Retraction
Revision | Date | Description |
|---|---|---|
| 17.02.2025 | Init document |
Why Calibrate Retraction?
Retraction (filament retraction) prevents stringing and excessive filament oozing. When the printer moves the nozzle between print sections, the filament may stretch and leave thin strings. Proper retraction calibration reduces stringing while avoiding extruder clogs.
Too little retraction → strings appear between printed parts
Too much retraction → the filament may retract too far, causing nozzle clogs or inconsistent extrusion
How Does Retraction Work?
During nozzle movement, the extruder retracts the filament by a specified distance and speed to prevent oozing. Once it reaches the new position, the filament is pushed back.
Key retraction parameters:
Retraction Distance
Determines how many mm of filament are pulled back.
Typical values for Ender 3 V3 KE (direct drive): 0.8 - 1.2 mm
For Bowden setups: 4 - 6 mm (much higher values due to PTFE tube elasticity).
Too high a value may cause nozzle clogs!
Retraction Speed
Determines how fast the filament is retracted.
Too slow – the filament may stretch, failing to prevent stringing.
Too fast – the extruder may skip steps, and the filament may wear out.
Typical values for Ender 3 V3 KE: 25 - 40 mm/s.
Coasting
A slicer option that stops extrusion slightly before the end of a path to avoid blobs.
Values around 0.1 - 0.3 mm can help.
Combing Mode
"Within Infill" → avoids retraction where it is not visible (e.g., internal structures).
"Off" → forces retraction on every move (eliminates stringing but may increase print time).
How to Calibrate Retraction?
Download and Prepare a Test Model
Download a "Retraction Test" model from Printables.com or Thingiverse. These models usually consist of several pillars, requiring the nozzle to move between them without leaving strings.
Retraction Distance: 1 mm
Retraction Speed: 35 mm/s
Combing Mode: Within Infill
Coasting: Disabled (calibrate retraction first)
Save and print the test model.
Analyzing the Results
If you see stringing → Increase Retraction Distance by 0.2 mm and retest.
If you notice blobs at the end of paths → Try Coasting (0.1 - 0.3 mm).
If the print looks good, but the filament retracts too much and leaves gaps → Decrease Retraction Distance.
Final Value Adjustments
Typical values for Ender 3 V3 KE (direct drive):
✅ PLA → 1 mm / 35 mm/s
✅ PETG → 0.6 mm / 30 mm/s
✅ ABS → 1.2 mm / 35 mm/s