Laser cutting parameters, power, speed, gas and focus by material
Two laser sources see materials completely differently, because a CO2 laser and a fibre laser cut on wavelengths nearly ten times apart. Choose your laser type, material and thickness, and read back a starting power, speed, assist gas and focus setting, with the kerf and heat affected zone shown alongside.
Open the cutting parameters tool A free account opens this tool. The interface is in English and nothing you enter leaves your browser.How it works
Three steps. The laser type and the material decide whether a cut is even possible before power and speed matter.
Choose your laser type
A CO2 laser runs at 10.6 micrometres, a fibre laser at around 1064 nanometres, a wavelength difference of close to a factor of ten. Organic materials such as wood, acrylic and paper absorb the CO2 wavelength strongly and the fibre wavelength barely at all. Metals do the opposite while cold, absorbing the fibre wavelength far better than the CO2 wavelength. This single choice decides which materials are even visible to the beam before power or speed enter the picture.
Enter the material and thickness
Pick the material and its thickness, and the tool checks it against the materials a given laser type cannot cut safely at all. Clear acrylic does not absorb a fibre laser's wavelength, so the beam passes straight through rather than cutting slowly, and copper or brass reflect enough CO2 light to risk sending energy back into the machine's own resonator. Getting this step wrong is not a slow cut, it is no cut, or in the reflective case, a damaged machine.
Read the parameter set and its limits
The tool returns a starting power and speed, the assist gas and its pressure, a focus offset, the expected kerf and the heat affected zone for the combination you entered. Treat the numbers as a starting point to fine tune on scrap, not a guarantee, because nozzle condition, exact optics and gas purity shift the real result on any specific machine.
The gas is not just blowing the melt away
Oxygen, nitrogen and air each do a different job, and the pressure difference between them is not small.
Built to stop the expensive mistake before it happens
The costliest error in laser cutting is not a bad parameter, it is pointing the wrong laser type at a material it cannot see at all.
Two physics, one machine category
The wavelength difference between CO2 and fibre lasers is not a technical footnote, it decides which materials the beam can even interact with. Cold metal absorbs fibre light far better than CO2 light, by a wide margin for a material like aluminium, while organic polymers, wood and paper do the reverse. Choosing the laser type is the first and most consequential decision the tool makes.
The assist gas does chemistry, not just blowing
Oxygen on carbon steel is not simply clearing the melt away, it burns the metal surface in an exothermic reaction that adds its own energy to the cut, which is why the required pressure is low, typically 0.5 to 2 bar. Nitrogen on stainless steel is inert and works purely mechanically, ejecting molten metal at high speed, so it needs far higher pressure, typically 10 to 20 bar or more, at a cost in both consumable use and cutting speed.
Focus moves with material and thickness, not by habit
On thin material the focal point should sit right at the surface, where energy density is highest, for the sharpest possible cut. On thick carbon steel cut with oxygen, the focus is raised above the surface instead, because the reaction needs to penetrate cleanly to the bottom of a thick section, and a beam focused exactly on the surface diverges too quickly lower down to keep the energy density where it is needed.
Materials that must never touch a laser are flagged outright
PVC and other chlorine bearing plastics release hydrogen chloride on heating, which forms corrosive acid with moisture and attacks the optics for days afterwards. PTFE releases fluorine compounds that are even more aggressive, and chrome tanned leather can release hexavalent chromium, a recognised carcinogen. These are not materials to avoid when convenient, they are excluded outright, alongside a practical warning about expanded polystyrene foam, which self ignites at a readily reached cutting temperature.
Frequently asked questions
Why can't I just use one machine for both metal and acrylic?
Because the two jobs need opposite wavelengths to work at all, not just different settings on the same machine. A fibre laser barely interacts with clear acrylic, so instead of a slow cut you get no cut, or internal cracking and clouding from stray absorption inside the material. A CO2 laser reflects heavily off cold metals such as copper or brass, and enough of that reflected light can return through the optical path and damage the resonator itself. If your work genuinely spans both families of material, the honest answer is usually two machines or outsourcing one side of the work, not a compromise machine that does both poorly.
Why is the nitrogen pressure so much higher than the oxygen pressure?
Oxygen on carbon steel is doing chemical work as well as mechanical work: it burns the surface of the metal in a reaction that adds energy to the cut, so a comparatively low pressure of roughly 0.5 to 2 bar is enough to keep that reaction stable. Nitrogen on stainless steel does not react chemically at all, it is inert precisely so the cut edge stays bright and unoxidised, so all the work of clearing molten metal from the kerf has to come from sheer mechanical pressure, typically 10 to 20 bar or more, several times the oxygen figure.
How does kerf change between metal and organic materials?
A fibre laser on metal typically produces a narrow kerf, around 0.1 to 0.3 millimetres, tight enough for parts to be nested closely on a sheet. A CO2 laser on acrylic, wood or MDF typically produces a wider kerf, around 0.25 to 0.5 millimetres, because the focused spot is usually larger and the material melts or chars at the edge rather than vaporising cleanly the way metal does. Anyone carrying a kerf habit from metal work into acrylic or wood needs to widen their compensation accordingly, or a finger joint or similar fitted part comes out visibly loose.
Why does the heat affected zone differ so much between cutting methods?
A fibre laser focuses energy into a spot a fraction of a millimetre wide and cuts fast, which keeps its heat affected zone the narrowest of the common thermal methods, typically 0.1 to 0.4 millimetres. Plasma arc cutting is physically a wider process, with a heat affected zone typically 0.5 to 2.0 millimetres. Oxy-fuel cutting is slower still and relies on a reaction that spreads deeper into the material, typically 1.0 to 5.0 millimetres. Where the metallurgy right at the cut edge matters, before welding for example, that narrower zone is the laser's real advantage.
Does more machine power let me cut proportionally thicker material?
No, and this is one of the more counter-intuitive parts of specifying a machine. Published fibre laser tables show a 1 to 2 kilowatt class machine reaching around 10 millimetres of carbon steel, a 6 kilowatt class machine reaching around 25 millimetres, and a 20 kilowatt and above class reaching around 50 millimetres. Each step up in power buys progressively less extra thickness, because on thick material an increasing share of the energy dissipates as heat into the surrounding metal before it reaches the bottom of the cut, and the cutting speed drops as well.
What does ISO 9013 actually cover, and where does it stop applying?
ISO 9013:2017 defines the terms and tolerances for thermal cutting, and it formally limits its scope for laser cutting to thicknesses between 0.5 and 32 millimetres. Outside that range the standard does not give a formal quality classification, so the tolerance has to be agreed directly between the buyer and the shop rather than assumed from the standard. That is a limit on the standard's coverage, not on what a machine can physically cut thinner or thicker than that range.
Other tools
Part of the EduFacturing tool set for laser cutting and CNC.
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