As we all know, optical fiber laser cutting machine has been widely used and recognized in the market since it came out. What are the commonly used cutting auxiliary gases for optical fiber laser cutting machine?
First, let's understand the principle of optical fiber laser cutting machine. The laser beam emitted by the fiber laser generator changes direction through the reflector and is focused through the lens to form a high-power, high-density laser beam. The metal material in the irradiation area is rapidly melted, evaporated and ablated to complete the cutting. In this process, there is gasification, so there must be auxiliary gas. Common cutting auxiliary gases include nitrogen, oxygen, compressed air, and sometimes argon.
The role of cutting auxiliary gas in the cutting process mainly includes:
1. Combustion supporting and heat dissipation;
2. Protect the focusing lens and extend its service life;
3. Blow off the molten stains generated by cutting in time to prevent the molten stains from rebounding upward and entering the nozzle.
According to the different materials to be cut, the power of optical fiber laser cutting machine is different, and the selection of auxiliary gas is different for different laser cutting processes. Let's have a look.
1. The nitrogen used as the cutting auxiliary gas will form a protective layer around the metal of the cutting material to prevent the material from being oxidized and forming an oxide film. At the same time, it can be handled directly. The end face of the cut is bright and white, which is common in cutting stainless steel and aluminum plates.
2. Argon, like nitrogen, is an inert gas, which can also prevent oxidation and nitridation in laser cutting. However, the price of argon is high. It is very uneconomical to use argon for ordinary laser cutting of metal plates. Argon cutting is mainly used for titanium and titanium alloys.
3. Oxygen. During the cutting process, oxygen reacts with iron to promote the endothermic melting of metal and greatly improve the cutting efficiency and cutting thickness. However, due to the presence of oxygen, an obvious oxide film will be produced on the cut face, which will produce a quenching effect around the cut face and have a certain impact on the subsequent processing. The cut end face will be black or yellow, mainly used for cutting carbon steel plates.
4. Compressed air
If compressed air is used as the auxiliary gas for cutting, we know that there is about 21% oxygen and 78% nitrogen in the air. As far as the cutting speed is concerned, it is indeed not as fast as the pure oxygen melt assisted cutting method. As far as the cutting quality is concerned, it is really not as effective as the pure nitrogen protection cutting method. However, compressed air can be directly supplied by the air compressor, which is easier to obtain than nitrogen, oxygen and argon, and there is no risk of gas leakage. Most importantly, the price of compressed air is very cheap. With an air compressor, the compressed air flows continuously, and its cost is about a small part of the cost of using nitrogen.
Finally, let's briefly summarize that although the nitrogen used by the optical fiber laser cutting machine is of good quality, its speed is the slowest; The use of oxygen is fast, but the quality is poor; The high price of argon restricts its wide use and can only be used under special circumstances; The price of compressed air is the cheapest. It can't keep up with oxygen in speed and nitrogen in quality, so they have their own advantages and disadvantages.