Metal fiber laser cutting machine generates a lot of heat when processing sheet metal parts. Under normal circumstances, the heat generated by cutting will diffuse into the processed sheet metal along the gap to obtain sufficient cooling.
In the metal metal fiber laser cutting machine, the outside of the hole can be completely cooled, but the small hole inside the single hole has a small space for heat diffusion, and the heat energy is too concentrated, which leads to excessive combustion and slagging. In addition, when cutting thick metal, the accumulation of molten metal on the surface of the material and the accumulation of heat generated during the perforation process will cause turbulence in the auxiliary airflow and excessive heat input, resulting in excessive combustion.
How to solve the problem of burning edge slagging
The solution to excessive combustion when cutting carbon steel small holes with a metal fiber laser cutting machine: In carbon steel cutting with oxygen as an auxiliary gas, the key to solving the problem lies in how to suppress the generation of oxidation reaction heat. You can use auxiliary oxygen during the piercing process and switch to auxiliary air or nitrogen for cutting after a delay.
Pulse cutting conditions with low frequency and high peak output power have the characteristics of reducing heat output, which helps to optimize cutting conditions. Setting the conditions to a single pulse laser beam, high peak output with high energy intensity and low frequency conditions can effectively reduce the accumulation of molten metal on the surface of the material during the perforation process, and effectively suppress heat output.
Fiber laser cutting aluminum alloy and stainless steel cutting solutions: In this type of material processing, the auxiliary gas used is nitrogen, and the edges will not be burned during the cutting process. However, due to the high temperature of the material inside the small hole, the slagging phenomenon inside the small hole will be more frequent. An effective solution is to increase the pressure of the auxiliary gas and set the conditions to pulse conditions with high peak output and low frequency. When air is used as the auxiliary gas, it is the same as when nitrogen is used. It will not burn excessively, but it is easy to slag at the bottom. The conditions need to be set to high auxiliary gas pressure, high peak output and low frequency pulse conditions.
Influencing factors of laser cutting surface roughness
The surface roughness of laser cutting mainly depends on the following three aspects:
①Intrinsic parameters of the cutting system, such as spot mode, focal length, etc.;
②Adjustable process parameters during the cutting process, such as power size, cutting speed, auxiliary gas type and pressure, etc.;
③The 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 and the surface tension of the metal oxide. In addition, the thickness of the workpiece also has a great influence on the surface quality of laser cutting. On the contrary, the smaller the thickness of the metal workpiece, the higher the roughness of the cutting surface.
In order to obtain a better level of surface quality, process parameters such as laser power and cutting speed must be optimized multiple times. Generally speaking, for materials with the same characteristics and thickness, the process parameters have a set of optimal cutting process parameters. Different cut surface qualities will also be obtained. Metal materials have a low melting point, high thermal conductivity, low melt viscosity and low surface tension of metal oxides. It is easy to obtain high surface quality during laser cutting.
The surface quality of the laser cutting machine plate is easy to measure, but it is difficult to measure directly when performing fine processing or cutting some complex patterns. The surface quality can only be controlled by optimizing the test parameters. Therefore, in order to facilitate automatic cutting, the corresponding relationship between the external optimization parameters and the surface quality level should be established.
