Before, during and after the retrofit of the fiber laser cutting machines, we always get a lot of questions about the gas consumption when cutting metals. Below we give some tips of the auxiliary gases consumption of laser cutting.

The auxiliary gas nitrogen and oxygen used in cutting the metals must be available to the machine under the correct pressure.
At least 8 bar (800 kPa) must be available for oxygen, adjustable from 5 to 10 bar.
Up to 20 bar (2 mPA) must be available for nitrogen, adjustable from 10 to 20 bar.

So what are the factors affecting auxiliary gas consumption ? Let’s check together.

1. Nozzle diameters

The larger the hole in the cutting nozzle, the more liters of gas per unit time is required to maintain the same PRESSURE. If the nozzle diameter doubles, the gas consumption will be squared higher  and will therefore consume 4x more gas.

2.The gas pressures

Higher pressures often result in a cleaner cutting notch, but this also consumes more gas.

3. The cutting speed

During cutting, auxiliary gas is continuously blown out through the nozzle. At a slower speed, the process takes longer and more gas will be consumed per linear meter of cut material.

4. The material type and thickness

Obviously thicker material will cut more slowly, but the gas pressure will also have to vary with the thickness of the material. In general it can be stated that:

• oxygen pressures decrease with thicker materials (steel)
• nitrogen pressures increase with thicker materials (stainless steel)

5. The power of the laser source and the type / brand of laser source

Depending on the power of the laser source and the characteristics of the laser beam itself, the machine will be able to pierce the material faster or slower and then cut it. Heavier laser sources are cheaper to use in practice due to higher speeds and less gas consumption.

6. Parameter settings

The fine-tuning of parameters also has a major influence on the final gas consumption. For example, a difference in focus setting of 0,1 mm. already cause a difference in speeds of 15% or more. In addition, the operator can consciously choose variables such as an extremely clean cutting notch, high speed, wide or narrow notch, cooling points, automatic speed regulation, etc., which means that the gas consumption varies greatly.

7. The gas losses in the installation

The installation of high pressure tanks, packages, pipes and pressure reducing valves can also lead to significant gas losses. Supply lines must be depressurized when the machine is closed. The longer the supply lines are, the larger the diameter must be, and the higher the gas loss.
The choice between fillings with 300 bar or 200 bar also makes a lot of difference. The last 18-20 bar will always remain in the tanks. By choosing a package with 300 bar filling, the efficiency of the packages is considerably higher and ultimately less gas will be lost.