Calibrating Z-Offset with AutoZ (Calibrate_Z)

The video Never adjust your 3D Printer Z Offset again with Klipper and a plugin is a great resource for Z-offset calibration, but the macros for auto_z have changed since it was made. Therefore, these notes reflect the current process and configuration.

A good calibration model is essential for dialing in the Z-offset. I use the calibration model First Layer Test and slice it with my normal settings. This process may also be necessary when changing components that could affect the Z-offset, such as cooling ducts or other modifications. For example, after installing a new tri horn with a built-in Klicky probe, I had to perform this calibration.

Once that’s done, I proceed with the following steps:

1. Console Output After Running CALIBRATE_Z

These results are shown in the console output after the CALIBRATE_Z macro has run (usually as part of start_print):

• current z axis position_endstop=0.475 - new offset=0.736250
• bed_probe=6.944 - (switch=6.679 - nozzle=0.481 + switch_offset=0.010) --> new_offset=0.736250.
• Ignoring “POSSIBLE SUGGESTION” values for position_endstop.

2. Adjusting position_endstop

Adjusting the position_endstop, which is defined in the [stepper_z] section of the configuration:

• position_endstop: 0.475 (derived from CALIBRATE_Z).
• I get to this number by printing and manually adjusting the Z-offset. I start with +0.1 and gradually bring it down. I take note of the number and calculate the delta between the “new_offset” output and my manually adjusted value.
• If the calculated position_endstop is out of range, I update the autoz.cfg file, particularly the offset_margins parameter, to ensure proper calibration.

3. Fine-Tuning with switch_offset

Fine-tuning can be done with the switch_offset parameter in autoz.cfg. The lower the number, the higher the nozzle will be, and the higher the number, the closer the nozzle will be to the bed. A standard switch_offset is 0.5, and if it’s too far from this value, I change the position_endstop accordingly.

These steps ensure precise Z-axis positioning for consistent first-layer quality and overall print success.