how does a fibre laser differ from a CO2 laser?
A CO2 laser generates the beam in a gas-filled resonator and steers it to the cutting head through a series of mirrors; a fibre laser generates it in a doped optical fibre and delivers it down that fibre directly to the head. No mirror path means nothing to drift out of alignment, and the shorter wavelength focuses to a smaller spot.
The smaller spot concentrates the same power into less metal, which is where the practical differences start: narrower kerf, finer detail and faster travel in sheet thicknesses. The solid-state source also has fewer moving and consumable parts than a gas resonator, so the machine spends more of its life cutting.
why is fibre faster in sheet metal?
Because sheet metal absorbs the fibre wavelength more readily, and the smaller spot puts more of the power where the cut is. More absorbed energy per millimetre of cut means the head can travel faster for the same clean edge, and the advantage is largest in the sheet-gauge thicknesses that make up most laser cutting work.
Speed is not just throughput - it is also heat. A faster cut leaves less time for heat to soak into the surrounding metal, which helps parts stay flat and features stay where the drawing put them.
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upload your fileswhy can fibre lasers cut brass and copper?
Brass and copper are highly reflective, and at the CO2 wavelength they bounce much of the beam straight back - older CO2 machines struggle with them, and reflections can damage the optics. The fibre wavelength is absorbed far better by reflective metals, so a fibre source cuts them cleanly and safely.
This is the practical reason the fibre vs CO2 question matters when you are choosing a supplier. OneLaser runs a 3kW fibre source and cuts brass to 6 mm and copper to 4 mm as everyday work, alongside mild steel, stainless and aluminium.