Causes and Solutions of Black Edges When Cutting Carbon Steel
It is well known that laser cutting machines are generally used for the processing of carbon steel sheets. And the treatment method is carried out by heating. Therefore, it is inevitable to encounter various problems in the process of processing. Each problem has a different cause and solution. Many customers often ask why laser cutting machines always cause black edges when cutting carbon steel? This problem is also the most frequently encountered problem. So what is the reason for the black edge caused by the laser cutting machine cutting carbon steel? How to solve it?
Causes of black edges caused by laser cutting machine cutting carbon steel
In fact, the reason why the laser cutting machine cuts carbon steel black edges is that a lot of heat is released during cutting. Because the thermal conductivity of metal is relatively good, under normal circumstances, the heat generated by cutting will spread to the processed sheet along the cutting seam. The gold is fully cooled. However, in the processing of small holes by metal laser cutting machine, the outside of the hole can be fully cooled, but the small hole inside the single hole has a small space for heat to diffuse, and the heat energy is too concentrated, causing black edges, slag and so on. In addition, in the thick plate cutting, the molten metal accumulated on the surface of the material and the heat accumulation generated during the perforation will cause the auxiliary airflow to be disturbed and the heat input to be too much, thereby causing black edges.
In carbon steel cutting with oxygen as auxiliary gas, the key to solving the problem is how to suppress the generation of oxidation reaction heat. The method of auxiliary oxygen during perforation and switching to auxiliary air or nitrogen can be used for cutting. This method can process small holes of up to 1/6 thick plate. 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 as 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 the heat output.
In the processing of such materials, the auxiliary gas used is nitrogen, and no edge burning occurs during cutting. However, due to the high temperature of the material inside the small hole, the phenomenon of slag hanging on the inside will be more frequent. The effective solution is to increase the pressure of the auxiliary gas and set the conditions to high peak output, low frequency pulse conditions. When the auxiliary gas uses air, it is the same as when using nitrogen. Black edges will not occur, but it is easy to form slag at the bottom. The conditions need to be set to high auxiliary gas pressure, high peak output, and low frequency pulse conditions.
The above are the specific reasons and solutions for the black edges caused by the laser cutting machine when cutting carbon steel. In fact, it is not difficult to see that this problem is a very common problem. As long as a little attention in the process of processing can be avoided. We can check the operation according to the actual situation according to the above method.