3D Print Stringing: Causes and Fixes
Stringing means the settings are off. Not slightly off — wrong in a specific, fixable way. Five adjustments cover 90% of stringing problems. Work through them in order and the threads disappear.
Why Your Print Strings (The Real Reasons)
When the nozzle moves between two printed areas without extruding, molten plastic can leak out and leave a thin thread. The technical term for that movement is a travel move. Stringing happens when plastic is still fluid enough to ooze during travel.
Some materials stay fluid longer at a given temperature than others. PETG and TPU are more prone to stringing than PLA — this is normal, not a sign something is broken. The fix is the same across materials: pull plastic back before travel (retraction), reduce temp to make it less fluid, and move fast so there's less time to ooze.
The Five-Step Fix That Stops 90% of Stringing
Check retraction distance
Retraction pulls plastic back into the nozzle before a travel move. Too little and plastic leaks. Too much and you risk grinding the filament or pulling molten plastic into the cold zone.
Bowden extruder
(Ender 3, CR-10 style)
4-7mm
Direct drive
(Bambu, Prusa MK4, Voron)
0.5-2mm
Start at the middle of the range. Adjust by 0.5mm increments and test.
Lower print temperature by 5°C
Hotter plastic is more fluid. More fluid means more ooze during travel. Drop temp by 5°C and test. Keep going in 5°C steps until stringing improves or print quality starts to suffer (under-extrusion, weak layer bonds).
PLA
Try 195°C
(from 210°C)
PETG
Try 235°C
(from 245°C)
ABS
Try 235°C
(from 245°C)
TPU
Try 225°C
(from 235°C)
Enable combing in your slicer
Combing tells the slicer to route travel moves over already-printed areas instead of open air. Even if some ooze happens, it lands on printed material — not empty space — so no thread forms. In Cura, go to "Travel" settings and set Combing Mode to "Not in Skin" or "All." In PrusaSlicer and Bambu Studio, it's called "Avoid crossing perimeters." This single setting often eliminates most stringing on complex prints without changing any physical parameters.
Increase travel speed
Faster travel means less time for plastic to ooze. This is separate from print speed. A target of 150-200 mm/s travel speed works well for most printers. Faster printers (Bambu, Voron) can go higher. Slower printers (stock Ender 3) should stay at the lower end to avoid frame vibration causing print artifacts.
Dry the filament
Wet filament strings dramatically worse than dry material. If you've tried the four steps above and still have heavy stringing, drying is probably the culprit — especially for PETG, TPU, and Nylon. See our complete filament drying guide for temps, times, and methods.
Why PETG Always Strings More Than PLA (And What to Do About It)
PLA
Minimal stringing with standard settings. If PLA is stringing badly, retraction is set wrong or you're printing too hot. PLA is the easiest material to dial in — stringing should be nearly zero with correct settings.
PETG
Strings more than PLA — this is normal. Some thin wisps are acceptable and easy to remove with a heat gun pass. If you have heavy cobwebbing, lower temp first (5°C), then check retraction. Enable combing. PETG stringing should never be as heavy as what you see from Nylon or wet filament.
TPU
Strings heavily due to high flexibility. Reduce retraction to near-zero (0-1mm on direct drive) and print slow (30-35 mm/s). Combing helps a lot. Accept some stringing — TPU is difficult to print completely clean and most stringing snaps off easily once the print is done.
Nylon
Strings badly when wet. Always dry Nylon before printing — 70-80°C for 12+ hours. After drying, tune retraction and use combing. Dry Nylon should string at roughly the same level as PETG.
Test Your Fix in 20 Minutes, Not Two Hours
Print a stringing torture test. The classic "spiked sphere" or Cthulhu model from Printables or Thingiverse works well. It has many tall spikes and open space between them — exactly the conditions that reveal stringing. One test print takes 15-25 minutes and tells you more than 30 minutes of guessing.
Critical rule: change one variable per test
Change ONE setting, print the test, evaluate. Never change two variables at once. If you change temp and retraction at the same time and stringing gets better, you won't know which fix worked — or which one to keep.
Log the Retraction Settings That Fixed It. Never Tune the Same Spool Twice.
You found the retraction distance that killed the stringing. Write it down somewhere you'll actually find it. Log retraction distance, print temp, and travel speed per spool in PrintLog3D. Next time you load that brand, you open the app and start from what worked. No torture test. No wasted filament. Just print.
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