Key takeaways
- ISO 9013 defines four quality ranges; range 2 at 6 mm allows 0.19 mm of perpendicularity and 44.8 µm of Rz5, and the worse of the two measurements sets the range.
- On a 12 kW fibre laser, range 2 is repeatable to about 6 mm, range 3 is the realistic result at 10–12 mm, and range 1 above 3 mm needs a slower pass or a finishing operation.
- Dross, burr and heat-affected zone are not classification parameters in ISO 9013; they need their own acceptance note on the drawing.
- The standard describes the cut edge, not the part: hole position, flatness and bend angle follow other tolerances and are not covered by a range callout.
A drawing note that reads cut edges to ISO 9013 specifies nothing, because the standard contains four quality ranges and two measurements. Range 2 at 6 mm allows 0.19 mm of perpendicularity and 44.8 µm of roughness; range 4 at the same thickness allows 0.92 mm and 120.8 µm. Both are ISO 9013, and one of them will be rejected on a visible panel.
The standard is a classification, not a pass mark. It describes the cut face in two numbers, and the worse of the two decides the range. Once the range is on the drawing, the edge becomes a measurable contract instead of a description like clean or smooth.
The sections below give the range values, work them at production thicknesses, and set out what the standard does not cover. The rest of the cut-quality material is in the standards and compliance hub.
What does ISO 9013 classify?
ISO 9013:2017 gives geometrical product specifications and quality tolerances for thermal cuts. It applies to laser cuts from 0.5 mm to 32 mm, plasma cuts from 0.5 mm to 150 mm and oxy-fuel cuts from 3 mm to 300 mm. For laser work, the part that matters is the classification of the cut edge by perpendicularity and roughness.
Perpendicularity, written u, is the deviation of the cut face from a true 90° to the sheet surface, in millimetres. Roughness, written Rz5, is the mean peak-to-valley height of the striations over five sampling lengths, in micrometres. The standard gives each as a formula that scales with thickness, because a thicker cut naturally carries more taper and deeper striations.
There are four quality ranges. Range 1 is the tightest and range 4 the loosest. A cut must satisfy both parameters to claim a range, and the worse of the two sets the result: a cut that holds range 1 on perpendicularity and range 3 on roughness is a range 3 cut.
The range values by thickness
The table below applies the standard formulas at the thicknesses that come through a fabrication shop. The two figures in each cell are u in millimetres and Rz5 in micrometres.
| Thickness | Range 1 (u / Rz5) | Range 2 (u / Rz5) | Range 3 (u / Rz5) | Range 4 (u / Rz5) | Ganesh limit or note |
|---|---|---|---|---|---|
| 1 mm | 0.053 mm / 10.6 µm | 0.157 mm / 40.8 µm | 0.41 mm / 71.2 µm | 0.82 mm / 111.8 µm | Range 2 routine; range 1 on a slowed pass |
| 3 mm | 0.059 mm / 11.8 µm | 0.171 mm / 42.4 µm | 0.43 mm / 73.6 µm | 0.86 mm / 115.4 µm | Range 2 the production target on CRCA |
| 6 mm | 0.068 mm / 13.6 µm | 0.192 mm / 44.8 µm | 0.46 mm / 77.2 µm | 0.92 mm / 120.8 µm | Range 2 repeatable; range 3 on stained plate |
| 10 mm | 0.080 mm / 16.0 µm | 0.220 mm / 48.0 µm | 0.50 mm / 82.0 µm | 1.00 mm / 128.0 µm | Range 3 realistic; range 2 on a slow pass |
| 20 mm | 0.110 mm / 22.0 µm | 0.290 mm / 56.0 µm | 0.60 mm / 94.0 µm | 1.20 mm / 146.0 µm | 20 mm is the laser maximum; range 3–4 typical |
Read the table as a ladder, not a menu. Moving from range 3 to range 2 at 10 mm cuts the allowed roughness from 82 µm to 48 µm, a 41% reduction, and the allowed taper from 0.50 mm to 0.22 mm. That is a different cut, usually a slower one with more gas, and it is priced accordingly.
The same standard also carries dimensional tolerance classes for cut parts, which are separate from the edge ranges. Class 1 is the tight one, around ±0.20 mm at 3 mm thickness on a 10–35 mm nominal dimension; class 2 is around ±0.70 mm on the same feature. Most drawings that say ISO 9013 mean the edge range, so say which you mean.
