In some rare situations the calibration routine may fail without any warning.
The calibration process should go down to probe the bed 3 or more times and take about 2 minutes before it is completed. (Click here to learn how to activate the Calibration routine)
Calibration Failure can produce these problems:
1. Uneven printing of first layer
2. Print is too close to the bed causing the extruder motor to make a ‘clicking sound’
3. Prints warp or lift up from the bed, since the nozzle is too far away
4. Hot end scrapes against the bed and no filament comes out.
There is no known fix for calibration failure, the only way is to fix this is to run the calibration routine until it works correctly. If you are having the problems above, then you should visually check the calibration routine. (NOTE: Go through the Troubleshoot Checklist as it may be more than one issue.)
Checking the Calibrate Routine visually for Failure
Below is a diagram of the calibration routine, the path it follows, and the points it touches the bed. This is useful for checking if the calibration is failing as it will fail while it is touching down (probing) the center point. It will then return to its home position. If this happens, re-run the ‘Calibrate Bed’ command until it successfully completes.
If it continues to fail, try deleting your 'config-override' file in the Altair-(Plug in the Altair via USB and delete it manually)
Then run the 'Calibrate Bed' again. This creates a new config-override file automatically with the correct calibration.