In the BS3015D-1500W Fiber Laser Cutting Machine process of general materials, due to the fast cutting speed, the thermal deformation of parts is very small, the dimensional accuracy of cutting parts mainly depends on the mechanical precision and control precision of the laser cutting machine table. In pulse laser cutting processing, the use of high precision cutting device and control technology, dimensional accuracy can reach um level.
Laser cutting quality evaluation, the international has not yet a unified standard. Up to now, there is no standard for laser cutting quality in China. The main basis for detecting laser cutting quality is JIS and WES (welding specifications). There are standardization issues concerning laser cutting in CEN (European Standardization Agency) and ISO (International Standardization Agency). In the ISO9000 series quality assurance methods mainly provided by EU, the laser cutting standards and standard sample regulations are studied, including: cutting quality grade division, sample setting and processing standard, optical system, price sample model and beam characteristics.
For laser cutting processing, the evaluation of its processing quality mainly includes the following principles:
1. Smooth cutting, no stripe, no brittle fracture;
2. Slit width is narrow, which is mainly related to the diameter of the laser beam spot;
3. Good verticality of slit, small heat affected zone;
4. No material combustion, no melting layer formation, no large slag;
5 incision surface roughness, the size of the surface roughness is the key to measure the quality of laser cutting surface.
In addition to the above principles, the state of the melting layer and the final molding in the processing process directly affect the above processing quality evaluation indexes.
Laser cutting surface roughness mainly depends on the following three aspects:
1. The inherent parameters of the cutting system, such as spot mode and focal length;
2. Adjustable process parameters during cutting, such as power size, cutting speed, auxiliary gas type and pressure, etc.;
3. Physical parameters of processing materials, such as absorption rate of laser, 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 impact on the surface quality of laser cutting. Relatively speaking, the smaller the metal workpiece thickness, the higher the cutting surface roughness grade.
In order to obtain better surface quality, it is necessary to optimize the laser power, cutting speed and other technological parameters for several times. In general, for materials with the same characteristics and thickness, there is an optimal set of cutting parameters that will yield different cut surface qualities. The melting point of metal materials is low, the thermal conductivity is large, the viscosity coefficient of melt is small, the surface tension of metal oxide is small, and the laser cutting is easy to obtain higher surface quality. When laser cutting flat plate, it is easy to measure the surface quality, but in fine machining or cutting some complex patterns, it is difficult to directly measure it, only by optimizing the test parameters to control the surface quality. Therefore, in order to realize automatic cutting, the corresponding relationship between external optimization parameters and surface quality grade should be established.