Worked example: specifying range 2 on 10 mm plate
Suppose a bracket in 10 mm mild steel is drawn with cut edges to ISO 9013 range 2 and a visible face that will be powder coated.
Range 2 at 10 mm permits u ≤ 0.22 mm and Rz5 ≤ 48 µm. On a 12 kW fibre laser, a normal production pass at 10 mm produces a roughness nearer 58 µm, which is range 3, and a taper around 0.3 mm. The part fails the note, and the shop has three options: slow the cut and accept the cost, accept range 3 and change the drawing, or machine the edge.
If the edge is only going to be painted, range 3 is the sensible callout. A 82 µm striation profile is covered by a 70 µm powder film after pretreatment, and the coating hides the difference that the range is measuring. If the edge is a sealing face or a sliding guide, neither range is enough and the edge needs machining, because the roughness that matters there is an Ra value on a finished surface, not a thermal cut classification.
That is the decision rule: choose the loosest range the function tolerates, and move the requirement to a machining callout when the function needs a seal, a bearing or a precision fit.
Slowing the cut is the usual way to move one range. Cutting speed and edge roughness trade directly: a contour run at 70% of the normal speed takes 1/0.7 = 1.43 times as long, so a part with 1.8 m of edge adds 43% to the time on that edge for one range. On a bracket with a short perimeter the cost is small; on a panel with 6 m of cut it is the difference between a competitive quote and a lost one.
Measuring the range in the shop
Perpendicularity is the easy one to check. Stand the part on a surface plate, offer a machinist square to the cut face, and measure the gap with feeler gauges at the mid-point of the thickness. Exclude the top and bottom 10% of the edge, where the burr and the pierce crater distort the reading, and record the maximum gap over the functional length. A profile projector does the same job faster on thin sheet.
Roughness needs a profilometer or an approved comparator. Rz5 is the mean peak-to-valley height over five sampling lengths, so a single deepest striation is not the measurement. Take the reading on the functional face, away from the lead-in and the corner slowdown, and record it with the thickness and the material, because 45 µm means different ranges at 3 mm and at 12 mm.
Both readings then go against the table. A cut that measures u = 0.18 mm and Rz5 = 52 µm at 8 mm is range 3, because the roughness fails range 2 even though the perpendicularity passes it. Writing both numbers on the inspection record is what makes the range defensible.
Where the cut edge actually varies
Four things move a laser cut edge across the range boundaries, and only one of them is the machine.
Thickness. The formulas scale with thickness, so the same process drifts towards a looser range as the plate gets thicker. The 6 mm to 10 mm step alone takes the range 2 roughness limit from 44.8 µm to 48.0 µm while the process roughness rises faster.
Material. Mild steel cut with oxygen carries an oxide edge and a wider heat-affected zone than stainless cut with nitrogen. Stainless holds a cleaner face at the same thickness but is more prone to dross at the exit when the gas pressure is marginal. Aluminium sits between the two and marks easily.
Gas and focus. Roughness is mostly a function of focus position and assist gas. A nozzle that is off-centre by 0.1 mm produces a directional edge: clean on one side of the part, drossy on the other, on the same sheet and the same program. That is a maintenance finding, not a drawing finding.
Nesting and heat. A dense nest heats the sheet, the focus distance changes as the sheet bows, and the edge quality at the far end of a long cut differs from the start. On a 3,000 mm part the difference can cross a range boundary without any parameter change.
What ISO 9013 does not cover
The scope is the cut edge, and that leaves several things outside it.
- Dross and burr. These are not classification parameters. A part can hold range 2 and still have a dross beard on the underside. Specify burr height and dross separately, for example 0.10 mm maximum burr on a handled edge.
- Heat-affected zone. The standard does not set a HAZ width or a hardness limit. If the part will be fatigue loaded or welded, that is a separate metallurgical requirement.
- Hole size and position. These are dimensional tolerances, not edge quality. A hole can have a perfect edge and be 0.3 mm off position.
- Flatness and twist. A long part can have range 2 edges and 4 mm of bow. Flatness is a separate callout, measured after the part has cooled.
- Edge squareness for a sealing face. A thermal cut edge is not a sealing surface at any range. If the face must seal, it needs machining or a gasket that tolerates the profile.
That list is also the answer to the most common first-article argument. The supplier measures the edge and passes it; the customer measures the hole pattern and fails it. Both are right, because the drawing asked for one and assumed the other.
