What Causes Stringing
Stringing happens when the nozzle moves between two separate parts of the print — a travel move — and molten filament oozes out of the tip during that move. When the ooze is thin and spans a gap, it solidifies into a string. When it's heavier, it becomes a blob or a hair clump.
Three things control how much oozing happens:
- Temperature — hotter filament is more liquid and flows more freely. The hotter your nozzle, the more it oozes.
- Retraction — your slicer can pull the filament back into the nozzle before a travel move, creating negative pressure that reduces oozing. If retraction is too small, oozing happens. If it's too large, you get jams and underextrusion.
- Travel speed and distance — a fast nozzle spends less time in the air and has less time to ooze. Long travel moves across large gaps give more time for oozing.
That's the complete list. Stringing is always one of these three things — or wet filament making all three worse. Everything in this guide traces back to those root causes.
Run a retraction test tower before changing anything else. Print one, identify the best layer, and you'll know whether retraction is the problem. It takes 20 minutes and removes most of the guesswork. Search "retraction test" on Printables and use the first result.
Fix Order — Fastest First
Most stringing guides tell you to change everything at once. That's how you end up with settings you don't understand and a printer you can't diagnose. Instead, fix one thing at a time in this order — you'll usually solve it before reaching step 4.
- Lower print temperature by 5–10°C
- Tune retraction distance and speed
- Increase travel speed
- Enable combing in your slicer
- Dry your filament (if all else fails)
Fix 1: Lower Your Print Temperature
This is the most impactful single change you can make and the one most people skip. Lower temperature makes the filament less fluid, so there's less to ooze during travel.
Drop your nozzle temperature by 5°C. Reprint your test piece. Repeat until stringing stops or print quality degrades. Most materials have 10–15°C of useful range below their starting point.
The risk of going too cool is weaker layer adhesion and potential under-extrusion. Signs you've gone too far: layers that peel apart under stress, rough surface texture, or the extruder clicking (skipping). If you hit any of those, go back up 5°C.
For PLA, a starting temperature of 215°C is often higher than necessary — try 205°C. For PETG, 245°C is a common default; 235°C often prints better with less stringing. For ABS and ASA, temperature has less room to move without causing layer delamination — reduce by only 5°C at a time.
Fix 2: Tune Retraction Distance and Speed
Retraction is the setting most people think of first for stringing — and it's effective, but it needs to be tuned correctly. Too little retraction and the nozzle oozes. Too much and you get grinding, jams, and underextrusion after retraction.
Retraction distance
The correct retraction distance depends entirely on your extruder type:
Don't go above 2mm on direct drive or 7mm on Bowden. Beyond these limits you risk pulling the filament into the cold zone, causing heat creep and clogs that are much harder to fix than stringing.
How to find your optimum retraction
A retraction distance test prints a tower with different retraction distances on each layer. Print one, look at where the strings disappear, note the layer height, and set that as your retraction distance. This is faster and more reliable than changing the setting blindly.
OrcaSlicer has a built-in retraction calibration under Calibration → Retraction Test. In Cura, download the Calibration Shapes plugin. Both generate a retraction tower configured for your specific printer.
Retraction speed matters too
Retraction speed controls how fast the filament is pulled back. Too slow and the retraction doesn't happen fast enough to prevent oozing. Too fast and the extruder motor skips or grinds. For most printers, 25–45mm/s (direct drive) or 40–60mm/s (Bowden) works well. If you're getting clicking sounds during retraction, slow down by 5mm/s.
Fix 3: Increase Travel Speed
Travel speed is how fast the printhead moves during non-printing moves. A faster printhead spends less time in the air between features, giving molten filament less time to ooze.
On older Cartesian printers (Ender 3, CR-10), 150mm/s is common and 200–250mm/s is a safe increase. Don't go much higher without checking whether your printer can handle the acceleration — fast travel moves on a printer with loose belts cause ringing artifacts.
On CoreXY printers (Bambu, Voron, Prusa Core One), travel speed is rarely the issue because they already travel fast. If you're on a Bambu and still getting stringing, focus on temperature and retraction instead.
