Shanghai Royal Machinery Co.,Ltd

The schematic diagram of laser cutting is shown in the following.
During the process, auxiliary gas is necessary to blow off the slag/dross in the kerf and cool down the cutting surface, also it protects lens and nozzle of laser. Basically there are 3 kinds of gas: Oxygen, Nitrogen and Air, any of them affects directly to the cutting performance, speed, thickness etc. So we really need to think better before action.

1.Oxygen
Oxygen is commonly used to cut thick carbon steel because the chemical reaction between iron element and oxygen helps the metal absorb heat and promotes it melt, which can greatly improve the cutting efficiency.

However, oxygen will cause a marked oxide film on the cut surface and it will have a quenching effect around, increases the hardness which impact on subsequent processing. It also turns kerf  to black or dark yellow.

Generally, Oxygen assists carbon steel plates cut, low-pressure punching, and low-pressure cutting. Oxygen is generally vaporized from liquid oxygen which provided by the local supplier, so the quality of the gas source is clean and no need special treatment.

2. Nitrogen
Nitrogen will form around the molten metal as protective atmosphere while it's assisting the cut, prevent oxidation of the material, avoid the formation of oxide film. However, the cutting speed is not as fast as oxygen, and the nitrogen consumption of the nitrogen is large which means the cost will be higher.
The non-oxidized surface has the characteristics of direct welding, strong corrosion resistance and the kerf turns white.
Generally, nitrogen is used to cut stainless steel, galvanized sheet, aluminum, aluminum alloy, brass and other materials, by low-pressure perforation and high-pressure cutting. When cutting with nitrogen, the change of the gas flow has a great impact on the cutting performance, in this case, make sure the gas flow is sufficient and constant. Nitrogen is usually vaporized from liquid nitrogen provided by supplier, so the quality should be clean.

3. Air
Air, as it's the most economic medium because it's much easier to obtain than oxygen and nitrogen, nobody can charge you for air!
Every one knows the air contains about 20% oxygen and about 78% nitrogen, so it can make up for both shortage and cutting speed is slower than oxygen but faster than nitrogen. Since the oxygen is involved, the kerf turns a little bit yellow. It's the most economic option for you as long as you are okay with the color change.
Generally compressed air can be used for cutting sheet-metal parts, aluminum sheet, nonmetal and galvanized sheet etc., air assist can certainly reduce the oxide film and absolutely save your cost, therefore, air assist is more and more equipped in fiber laser cut industry.
Compressed air can be obtained easily with an air compressor, but not any air compressor can be equipped for Fiber Laser Cutter as the Air itself is not clean, especially after compressing, there are plenty of water, oil and particles and any of them sprayed on the lens, the transmission of laser beam will be seriously affected and focus scattered, resulting bad cutting effect such as bottom burrs or rough kerf, even obsolescence.

Situation could be much worse if it is high-power fiber laser, even a tiny particle or a little spray will very possibly burn your entire lens cone.

In order to make the most economic (Air assist) way workable, ensure cutting quality and avoid any damage for your fiber laser, the compressed air must be pure and constant.

Our 4-in-one (Compressor + receiver tank+ dryer + filters) high pressure air compressor is special designed air compressor for Fiber Laser Cutting industry, custom built to provide filtered, dried, continuous reliable supply of high pressure compressed air at 2~10ºC dew point to assist laser cutting. Produce your own assist air at a fraction of the cost of cylinder.