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Machine Calibration

Extruder Rotation Distance Calibration​

rotation_distance refers to the distance the extruder shaft moves when the stepper motor rotates one full revolution. Accurate calibration of this value is crucial for ensuring precise extrusion.

Reference: Klipper Official Documentation - Rotation Distance

Estimating Initial Value​

Estimate the initial value based on the diameter of the extruder drive gear:

rotation_distance = drive 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 should only be the calculated value for the drive gear itself:

gear_ratio: 50:17   # BMG example (driver gear teeth:driven gear teeth)

Common gear ratios: BMG is 50:17

Measurement and Correction​

This is the most accurate method for extruder calibration, correcting the configuration value by measuring actual extrusion.

Preparation​

  • Filament is loaded into the extruder
  • Heat the hot end to the recommended temperature for the filament (PLA around 200°C)
  • Prepare a caliper or ruler (precision ≥ 0.1mm)

Procedure​

1. Mark the Filament

Make a mark on the filament about 70mm from the extruder entry point. Use a caliper to precisely measure this distance and record it as the initial mark distance.

2. Execute Extrusion Command

G91
G1 E50 F60
Note
  • It is recommended to use F60 (low speed); high speed may cause pressure deviations affecting accuracy
  • Wait for the extrusion to complete

3. Measure and Calculate

After extrusion, measure the distance from the mark to the extruder entry point again and record it as the final mark distance. Use the following formula to calculate the new value:

Actual Extrusion Length = Initial Mark Distance - Final Mark Distance
New Rotation Distance = Old Value × Actual Extrusion Length / 50

4. Update Configuration

printer.cfg
[extruder]
rotation_distance: 23.280  # Replace with the calculated new value
Recommendation
  • Recalibrate if the error exceeds 2mm
  • Repeat 2-3 times to ensure consistent results
  • The final error should be less than 1mm

Rotation Distance Calculator​

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Z Offset Calibration (Paper Method)​

The Z offset determines the initial distance between the nozzle and the build plate. Precise adjustment prevents poor first layer adhesion or nozzle scratching the build plate.

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

Required Tools​

  • One sheet of A4 paper

Calibration Steps​

1. Home and Move to Bed Center

G28
G90
G1 X[bed center X] Y[bed center Y] F3000

2. Move Z Axis Close to 0

G1 Z2 F300

3. Insert Paper and Fine-Tune Z Value

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

  • The paper is lightly pinched but can still be slowly pulled out
  • A slight resistance indicates the correct position
Judgment Criteria
SituationCauseAction
Paper cannot be pulledNozzle too lowIncrease Z offset (increase the value)
Paper moves with no resistanceNozzle too highDecrease Z offset (decrease the value)
Slight resistance, paper can be pulledPosition correctSave this value

4. Save Z Offset

Once the correct position is found, execute the corresponding command based on the 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, the first layer height can be fine-tuned via the web interface
  • After fine-tuning the first layer height, the configuration can be saved again
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