TL;DR
Inert gas flow faults interrupt the build to protect part quality and prevent fire. Check the gas supply pressure, verify the flow sensor, and inspect the filter cartridge before resuming.
What you might see
- build pauses with an inert gas flow alarm
- oxygen level inside the chamber rising above the threshold
- gas flow sensor reading below minimum
- filter pressure drop alarm active
Likely causes
Inert gas supply bottle pressure low or bottle empty
Recirculation filter cartridge saturated with metal spatter reducing flow
Gas flow sensor contaminated or failed
Chamber leak allowing air infiltration and raising the oxygen level
Required tools
- Replacement recirculation filter cartridge (EOS-specified)
- Oxygen detector
- Inert gas supply (argon or nitrogen, machine-specified)
- LOTO kit
Safety first
- Metal powder in the chamber is combustible. Maintaining the inert atmosphere is a critical safety function. Do not bypass gas flow interlocks.
- Inert gas build-up in the machine room is an asphyxiation hazard. Ensure adequate room ventilation during gas supply maintenance.
- Wear a P100 respirator and nitrile gloves when accessing the filter compartment due to captured metal spatter.
Procedure
- 1
Check the inert gas supply pressure at the regulator. Replace the bottle or switch to the backup supply if pressure is below the EOS minimum.[1]
- 2
Lock out the EOS system power before accessing the filter compartment.
Warning: Never open the EOS build chamber or gas circuit with a live build in progress without following the EOS emergency stop and depressurization procedure. - 3
Inspect the recirculation filter cartridge. Replace the filter if the pressure drop indicator is in the red or if the filter has reached its service hour limit.[1]
- 4
After filter replacement, verify the oxygen reading inside the chamber drops below the threshold within the purge time specification during the pre-build purge cycle.
- 5
If the oxygen level does not drop, inspect the chamber seals and door gasket for leakage.
- 6
Verify the gas flow sensor function by comparing the flow sensor reading to a manual flow measurement at the process outlet if accessible.
Sources
EOS EOS M 290 / M 400 Metal Additive Manufacturing general technical documentation, EOS
EOS M 290 / M 400 operator manual, inert gas system maintenance and filter replacement procedures (general)
More guides for EOS EOS M 290 / M 400
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