HOW TO FIX 3D PRINT STRINGING

Stringing (also called oozing or hairy prints) happens when small strings of filament are left behind as the nozzle moves between separate parts of a print. It looks like thin cobwebs or hairs stretching across gaps. While it doesn't usually affect structural integrity, it ruins surface quality and requires tedious post-processing.

Stringing is caused by molten filament leaking from the nozzle during travel moves — when the print head moves without extruding. The main culprits are: • Retraction disabled or too low — The filament isn't pulled back far enough to relieve pressure in the nozzle. • Temperature too high — Higher temperatures make filament more runny and prone to leaking. • Travel speed too slow — Slower travel gives filament more time to ooze. • Wet filament — Moisture in the filament creates steam and causes irregular extrusion. • Bowden tube gap — A gap between the PTFE tube and nozzle can trap filament.

Start with retraction — this is the single biggest factor. Enable retraction and increase the distance to 4–6 mm for Bowden setups or 1–2 mm for direct drive. Set retraction speed to 40–50 mm/s. Next, lower your nozzle temperature by 5°C increments until stringing stops. For PLA, try 195–200°C instead of 210°C. Increase your travel speed to 150–200 mm/s. The faster the nozzle crosses gaps, the less time filament has to ooze. Enable "Combing" in Cura or "Avoid crossing perimeters" in PrusaSlicer — this keeps the nozzle over already-printed areas during travel. If nothing works, your filament may be wet. Dry it at 45°C for 4–6 hours (PLA) or 65°C for 4–6 hours (PETG).

Store filament in sealed bags with desiccant. Run a retraction test (like a stringing tower) whenever you switch filament brands. Keep your PTFE tube properly seated in the hotend. Calibrate your e-steps occasionally to ensure accurate extrusion.