For laser cutting processing, evaluating its processing quality mainly includes the following principles:
1. Smooth cutting, no streaks, and no brittle fracture;
2. The slit width is narrow, which is mainly related to the diameter of the laser beam spot;
3. The verticality of the cutting seam is good, and the heat-affected zone is small;
4. No material burning, no molten layer formation, no large slag;
5. The surface roughness of the incision, the size of the surface roughness is the key to measure the surface quality of laser cutting.
In addition to the above-mentioned principles, the state and final shape of the molten layer during processing directly affect the above-mentioned processing quality evaluation indicators.
The surface roughness of laser cutting mainly depends on the following three aspects:
1. The inherent parameters of the cutting system, such as spot mode, focal length, etc.;
2. Adjustable process parameters during the cutting process, such as power size, cutting speed, auxiliary gas type and pressure, etc.;
3. The physical parameters of the processed material, such as the absorption rate of the laser, the melting point, the viscosity coefficient of the molten metal oxide, the surface tension of the metal oxide, etc. In addition, the thickness of the processed part also has a great influence on the surface quality of laser cutting. In contrast, the smaller the thickness of the metal workpiece, the higher the cut surface roughness level.