Filament issues like tangles and overlaps can disrupt a 3D print, but they’re often misunderstood. While they may look similar, they have different causes and solutions.
Tangles
A true tangle occurs when the filament loops under itself, creating a knot that prevents smooth unwinding.
Causes:
- The filament end is left loose and re spool incorrectly.
- Removing and rewinding the spool carelessly.
Effects:
- The extruder hits a hard stop due to the blockage.
- The filament physically cannot move without untangling.
Prevention:
- Always secure the filament end when handling spools
- Before printing, manually unwind a few rotations to check for loose loops from the factory if you believe they may been a tangle or watch initial couple metres.
- Be cautious when manually rewinding filament, especially in an AMS system.
Verdict: Most tangles mid way through a spool are due to user handling rather than manufacturing defects, as usually if tangle does occur it only occur at start of spool when factory work miss spool into holes.
Overlaps
An overlap happens when filament crosses over another layer without forming a true knot, causing resistance or snags. Two loops stacked or squashed on top of each other.
Causes:
- Neat and tight factory winding can sometimes cause this issue, especially if the spool has imperfections that lead to uneven spooling. Because the filament is wound tightly and runs parallel to the spool edges, tension can cause the winding to shift and overlap. This usually occurs at the start or end of the neat winding.
Effects:
- Increased tension but can often be pulled through with minimal effort.
- Rarely causes a complete stoppage unless severely tight.
Prevention:
-
Avoid actively drying materials while printing, as this can cause the spool to expand or deform. It's best to dry the filament before use and allow the spool to cool down inside the dryer (running on the lowest setting) or in a dry box.
This recommendation is based on our experience. We've seen no issues reported by users with PLA materials—which typically don't require drying. Most of these cases involved newer batches with neater winding, being actively dried.
- Newer printers or you can install additional add-ons which can monitor filament clog and tangle such as SFS which can detect. This should prevent printing air and allow operator to loosen spool to resume the print.