Nozzle crashing into the bed
The nozzle digs into the bed at the start of a print, scrapes the surface, or the printer only manages a damaged first layer.
Also described as hotend crashing into bed, nozzle digging into bed, nozzle scraping bed, gouging the bed, nozzle hits the bed, only prints first layer
Try these in order
Most likely and quickest to check first. Change one thing at a time so you know what fixed it.
Z offset too low
- Raise the Z offset, then lower it in 0.02 mm steps while printing a first layer test.
- After changing the nozzle, always re-set the Z offset.
Bed probe not working
If the probe doesn't trigger, the printer keeps moving down.
- Check the probe triggers by hand and its cable isn't loose.
- Clean the probe tip, and on a magnetic sheet make sure the sheet is fitted (some probes need the steel).
Bed mesh not loaded or out of date
- Add the command that loads or runs the mesh to the start G-code (G29, or BED_MESH_PROFILE LOAD=default in Klipper).
- Redo the mesh after moving the printer or changing the sheet.
Wrong printer profile in the slicer
- Check the slicer's printer profile matches your printer, including its start G-code.