Laser cutting quality is closely related to focus position, cutting speed, gas pressure, and power settings.
Below is a practical summary of common cutting issues, categorized by material type, along with recommended cutting parameters.
Stainless Steel Cutting Issues
(Defocus value should be adjusted according to plate thickness)
① The higher the focus, the brighter the cut surface.
② Hard slag on the bottom surface is caused by:
Focus too high.
Cutting speed is too slow.
Gas pressure is too low.
③ The lower the focus, the rougher the cut surface.
④ Soft slag on the bottom surface is caused by:
Focus too low.
Cutting speed is too fast.
Gas pressure is too high.
Excessive power.
⑤ Incomplete cutting (not cut through) is caused by:
Incorrect focus position.
Insufficient power.
Cutting speed too fast.
Carbon Steel Cutting Issues
(Defocus value should be adjusted according to plate thickness)
Hard slag on the bottom surface is caused by:
① Focus too low.
② Gas pressure is too low.
③ Power too low.
④ Cutting speed too fast.
Rough cut surface is caused by:
① Focus too high.
② Gas pressure is too high.
③ Power too high.
④ Material quality issues.
Selection of Cutting Nozzles and Lenses (Cutting Parameters)
1. Carbon Steel: Nozzle & Lens Selection
Lens Selection
1–8 mm carbon steel → 5-inch lens.
8–10 mm carbon steel → 7.5-inch lens.
Nozzle Selection
1–6 mm carbon steel → Φ1.4 nozzle.
6–10 mm carbon steel → Φ2.0 nozzle.
2. Stainless Steel: Nozzle & Lens Selection
Lens Selection
1–4 mm stainless steel → 5-inch lens.
4–6 mm stainless steel → 7.5-inch lens.
Nozzle Selection
1–3 mm stainless steel → Φ1.5 nozzle
(Nitrogen pressure: 10–13 kg)3–4 mm stainless steel → Φ2.0 nozzle
(Nitrogen pressure: 13–15 kg)5–6 mm stainless steel → Φ2.5 nozzle
(Nitrogen pressure: 14–16 kg)
Types of Gases and Their Functions
Air
① Used as a cutting gas.
② Used for cooling the cutting head.
③ Used for internal optical path dust removal.
(Protects lenses and extends lens service life).
Industrial Oxygen
Used for carbon steel cutting.
Supports combustion.
Purity: 99.5%.
Pure Nitrogen
Used for stainless steel cutting.
Provides cooling effect.
Purity: 99.9%.
(Cutting speed for carbon steel is about 3/4 of oxygen cutting).
High-Purity Nitrogen
Used for laser source operation
Purity: 99.999%
High-Purity Helium
Used for laser source operation
Purity: 99.999%
High-Purity Carbon Dioxide
Used for laser source operation
Purity: 99.999%
Hole Size Requirements (By Material & Thickness)
① For carbon steel plates ≤ 8 mm, the hole diameter must not be smaller than the plate thickness.
For plates ≤ 10 mm, the hole diameter must be at least 1.2× the plate thickness.
② For stainless steel plates ≤ 4 mm, the hole diameter must not be smaller than the plate thickness.
For plates > 4 mm, the hole diameter must be at least 1.2× the plate thickness.
③ If the hole diameter exceeds these limits, use pulse cutting or marking first.
Pulse Cutting (Compared to Continuous Wave Cutting)
① Cutting speed should be 30–50% of continuous wave cutting.
② Power should be slightly higher than continuous wave cutting.
③ Gas pressure should be about twice that of continuous wave cutting.
⚠ Continuous wave cutting is recommended for piercing.
Piercing Methods (For Carbon Steel Cutting)
① Standard Piercing
Suitable for carbon steel ≤ 5 mm
② Progressive Piercing
Suitable for 6–8 mm carbon steel
Requires modification of parameter P990012
③ High-Power Piercing (Blast Piercing)
Suitable for 10–12 mm carbon steel
Piercing height should not be lower than cutting height
Piercing gas pressure should not be lower than 1.0
Lead-In Line Parameters (For Stainless Steel Cutting)
① 1–3 mm stainless steel
→ Use single method (small circle or speed reduction)
② 3–6 mm stainless steel
→ Use two methods combined (small circle + speed reduction)
③ Gas pressure for small-circle cutting should be 1.5× higher than normal cutting pressure
Blast Piercing Issues (Over-Piercing)
Common causes include:
① Insufficient piercing time
② Excessive gas pressure
③ Incorrect focus position
④ Piercing height too low
⑤ Inconsistent pulse frequency
⑥ Excessive power
Conclusion
That concludes today’s technical sharing.
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