Confirm the problem

Is it really layer splitting?

Layer splitting looks similar to under-extrusion and warping but has a different root cause and different fixes.

Problem	Where it appears	What it looks like
Layer splitting	Middle or throughout print	Clean horizontal crack lines, layers pull apart with fingers
Under-extrusion	Everywhere	Gaps and holes in walls, porous/spongy material at break
Warping	Bottom layers only	Corners lifting off the build plate

If the break surface is clean and smooth (the layers formed correctly but didn't bond), you have layer splitting. If the break surface is porous or rough, it's under-extrusion. Go to the under-extrusion guide →

2

Most common fix

Raise the nozzle temperature

Low print temperature is the primary cause of layer splitting. The nozzle must be hot enough to re-melt the previous layer slightly when each new layer lands. Without this, layers bond by contact only and separate under any stress.

Raise in 5 °C increments, run a test print after each change.

Material	Start here if splitting	Maximum
PLA	215–225 °C	230 °C
PETG	240–255 °C	265 °C
ABS	255–265 °C	270 °C
ASA	260–270 °C	275 °C
PA / Nylon	255–270 °C	280 °C
PC	275–290 °C	300 °C

To change in Bambu Studio: click the filament box → Nozzle temperature. Create a custom profile so you don't lose the change.

3

Cooling

Reduce the cooling fan speed

Aggressive cooling locks each layer before the next one can bond to it. This is the second most common cause of layer splitting, especially with ABS, ASA, PETG, PA, and PC.

Material	Part Cooling Fan	Enclosure needed?
PLA	50–100% (reduce if splitting)	No (open for PLA)
PETG	30–50%	Optional
ABS / ASA	0–20%	Required
PA / Nylon	0–40%	Required
PC	Minimal	Required

⚠ A1 and A1 Mini users: The open-frame design makes ABS, ASA, PC and PA prone to layer splitting even with fan at 0%, because ambient air cools layers too fast. Bambu states: "significantly reduced interlayer strength due to excessive cooling" on these models. For large structural parts in these materials, a closed-frame printer (X1C, P1S) is required.

In Bambu Studio: Filament settings → Cooling tab → Part Cooling Fan Speed. Also reduce Auxiliary Cooling Fan to 0% for ABS/ASA/PA/PC.

4

Filament

Dry your filament

Moisture in filament creates steam bubbles during printing that interrupt the melt and break the bond between layers. PA (Nylon) and PC are extremely hygroscopic and must be dried before every use. Even a freshly opened sealed bag in a humid room will absorb moisture within hours.

Signs of wet filament: crackling/popping sounds during printing, steam or small bubbles at the nozzle tip, rough or bubbly surface texture, worse-than-expected stringing.

Material	Temp	Time
PLA	45–55 °C	6–8 h
PETG	60–65 °C	8 h
ABS / ASA	65–80 °C	6 h
TPU	50–60 °C	8 h
PA / Nylon	80 °C	12+ h
PC	80–90 °C	8 h

💡 The original AMS has no active heating, only a humidity sensor. The AMS 2 Pro has an active drying mode up to 65 °C, which works for PLA and PETG. For PA (needs 70–80 °C) and PC (needs 80–90 °C), use a dedicated filament dryer or oven regardless of which AMS you own.

5

Advanced

Less common causes

The nozzle must physically press into the previous layer for polymer chains to bond. If the layer height exceeds ~75–80% of the nozzle diameter, there isn't enough contact. Rule: max layer height = nozzle diameter × 0.75. For a 0.4 mm nozzle, that's 0.30 mm. Printing at 0.35 mm or higher with a 0.4 mm nozzle is a reliable path to delamination. Reduce layer height and test.

Higher speed means less time for heat transfer between layers. At very high speeds, even a correct temperature setting may not deliver enough thermal energy. Reduce print speed by 20–30% as a test. For non-Bambu filaments and difficult materials (PA, PC), use the "Silent" profile as a starting point (typically 50–60 mm/s outer wall). TPU must be printed slowly: max 20–30 mm/s.

The key hidden difference between Generic and Bambu filament profiles is Max Volumetric Speed (MVS): Bambu PLA is set to 21 mm³/s, Generic PLA to 12 mm³/s. If you use a high-speed print profile (Sport, Ludicrous) with a Generic filament that has a lower MVS, the slicer throttles speed correctly. But if MVS is set higher than your filament can handle, you get under-extrusion between layers that looks like delamination. For third-party filaments: start with a Generic profile and calibrate MVS by slowly increasing until extrusion becomes inconsistent.

Moisture absorption alone is usually reversible with drying. But long-term exposure causes hydrolysis, which permanently breaks polymer chains. Signs of irreversible degradation: the filament snaps with a brittle crack (no flex at all) when you try to bend it, the printed surface turns dusty or chalky, layer splitting persists after multiple full drying cycles. PLA older than 2 years stored without protection is often too degraded to print reliably. If drying 8+ hours at correct temperature doesn't help: discard the spool.

Click the filament box in the Prepare tab → a popup or sidebar opens showing the filament parameters. Change Nozzle Temperature directly. To save permanently: click the pencil/edit icon → modify the profile → save as a new custom preset (don't overwrite Bambu's official profiles). Fan speed is under the Cooling tab in the same settings panel.

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