Quick starting values
A commonly used starting point for a direct drive extruder is a retraction distance of about 0.5 mm at a speed of about 35 mm/s, and many users try to stay under roughly 1 mm. If you see stringing, raise the distance in small steps rather than jumping to large values.
These are starting values, not guarantees. The best numbers depend on your hotend, extruder, filament, and temperature.
| Setting | Typical starting point (direct drive) |
|---|---|
| Retraction distance | about 0.5 mm, rarely above about 1 mm |
| Retraction speed | about 30 to 35 mm/s |
| Z-hop | none, or about 0.2 mm |
Why direct drive needs less retraction
On a direct drive printer, the extruder sits right above the hotend, so there is very little filament between the gears and the nozzle. When the motor reverses, the filament responds quickly. A Bowden setup has a long tube, which allows slack and compression, so it usually needs more retraction distance (often cited starting around 1 mm or more). That is why direct drive values are small, and why settings copied from a Bowden profile often retract too far.
Before tuning: fix other stringing causes
Retraction is often blamed when the real cause is elsewhere. Check these first:
- Wet filament. Moisture can cause stringing that retraction cannot fix. Even new, sealed spools can be damp, so drying is worth trying.
- Print temperature. Too hot makes the plastic runny. Try lowering it a little.
- Extruder backlash or a loose grub screw. Excess play means the filament does not move when the motor reverses.
- A loose or leaking nozzle or heat break. Nozzles are typically tightened when hot, following the manufacturer’s guidance.
- A dirty or worn nozzle.
- Too much z-hop. Large lift heights can add stringing.
- Overextrusion or incorrect flow.
- Pressure advance (linear advance). Some tuning guides recommend setting this first, because it can reduce the retraction needed.
Retraction speed (PLA and others)
There is no single correct speed. Many people start around 30 to 40 mm/s for PLA on direct drive. Too fast can cause grinding or a poorly controlled pull on the filament, while too slow can leave time for the nozzle to ooze. Some tuning guides report better results with slower speeds near 30 mm/s. If you change speed, change the retraction and unretraction speeds together, and keep distance constant while testing.
How to tune with a retraction tower
A retraction tower prints a column in which the retraction distance changes at set heights. You inspect where the stringing disappears.
- Clean the nozzle and make sure the filament is dry.
- Set part cooling fan high, since the tower is small. Higher fan speeds are commonly suggested.
- Set retraction and unretraction speed to around 30 mm/s.
- Generate a tower in your slicer or a calibration tool, starting at 0 mm and increasing by 0.1 mm per step for direct drive, up to around 1 mm.
- Optionally print the tower at a few temperatures, since temperature affects stringing.
- Print it and find the lowest height where stringing disappears.
- Convert height to distance: count rings from the bottom, subtract one (the first ring has no retraction), and multiply by the step.
- Choose a value one or two steps above that point to leave a little headroom.
Keep any z-hop you normally use enabled during the test, but keep it small.
Does too much retraction cause stringing?
It can. Retracting too far pulls molten plastic back up into the cooler part of the hotend, which can lead to under-extrusion after the travel move, blobs, or even clogs and filament grinding. Increasing retraction does not always reduce stringing past a certain point, so if stringing persists after a modest increase, look at temperature, moisture, and mechanical causes rather than increasing it further.
Should you disable retraction?
Generally no. Without retraction, most prints will ooze and string during travel moves. It can sometimes be reduced for specific cases, such as very short travel moves or models where travel stays inside the part, but turning it off completely tends to lower print quality. A more useful approach is to tune distance and speed, and use slicer options such as minimum travel distance.
Z-hop and travel settings
Z-hop lifts the nozzle during travel to avoid hitting the print. Small lifts around 0.2 mm are often enough, and much higher lifts may increase stringing. Reducing travel across open areas, for example with combing or a similar setting that keeps travel inside the infill, can also reduce visible strings. It may slightly increase slicing and print time.
PETG and other stringy materials
PETG is known for being harder to get free of strings than PLA (see PETG vs nylon for how it compares with other functional filaments). Some residual stringing may be unavoidable. Tuning temperature, cooling, and pressure advance can help, as can keeping travel moves inside the part. Flexible filaments usually need gentler retraction than rigid ones, and often much lower speeds, so start conservatively and follow the filament manufacturer’s recommendations.
Troubleshooting table
| Symptom | Possible cause | Things to try |
|---|---|---|
| Thin strings between parts | Retraction too low, temp too high, wet filament | Raise distance in 0.1 mm steps, lower temperature, dry filament |
| Gaps or under-extrusion after travel | Retraction too long or too fast | Reduce distance or speed |
| Blobs at travel starts | Retraction or unretract settings off, overextrusion | Lower speed, check flow |
| Clicking or grinding during retraction | Speed too high or partial clog | Lower speed, check nozzle |
| Strings that tuning does not fix | Wet filament, loose nozzle, extruder backlash | Dry filament, hot-tighten nozzle, inspect extruder |
FAQ
What are good retraction settings?
For direct drive, roughly 0.5 mm at 30 to 35 mm/s is a common starting point. Tune from there with a retraction tower.
What should my retraction speed be for PLA?
Around 30 to 40 mm/s is a typical starting range. Adjust based on test prints and watch for grinding or blobs.
Does too much retraction cause stringing?
It can contribute to problems, and past a point more retraction does not help. If strings remain after a small increase, check temperature, moisture and mechanical issues.
Should I disable retraction?
Usually not. Tune it instead.