Laser cutting machine processing quality evaluation standard
In the laser cutting process of general materials, due to the fast cutting speed, the thermal deformation of the parts is very small. The dimensional accuracy of the cut parts mainly depends on the mechanical accuracy and control accuracy of the worktable of the laser cutting machine. In the pulse laser cutting process, the high-precision cutting device and control technology are used, and the dimensional accuracy can reach the um level.
The quality evaluation of laser cutting, there is still no unified international standard. So far, there is no standard for laser cutting quality in our country. The main basis for testing the quality of laser cutting is JIS and WES (welding specifications). There are standardization issues related to laser cutting in CEN (European Standardization Agency) and ISO (International Standardization Agency). The relevant ISO9000 series quality assurance methods mainly provided by EU have conducted research on laser cutting standards and standard sample regulations. The contents include: cutting quality grade division, setting samples and processing samples standards, optical systems, and price samples The model and beam characteristics of the machine.
For laser cutting processing, the evaluation of 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 slit has good verticality and small heat-affected zone;
4. No material burning, no melting layer formation, no large slag;
5. The surface roughness of the incision, the size of the surface roughness is the key to measuring the surface quality of laser cutting.
In addition to the above principles, the state of the melted layer and the final shape 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 cutting, such as power, cutting speed, auxiliary gas type and pressure, etc.;
3. Processing materials Physical parameters, such as laser absorption, melting point, viscosity coefficient of molten metal oxide, surface tension of metal oxide, etc. In addition, the thickness of the workpiece also has a great influence on the surface quality of laser cutting. Relatively speaking, the smaller the thickness of the metal workpiece, the higher the cut surface roughness level.
To obtain a better surface quality level, process parameters such as laser power and cutting speed must be optimized many times. Generally speaking, for materials with the same characteristics and thickness, there is a set of optimal cutting process parameters, which will also result in different cut surface quality. Metal materials have low melting point, high thermal conductivity, low viscosity coefficient of melt, and low surface tension of metal oxides. It is easy to obtain high surface quality during laser cutting. When laser cutting flat plates, it is easy to measure the surface quality, but in fine processing or cutting some complicated