¶ Replace nozzle, protective window, ceramic, and inspect CO₂ lenses
These factory clips are short, silent, and easy to copy badly. Power down, close the gas, and purge residual line pressure before any of them. Do not wipe a fiber connector with a shirt.
¶ Nozzle replacement
The 12-second official clip is only the mechanical swap. After a nozzle change:
- Fit a nozzle of the size the process row expects (single-layer for nitrogen/air rows; double-layer for the published oxygen carbon-steel rows).
- Check seating and that the opening is round.
- Recenter the nozzle to the beam if your build has a centering procedure, then recalibrate the floating head on clean supported metal.
- Blow-test gas. A cross-threaded nozzle leaks and drosses.
¶ Protective window / protective lens
The official clip shows removing the protective window from the fiber head. That window is a wear part. Haze, spatter, or a crack is a stop: it will dump heat into the head. Handle it by the edge, use the supplied lint-free method, and never run a coupon “to see if it burns off.” Recalibrate height after reassembly.
¶ Ceramic ring
The ceramic is part of the height-sensing path. A cracked, sooted, or loose ceramic is a common reason an FTC alarm appears after a crash. Replace it with the matching part, confirm the nozzle still centers, and do not bypass height control to keep cutting.
¶ CO₂ lens inspection
The official CO₂ lens clip is an inspection, not a field polish. Look for contamination, chips, and mounting tilt. A dirty CO₂ lens is not cleaned with the same wipe as a fiber window. If the inspection fails, stop CO₂ work and use the supplier/service path. Confirm the chiller is actually circulating through the tube before the next emission test.
Related: maintenance schedule, cut quality.