Laser cutting guide
Maximum thicknesses for laser cutting: a practical guide
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Why the maximum thickness is not the same for every material
When we talk about the “maximum thickness that can be laser cut”, there’s no single number that applies to every sheet: the limit depends on the material, the power of the laser source and the assist gas used. On the same machine, different alloys behave differently because they have different thermal conductivity and mechanical strength, which translates into different practical limits even when the available power is the same.
In general, the thicker the material, the longer it takes to cut: cutting speed decreases as thickness increases, while the power needed to melt and remove the material through the whole thickness grows. Beyond a certain threshold the process loses efficiency and laser cutting is no longer the most cost-effective solution compared with other sheet metal cutting technologies.
Maximum thicknesses by material
The thicknesses actually available depend on the alloy and the surface finish chosen. These are the workable ranges for the materials offered on this site:
| Material | Minimum thickness | Indicative maximum thickness |
|---|---|---|
| Mild steel (carbon steel) | 0.8 mm | 10 mm |
| Stainless steel AISI 304 (2B / SB / BA) | 0.8 mm | 6 mm |
| Stainless steel AISI 316 (2B / BA) | 0.8 mm | 5 mm |
| Stainless steel AISI 316 SB | 0.8 mm | 4 mm |
Mild steel allows greater thicknesses than stainless steel for the same laser power, mainly because it has higher thermal conductivity and lends itself well to oxygen cutting, which uses an exothermic reaction to speed up the process even on substantial thicknesses. Stainless steel, typically cut with nitrogen to get a clean, oxide-free edge, needs more energy for the same thickness, which lowers the practical limit.
What changes as thickness increases
Increasing sheet thickness doesn’t only affect whether the cut is feasible, but also some practical aspects of the project:
- Cutting time: the laser’s feed rate decreases as thickness increases, so machine time per metre of cut goes up.
- Edge quality: on greater thicknesses a slight edge taper becomes more likely (the cut is not perfectly perpendicular through the whole thickness) and, with oxygen cutting, a higher degree of surface oxidation.
- Part weight: weight grows in proportion to thickness, and so does the material cost, since sheet metal is bought and invoiced by weight.
- Pierce points: on thick material it is sometimes necessary to provide more pronounced pre-piercing points before starting to cut the profile, with a slight impact on cycle time.
Thickness and part cost
The cost of a laser-cut part depends on both the weight of material used and the cutting time, and both of these factors increase with thickness. A part with an identical shape but made in double the thickness doesn’t simply cost twice as much: it weighs more (proportional material cost) and takes longer to cut for the same profile length, because the laser’s feed rate drops as thickness increases. For this reason, for the same drawing, it’s always worth choosing the minimum thickness that meets the part’s mechanical requirements, without oversizing for an unnecessary safety margin.
How to choose the right thickness: quick checklist
- Define the part’s real mechanical requirement (load, stiffness, impact resistance) before choosing the thickness: a thickness greater than necessary adds weight and cost with no benefit.
- Check that the chosen thickness falls within the ranges available for the selected alloy, because the maximum limit differs between mild steel and stainless steel and between the different stainless finishes.
- If the part needs bending, remember that greater thicknesses require larger bend radii and more powerful press brakes: check the feasibility of the bend together with that of the cut.
- For structural components or parts under significant loads, if in doubt request a specific technical check rather than relying only on general rules.
- If the project requires a thickness above the maximums shown, contact us before finalising the drawing: we can assess together the most suitable alloy or an alternative cutting process.
Frequently asked questions
- What is the maximum thickness that can be laser cut?
- It depends on the material. Mild steel (carbon steel) typically goes up to 10 mm, while the practical limit for AISI 304 stainless steel is around 6 mm and for AISI 316 around 4-5 mm, depending on the finish. Beyond these thicknesses laser cutting becomes less cost-effective than other cutting technologies.
- Why can stainless steel only be cut to lower thicknesses than mild steel?
- Because stainless steel has lower thermal conductivity and needs more power and energy to cut than mild steel of the same thickness. Above a certain threshold the cut becomes slower, edge quality drops and the process is no longer economically competitive with alternatives such as plasma or waterjet cutting.
- Does a greater thickness always mean a higher cost?
- Yes, for the same alloy the cost rises with thickness for two reasons: the part weighs more (and so does the material cost) and the cut takes longer per millimetre of path, because cutting speed decreases as thickness increases.
- Is there also a minimum thickness for laser cutting?
- Yes. Below a certain thickness (roughly 0.8 mm for the materials available on this site) the sheet becomes hard to handle without deforming and the cut risks causing vibration or irregular edges. That's why the materials catalogue starts at 0.8 mm.
- What can I do if my part exceeds the maximum available thickness?
- It's best to contact us directly to assess the project: in some cases a different alloy better suited to high thicknesses can be used, or alternative cutting processes can be considered for that specific thickness.