Here are the main points about auxiliary gases for fiber laser cutting:
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When you cut metal with a fiber laser you need to use an auxiliary gas.
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For stainless steel, aluminum, brass, and thin carbon steel, you'll need Nitrogen or an Air Compressor.
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For thicker carbon steel and copper, Oxygen is the way to go.
Nitrogen vs. Air Compressor (Stainless Steel/Aluminum)
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Quality First? If you need that perfect mirror finish on stainless steel or aluminum, go with Nitrogen or a Nitrogen Generator. Nitrogen quality is better than air.
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But Nitrogen is Pricey! Seriously, a single bottle lasts only about 15 minutes! A 12-pack gets you 3 hours of continuous cutting.
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Air is Cheap and Easy. People switch to an Air Compressor because it's super low-cost and you just turn it on. The catch? The cutting surface won't have that perfect mirror look and will include oxidation which can be bad for welding.
Article Focusing on Air Compressor vs Nitrogen
Carbon Steel Choices
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Thick Stuff: Use Oxygen.
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Thin Stuff: You can use Oxygen, Nitrogen, or an Air Compressor.
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Speed Demon: Nitrogen/Air Compressor cutting is MUCH faster than Oxygen. That's why people get higher power lasers (3kw, 6kw, 12kw) to cut thicker carbon steel faster using Nitrogen/Air instead of Oxygen.
Slag/Dross & The Mixed Gas Option (Carbon Steel)
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Air vs. Nitrogen: Air Compressor cutting leaves more dross/slag (the drippy leftovers) than Nitrogen.
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Nitrogen slag/dross: Even Nitrogen leaves some slight slag on thicker carbon steel—the thicker the metal, the more slag/dross.
- Mixed Gas: If you use Mixed Gas (Liquid Nitrogen + a bit of Liquid Oxygen), you can cut even thicker carbon steel, the surface looks great, and you get a 10-30% speed boost. This is recommended for high-power lasers. We can add mixed gas cutting to your machine on request.
