tube fiber laser cutting machine

Three Key Technologies for Laser Cutting of Metal Pipes

This article mainly introduces the key technologies of the pipe laser cutting system and the influence of the main process parameters. Let’s take a look at it together with DXTECH laser.

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 need to be processed into different shapes and sizes to meet the needs of different industries. Laser processing technology is particularly suitable for the processing of various metal pipes. The pipe laser cutting system has the characteristics of high flexibility and high automation, and can realize the production mode of small batches and multiple varieties of different materials.

Key Technologies of Pipe Laser Cutting System

1. Light guide focusing system

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

2. Trajectory control of cutting head

In pipe cutting, the pipe being processed is a space surface with a relatively complex shape. It will be difficult to program and process using conventional methods. This requires the operator to choose the correct processing path and appropriate reference points according to the processing technology requirements. The CNC system is used to record the feed status of each axis and the coordinate values of the reference point, and then the spatial linear and arc interpolation functions of the laser cutting system are used to record the coordinate values of the processing process and generate a processing program.

3. Automatic control of laser cutting focus position

How to control the focus position of laser cutting is an important factor affecting cutting quality. Keeping the focus in the vertical direction relative to the workpiece surface through automatic measurement and control devices is one of the key technologies for laser cutting pipes. By integrating the control of the laser focus position with the linear axis ( Collision with cutting pipes or other objects.

PInfluence of Main Process Parameters

1. Influence of optical power

For continuous wave output laser generators, the size of the laser power will have an important impact on laser cutting. Theoretically, the greater the laser power of the laser cutting pipe equipment, the greater the cutting speed that can be obtained. However, 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 affects the focus of the laser beam. In actual processing, we often choose to allow the focus to obtain the highest power density when the power is less than the maximum power, thereby ensuring the efficiency and cutting quality of the entire laser cutting.

2. Influence of cutting speed

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

3. Influence of pipe diameter

When laser cutting pipes, the characteristics of the pipe itself will also have a great impact on the processing process. For example, the diameter of round pipes has a significant impact on the processing quality. Research on laser cutting of thin-walled seamless steel pipes has found that when the process parameters of laser cutting pipe equipment remain unchanged, the diameter of the pipe continues to increase. The width will also continue to increase.

4. Type and pressure of auxiliary gas

When cutting non-metallic and some metal pipes, compressed air or inert gas (such as nitrogen) can be used as auxiliary gas, while 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 a pipe with a small wall thickness at a high speed, the pressure of the auxiliary gas should be increased to prevent slag from hanging on the incision; when the pipe wall thickness is large or the cutting speed is slow, the auxiliary gas should be appropriately reduced pressure to prevent the pipe from being unable to be cut through or being cut continuously. When laser cutting pipes, the location of the beam focus is also very important. When cutting, the focus position is generally on the surface of the cutting pipe. When the focus is at a good position, the cutting seam is smallest, the cutting efficiency is the highest, and the best cut is obtained at the same time.