Main working parameters of equipment for laser cutting and laser welding
Laser cutting heads are basically similar to welding heads, except that the welding heads require the use of a laser welding head, and each requires the use of a laser cutting torch (also known as a cutting gun). Laser cutting mostly adopts CO2 laser cutting equipment, which is mainly composed of laser, light guide system, numerical control motion system, cutting torch, smoking system, etc. The main working parameters of laser cutting equipment are:
Beam Patterns for Laser Cutting Heads and Welding Heads
The fundamental mode, also known as the Gaussian mode, is the most ideal cutting mode and occurs mainly in low-power lasers with powers less than 1 kW. The low-order modes are close to the fundamental mode and mainly occur in 1–2 kW medium-power lasers. Multimode is a mixture of higher-order modes and occurs in high-power lasers with power greater than 3 kW.
At the same power, multiple dies have poor focusing and lower cutting power. The cutting capability of single-mode lasers is due to multimode. For example, a 300W single-mode laser has the same cutting capability as a 500W multi-mode laser. 1 Parameters for commonly used materials for single-mode laser cutting processes. Multimode laser cutting process parameters.
Laser power for laser cutting and welding heads
The laser power required for laser cutting depends primarily on the type of cut and the nature of the stolen material. Vapor cutting requires the highest laser power followed by melt cutting and oxygen cutting. Laser power has a great influence on cutting thickness, cutting speed, kerf width, etc. In general, the thickness of the material that can be cut increases as the laser power increases, the cutting speed increases, and the kerf width increases.
The focal position of the laser cutting head and the welding head
The focus position, i.e. the amount of defocus, has a big effect on the notch width. Typically, the depth of cut is greatest and the mouth width is smallest when the focal point is about 1/3 of the thickness below the surface of the material.
Depth of focus for laser cutting and welding heads
When cutting thicker steel plates, a beam with a larger focal depth should be used to obtain a cut surface with good squareness. When the focal depth is larger, the spot diameter increases and the power density decreases, which means that the cutting speed decreases. In order to maintain a certain cutting speed, the laser power must be increased. It is recommended to use a smaller depth of focus to cut thin plates, so that the spot diameter is small, the power density is high, and the cutting speed is fast.
Auxiliary gas for laser cutting and welding heads
Oxygen is mainly used as an auxiliary gas for cutting mild steel, and the heat of the ferrite combustion reaction is used to facilitate the cutting process. In addition, the cutting speed is fast, the cutting quality is good, and slag-free cutting can be obtained. Its pressure increases, kinetic energy increases, and slag discharge capacity increases. However, if the pressure is too high, the cut surface will be rough. In addition, the purity of oxygen has a certain influence on the cutting speed. For example, if the oxygen purity is reduced by 2%, the cutting speed will be reduced by 50%.
Nozzle structure of laser cutting head and welding head
The structural shape of the nozzle also affects the quality and efficiency of laser cutting. Different cutters use different shaped nozzles. Common nozzle shapes include: cylindrical, conical, square, etc. Laser cutting typically uses coaxial (airflow concentric with optical axis) nozzles. If the airflow is different from the optical axis, it is easy to generate a lot of splash during the cutting process. In order to ensure the stability of the cutting process, the distance between the nozzle end face and the workpiece surface is usually reduced to 0.5~2.0mm, so that the cutting can be carried out smoothly. Process parameters for laser cutting common metal materials.
