The metal laser cutting machine will generate a lot of heat when processing sheet metal. Normally, the heat generated by cutting will spread to the processed sheet metal along the cutting seam and be fully cooled. In the process of metal laser cutting machine, the outer side of the hole can be fully cooled, while the inner side of the hole is easy to cause over burning and slag hanging due to small heat diffusion space and excessive concentration of heat energy. In addition, during the cutting of thick plates, the molten metal accumulated on the material surface during the perforation and the heat accumulation will lead to the disorder of auxiliary air flow and excessive heat input, which will lead to over burning.
How to avoid overburn when laser cutting sheet metal?
【1】 Add cooling point at the corner
When cutting sharp metal plates, the place where overburning is easy to occur is often at the sharp corner, and overburning will cut the sharp corner into a circle. At this time, a cooling point can be added at the sharp corner, and a pause can be made at the sharp corner to blow air.
【2】 Use high power laser
When cutting carbon steel, a higher power laser can be used, and the bright side cutting process can effectively avoid overburning, and this cutting process can cut the finished product without burrs and with bright section.
【3】 Cutting with nitrogen
In the sheet metal cutting with oxygen as the auxiliary gas, nitrogen can be switched for cutting. During nitrogen cutting, the material is completely melted by laser energy, and nitrogen is blown out of the kerf to avoid inappropriate chemical reaction. The temperature in the melting point area is relatively low. With the cooling and protection of nitrogen, the reaction is stable and uniform, and the cutting quality is high. The section is fine and smooth, the surface roughness is low, and there is no oxide layer.
【4】 Increase air pressure
When optical fiber laser cutting machine is used to process aluminum alloy and stainless steel, nitrogen or air is used as the auxiliary gas, and edge burning will not occur during the cutting process. However, due to the high temperature of the material inside the small hole, slag hanging will occur frequently inside. In this case, burr and slag can be reduced by increasing the pressure of auxiliary gas.