60kW Laser: Burr-Free Cuts on 50mm Carbon Steel with Mixed Gas
Verified parameters from a heavy-plate fabricator running a 60kW fiber laser — where mixed gas eliminated the need for post-cut machining on thick plate parts.
The Challenge
A structural steel fabricator producing heavy machinery components needed to cut carbon steel plates from 30mm to 50mm thickness. Their existing process used pure nitrogen on a 60kW fiber laser — edge quality was acceptable but cutting speed was a bottleneck. Worse, parts above 40mm often required post-cut grinding before welding.
- Laser: 60kW fiber laser
- Material: Carbon steel (30mm–50mm)
- Application: Heavy machinery structural components
- Previous gas: Pure nitrogen — slow on thick plate, inconsistent edge quality
- Pain point: Post-cut grinding on 40mm+ plates was eating 2–3 hours per shift
The Solution: Mixed Gas for High-Power Thick Plate
LISHI Series configured a mixed gas station tuned specifically for high-power thick-plate cutting. At 60kW, the precise N₂/O₂ blend generates an optimized cutting front temperature — hot enough to melt through 50mm plate efficiently, with enough nitrogen to protect the kerf from oxidation.
The result: clean, silver-white edges across all thicknesses. Parts go directly from the laser bed to welding — the grinding station was reassigned to other work.
Verified Cutting Parameters
On-site test data from the 60kW end user. All cuts verified with caliper-measured kerf quality and weld testing.
| Thickness | Mixed Gas Speed | Previous N₂ Speed | Speed Gain | Edge Quality |
|---|---|---|---|---|
| 20mm | ~6.5 m/min | ~4.5 m/min | 1.4x | Weld-ready, no grinding |
| 25mm | ~5.0 m/min | ~3.2 m/min | 1.6x | Clean, burr-free |
| 30mm | 4.0 m/min | ~2.3 m/min | 1.7x | Silver-white edge |
| 35mm | ~3.2 m/min | ~1.8 m/min | 1.8x | No oxidation |
| 40mm | 2.5 m/min | ~1.3 m/min | 1.9x | Weld-tested, passed |
| 50mm | 1.5 m/min | ~0.7 m/min | 2.1x | Burr-free, no post-processing |
Key Takeaways
Thick Plate Without Compromise
Mixed gas makes 50mm carbon steel cuts that are clean enough to skip grinding entirely. The N₂ component protects the kerf while O₂ delivers the cutting energy — best of both worlds at high power.
Speed Gap Widens with Thickness
The speed advantage vs. pure nitrogen grows as plate thickness increases: 1.4x at 20mm, 2.1x at 50mm. The thicker the plate, the more mixed gas outperforms.
Eliminated 2-3 hrs/day Grinding
Post-cut machining was the hidden cost of pure N₂ thick-plate cutting. Mixed gas eliminated it entirely — saving 10–15 hours of labor per week and freeing the grinding station for other work.
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