TL;DR
Degraded cut quality on a fiber laser is most often contaminated or damaged cutting optics, incorrect focus position, or inadequate assist gas pressure. Clean the protective glass first.
What you might see
- striation marks on cut edges worsening
- edge roughness increasing on stainless steel or aluminum
- burr height increasing on carbon steel
- protective glass replacement interval shortening unexpectedly
Likely causes
Contaminated or micro-cracked protective glass scattering the beam
Focus position drifted from the material surface due to nozzle wear or thermal shift
Assist gas pressure or purity insufficient for the material being cut
Beam alignment drift in the cutting head from a nozzle collision event
Required tools
- Replacement protective glass cartridge
- Cutting nozzle (spare set)
- Assist gas purity certificate
- Laser safety goggles rated for fiber laser wavelength (1064 nm)
- LOTO kit
Safety first
- Fiber laser radiation at 1064 nm is invisible and causes instant permanent eye damage. Always follow the full TRUMPF beam-path lockout procedure before opening the cutting head.
- Never look into the beam path or cutting head aperture even when the laser appears to be off.
- Cutting fumes from coated or galvanized steel are toxic. Ensure the extraction system is operating before cutting.
Procedure
- 1
Lock out the machine per the TRUMPF lockout procedure before opening the cutting head.
Warning: The TruLaser uses a high-power fiber laser. Never open the laser beam path without following the full TRUMPF lockout and beam-path verification procedure. Laser radiation is invisible and causes permanent eye injury. - 2
Remove the protective glass cartridge from the cutting head and inspect both surfaces under a strong light for spatter, scratches, or haze.[1]
- 3
Replace the protective glass if any contamination is visible. Do not attempt to clean a scratched or pitted glass as it will scatter the beam.
- 4
Verify the focus position parameter in the CNC matches the material type and thickness in the job program.[1]
- 5
Check the cutting nozzle for concentricity damage from a collision. Replace if the nozzle bore is off-center or deformed.
- 6
Verify assist gas pressure and purity at the machine inlet. For nitrogen cutting on stainless, purity must be 99.998 percent or better.
- 7
Run a focus test cut (BKT procedure or equivalent) on scrap material to confirm the focus position is at the cut surface.
- 8
Make a test cut on the production material and evaluate edge quality against the acceptance specification.
Sources
TRUMPF TRUMPF TruLaser 3030 / 5030 Laser Cutting Machine (Fiber) general technical documentation, TRUMPF
TRUMPF TruLaser 3030 / 5030 operator documentation, cutting head maintenance and cut quality optimization (general)
More guides for TRUMPF TRUMPF TruLaser 3030 / 5030
How to fix chiller overtemperature on a TRUMPF TruLaser 3030 / 5030
Chiller overtemperature stops the laser to protect the source. Check coolant level, clean the chiller condenser, and verify ambient temperature is within specification before restarting.
How to recover from a cutting head collision on a TRUMPF TruLaser 3030 / 5030
After a collision, stop the machine, inspect the nozzle and protective glass, check beam centering, and do not restart cutting until beam centricity is verified on the nozzle hole.
Stop fixing the same fault twice.
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