Layers separate when they never bonded: more heat, less cooling, dry filament.

Step 1 of 5

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 →

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 from your filament profile's value, run a test print after each change, and stay inside Bambu's nozzle range for the material.

Material	Bambu nozzle range
PLA	190–240 °C
PETG	240–270 °C
ABS	240–280 °C
ASA	240–280 °C
PA / Nylon	240–280 °C
PC	260–290 °C

Ranges: Bambu Lab filament material table, listed with a ±10 °C tolerance. Plain PA is not in that table; its range is from Bambu Studio's Generic PA profile.

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

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's filament guide assigns ABS, ASA, PC and PA to enclosed printers, and the A1 FAQ explains why: the open frame and lower chamber temperature make the A1 prone to reduced interlayer strength with high-temperature filaments, so Bambu does not recommend them for large parts that need high interlayer strength. For those parts use an enclosed printer (H2 series, X2D, P2S, X1 series or P1S).

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

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	50 °C	8 h
PETG	60–65 °C	8 h
ABS / ASA	75–85 °C	8 h
TPU	70 °C	8 h
PA / Nylon	75–85 °C	8–12 h
PC	75–85 °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 and PC use the AMS HT (Bambu: PC 80 °C for 8 h, PA and PA-CF 85 °C for 12 h), the heated bed of an enclosed Bambu printer, a filament dryer or an oven.

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 speed level (50 % of speed and acceleration) as a starting point. TPU must be printed slowly: Bambu Studio's Generic TPU profile caps flow at 3.2 mm³/s, roughly 35–40 mm/s at 0.2 mm layers with a 0.4 mm nozzle.

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. The slicer caps the sliced speeds at the filament's MVS, but the Sport and Ludicrous speed levels (124 % and 166 %) are applied on top at print time and can push past it, which Bambu names as a cause of under-extrusion. 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.

Nothing worked?

Ask in the official Bambu Lab forum or open a ticket via Bambu Lab support; photos help a lot. You can also contact us or post in our community forum. Or try the interactive troubleshooter.

Layers are bonding again!

Bookmark this page for next time.

Troubleshooting Warping & bed adhesion Our Picks

Tools that fix this

Restore consistent extrusion so layers bond instead of splitting.

SUNLU FilaDryer S2

Wet filament prints weak, brittle bonds between layers; drying it lets layers fuse properly and stop delaminating.

Amazon →

Capricorn PTFE Tube XS

Capricorn XS, 1.9 mm ID, for replacing a worn tube. Narrower than Bambu's stock tubes (2.0 mm inside the AMS and on the X1/P1, 2.5 mm on the A1, A1 mini, A2L, P2S, X2D, H2C, H2D and H2S); Bambu advises against a smaller ID because it adds friction. In our own printers it has still worked better than the stock tube, which is why we keep recommending it; if feeding gets worse, go back to the stock size.