Laser cutting equipment and welding equipment is basically similar, the difference is that welding requires the use of laser welding gun, and each need to use laser cutting torch (also known as cutting gun).Most of the laser cutting equipment is CO2 laser cutting equipment, which is mainly composed of laser, light guide system, CNC motion system, cutting torch, smoking system, etc.The main work parameters of laser cutting are:
The beam transverse mode
The base mode, also known as gaussian mode, is the most ideal mode for cutting, mainly appearing in small power lasers with power less than 1kW.Low order mode, which is close to the base mode, mainly appears in 1 ~ 2kW medium power laser.Multimode, which is a mixture of high-order modes, occurs in high-power lasers with power greater than 3kW.
Under the same power, the multi-mode focusing is poor and the cutting ability is low. The cutting ability of single-mode laser is due to the multi-mode.For example, a 300W single-mode laser has the same cutting capability as a 500W multi-mode laser.The technical parameters of single-mode laser cutting for commonly used materials are shown in figure 1.Technical parameters of multi-mode laser cutting are shown in figure 2.
The laser power required for laser cutting mainly depends on the type of cutting and the nature of the stolen material.The laser power required for gasification cutting is the largest, followed by melting cutting and oxygen cutting.Laser power has great influence on cutting thickness, cutting speed and cutting width.As the laser power increases, the thickness of the cutting material increases, the cutting speed increases and the cutting width increases.
The focus position
The focal position, or defocus, has a greater effect on the width of the cut.Generally, the selected focus is located about 1/3 below the surface of the material with the maximum cutting depth and the minimum width of the mouth.
The depth of focus
When cutting thick steel plate, the beam with larger focal depth should be used to obtain the cutting surface with good perpendicularity.The focal depth is large, the spot diameter increases, the power density decreases, and the cutting speed decreases.To maintain a certain cutting speed needs to increase the laser power.It is advisable to use a small focal depth for cutting sheet, so that the spot diameter is small, the power density is large, and the cutting speed is fast.
Cutting low carbon steel using oh as auxiliary gas, in order to use iron-oxygen combustion reaction heat to promote the cutting process, and cutting speed, cutting quality is good, can get no slag notch.The pressure increases, the kinetic energy increases and the slag discharge capacity increases.But too much pressure can lead to rough cutting surface.In addition, the purity of oxygen has a certain effect on the cutting speed.For example, a 2 percent reduction in oxygen purity would reduce the cutting speed by 50 percent.
The nozzle structure
The shape of the nozzle also affects the quality and efficiency of laser cutting.The commonly used nozzle shapes are: cylindrical, conical, square and so on.Laser cutting generally USES coaxial (airflow and optical axis concentric) nozzle, such as airflow and optical axis is not coaxial, so easy to produce a lot of spatters in cutting.In order to ensure the stability of the cutting process, it is usually necessary to reduce the distance between the nozzle end face and the workpiece surface, usually 0.5 ~ 2.0mm, in order to facilitate the smooth cutting.The technical parameters of laser cutting for commonly used metal materials are shown in figure 3.