How to Prevent “Over-Heating” When Cutting Metal Plate?

What is Over-Heating?

The laser cutting machine generates a lot of heat when processing sheet metal. Under normal circumstances, this heat will spread along the cutting section inside the sheet metal. And in the processing of small holes by laser cutting machine, the outside of it can be sufficiently cooled, but the diffusion space inside the hole is small, and the heat can be too concentrated, causing over-burning, slagging, etc.

In addition, during thick plate cutting, the molten metal accumulated on the surface during the piercing process and the high heat accumulation required for thick plate cutting will cause the auxiliary gas to be turbulent, resulting in an increase in heat, which can lead to overheating.

How to Avoid Over-Heating ?

1. Make a Cooling Point or Use Annular Cutting

When cutting boards with sharp corners, the location where overheating is more likely to occur is often at the sharp corners. Overheating will cut the sharp corners into rounds. At this time, you can add a cooling point at the sharp corners, pause at the corners, and blow air to effectively avoid overheating. Or we can use the circumcision function, so that overheating caused by slow speed can be avoided at sharp corners.

2. Use High-Efficient Laser Head

When cutting carbon steel, a higher power laser can be used, and a bright surface cutting process can also help to effectively avoid overheating. This cutting process can cut a finished product with no burrs and a bright cut surface. High power can effectively avoid overheating.

3. Use Nitrogen Cutting

Usually we apply oxygen as the auxiliary gas, but nitrogen can also be used for cutting. When nitrogen cutting, the material is completely melted by laser energy. The nitrogen and the sheet metal itself will not easily react chemically. The temperature in the melting point region is relatively low, coupled with the cooling and protection of nitrogen, the response is stable and uniform, and the cutting quality is high. Under such circumstances, the section is fine and smooth, the surface roughness is low, and there is no oxide layer. 

4. Increase Air Pressure

When using a laser cutting machine to process aluminum alloy and stainless steel, the auxiliary gas used is nitrogen or air, and edge burning will not occur during cutting. But due to the high temperature of the material inside the small hole, the slagging phenomenon on the inside will be more frequent. In this case, burrs and dross can be reduced by increasing the pressure of the auxiliary gas.