Heat creep with PLA is what happens when heat travels too far up the hot end and softens the PLA before it reaches the melt zone. The softened PLA swells, grips the walls, and jams, so the print slowly loses flow and may stop. PLA is the filament most prone to this, because it softens at a low temperature, around 55 to 60 C. Bambu’s heat-creep guide is clear on the cause.
The jam builds over a long print, so the first layers look fine and the trouble starts partway up. Clear the jam, then cool the heat path so it does not return.
PLA softens far lower than PETG or ABS, so a weak hot-end fan or a long retraction hurts PLA first.
Causes, in order
| Likely cause | Fix | Severity |
|---|---|---|
| Hot-end fan weak or dead | Replace or fix the fan so it cools the heat break whenever the hot end is warm. | hi |
| Retraction too long | Cut retraction distance back so PLA does not sit up in the heat zone. | hi |
| Nozzle too hot | Lower the nozzle toward 200 C so less heat climbs the heat break. | md |
| PTFE gap or heat-break block | Reseat the PTFE tube flush and clean the heat break. | md |
| Hot enclosure on PLA | Open the enclosure or cool the chamber when you print PLA. | lo |
Quick fixes to try first
Clear the blockage first, then cool the heat path. Reprint after each step.
Check the hot-end fan
Make sure the fan on the heat break spins at full speed whenever the hot end is warm.
Cut retraction back
Reduce retraction distance so the PLA does not pull up into the heat zone.
Lower the nozzle temp
Drop the nozzle toward 200 C and reprint to see if the jam clears.
Open the enclosure
For PLA, open the doors or cool the chamber so heat does not pool around the hot end.
Deeper tuning to try next
When the fan and the temps look right, the heat break and the tube are next.
Clean the heat break
Let the hot end cool, take it apart, and clear any softened PLA from the heat break.
Reseat the PTFE tube
On a Bowden hot end, push the tube flush to the nozzle so there is no gap for PLA to swell into.
Add a silicone sock
A hot-end sock stabilizes the temperature and blocks radiant heat from rising into the heat break.
How PLA differs
PLA softens at a low temperature, around 55 to 60 C, the lowest of the common filaments, so it creeps the easiest when the heat path runs warm. PETG and ABS need higher nozzle heat and tolerate it better, but they still creep if the hot-end fan is weak. PLA also prints cool, around 200 C, so you rarely need to push the nozzle high, which helps keep the creep down.
Mistakes that bring the creep back
A few choices clear the jam but leave the cause in place.
Avoiddo not
- Only pushing fresh PLA through, without fixing the fan or the retraction.
- Setting retraction long to fight stringing, which feeds the creep.
- Running PLA in a hot, closed enclosure.
- Ignoring a fan that spins but runs slow or noisy.
Key takeaways
- PLA heat creep softens the filament too high in the hot end and jams it.
- PLA is the most prone because it softens low, around 55 to 60 C.
- Check the hot-end fan and cut retraction back first.
- Fix the heat path, not just the jam.
For the general version, the heat creep guide covers any material, and the PLA hub covers the material in depth.
Related guides
Related
More in this area
Cross-reference
Sources & methodology
2 citations · reviewed 2026-07-10- 01Bambu Lab Wiki: Heat creep (enclosure heat into the extruder)accessed 2026-07-09Tier 1
- 02All3DP: Heat creep causes and fixesaccessed 2026-07-09Tier 2