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Machine Calibration

Extruder Rotation Distance Calibration​

rotation_distance is the distance the extruder axis moves per full rotation of the stepper motor. Precisely calibrating this value is crucial for ensuring accurate extrusion.

Reference: Klipper Official Documentation - Rotation Distance

Estimating Initial Value​

Estimate the initial value based on the extruder's hobbed gear diameter:

rotation_distance = hobbed gear diameter × π
Gear Ratio

If the extruder has a reduction gear (e.g., BMG, Orbiter, etc.), set gear_ratio separately in the configuration. rotation_distance only uses the calculated value of the drive gear itself:

gear_ratio: 50:17   # Example for BMG (drive gear teeth: driven gear teeth)

Common gear ratio: BMG is 50:17

Measuring and Correcting​

This is the most accurate method to calibrate the extruder, using the actual extrusion amount to correct the configuration value.

Preparation​

  • Filament is already loaded in the extruder
  • Heat the hotend to the filament's recommended temperature (PLA ~200°C)
  • Prepare calipers or a ruler (accuracy ≥ 0.1mm)

Procedure​

1. Make a mark on the filament

Make a mark approximately 70mm from the extruder's entry point. Use calipers to precisely measure this distance, record it as the Initial Mark Distance.

2. Execute an extrusion command

G91
G1 E50 F60
Note
  • It is recommended to use a slow speed F60; high speed can cause pressure deviations affecting accuracy.
  • Wait for the extrusion to complete.

3. Measure and calculate

After extrusion completes, re-measure the distance from the mark to the extruder's entry point. Record it as the Final Mark Distance. Use the calculator below to find the new value:

Actual Extruded Length = Initial Mark Distance - Final Mark Distance
New rotation_distance = Old value × Actual Extruded Length / 50

4. Update configuration

printer.cfg
[extruder]
rotation_distance: 23.280  # Replace with the calculated new value
Suggestion
  • If the error exceeds 2mm, it is recommended to re-calibrate.
  • Repeat the process 2 to 3 times to ensure stable results.
  • The final error should be less than 1mm.

Rotation Distance Calculator​

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Z Offset Calibration (Manual Paper Method)​

Z offset determines the initial distance between the nozzle and the heat bed. Correct adjustment prevents the first layer from not sticking or scratching the bed.

Explanation
  • For machines using mechanical endstops for homing (e.g., Voron), the Z offset is stored in the configuration's position_endstop.
  • For machines using probes (BLTouch / Tap / CR Touch, etc.), the Z offset is stored in z_offset.

Preparation​

  • One sheet of A4 printer paper

Calibration Steps​

1. Home and move to the center of the heat bed

G28
G90
G1 X[Heat Bed Center X] Y[Heat Bed Center Y] F3000

2. Move the Z axis near 0

G1 Z2 F300

3. Insert paper and fine-tune Z value

Place a sheet of A4 paper under the nozzle. Manually fine-tune the Z value via console or interface in steps of 0.025mm or 0.1mm until:

  • The paper can be gently pinched but still pulled out slowly
  • A slight resistance indicates the correct position
Judgment Criteria
ConditionCauseAction
Paper cannot be movedNozzle is too lowIncrease Z offset (increase value)
Paper slides completely freelyNozzle is too highDecrease Z offset (decrease value)
Slight resistance, can be pulled✅ Position is correctSave

4. Save Z offset

Once the correct position is found, execute the corresponding command based on your homing method:

# Mechanical endstop (e.g., Voron)
Z_OFFSET_APPLY_ENDSTOP

# Probe leveling (e.g., BLTouch / Tap)
Z_OFFSET_APPLY_PROBE

Then save the configuration:

SAVE_CONFIG
First Layer Fine-Tuning
  • During actual printing, you can fine-tune the first layer height via the web interface.
  • After fine-tuning the first layer height, you need to re-save the configuration.
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