TL;DR
Laser power drift causes inconsistent melt pool size and part density. Perform a laser power measurement with the EOS power meter and recalibrate if output deviates from the nominal parameter by more than 3 percent.
What you might see
- part density decreasing over multiple builds without parameter change
- melt pool monitoring shows smaller or irregular melt pools
- surface roughness of built parts increasing
- power meter test shows output below nominal
Likely causes
Laser source power degradation from service hours
Focus optics or protective window contaminated with spatter reducing transmitted power
Beam delivery fiber or coupler degraded
Laser water cooling circuit under-performing reducing laser output stability
Required tools
- EOS integrated laser power meter (built-in)
- Replacement protective window
- Laser safety goggles rated for fiber laser wavelength (1070 nm)
- EOS laser safety procedure documentation
Safety first
- The EOS M series uses a high-power fiber laser. Never open any optical enclosure without following the full EOS laser safety lockout procedure.
- Laser power measurement must use the EOS-specified built-in method. Do not use external power meters unless EOS-approved.
- Metal powder in the build chamber is a fire and explosion hazard. Follow all EOS powder safety procedures when accessing the build chamber.
Procedure
- 1
Run the EOS laser power measurement procedure using the machine-integrated power meter before opening any optical component.[1]
- 2
Compare the measured laser output to the nominal power value in the build parameter set. A deviation above 3 percent requires investigation.[1]
- 3
Follow the EOS optics inspection procedure to access the protective window in the build chamber. Inspect for spatter contamination or coating damage.
Warning: Follow the full EOS laser safety procedure before accessing any optical component. The EOS M series uses a high-power fiber laser. Never look into the beam path or open the laser source enclosure without proper laser safety training and appropriate eyewear. - 4
Replace the protective window if any spatter or damage is visible. Do not clean a scratched protective window.
- 5
Verify the laser cooling circuit water temperature and flow rate are within the EOS specification.
- 6
If power is still below specification after optics cleaning and cooling verification, contact EOS service for laser source evaluation.
Sources
EOS EOS M 290 / M 400 Metal Additive Manufacturing general technical documentation, EOS
EOS M 290 / M 400 operator and service documentation, laser power monitoring and optics maintenance (general)
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