Metal pipe is 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 machining technology is especially suitable for the processing of various metal tubes.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 various varieties.
What are the key technologies of the laser cutting system?
Light focusing system
The function of the laser focusing system is to direct the beam from the laser generator to the cutting head of the focusing path.For laser-cut pipe, to get high quality slit, it is necessary to focus the beam with small diameter and high power.This allows the laser generator to perform low-order mode output.In order to obtain a smaller beam focusing diameter, the transverse mode of the laser is less important and the basic mode is better.The cutting head of the laser cutting equipment is equipped with a focusing lens. After the laser beam is focused through the lens, a small focusing spot can be obtained, so that high-quality pipe cutting can be carried out.
Track control of cutting head
In pipe cutting, the processed pipe belongs to the space curved surface, the shape is more complex, if using conventional methods processing programming has the certain difficulty, which requires the operator according to process requirements, select the correct processing path and the appropriate reference point, using the numerical control system to record the axial feed and reference point coordinates, again through the laser cutting system of space line and arc interpolation function, record the process of coordinate values, and generate the processing procedure.
Automatic control of laser cutting focus position
How to control the laser cutting focus position is an important factor affecting the cutting quality.It is one of the key techniques of laser cutting pipe that the vertical direction of the focus relative to the workpiece surface is fixed by automatic measurement and control device.Through the control of the laser focus position and the integration of the straight axis of the laser processing system (x-y-z), the laser cutting head movement is more light and flexible, and the focus position can be well known, avoiding the collision between the cutting head and the cutting pipe or other objects in the process of processing.
The influence of main process parameters
The influence of light power.
For the continuous wave output laser generator, the laser power will have an important effect on the laser cutting.Theoretically, the higher the laser power of the laser cutting pipe equipment, the higher the cutting speed can be. However, considering the characteristics of the pipe itself, the maximum cutting power is not the best choice.When the cutting power is increased, the laser's own mode will also change, which will affect the laser beam focus.In the actual processing, we often choose to obtain the highest power density in the focus under the condition of less than the maximum power, so as to ensure the efficiency and cutting quality of the entire laser cutting.
The impact of cutting speed.
Laser cutting pipe must ensure the cutting speed in a certain range to obtain a better cutting quality.If the cutting speed is too slow, too much heat will accumulate on the surface of the pipe, the heat-affected area will become larger, the cutting seam will become wider, and the hot melt material discharged from the cutting surface will burn the cutting surface, making the cutting surface become rough.When the cutting speed is accelerated, the average slit width of the circumference of the pipe becomes smaller, and the smaller the pipe diameter is cut, the more obvious this effect is.With the acceleration of cutting speed, the time of laser action is shortened, the total energy absorbed by the pipe becomes less, the temperature of the front end of the pipe drops, and the width of the slit decreases. If the cutting speed is too fast, the pipe will not be cut through or cut continuously, thus affecting the overall cutting quality.
The effect of pipe diameter size.
When laser cutting pipe, the characteristics of the pipe itself will also have a great impact on the processing process.For example, the diameter of round pipe has a significant impact on the processing quality. Through the research on the laser-cut thin-wall seamless steel pipe, it is found that the pipe diameter will increase continuously and the slit width will also increase continuously when the various technological parameters of the laser-cut pipe equipment remain unchanged.
The type and pressure of the auxiliary gas.
When cutting non-metallic and partial metal tubes, either compressed air or an inert gas (such as nitrogen) can be used as an auxiliary gas, while for most metal tubes an active gas (such as oxygen) can be used.After determining the type of auxiliary gas, it is also very important to determine the pressure of the auxiliary gas.The pressure of auxiliary gas should be increased to prevent slagging when cutting the pipe with smaller wall thickness at a higher speed.When the wall thickness of the cutting pipe is large or the cutting speed is slow, the pressure of auxiliary gas should be appropriately reduced to prevent the pipe from not cutting through or cutting continuously.
The focus of the beam is also very important when cutting the pipe with laser.When cutting, the focus position is generally on the surface of the cutting pipe fitting. When the focus is in a good position, the slit is the smallest, the cutting efficiency is the highest, and the cutting effect is also the best.
