Layer adhesion is the bond between each horizontal slice of your print. When it's good, your parts are strong and consistent. When it's bad, layers split apart, parts snap along layer lines, and surfaces look rough and separated.
Here's why it happens and exactly how to fix it.
The most common cause. If your nozzle temperature is too low, the filament doesn't fully melt and bond to the previous layer.
Fix: Increase nozzle temperature in 5°C increments until adhesion improves.
Typical temperature ranges:
| Material | Min | Recommended | Max |
|---|---|---|---|
| PLA | 180°C | 200-215°C | 230°C |
| PETG | 220°C | 235-245°C | 260°C |
| ABS | 220°C | 235-250°C | 260°C |
| TPU | 210°C | 220-235°C | 250°C |
Different filament brands behave differently even within the same material type. A temperature tower test (printing at multiple temperatures in one go) finds your specific filament's sweet spot quickly. Download a free temperature tower from Printables.
Printing too fast doesn't give each layer enough time to bond to the previous one. The molten filament needs a moment to fuse - too fast and it just sits on top without properly bonding.
Fix: Reduce print speed by 20-30% and test. For critical structural parts, slower is always better.
Try:
Part cooling is a double-edged sword. Good cooling improves surface finish and detail - but too much cooling chills the layer before the next one bonds to it, especially with materials that need high temperatures to fuse properly.
Material-specific cooling settings:
| Material | Fan Speed |
|---|---|
| PLA | 50-100% (after first layers) |
| PETG | 20-40% maximum |
| ABS | 0-10% maximum |
| ASA | 0-10% maximum |
| Nylon | 0% (no cooling) |
If you're printing PETG or ABS with high cooling and getting delamination, reduce your fan speed first.
Each layer needs to be compressed into the previous one to bond properly. If your layer height is too large relative to your nozzle diameter, there isn't enough overlap for good adhesion.
Rule: Layer height should be no more than 75-80% of your nozzle diameter.
For a 0.4mm nozzle: maximum 0.3mm layer height. 0.2mm is the standard and gives excellent adhesion.
If you're using 0.3mm layers and getting adhesion issues, drop to 0.2mm.
Moisture in filament turns to steam during printing, creating micro-bubbles between layers that destroy adhesion. If your prints sound like popcorn or have a rough, bubbly texture, wet filament is likely the cause.
Fix: Dry your filament in a filament dryer or food dehydrator before printing.
Drying temperatures:
If your printer isn't pushing out enough filament, each layer is thinner than intended and doesn't bond properly to the layer below.
How to check: Print a single-wall cube (no infill, no top layers, 1 perimeter) and measure the wall with digital calipers. It should match your set line width (typically 0.4-0.45mm for a 0.4mm nozzle).
Fix: Increase flow rate / extrusion multiplier in your slicer by 2-5% increments until the wall matches target thickness.
Also check:
Z-hop lifts the nozzle between travel moves to avoid hitting the print. If set too high, it can cool the previous layer too much before the next is deposited.
Fix: Reduce or disable Z-hop if you're experiencing layer adhesion issues. Most prints don't need it.
ABS is especially prone to delamination - not just poor bonding, but layers physically splitting apart mid-print or after. This is almost always caused by:
Fix for ABS delamination: Enclosed printer, zero part cooling, bed at 105-110°C, and keep the enclosure sealed throughout the print.
The best test is a simple pull test:
Compare breaks across different temperature settings using the same model to find your optimal temperature quickly.
Work through this list in order - temperature and cooling fix the majority of layer adhesion problems.