Laser cutting defects: dross, incomplete cuts, 39 causes and 10 checks
Pick what you see on the cut part, for example an incomplete cut or dross, and get the causes in five layers, each with a check and an action. Ten quick checks use published values, and eight of them compare your measurement and return a verdict.
Opens without an account 3 times a day. A free account removes the limit.
- 7 symptomsfrom incomplete cut to burn-through
- 39 causesoptics, gas, machine, program, material
- 10 checks8 of them give a verdict
- 14 rulespublished values, built into the tool
What the laser cutting troubleshooting tool shows
Laser cutting defects is a free online tool from EduFacturing that starts from a finished part with a problem and leads to the cause. It has seven symptoms, 39 causes in five layers (optics, gas, machine, program, material) and ten checks against published values, eight of which compare your measurement and return a verdict.
The numbers come from a built-in copy of 14 rules from the EDi Brain core; the judgement of when a microjoint (a small tab that holds the part in the sheet) is needed is marked as an EduFacturing engineering estimate. The calculations run in the browser.
Laser cutting dross, incomplete cuts and taper
Starts from the symptom
Seven symptoms: incomplete cut, dross (stuck molten metal) on the bottom edge, wide or tapered kerf, burning, deviation from the contour, a fallen part and pierce burn-through.
Shows the layer of each cause
39 causes in five layers: program 12, machine 10, optics 6, material 6, gas 5. Each has a check and an action, and the order follows how common the cause is in practice.
Checks with a number
Ten checks, for example gas pressure, heat-affected zone, kerf width and size. Eight give a verdict, and two give the effect of the gas on the edge and a focus recommendation.
Says when there is no rule
For focus on thick material with nitrogen, or on a metal other than steel, the core has no published direction, and the tool says so.
Why is my laser not cutting through: who checks what
Before touching the program, check what takes minutes.
Incomplete cut: the laser operator
Checks the thickness against the machine ceiling, the gas pressure and the focus before changing the program.
A part falls in the machine or the pierce leaves a mark
The planner checks the microjoints and the pierce clearance: 3 mm up to 10 mm thickness and 5 mm above that.
The size is off
The measured deviation is compared with a general tolerance under ISO 2768-1 for the nominal size.
How your number is checked against a rule
The tool links a symptom to causes and causes to checks. Each check compares your number with a published value.
Number against a rule
The measured value is compared with a value from the built-in copy of the core: oxygen 0.5 to 2 bar, nitrogen at least 10 bar, heat-affected zone for a fiber laser 0.1 to 0.4 mm.
Three answers
“Within norm” is inside the published range, “Attention” is the first step outside it, and “Outside the norm” is a much larger deviation: over 2 times for kerf width and over 3 times for taper.
| Applies to | Formula | Meaning |
|---|---|---|
| Taper, ISO 9013 Range 1 | u = 0.05 + 0.003 · t | t is the thickness in mm; best achievable for a laser: at 10 mm u is 0.08 mm, at 32 mm 0.146 mm |
| Pierce | t ≤ 10 mm: 3 mm; t > 10 mm: 5 mm | minimum distance from the pierce point to the contour |
| Microjoint | width 0.25 to 0.38 mm | for a free part: size to thickness above 12 is a moderate risk of falling, up to 12 is a high risk; with 20 or more parts on the sheet the risk is high |
Laser cutting problems checked against rules, not memory
The numbers come from rules, not memory
The numbers come from a built-in copy of 14 laser cutting rules from the EDi Brain core, and a test checks that each of them exists.
A dark edge with oxygen is not a defect
Oxygen gives an oxidised dark edge as the expected result. With nitrogen the same darkening points to pressure, flow or the purity of the cylinder.
The tool does not give a diagnosis: the causes follow how common they are in practice, and only a test cut on scrap confirms what happens on your machine. The numbers are typical values, not a guarantee for a particular installation.
It does not check the geometry of the part (holes, slots, strips), does not choose a laser, material or regimes, and does not give power and speed. The size check uses an ISO 2768-1 table from the core that is currently under review; for an exact tolerance see the standard.
Questions about dross, gas pressure and taper
Why is my laser not cutting through?
Check three things first: the thickness against the machine ceiling, the gas pressure and the focus. Only then change the program.
Is a dark edge with oxygen a defect?
No. Oxygen burns the surface and a dark, oxidised edge is the expected result. With nitrogen the same darkening points to pressure, flow or the purity of the cylinder.
What gas pressure is normal?
For oxygen on carbon steel 0.5 to 2 bar, for nitrogen on stainless steel at least 10 bar. Outside these values the tool returns “Attention”, and for a very large deviation “Outside the norm”.
What taper is normal for a good cut?
Under ISO 9013 Range 1, the finest class, u = 0.05 + 0.003 · t, in mm; at 10 mm thickness that is 0.08 mm. Taper in one direction along the whole length usually points to a head that is not square to the sheet.
How thick can a laser cut?
The ceiling of one European job shop is 25 mm for carbon steel, 20 mm for stainless and 10 mm for aluminium. That is one shop's ceiling, not a general limit.
Why does a part fall in the machine?
A free part with no microjoints, or with joints that are too thin, can fall before the end. A microjoint is 0.25 to 0.38 mm wide, and with 20 or more parts on the sheet the risk is higher.
Is the laser cutting defects tool free?
Yes. Without an account it opens 3 times a day, and with a free account there is no limit. Pro is not needed.
The laser cutting defect tool is free. Pro opens the rest
Pro costs 15 EUR a month and opens 45 Pro tools.
Related tools
Laser cut edge quality (ISO 9013)Check laser cut edge quality against ISO 9013: thickness, Rz5 roughness and perpendicularity u give a Range 1 to 4 roughness class and a check of u. Free.
Laser nozzle and lens lifeLaser cutting consumables: how many hours and days the nozzle and protective lens last, which nozzle diameter and what a late replacement costs. Free to use.
CNC milling defectsFree CNC milling defects tool: pick a symptom such as chatter or a burr and get 33 ranked causes, each with a check and an action.
Find the cause of the cut defect
Opens without an account 3 times a day. A free account removes the limit.