Many customers are very concerned when using laser cutting machine: how to produce high quality workpiece with laser cutting machine? Let us show you how to control the cut quality of your laser cutting machine.
The following factors affect the cut quality: cutting speed, focus position, auxiliary gas and laser output power.
1. The effect of cutting speed on cutting quality
For a given laser power density and material, the cutting speed conforms to the empirical formula. As long as the cutting speed of the material is proportional to the laser power density, increasing the power density will increase the cutting speed. The power density referred to here is not only related to the laser output power, but also to the beam quality mode. In addition, the characteristics of the beam focusing system, i.e. the spot size after focusing, also have a great influence on laser cutting.
Particularly for metallic materials, the laser cutting speed can have a relative range of adjustment while maintaining satisfactory cut quality while maintaining other processing variables. This adjustment range is slightly thicker than when cutting thin metals. Width. At times, slower cutting speeds can also result in ablation of the mouth surface by the hot melt material, which can roughen the cut surface.
2. The effect of focus position adjustment on cutting quality
Since the laser power density has a great influence on the cutting speed, the selection of the focal length of the lens is an important issue. However, the disadvantage is that the focal depth is very short and the adjustment margin is adjusted. The small size is usually suitable for high speed cutting of thin materials. Since the telephoto lens has a wide depth of focus, it is suitable for cutting thick workpieces as long as it has sufficient power density.
Due to the high power density at the focal point. In most cases, the position of the focal point during cutting is only on the surface of the workpiece. Ensuring a constant relative position of the focal point with respect to the workpiece is important for obtaining consistent cut quality. Sometimes, the lens causes the focal length to change, which requires timely adjustment of the focus position.
In most applications, the beam focus is adjusted just below the nozzle. The distance between the nozzle and the workpiece surface is usually about 1.5 mm.
3. Influence of auxiliary gas pressure on cutting quality
As a rule, an auxiliary gas is required for material cutting. And the problem mainly concerns the type and pressure of the auxiliary gas. Usually, the auxiliary gas is coaxial with the laser beam, thus protecting the lens from contamination and blowing away slag at the bottom of the cutting area.
For most metal laser cutting, reactive gases (as long as O2) are used to form an oxidizing exothermic reaction with the iron. This extra heat increases the cutting speed by 1/3 to 1/2.
Gas pressure is an extremely important factor in securing an auxiliary gas.
Laser cutting practice shows that when the auxiliary gas is oxygen. Its purity has a significant impact on cut quality. Oxygen purity reduced by 2% will make the cutting speed reduced by 50%, and lead to cutting quality significantly worse.
4. The impact of laser output power on cutting quality
For continuous wave output lasers, the laser power size and mode will have a significant impact on cutting. In practice, it is usually necessary to set a higher power to obtain a higher cutting speed. or to cut thicker material. However, the beam pattern is sometimes more important and this pattern usually changes slightly as the output power is increased. It is often found that higher power densities and better cut quality can be obtained at lower focuses than under higher power conditions. These patterns are not consistent throughout the effective working life of the laser. The state of the optics, subtle variations in the laser operating mixture, and fluctuations in the flow rate can all affect the mode mechanism.
In summary, although the factors affecting a laser cutter are complex. Cutting speed, focus position, auxiliary air pressure and laser power are four important variables.
