Retraction Settings: Distance, Speed and How to Test
Contents
While the nozzle moves from one point to another through empty space, the melted plastic inside it keeps oozing. To prevent this, the printer pulls the filament back a few millimeters before each move. This retraction has two settings: distance and speed. The right values depend on your extruder type and the filament you use.
What does retraction do?
There is always melted plastic under pressure inside the nozzle. When the nozzle travels through empty space, that plastic leaks out and stringing appears. Retraction reduces the pressure by pulling the filament back a few millimeters. When the nozzle reaches the new point, the filament is pushed forward by the same distance and printing continues.
Identify your extruder type
Retraction values depend largely on the extruder type:
- Direct drive: The extruder motor sits on the toolhead, so the filament travels only a very short path between the motor and nozzle. A small retraction is enough.
- Bowden: The extruder motor stays on the printer's frame, and the filament goes to the nozzle through a long tube. Because of the gap inside the tube and the filament's flexibility, a larger retraction is needed.
Starting values
| Setting | Direct drive | Bowden |
|---|---|---|
| Retraction distance | 0.5–2 mm | 4–6 mm |
| Retraction speed | 25–45 mm/s | 35–50 mm/s |
| Deretraction speed | Same as retraction speed or slightly lower | Same as retraction speed or slightly lower |
These ranges are starting points. The exact value is found with a test print.
Test print
For a retraction test use a model made of two thin pillars 5–10 cm apart. The nozzle travels back and forth between the two pillars on every layer, and if there is oozing, strings form between them.
Test the distance
- Keep the temperature constant. It helps to have found the right temperature first with a temperature tower.
- Leave the retraction speed at its starting value.
- Print the model, changing the distance in steps of 0.5 mm for direct drive and 1 mm for Bowden. In OrcaSlicer and Bambu Studio, the "Calibration > Retraction test" menu tries different distances automatically on a single tower.
- Choose the lowest distance at which the strings disappear.
Test the speed
- Keep the distance you found constant.
- Print the model again, changing the speed in steps of 5 mm/s.
- Choose the value at which stringing is lowest and the extruder does not grind the filament.
The harm of too much retraction
Raising retraction more than needed creates new problems:
- Clogs and heat creep: When the filament is retracted too far, softened plastic is carried into the cold zone of the hotend and hardens there. See Clogged nozzle.
- Filament wear: When the extruder gear pulls the filament back and forth over the same spot many times, a groove forms in the filament and the gear slips.
- Under-extrusion: After each move a few millimeters of plastic is missing at the start of the new move, leaving gaps at the start of walls.
- Print time: On parts with many small moves, retraction lengthens the total time.
Other retraction-related settings
- Minimum travel: No retraction is done on short moves below this distance. Keeping it around 1–2 mm reduces unnecessary retractions.
- Maximum retraction count: In Cura, the "Maximum Retraction Count" setting limits how many times the same piece of filament can be retracted within a certain distance. It prevents filament wear.
- Combing / avoid crossing walls: Makes the nozzle travel through the inside of the part. Retraction may not be needed for moves made inside, and any oozing is not visible.
- Wipe: During retraction the nozzle moves a short distance along the wall to wipe its tip.
- Z hop: Lifts the nozzle slightly during travel. It prevents collisions but can increase stringing.
- Extra restart distance: A small amount added to the filament pushed back after retraction. If there is a gap at the start of a wall, try a small positive value, and if there is a blob, a small negative value.
- Pressure advance / linear advance: A feature in Klipper and Marlin that balances nozzle pressure during speed changes. When tuned correctly it gives clean results with less retraction.
Notes by material
- PLA: Standard values usually work well.
- PETG: It oozes by nature. Raising retraction a little helps, but the main difference comes from lowering the temperature and drying the filament.
- TPU: Flexible filament can jam during retraction. Reduce or turn off retraction and lower the speed. See the TPU printing guide.
- ABS/ASA: Values similar to PLA are mostly enough.
Frequently asked questions
When does it make sense to turn retraction off?
On single-piece models with continuous walls (for example vase mode), retraction is unnecessary. With very flexible filament such as TPU, turning it off can also reduce problems.
Is retraction set on the printer or in the slicer?
Usually in the slicer. Some firmware has a "firmware retraction" feature; in that case the setting is kept on the printer and the slicer only sends the command.