First layer not sticking

The most common failure in FDM, and almost never the fault of the bed surface people usually blame. Work through these in order — the first two fix the large majority of cases.

Looks like: The print peels off the bed, or the first layer never bonds and turns into spaghetti.

Fixes, in the order worth trying

1 · Try this first

Wash the bed with soap and water

Fingerprints leave an invisible oil film that nothing sticks to. Isopropyl alcohol smears oil around rather than removing it — dish soap and warm water actually lifts it. This fixes more "my PEI sheet is dead" cases than any setting.

Take the sheet off, wash both sides with dish soap and warm water, rinse, dry with a clean paper towel, and handle it by the edges afterwards. On smooth PEI, an occasional light scuff with a green scouring pad restores tooth.

2 · Try this first

Set the Z-offset so the first layer is squished

A correct first layer is slightly squashed, not round. If you can see gaps between the first-layer lines, the nozzle is too high. Lower in 0.02–0.025 mm steps while printing and watch the lines merge.

Print a first-layer test patch and adjust live (on most printers: Tune → Z-offset, or the Live-Z / Baby-stepping menu). The lines should touch each other with no valleys, and the surface should look smooth rather than corduroy.

3 · Common cause

Raise the bed temperature

A cold bed will not let the plastic bond. It also matters that the bed reaches temperature before probing, since the sheet expands as it heats.

Build Plate Temperature: Cura → Material → PLA 55–65 °C · PETG 70–85 °C · ABS/ASA 95–110 °C
Bed temperature: OrcaSlicer → Filament → Filament → PLA 55–65 °C · PETG 70–85 °C · ABS/ASA 95–110 °C

4 · Common cause

Slow the first layer down

The first layer needs time to melt into the texture of the sheet. Anything above about 30 mm/s on the first layer is asking for trouble, no matter how fast the rest of the print runs.

Initial Layer Speed: Cura → Speed → 20–25 mm/s
First layer speed: OrcaSlicer → Process → Speed → 20–30 mm/s
First layer speed: PrusaSlicer → Print Settings → Speed → 20–25 mm/s

5 · Less common

Add a brim

A brim multiplies the contact area at the corners, which is where lifting starts. Costs a few grams and a knife-trim, and rescues tall or small-footprint parts that will never stick otherwise.

Build Plate Adhesion Type: Cura → Build Plate Adhesion → Brim, 5–8 mm width
Brim type / width: OrcaSlicer → Process → Support → Raft/Brim → Outer brim, 5 mm

6 · Less common

Turn the first-layer fan off

Cooling air on the first layer fights the bed heat and causes lifting, especially with PETG, ABS and ASA. Nearly every stock profile already disables it — if yours does not, that alone can be the whole problem.

Regular Fan Speed at Layer: Cura → Cooling → Start fan at layer 2–4, 0 % before that
Fan speed → first layer: OrcaSlicer → Filament → Cooling → 0 %

Change one thing at a time. If you adjust temperature, retraction and speed together and the problem goes away, you have learned nothing and you will be back here next month. Re-print the same test object after each single change.

Frequently asked questions

Should I use glue stick or hairspray?

Only as a release agent, not as glue. On smooth PEI, PETG and TPU bond so well they can tear chunks out of the sheet — a thin layer of glue stick there is protecting the plate, not improving adhesion. If PLA needs glue to stick, something else is wrong.

My bed is level but the first layer is still bad. Why?

Level and Z-offset are different things. Level means the four corners are the same height; Z-offset is how far the nozzle sits above that plane. A perfectly level bed with a Z-offset 0.1 mm too high will still fail everywhere, evenly.

Does auto bed leveling replace manual levelling?

No. Probes compensate for a warped or tilted surface, but the mesh is built relative to whatever Z-offset you set, and most probes cannot correct a bed that is badly out to begin with. Manually get the corners close, then let the probe handle what is left.