PETG is widely praised for its strength, durability, and ease of printing compared to more finicky filaments. However, even experienced users know the pain of PETG stringing—those wispy, stubborn threads that cling to prints and ruin otherwise perfect surfaces. Preventing stringing in PETG isn’t just a matter of luck or expensive hardware; with expert slicer tweaks and an understanding of the filament’s unique behaviors, you can consistently achieve smooth, string-free prints.
Understanding PETG Stringing
Stringing refers to the thin, hair-like strands that sometimes appear between different parts of a 3D print, especially when the nozzle travels across open spaces. With PETG, stringing is particularly common due to its lower viscosity compared to PLA and ABS. PETG loves to ooze, and this tendency makes it critical to dial in the right slicer settings. If you notice spider-web-like strands between the structures of your print, or if removing your print from the bed feels like untangling a mess, stringing is the likely culprit.
Retraction Settings: Your First Line of Defense
Retraction is the process by which the printer pulls filament back into the nozzle before moving across open spaces. Proper retraction settings can make a world of difference in reducing PETG stringing.
Retraction Distance: For PETG, a starting point of 4-6 mm (on Bowden setups) or 2-4 mm (on Direct Drive) is recommended. Too little retraction won’t prevent oozing, while too much can cause jams.
Retraction Speed: PETG generally prefers slower retraction speeds than PLA—around 25-40 mm/s. If you retract too fast, you risk grinding or stripping the filament.
Begin with the manufacturer’s PETG profile if available, then run simple two-tower stringing tests to dial in the ideal retraction distance and speed for your specific setup. Adjust in small increments until you see a noticeable decrease in stringing.
Optimizing Printing Temperature
PETG prints at higher temperatures than PLA, usually between 230°C and 250°C. The catch: higher temperatures make PETG flow more easily, increasing the risk of stringing.
If you see excessive stringing, try lowering your nozzle temperature by 5–10°C at a time. Find the lowest temperature that still provides good layer adhesion and extrusion without causing under-extrusion. Some brands of PETG, such as Filalab’s premium PETG, may allow successful printing at the lower end of the temperature spectrum, which directly helps reduce stringing.
Tuning Travel Movements and Coasting
How your nozzle moves between print points also influences stringing. In your slicer, look for travel movement settings like “avoid crossing perimeters” or “optimized travel.” Increasing travel speed can help, as it gives the filament less time to ooze out.
Coasting is another valuable slicer feature. It works by stopping extrusion slightly before the end of a printing path, letting the last bit of filament fill the gap using existing pressure in the hotend. Start with a coasting value of 0.2–0.5 mm³ and adjust as needed. Just be careful: too much coasting can cause gaps or weak spots at the end of each path.
Wipe and Combing Settings
Most slicers offer a “wipe” setting, which tells the nozzle to move back slightly along the print path while retracting. This helps clean off the nozzle tip and further minimizes stringing.
“Combing” is another slicer option where the nozzle is instructed to travel only within the print’s already-printed areas whenever possible. This prevents the nozzle from dragging strings across open spaces.
For Filalab PETG, enable moderate wiping (2–4 mm) and set combing mode to “within infill” or “not in skin” for optimal results. Slicer recommendations may vary, so check your slicer’s documentation for the best defaults and adjust for your setup.
Advanced Slicer Features: Z-Hop and Minimum Travel Distance
Z-Hop raises the nozzle slightly while moving between print areas, which can prevent the nozzle from knocking over parts of your print or picking up stray strings. While not always essential for stringing, it can help in some situations.
Minimum travel distance is another slicer tweak worth exploring. By setting a minimum distance for retraction to activate, you avoid unnecessary retractions for short moves, reducing the wear on your filament and extruder.
Troubleshooting and Fine-Tuning
If you’ve tweaked all the above and still experience stringing, run controlled test prints. Change one variable at a time—like retraction distance, speed, or temperature—and record the results. Often, cleaning your nozzle or using freshly dried filament (PETG is hygroscopic) can solve lingering issues.
Don’t overlook the importance of filament quality. High-grade PETG, like the formulations available from Filalab, are engineered for consistency, which means fewer surprises and easier tuning.
Pro Tips from the Filalab Team
- Keep Your Filament Dry: Store PETG in a dry box or with desiccant packs.
- Clean Your Nozzle Regularly: Even small debris can increase stringing.
- Experiment with Slicer Profiles: Try the latest PETG profiles for Cura, PrusaSlicer, or your slicer of choice.
- Don’t Fear Tuning: Consistent, string-free prints are always possible with the right adjustments.
Conclusion
Preventing stringing in PETG comes down to understanding the filament and making expert-level slicer tweaks. Focus on dialing in retraction, printing temperature, travel, and advanced features. Take the time to experiment—string-free PETG prints are closer than you think. Ready to put your skills to the test? Explore Filalab’s range of PETG filaments and experience reliable, high-performance printing every time.