The key technology of tube laser cutting system

Metal pipes are widely used in aircraft manufacturing, engineering machinery, automobile industry, petrochemical industry, agricultural and animal husbandry machinery and other industries. Due to different application scenarios, parts of different shapes and sizes need to be processed to meet the needs of different industries. Laser processing technology is particularly suitable for processing various metal pipes. The tube laser cutting system has the characteristics of high flexibility and high automation, which can realize the production mode of different materials in small batches and multiple varieties.

What are the key technologies of the tube laser cutting system?

Light guide focusing system

The function of the light guide focusing system is to guide the light beam output by the laser generator to the cutting head of the focused light path. For laser cutting pipes, in order to obtain high-quality slits, the focused spot of the focused beam needs to be small in diameter and high in power. This allows the laser generator to perform low-order mode output. When performing tube laser cutting, in order to obtain a smaller beam focus diameter, the order of the transverse mode of the laser should be small, preferably the fundamental mode. The cutting head of the laser cutting equipment is equipped with a focusing lens. After the laser beam is focused by the lens, a smaller focused spot can be obtained, so that high-quality pipe cutting can be performed.

Trajectory control of the cutting head

In pipe cutting, the processed pipe belongs to the space surface and the shape is more complicated. It will be difficult to program and process with conventional methods. The operator is required to select the correct processing path and the appropriate reference point according to the requirements of the processing technology, use the CNC system to record the feed of each axis and the coordinate value of the reference point, and then use the spatial straight line and arc interpolation of the laser cutting system Function, record the coordinate value of the machining process, and generate the machining program.

Automatic control of the laser cutting focus position

How to control the laser cutting focus position is an important factor that affects the cutting quality. It is one of the key technologies for laser cutting pipes to make the vertical direction of the focal point relative to the surface of the workpiece unchanged through automatic measurement and control devices. Through the integration of the laser focus position control and the laser processing system linear axis (XYZ), the movement of the laser cutting head is lighter and more flexible, and the position of the focus point can be fully understood, avoiding the cutting head and cutting pipe during the processing process. Or other objects collide.

The influence of main process parameters

⑴The influence of optical power.

For continuous wave output laser generators, the size of the laser power will have an important impact on laser cutting. In theory, the greater the laser power of the laser cutting pipe equipment, the higher the cutting speed can be obtained, but combined with the characteristics of the pipe itself, the maximum cutting power is not the best choice. When the cutting power is increased, the mode of the laser itself also changes, which will affect the focus of the laser beam. In actual processing, we often choose to obtain the highest power density for the focus when the power is less than the maximum power, so as to ensure the efficiency and cutting quality of the entire laser cutting.

⑵The influence of cutting speed.

When laser cutting pipes, it is necessary to ensure that the cutting speed is within a certain range to obtain better cutting quality. If the cutting speed is slow, excessive heat will accumulate on the surface of the pipe, the heat-affected zone becomes larger, the slit becomes wider, and the discharged hot melt material burns the surface of the incision, making the surface of the incision rough. When the cutting speed increases, the average slit width of the pipe circumference becomes smaller, and the smaller the diameter of the pipe being cut, the more obvious this effect. As the cutting speed increases, the laser action time shortens, the total energy absorbed by the pipe decreases, the temperature at the front end of the pipe decreases, and the slit width decreases. If the cutting speed is too fast, the pipe may not be cut through or cut continuously. Thereby affecting the overall cutting quality.

⑶The influence of pipe diameter.

When laser cutting pipes, the characteristics of the pipes themselves will also have a great impact on the processing process. For example, the diameter of a round tube has a significant impact on the processing quality. Through the study of laser cutting thin-walled seamless steel pipes, it is found that the laser cutting pipe equipment keeps the same process parameters, the pipe diameter continues to increase. The width will continue to increase.

⑷Type and pressure of auxiliary gas.

When cutting non-metal and some metal pipes, compressed air or inert gas (such as nitrogen) can be used as auxiliary gas, and for most metal pipes, active gas (such as oxygen) can be used. After determining the type of auxiliary gas, it is also extremely important to determine the pressure of the auxiliary gas. When cutting pipes with a small pipe wall thickness at a higher speed, the auxiliary gas pressure should be increased to prevent slagging in the cut; when the cutting pipe wall thickness is large or the cutting speed is slow, the auxiliary gas should be appropriately reduced The pressure to prevent the pipe from cutting through or cutting continuously.

When laser cutting pipes, the position of the beam focus is also very important. When cutting, the focus position is generally at the surface position of the cutting pipe. When the focus is in a better position, the slit is the smallest, the cutting efficiency is the highest, and the cutting effect is the best.