,40dB,30dB are designed to solve the conducted RF interference.
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