The influence of laser cutting machine focus position adjustment on cutting quality
Many companies are very concerned about laser cutting machines: how to use laser cutting machines to process good quality workpieces?
High-quality, high-precision cutting is related to the diameter of the lens and the material to be cut, so it is also important to control the position of the focus and the surface of the material to be cut.
Since the laser power density has a great influence on the cutting speed, the choice of lens focal length is an important issue. After the laser beam is focused, the spot size is proportional to the focal length of the lens. After the beam is focused by a short focal length lens, the spot size is small, and the power density at the focal point is very high, which is very beneficial for material cutting; but its disadvantage is that the focal depth is very short and the adjustment margin Small, generally suitable for high-speed cutting of thin materials. Since the long focal length lens has a wider focal depth, as long as it has sufficient power density, it is more suitable for cutting thick workpieces.
When the focus is at a better position, the slit is smaller and the efficiency is higher, and better cutting speed can obtain better cutting results.
How to adjust the focus position of the laser cutting machine?
In most applications, the beam focus is adjusted to just under the nozzle. The distance between the nozzle and the surface of the workpiece is generally about 1.5 mm. However, the cutting focus needs to be adjusted accordingly due to different materials and requirements. Adjusting the focus position of the laser cutting machine can be divided into the following three aspects:
1. Positive focal length
That is, the cutting focus is inside the workpiece. When the workpiece to be cut is stainless steel or aluminum steel plate, the mode that the cutting point is inside the workpiece is often used. In this mode, since the focus is far away from the cutting surface, the cutting width is relatively larger than the cutting point on the surface of the workpiece. At the same time, the cutting airflow is required, the temperature is sufficient, and the cutting and piercing time is slightly longer; therefore, the workpiece material is selected to be stainless steel or aluminum. Choose for large materials.
2. Negative focal length
That is, the cutting focus is on the workpiece. The reason why the focus is positioned above the cutting material is mainly because the thick plate requires a large cutting width, and the nozzles are prone to insufficient oxygen delivery, which may cause the cutting temperature to drop. The disadvantage of this mode is that the cutting surface is relatively rough, which is not suitable for high-precision cutting.
3.0 focal length
That is, the cutting focus is on the surface of the workpiece. The upper and lower surfaces of the workpiece are different in smoothness. Generally, the cutting surface close to the focus is relatively smooth, while the lower surface far away from the cutting focus is rough. This mode needs to be determined according to the process requirements of the upper and lower surfaces in actual applications.
The above are the more common methods for adjusting the focus position of laser cutting machines. It is recommended that you determine the focus position of the laser cutting machine according to the actual situation, so that the laser cutting machine can work more reasonably.