Bridging issues occur when filament sags or droops while being extruded across an unsupported gap between two points. Poor bridging results in messy undersides, failed overhangs, and stringy or droopy spans.
Common Causes
- Insufficient cooling — Filament needs to solidify quickly to hold its shape mid-air
- Print speed too slow — Slow bridging allows gravity to pull filament down before it cools
- Temperature too high — Overly fluid filament sags more during unsupported spans
- Flow rate too high — Excess material is heavier and harder to bridge cleanly
- Bridge span too long — Very long distances are inherently difficult to bridge
Recommended Fixes
- Increase fan speed to 100% for bridging layers to maximize cooling
- Increase bridge print speed to 25-40 mm/s to stretch filament taut
- Lower nozzle temperature by 5-10°C for bridging sections
- Reduce bridge flow rate to 85-95% to minimize sagging weight
- Reorient the model to reduce bridge length where possible
- Add supports for spans longer than 50mm that cannot bridge cleanly
- Use a bridging test print to dial in optimal settings for your setup