How much nitrogen does laser cutting actually consume?
Updated:
Short answer
Consumption is driven by nozzle diameter and pressure, not by the laser power: a 2.0 mm nozzle at 15 bar puts roughly 30–45 m³/h through the kerf, and a 3.0 mm nozzle at 20 bar can exceed 90 m³/h. That is why thick-plate nitrogen cutting is often the largest single line in the cost per part.
Where the money goes
| Symptom | Likely cause | First action |
|---|---|---|
| Consumption jumps after a consumable change with no quality gain. | Oversized nozzle | Use the smallest nozzle that clears the melt — flow rises with the square of the diameter. |
| Habitual maximum pressure on all thicknesses. | Pressure set higher than needed | Reduce pressure until the edge starts to degrade, then step back one increment. |
| Consumption per shift far above the sum of cutting minutes. | Gas flowing during non-cutting moves | Check gas-off during rapids and pierce delays in the CAM and machine settings. |
| Cylinder or tank empties faster than the calculation predicts. | Leaks in the supply line | Pressure-test the line; a small leak at 20 bar is expensive around the clock. |
Gas consumption calculator: nozzle, pressure, cost per hour. Open SBM Laser Help →
Or take it with you:
Approximate nitrogen flow, m³/h
| Nozzle | 10 bar | 15 bar | 20 bar |
|---|---|---|---|
| 1.5 mm | 12–16 | 18–24 | 24–32 |
| 2.0 mm | 22–28 | 30–45 | 45–58 |
| 2.5 mm | 34–44 | 50–65 | 68–88 |
| 3.0 mm | 48–62 | 72–92 | 95–120 |
Orders of magnitude for planning, not billing: exact flow depends on nozzle geometry and how the machine ramps gas at corners and pierces.
Related questions
- Is a nitrogen generator worth it?
- It depends on hours and purity needs. High-purity generation for stainless is capital-heavy, but shops cutting stainless several shifts a day often reach payback within a couple of years — calculate against your real m³/h, not the machine’s maximum.
- Can I cut stainless with compressed air to save nitrogen?
- For non-critical parts, sometimes. Air leaves an oxidised edge and more burr, so it fails where the part is welded, polished or exposed to corrosion. Many shops run air for brackets and nitrogen for visible parts.