is mainly composed of hard glass, resonant cavity and electrode.1. Hard glass part; This part consists of discharge tube, water cooling sleeve, gas storage sleeve and gas return pipe made of GG17 material. Enclosed CO2 laser is usually of three-layer casing structure. The innermost part is the , the middle part is the water cleaning sleeve, the outermost layer is the gas storage sleeve, and the return pipe is used for connecting the discharge tube and the gas storage pipe. 2. Resonant cavity part: This part consists of total reflection mirror and output reflection mirror. The total of the resonant cavity is usually based on optical glass with a gold film on the surface, and the reflectivity of the gold film mirror is over 98% near 10.6um; The output mirror of the resonant cavity is generally made of germanium ( Ge ), an infrared material that can transmit 10.6um of radiation, as a substrate, and a multilayer dielectric film is coated on the substrate. 3. Electrode part: generally uses cold cathode with cylindrical shape. The choice of cathode material has great influence on the life of laser. The basic requirements for cathode material are: low sputtering rate and low gas absorption rate. For co2 laser marking machine, the quality and performance of laser tube directly affect the working efficiency of co2 laser marking machine, which is also one of the most important parts of . Generally, co2 laser marking machine lasers are usually made of hard glass and generally adopt a layer sleeve structure. The innermost layer is a discharge tube, the second layer is a water-cooled sleeve, and the outermost layer is a gas storage tube. The diameter of carbon dioxide laser discharge tube is thicker than He-Ne . Generally speaking, the thickness of discharge tube has no influence on the output power, mainly considering the diffraction effect caused by the spot size, which should be determined according to the tube length. The length of the pipe is thicker and the length of the pipe is shorter and thinner. The length of the discharge tube is proportional to the output power. Within a certain length range, the power output per meter of discharge tube length increases with the total length. The purpose of the water cooling jacket is to cool the working gas and stabilize the output power. The discharge tube is connected with the gas storage tube at both ends, i.e. one end of the gas storage tube is provided with a small hole which is communicated with the discharge tube, and the other end is communicated with the discharge tube through a spiral return tube, so that gas can circulate in the discharge tube and the gas storage tube, and the gas in the discharge tube can be exchanged at any time. It is widely used in non-metal marking and carving such as acrylic and plastic products. And develop the ability to mark electroplated low carbon steel. are also used in automation systems for flexible printed circuit board of electronic instruments and polyimide and polyester sheets of diaphragms.