Introduction
A perfect print starts with a perfect first layer. When that first layer fails to grip the build plate, everything above it is doomed: corners lift, parts warp, and the nozzle drags spaghetti across the bed. The good news is that first-layer adhesion problems are almost always fixable with a handful of simple adjustments.
Why the First Layer Peels
First-layer adhesion is a battle between two forces: the bond between your plastic and the build surface, and the thermal stress that tries to curl the part away as it cools. When the bond is weaker than the stress, the print peels. The usual culprits are a poorly levelled bed, a nozzle that is too far from the surface, a dirty build plate, or a bed temperature that is too low.
Level the Bed, Then Level It Again
An uneven bed is the number one cause of adhesion failure. If one corner sits lower than the rest, the filament laid there never gets squashed into the surface. Use the paper method or a feeler gauge at all four corners and the centre, then repeat the process after preheating the bed to printing temperature, because heat changes the geometry of the plate.
Nail the Nozzle Offset
The first layer should be slightly squashed, not dropped from a height. If the nozzle is too far away, the filament rounds and only lightly touches the plate. If it is too close, the filament is scraped thin or the nozzle clogs. Aim for a first-layer height of roughly 60–75% of your normal layer height and watch the bead as it lays down: it should look flat and slightly wider than the nozzle opening.
Keep the Build Surface Clean
Fingerprints, dust, and leftover plastic residue all act as a release agent. Wipe the plate with isopropyl alcohol before every print. For stubborn surfaces, a light wash with warm water and dish soap removes oils that alcohol can miss. On glass or PEI, allow the plate to dry fully before heating.
Use the Right Adhesion Aids
Sometimes the surface itself needs help. Common aids include a thin layer of glue stick, a fine mist of hairspray, or dedicated adhesion sprays. A brim adds a ring of sacrificial material around your part to spread the load at the edges, while a raft lifts the print onto a fresh, even foundation. Use brims for sharp corners and large flat parts, and reserve rafts for tricky warping-prone materials.
Set the Bed Temperature Correctly
Bed temperature matters more than many makers realise. Too cold and the first layer sets before it bonds; too hot and the bottom stays soft and can warp. For PLA, a bed of 50–60°C is a reliable starting point. For PETG and ABS, follow the filament maker's recommendation and give the bed a few minutes to stabilise before starting.
Conclusion
Most adhesion failures are not mysterious, they are mechanical: a level bed, the right nozzle offset, a clean surface, and the correct bed temperature solve the vast majority of them. Fix the first layer, and the rest of the print takes care of itself.