Key Takeaways

• Ferracut's fibre laser cuts mild steel up to 20mm, stainless steel up to 20mm, and aluminium up to 12mm.
• Cut quality and edge squareness decrease as thickness increases — thicker material needs more finishing for precision work.
• For structural plate above 16mm, plasma cutting may be more cost-effective if edge quality tolerance allows it.
• Thicker material costs more per kilogram due to slower cutting speeds and higher gas consumption.

How Thick Can You Laser Cut Steel in Australia?

Maximum thickness for laser cutting depends on the laser power, material type, and the assist gas used. Modern 3000W+ fibre laser systems — the industry standard in Australian job shops — can cut significantly thicker material than older CO₂ laser technology.

Maximum Thickness by Material

• Mild steel (250HR, 350HR): Up to 20mm with oxygen assist
• Stainless steel (304, 316): Up to 20mm with nitrogen assist
• Aluminium (5005, 5052, 6061): Up to 12mm
• Galvanised steel / Zincalume: Up to 3mm (zinc coating produces toxic fumes at higher thicknesses)

How Thickness Affects Cut Quality

At 1–6mm, fibre laser cutting produces clean, near-vertical edges with minimal dross. As thickness increases:

• 6–12mm: Slight edge taper (1–2°) may appear. Dross attachment increases on the bottom edge, particularly with oxygen assist.
• 12–20mm: More pronounced edge taper. Mechanical deburring is recommended before precision assembly. Tolerances widen to ±0.3mm.

Laser Cutting vs Plasma for Thick Plate

For mild steel above 16mm, plasma cutting is often more cost-effective because it is faster for heavy plate. However, plasma cut edges have a typical tolerance of ±0.5–1.0mm and a wider HAZ (heat-affected zone). If your application requires ±0.2mm tolerance or a clean edge without secondary finishing, laser cutting is the correct choice even at 16–20mm.

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