In short: A profile laser suits structural fabricators whose beams need many copes, slots and bevels, while a flatbed laser handles the connection plates.
The deciding factor for beams is not machine accuracy but how the machine measures each real section, because EN 10034 allows a beam to deviate far more than a laser's own tolerance. Plain cut-to-length and drilling work can stay on a saw and drill line.
Two different jobs in a steel shop
Structural fabrication has two cutting problems, and they usually need two machines.
- Connection plates, base plates and gussets are flat parts. A flatbed fiber laser such as our HL-F (20–40 kW) cuts them with holes in the same program.
- Beams, channels and hollow sections are long, heavy and not perfectly straight. They need a profile machine, such as a three-chuck HL-T or a dedicated beam line. Confirm the largest section, length and weight with the supplier before you compare anything else.
Machine makers advertise figures such as ±0.1 mm cutting accuracy, bevels up to 45° and profiles up to 2.4 tonnes on a three-chuck system (source 1, a maker's claim). Those numbers describe the machine. The next section explains why the beam matters more.
Why rolling tolerances decide the result
A rolled section is not the shape on the drawing. Under EN 10034, the tolerances for I and H sections are generous compared with a laser (source 2):
| Property (EN 10034) | Allowed deviation | On a 12 m beam |
|---|---|---|
| Straightness, 180 < h ≤ 360 mm | 0.15 % of length | 18 mm |
| Straightness, h > 360 mm | 0.10 % of length | 12 mm |
| Web off-centre, flange 110–325 mm, t < 40 mm | 3.5 mm | Same along the beam |
| Flanges out of square, b > 110 mm | 2 % of b, max. 6.5 mm | Same along the beam |
| Height, 180 < h ≤ 400 mm | +4.0 / −2.0 mm | Same along the beam |
Tolerance values as published from BS EN 10034:1993 (source 2). The 12 m column is our arithmetic.
A 12 mm bow is about 120 times the ±0.1 mm a machine maker quotes. If the machine cuts to the nominal drawing without measuring the actual beam, a bolt group can land in the wrong place, however accurate the axes are. So ask every supplier the same question: how does the machine measure each section before cutting, and which features does it correct? Ask them to show it on a bent beam, not a new, straight one.
EN 1090-2: qualify the cutting process
If you fabricate to EN 1090 in Europe, buying a laser is not the end of the work. The Belgian Welding Institute's guidance on cutting procedure qualification sets out the practical steps (source 3):
- Each cutting machine is qualified separately, and different materials such as carbon and stainless steel are qualified separately.
- Test pieces come from one minimum-thickness and one maximum-thickness production plate, and the cutting parameters are recorded.
- Squareness and edge roughness requirements apply from EXC2 upward, and EXC4 is stricter than EXC2 and EXC3.
- For carbon steel from S460, the guidance states that edge hardness should not exceed 450 HV10; preheating or light grinding can reduce it.
For exact values, use EN 1090-2 itself and your project specification. Check too whether the specification accepts thermally cut bolt holes, and which hole tolerance applies. ISO 9013:2017 provides the language for the edge: it grades laser cuts from 0.5 to 32 mm into tolerance classes and quality ranges (source 4).
Laser, saw-drill line or plasma
| Profile laser | Saw and drill line | Plasma beam or plate | |
|---|---|---|---|
| Copes, slots, complex ends | In one setup | Extra coping operation | In one setup |
| Bolt holes | Cut; check the project specification | Drilled | Cut; small holes often drilled |
| Bevels for welding | With a bevel head, up to about 45° | Separate step | With a bevel head |
| Heavy flanges | Limited by power and section capacity | Handled by drilling and sawing | Traditional strength |
| Marking for assembly | Etched in the program | Separate or integrated marking | Possible |
| Machine accuracy claim | ±0.1 mm (maker's claim, source 1) | Ask supplier | Ask supplier |
Qualitative summary by Halcyon Laser; compare your own sections and tolerances.
The right answer is often a mix. A laser earns its place where it removes coping, grinding and marking; a saw and drill line stays economical for simple members with round holes. Our comparison of tube laser vs saw and drill sets out how to calculate that, and laser vs plasma bevel cutting covers weld preparation.
Connection plates: where a flatbed pays first
For many fabricators the flatbed is the lower-risk first step. Plates are flat, so rolling tolerances do not apply in the same way, and holes, slots and part marks come out of one program. Three things matter:
- Thickness mix: list your plates by thickness and tonnes per month, then read our guide to choosing laser power.
- Assist gas: oxygen, nitrogen and air give different edges and costs, which matter if plates are painted or welded (see the gas guide).
- Fume extraction: heavy cutting needs extraction sized for the job, so include it in the plan from the start.
Questions to ask before you buy
- What are the largest section, length and weight the machine handles, and the smallest?
- How does it measure each section, and what does it correct: bow, twist, web off-centre?
- How does it import your detailing model, and does it keep part marks and bevels?
- Will the supplier cut a sample from your own stock, including a bent beam?
- Will the results support your EN 1090 cutting qualification, or your project specification?
Send a typical connection and a beam drawing through our test cut request, or see our steel structure page. Many steel building contractors also form their own purlins and panels; our sister company supplies roll forming machines.
Frequently asked questions
Can a fiber laser cut H-beams?
Yes, on a profile or beam machine with a suitable chuck or support system. Check the maximum section, length and weight. A flatbed laser cuts connection plates but not full-length beams.
Why do rolling tolerances matter for laser cutting beams?
EN 10034 allows 0.10–0.15 % straightness deviation, so a 12 m beam can bow 12–18 mm. The machine must measure the real section, or holes and copes land in the wrong place.
Does EN 1090 require cutting procedure qualification?
Guidance from the Belgian Welding Institute describes qualifying each cutting machine separately, with test pieces from minimum and maximum thickness plates. Use EN 1090-2 and your project specification for exact requirements.
Should a laser replace a saw and drill line?
Not always. A laser pays where it removes coping, grinding and marking. A saw and drill line stays economical for simple members with round holes, and many shops keep both.
Can laser-cut bolt holes be used in structural steel?
It depends on the project specification and the applicable standard. Check whether thermally cut holes are accepted and which hole tolerance applies before you plan production around them.
Sources
- Voortman, “V845 H-profile cutting” (machine maker’s page): ±0.1 mm cutting accuracy, bevels up to 45°, profiles up to 2.4 tons — www.voortman.net (accessed 2026-11-01)
- Steel-Sci, “Rolling tolerances to BS EN 10034:1993 for Universal shapes” (published tolerance tables) — ihsbb.steel-sci.com (accessed 2026-11-01)
- Belgian Welding Institute, “Cutting Procedure Qualification according to EN 1090” — bil-ibs.be (accessed 2026-11-01)
- ISO 9013:2017, Thermal cutting — Classification of thermal cuts (catalogue entry: scope and thickness ranges) — www.iso.org (accessed 2026-11-01)
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