Laser cutting DFM checker, nine geometry checks before the part goes under the beam
Enter the material, laser type, sheet thickness and the hole, slot, edge, web, corner and pierce dimensions from the drawing, and read nine checks back side by side against published minimums. This is the third step in the laser cutting workflow, after cutting parameters and after nesting: it looks only at whether the shape itself survives the physics of the cut, not at power, speed, gas or how the parts sit on the sheet.
Open the DFM checker A free account opens this tool. The interface is in English and nothing you enter leaves your browser.How it works
Three steps, from material and thickness to nine verdicts and a tolerance figure.
Set the material, laser type and sheet thickness
Choose carbon steel, stainless steel or aluminium, and fibre or CO2. The maximum thickness check runs immediately: the binding figure is whichever of three independent ceilings is strictest for that combination, a typical job shop's practical limit by material, the 32 millimetre scope of ISO 9013 itself, or, for a CO2 laser cutting steel specifically, the roughly 20 millimetre ceiling of a typical 4 kilowatt machine.
Enter the hole, slot, web, corner and pierce dimensions from the drawing
Type in the hole diameter and its distance to the nearest edge, the slot width and its own edge distance, the web left between two parallel cuts, the internal corner radius, and how far the pierce point sits from the visible contour. Each field is checked against a separate published minimum for the material and thickness already chosen, not one blanket rule applied to every feature.
Read the nine verdicts, the achievable tolerance and the microjoint risk
Each check returns ok, borderline or fail against its published minimum, with the source cited underneath. Below that, the tool states the linear tolerance available without extra machining and the perpendicularity of the cut edge for the chosen thickness, then, if the part separates completely from the sheet skeleton during the job, whether it needs a microjoint to stay in place until the program finishes.
Nine checks, one risk assessment
Every check returns ok, borderline or fail against a published minimum. The microjoint decision returns a risk level instead, because timing is engineering judgement, not a numbered rule.
Built to separate a real limit from a guess
Nine checks trace back to a specific published number or an explicitly labelled engineering judgement call, never a single pass or fail with no source underneath it.
Per-material lookup tables, not one flat rule
The general rule of thumb is a hole at least as wide as the sheet is thick, so a 6 millimetre sheet would need a 6 millimetre hole. Published production tables allow finer holes than that: 4 millimetres for 6 millimetre carbon steel, only 3 millimetres for 6 millimetre stainless steel because the nitrogen assist gas keeps the edge cleaner and tolerates a more aggressive geometry, and back up to 4 millimetres for aluminium, where the metal's own reflectivity to the beam sends part of the energy straight back out. The checker shows the flat rule and the material specific table side by side, so the gap between them is visible, not hidden behind one verdict.
The larger of two published minimums, not the first one found
The web left between two parallel cuts has two independently published minimums that do not agree: a structural floor of half the sheet thickness, and a more generous recommendation of twice the thickness from a separate fabricator for side by side cuts. On a 4 millimetre sheet that is 2 millimetres against 8 millimetres, a real difference. Rather than pick one source and ignore the other, the checker takes the larger, more conservative figure as binding, because when two published numbers disagree, the wider strip is the safer choice.
Nine checks come from one piece of physics
A laser cuts by focusing heat into a spot under a millimetre wide, and that heat has to escape sideways through the surrounding metal before the beam moves on. A hole too small, a strip too narrow, or a pierce point too close to the finished edge all fail for the same underlying reason: not enough neighbouring material to carry the heat away in time. That is also why a fibre laser's heat affected zone, typically 0.1 to 0.4 millimetres, stays so much narrower than plasma's 0.5 to 2 millimetres or oxy-fuel's 1 to 5 millimetres, and why the laser is the process to reach for on parts with tight, closely spaced features.
States plainly what it does not calculate
Kerf taper, the slight difference between the top and bottom cut width on thick material, has no published formula in the underlying rules data yet, so the tool says so instead of inventing one and points you at a test cut on the actual machine. Distortion from residual stress in long thin cuts depends on how the sheet is clamped and the order the program cuts contours in, not on geometry alone, so it is left out too. Cutting power, speed, gas and focus are not touched here either: they belong to the separate laser cutting parameters tool, so the same setting is never typed into two different places.
Frequently asked questions
Why does a small hole in thick material fail the check?
A laser cuts with heat concentrated in a spot under a millimetre wide, and that heat needs enough surrounding metal to carry it away sideways before it deforms the hole from the inside. Published production tables show the minimum hole diameter growing with thickness, but not linearly and not the same for every metal: 4 millimetres for 6 millimetre carbon steel, 3 millimetres for 6 millimetre stainless steel, and 4 millimetres again for aluminium, whose high reflectivity to the beam's wavelength works against it even though it conducts heat well.
Why does the checker compare web width against two different numbers?
Because two sources publish different minimums for the same thing. One is a structural floor of half the sheet thickness. The other is a more generous recommendation of twice the thickness from a separate fabricator, aimed specifically at side by side parallel cuts. On a 4 millimetre sheet that is 2 millimetres against 8 millimetres. The checker takes the larger of the two as the binding minimum, because a narrower strip that only satisfies the stricter source is still the one more likely to overheat between two closely spaced cuts.
Can the laser really cut a zero radius internal corner?
On paper, yes. Unlike CNC milling, where the cutter's own radius sets a hard geometric floor no program can get around, a laser has no rotating tool, so a nominally sharp internal corner is not blocked by the process itself. In practice the kerf, the width actually removed by the beam, typically 0.1 to 0.3 millimetres for a fibre laser, sets a separate practical floor: below about 0.15 millimetres, half the upper end of that range, the cut itself rounds the corner regardless of what the drawing specifies.
Why does the checker report three different maximum thickness figures?
Because three independent limits apply for different reasons, and the checker reports the strictest one as binding rather than picking a single number in advance. A typical job shop's practical ceiling by material, 25 millimetres for carbon steel, 20 for stainless steel, 10 for aluminium. The 32 millimetre scope of ISO 9013 itself, above which the standard defines nothing. And, only for a CO2 laser cutting steel, a roughly 20 millimetre ceiling typical of a 4 kilowatt class machine.
Does the checker tell me when to add a microjoint?
It gives a risk level, not a strict pass or fail. The width of the microjoint itself, 0.25 to 0.38 millimetres, is a published figure from a real fabricator. Deciding when one is actually needed is not: the checker applies its own proportional rule, comparing the smallest free dimension of the piece against the sheet thickness, and raises the risk further when the sheet is densely nested with many parts. That decision is stated as engineering judgement, not cited as a numbered rule, because the source data does not publish one.
What tolerance does laser cutting give without any extra machining?
If the drawing does not call out a tighter tolerance, the part inherits the general ISO 2768-1 medium class table by default: roughly plus or minus 0.1 millimetres up to 3 millimetres nominal, 0.3 millimetres up to 30 millimetres, and 0.5 millimetres up to 120 millimetres. Separately, the perpendicularity of the cut edge itself grows with thickness, about 0.08 millimetres at 10 millimetres and 0.11 at 20 millimetres. A tighter requirement than either of these needs a follow up operation on the critical dimensions, not a rework of the whole cut.
What does this tool not check at all?
Three things on purpose. Cutting power, speed, assist gas and focus belong to a separate laser cutting parameters tool, so the same figure is never set in two places. Nesting, how the parts are arranged on the sheet for minimum waste, belongs to a separate nesting tool. And kerf taper, the slight narrowing of the cut through thick material, has no published formula behind it yet, so the checker states that gap honestly rather than filling it with an invented number.
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