Fine threads of plastic left between printed features when the nozzle travels over open air without retracting filament.
Stringing results from molten filament oozing out of the nozzle during non-print travel moves. At elevated temperatures melt viscosity drops, increasing ooze. Retraction pulls filament back to create negative pressure in the nozzle, but if retraction distance or speed is insufficient, ooze continues. PETG and flexible filaments are especially prone due to high melt elasticity.
Tune retraction distance (2-7 mm Bowden, 0.5-2 mm direct drive) and speed (40-60 mm/s). Lower print temperature in 5 C increments while monitoring layer adhesion. Enable combing to keep travel moves inside the part. Use Z-hop sparingly.
Excessive retraction on direct-drive grinds filament and causes under-extrusion. Too-low temperature fixes stringing but causes delamination. Wet filament dramatically worsens stringing: dry at 65 C for 4-6 hours before diagnosing.
Related terms: Retraction, Filament Drying, Print Speed
| Field | 3D printing |
|---|---|
| Also called | oozing, cobwebbing |
| Source | EDi Brain: tech/fdm |
Engineer, author of The Big Book of 3D Printing and additive manufacturing expert