Fix 4: Enable Combing
Combing routes travel moves through the interior of the model instead of over open air. If the nozzle oozes during travel, that ooze lands inside the print where it's invisible — instead of spanning a gap and becoming a visible string.
In OrcaSlicer, this setting is called Avoid crossing perimeters under Print Settings → Travel. In Cura it's called Combing Mode. Set it to All or Within infill.
Combing works best on models with many separate tall features — miniatures, text, lattice structures, anything where the nozzle frequently travels across open space. It's less useful on solid objects where there isn't much interior space to route through.
The tradeoff is slightly longer print times, since the path through the interior is longer than a straight-line travel. For most prints the difference is under 5%. For complex miniatures it can add 15–20%.
Set Minimum travel distance for retraction (or Retraction Minimum Travel) to 0.5–1mm. This triggers retraction even on very short travel moves where it might otherwise be skipped, reducing the small strings that appear between closely-spaced features.
Fix 5: Dry Your Filament
If you've applied all the above fixes and still have stringing, wet filament is likely the culprit. Filament absorbs moisture from the air. Wet filament has lower viscosity at print temperature and produces steam bubbles that make the melt far more prone to oozing and stringing.
Signs of wet filament beyond stringing: popping or crackling sounds during printing, rough or bubbly surface texture, inconsistent extrusion, and steam visible near the nozzle.
Drying times and temperatures vary by material:
| Material | Temperature | Time | Signs of moisture |
|---|---|---|---|
| PLA | 45–55°C | 4–6 hours | Slight crackling, minor stringing increase |
| PETG | 60–65°C | 4–6 hours | Significant stringing, bubbles, rough surface |
| ASA / ABS | 65–70°C | 4–6 hours | Poor layer adhesion, warping, stringing |
| TPU | 45–55°C | 4–6 hours | Excessive stringing, poor flexibility |
| Nylon | 70–80°C | 8–12 hours | Severe warping, foam-like texture |
A food dehydrator set to the correct temperature works well. A dedicated filament dryer like the Sunlu S2 or Creality Filament Dryer handles most materials. An oven works but requires careful temperature calibration — most oven thermostats are inaccurate enough to melt PLA at the "50°C" setting.
Stringing Settings by Material
PLA
PLA is the easiest to fix. Start at 205°C and lower by 5°C if stringing persists. Retraction at 0.8mm (direct) or 5mm (Bowden). Travel speed at 200mm/s or higher. Enable combing. PLA stringing that survives all these adjustments is usually caused by a partial clog partially blocking flow, creating back-pressure that forces oozing.
PETG
PETG is the hardest common material to get string-free. It's stickier and more viscous than PLA — that's what makes it strong, but it also makes it cling. Start at 235°C (down from the typical 245°C default). Increase retraction to 1–1.5mm (direct) or 5–7mm (Bowden). Enable combing, set minimum retraction travel to 0.5mm. The number-one PETG stringing mistake is printing it too hot — most profiles ship with unnecessarily high temperatures.
TPU / flexible filaments
TPU behaves differently from rigid filaments. Because it's elastic, high retraction tends to grind rather than retract cleanly — the filament compresses instead of pulling back. Use minimal retraction (0.5–1mm direct drive, avoid Bowden for TPU entirely if possible), lower temperature to the minimum that extrudes cleanly, and increase travel speed. Combing is very effective for TPU because it avoids the retraction problem by routing travel through the model interior.
Stringing is fixable in the large majority of cases by lowering print temperature and tuning retraction. The order matters — temperature is faster to test and usually more effective, so check it first. Retraction is more nuanced and requires a test tower to tune correctly.
Most stringing that survives temperature and retraction adjustment comes down to wet filament or a partial clog. If you've dropped temperature, tuned retraction, increased travel speed, and enabled combing — and still have stringing — dry your spool and do a cold pull to clear any partial blockage before changing anything else.
Resist the urge to change five settings simultaneously. One change, one test print, note the result. You'll solve it faster and understand your printer better for it.