Layer Separation / Delamination
Layers don't bond to each other — the part splits along layer lines under stress or even spontaneously during printing.
High severity
Surface
What It Is
Layers don’t bond to each other — the part splits along layer lines under stress or even spontaneously during printing.
How It Forms
For two layers to bond, the new layer must partially re-melt the top of the previous layer. This creates a weld at the interface. If the previous layer has cooled too much, or the new material isn’t hot enough, the weld is weak or absent.
The bond strength depends on:
- Temperature of the new material — must be hot enough to melt into the layer below
- Temperature of the previous layer — must still be warm enough to accept bonding
- Contact pressure — the nozzle presses the new layer into the old one
- Time — the polymer chains need time to intermingle across the interface
If any of these are insufficient, the interface is weak. The part appears solid but fractures easily along layer lines.
Visual Signature
- Cracks visible along layer lines
- Parts split when flexed or stressed
- Layers peel apart like pages of a book
- Visible gaps between layers in cross-section
- Part fails at much lower force than expected
Root Causes
| Cause | Calibration Variable | Direction |
|---|---|---|
| Temperature too low | Extrusion Temp | ↓ |
| Cooling too aggressive | Cooling / Fan Speed | ↑ |
| Layer height too large | — (slicer) | — |
| Under-extrusion | E-Steps, Flow Rate | ↓ |
| Ambient drafts | — (environment) | — |
| Print speed too fast (layer cooling) | Speed Profile | ↑ |
How the Auto-Tuner Detects It
- Camera: Visible gaps between layers on test print cross-section
- Destructive test (manual): Break test print and examine fracture surface
How the Auto-Tuner Fixes It
- Calibration: Temperature optimization — find minimum temp for strong bonds. Fan speed calibration per material.