- September 3, 2025
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Two parts. Same CAD. Different metal—totally different day on the laser. The wins come from matching assist gas, pressure, and focus to how each metal moves heat and reacts at the cut. Use this playbook to get bright edges without extra polishing and speed without surprise dross.
Quick comparison table
| Factor | Stainless steel | Aluminum |
|---|---|---|
|
Recommended assist gas |
Nitrogen for bright, oxide-free edges; oxygen only for carbon steel, not stainless steel. |
Nitrogen for clean, dross-free cuts; compressed air is viable on thin gauges if finish tolerance allows. |
|
Typical gas pressure window |
About 8–14 bar for bright edge; increase with thickness and correct nozzle. |
High pressure nitrogen to clear melt; expect higher flow demand on wider kerf. |
|
Cutting speed tendency |
Moderate; balances quality and HAZ control. |
30–50 faster than stainless steel at same thickness when parameters are dialed. |
|
Edge finish risk |
Oxidation/discoloration if oxygen used; bright with N2. |
Dross tails if N2 flow or focus is low; reflectivity makes setup sensitive. |
|
Power sensitivity |
Stable on fiber; speed scales with kW and thickness. |
Needs careful focus/nozzle due to reflectivity; benefits from higher kW or optimized optics. |
| Cost levers |
Nitrogen purity/pressure optimization cuts OPEX; fewer secondary ops with bright edge. |
Consider compressed air on thin stock to save gas cost; validate finish first. |
What actually changes on the floor
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Gas choice drives rework: Nitrogen keeps stainless steel edges weld- and paint-ready; oxygen on stainless steel invites grinding and color cleanup.
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Speed vs dross: Aluminum rewards speed once the kerf is clear; under-pressured nitrogen or poor focus shows up immediately as dross tails.
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Power isn’t everything: Higher kW helps on reflective aluminum and thicker stainless steel, but focus position and nozzle alignment often move quality more.
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Field-tested dials to turn first
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Pressure: Start stainless steel around 8–14 bar and climb with thickness; aluminum often needs robust N2 flow to evacuate melt consistently.
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Focus: Small offsets restore kerf clearance; re-zero after nozzle swaps to curb dross on aluminum and striations on stainless steel.
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Nozzle and standoff: Concentric, clean jet reduces burr before it exists; check cut face after every nozzle change.
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Gas logistics: N2 consumption becomes a line-item—optimize purity and line losses to cut costs without sacrificing edge gloss.
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Design for manufacturability tips
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Stainless steel: If the part is cosmetic, specify “bright edge.” Use micro-tabs sparingly to avoid heat staining on thin features.
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Aluminum: Add generous lead-ins/outs; avoid hairline slots that trap melt. Trial compressed air on thin non-cosmetic panels.
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Three quick recipes
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3 mm stainless steel, visible bracket: Fiber + nitrogen, 8–12 bar, bright edge requirement; minimal post-finish.
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1.5 mm aluminum panel, non-cosmetic: Trial compressed air; if dross rises, switch to nitrogen and retune focus.
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6 mm aluminum structural plate: High-kW fiber, high-pressure N2, meticulous focus/nozzle alignment for dross control.
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Conclusion
Stainless steel loves nitrogen and rewards correct pressure with bright, weld-ready edges; aluminum runs faster but punishes sloppy focus or starved gas flow. Start with the right assist gas, tune pressure and focus for the metal, and use the table above to pick a path that cuts rework and time—before the first sheet goes under the beam.
Ready to Transform Your Project?
Whether you’re cutting stainless steel for cosmetic precision or aluminum for high-speed efficiency, Amorphous India equips you with the right technology and expertise. Stainless steel rewards nitrogen with bright, weld-ready edges, while aluminum pushes speed limits but demands careful focus and gas control.
From setup to final finish, we help you choose the right process—so your parts come off the table faster, cleaner, and competition-ready.