Laser Cutting Defect Analysis and Solutions

For Carbon Steel – Cut with O₂

DefectPossible CausesSolutions
No burrs, drag lines are consistentPower is appropriate
Feed rate is appropriate
Large offset in drag lines at the bottom; wider cut at the bottomFeed rate too high
Laser power too low
Gas pressure too low
Focal point too high
Reduce feed rate
Increase laser power
Increase gas pressure
Lower focal point
Burrs similar to slag on the bottom, droplet-like and easy to removeFeed rate too high
Gas pressure too low
Focal point too high
Reduce feed rate
Increase gas pressure
Lower focal point
Connected metal burrs that can be removed as a wholeFocal point too highLower focal point
Metal burrs on the bottom are difficult to removeFeed rate too high
Gas pressure too low
Impure gas
Focal point too high
Reduce feed rate
Increase gas pressure
Use purer gas
Lower focal point
Burrs only on one sideNozzle misalignment
Nozzle defect
Align nozzle
Replace nozzle
Material discharges from the topPower too low
Feed rate too high
Press pause immediately to prevent slag splash onto focusing lens.
Increase power
Reduce feed rate
Beveled cutting surface, two sides good/bad alternatelyFull reflection mirror not suitable, improperly installed or defective
Full reflection mirror installed in place of deflection mirror
Check full reflection mirror
Check deflection mirror
Blue plasma appears, workpiece not fully cut throughProcessing gas incorrect (N₂ used instead of O₂)
Feed rate too high
Power too low
Press pause immediately to prevent slag splash onto focusing lens.
Use oxygen as processing gas
Reduce feed rate
Increase power
Rough cutting surfaceGas pressure too high
Nozzle damaged
Nozzle diameter too large
Poor material quality
Reduce gas pressure
Replace nozzle
Install proper nozzle
Use smooth, uniform material
No burrs, drag lines tilted, narrower at the bottomFeed rate too highReduce feed rate
Crater formationGas pressure too high
Feed rate too low
Focal point too high
Rust on plate surface
Overheating during processing
Material impurity
Reduce gas pressure
Increase feed rate
Lower focal point
Use higher quality material
Very rough cutting surfaceFocal point too high
Gas pressure too high
Feed rate too low
Material overheated
Lower focal point
Reduce gas pressure
Increase feed rate
Cool material

For Stainless Steel – Cut with High-Pressure N₂

DefectPossible CausesSolutions
Small, regular droplet-like burrs– Focal point too low
– Feed rate too high
– Raise focal point
– Reduce feed rate
Long, irregular filament-like burrs on both sides, discoloration on large plates– Feed rate too low
– Focal point too high
– Gas pressure too low
– Material overheated
– Increase feed rate
– Lower focal point
– Increase gas pressure
– Cool material
Long, irregular burrs only on one edge– Nozzle misaligned
– Focal point too high
– Gas pressure too low
– Speed too low
– Align nozzle
– Lower focal point
– Increase gas pressure
– Increase speed
Yellowing on cut edges– Oxygen impurities in nitrogen– Use high-purity nitrogen
Plasma generated on straight sections– Feed rate too high
– Power too low
– Focal point too low
– Press pause immediately to prevent slag splash onto focusing lens.
– Reduce feed rate
– Increase power
– Raise focal point
Beam divergence– Feed rate too high
– Power too low
– Focal point too low
– Reduce feed rate
– Increase power
– Raise focal point
Plasma generation at corners– Angle tolerance too high
– Modulation too high
– Acceleration too high
– Reduce angle tolerance
– Reduce modulation or acceleration
Beam diverges at start– Acceleration too high
– Focal point too low
– Molten material not expelled
– Reduce acceleration
– Raise focal point
– Drill round hole first
Rough cut surface– Nozzle damaged
– Lens dirty
– Replace nozzle
– Clean lens, replace if necessary
Material discharges from the top– Power too low
– Feed rate too high
– Gas pressure too high
– Press pause immediately to prevent slag splash onto focusing lens.
– Increase power
– Reduce feed rate
– Reduce gas pressure

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