How Ganesh reads an edge requirement
Ganesh cuts on a 12 kW fibre laser with a 40 ft × 16 ft bed, supported by two 6 kW and two 3 kW machines, in mild steel, CRCA, stainless, aluminium, brass and copper, with plate to 20 mm on the laser and 30–40 mm on the iron worker. The edge result is confirmed at first-off against the range on the drawing rather than assumed from the machine specification.
For a coated part, the edge requirement is reviewed together with the pretreatment and coating route, because a heavy dross edge traps pretreatment chemistry and shows through a thin powder film. For a welded part, the edge that meets the weld is checked for squareness and dross before it reaches the fixture, since dross that detaches during welding contaminates the joint.
Repeat parts run with first article inspection and an approved sample, so the edge condition is checked against the range on the drawing rather than assumed from the machine setting. The laser cutting capability sets out the bed, power and material range. The mild steel thickness and edge quality guide gives the thickness-by-thickness edge result behind the ranges in this table.
What to put on the drawing
- The range and the standard year, for example cut edges to ISO 9013:2017 range 2, rather than the standard number alone.
- Which edges the range applies to, because a visible edge and a weld-prep edge rarely need the same finish.
- The measurement basis: u and Rz5 on the functional length, away from pierce marks and the burr zones.
- Burr and dross limits as separate numbers, since the range does not control them.
- The dimensional tolerances for hole size, hole position and flatness, referenced to their own standard or given explicitly.
- Any edge that must be machined, so the requirement moves to a milling or reaming operation instead of a tighter range.
Send the drawing with the edge function marked to our engineering team. We will say which range the thickness and material can hold, and where a secondary operation is cheaper than a slower cut. For the dimension side of the same part, laser cutting tolerances for OEM parts covers the cut figures, and deburring and edge quality after laser cutting covers what happens to the edge before coating.
When a tighter range is the wrong request
Range 1 on 12 mm plate is a machining request written as a cutting request. The taper and striation depth at that thickness are set by the process, and a slower pass improves them at a cost that usually exceeds a light machining operation. The same applies to a range 1 callout on a part that will be painted: the coating hides the difference, and the money spent on the slower cut buys nothing the customer can see.
The reverse is also a mistake. A range 4 note on a visible stainless panel is a note that permits a finish the application will reject, and it will be rejected at the customer rather than at the machine. Match the range to the function, put the dimension tolerances where they belong, and the edge stops being an argument.
Frequently asked questions
What does ISO 9013 range 2 mean on a laser-cut part?
It means the cut edge meets the second of four quality ranges. At 6 mm thickness that allows a perpendicularity deviation of 0.05 + 0.007 × 6 = 0.092 mm on the u side and a roughness of 40 + 0.8 × 6 = 44.8 µm on the Rz5 side, with the worse of the two setting the result.
Does ISO 9013 cover hole position and part flatness?
No. It classifies the cut edge, meaning perpendicularity and roughness. Hole position, part flatness, bend angle and hole size follow the dimensional drawing and standards such as ISO 2768-1, not the cut edge range.
What range can a 12 kW fibre laser hold on 10 mm mild steel?
Range 3 is the realistic production result at 10 mm, with range 2 possible on a slower pass with good gas coverage. Range 1 at that thickness needs a second operation, because the striation depth and taper are set by the process rather than by the machine.
Is dross covered by the ISO 9013 class?
No. Dross, burr and heat-affected zone are not classification parameters in the standard. A part can meet range 2 and still carry a dross beard on the underside, so the drawing needs a separate note for dross and burr height.
How is perpendicularity measured for ISO 9013?
With a square, a profile projector or a CMM, measuring the gap between the cut face and a true perpendicular to the sheet surface, away from the pierce point and the burr zones at the top and bottom of the edge. Record the maximum deviation over the functional length.
Sources and further reading
- ISO 9013:2017 — Thermal cutting, classification of thermal cuts, geometrical product specification and quality tolerances · reviewed 3 Nov 2026
- ISO 13715:2017 — Technical product documentation, edges of undefined shape, indication and dimensioning · reviewed 3 Nov 2026
- ISO 2768-1:1989 — General tolerances for linear and angular dimensions without individual tolerance indications · reviewed 3 Nov 2026
Send the part with the edge requirement
Tell us the material, thickness and what the edge has to do: weld, seal, slide or take paint. We will quote the range the process can hold and flag where a secondary operation is the cheaper route.
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