First layer not sticking: causes and checks

How to recognise the problem

According to Bambu Lab's guide, first-layer problems fall into two families. Nozzle too high: the lines stay separate with gaps between them, and the part comes off easily or the lines split when you remove it; during the print this can lead to warping, shifting or 'spaghetti'. Nozzle too low: the layer is heavily squished, sometimes transparent or ridged, the part is hard to remove and extrusion may block because the plastic has no room to come out; the nozzle may also scrape the plate.

An uneven first layer (good in some areas, too high or too low in others) points instead to a plate that is dirty in specific spots, a failed leveling or a mechanical issue. Bambu Lab notes that small imperfections on a minor part of the layer do not compromise the print as long as overall adhesion is good.

Checks in order, easiest first

Change one thing at a time and verify with a thin test print (a single layer) covering the affected area. Clean with the printer off and the plate cold: Anycubic says to unplug the power and wait for the bed to drop below 40 °C before touching it.

1. Clean the plate following the manufacturer. Bambu Lab (textured PEI): warm water, dish soap with no oils or moisturisers, a sponge or plastic brush, rinse and dry; alcohol on a textured surface may only spread the grease.
2. Prusa: ~90% isopropyl alcohol or denatured alcohol on a cold sheet for routine cleaning, warm water and a few drops of dish soap when alcohol is not enough. Elegoo and Anycubic: water, alcohol or neutral detergent, then dry thoroughly.
3. Handle the plate by its edges only. Bambu Lab suggests a simple test: after washing, water should form an even film; if it beads into droplets, the plate is still greasy.
4. In the slicer, check the plate type and the filament profile. For third-party filaments Creality recommends a generic profile for the same material.
5. Run the full calibration or automatic leveling before printing, especially after moving the printer, a long idle period or removing the bed. Before that, check that the nozzle is clean and properly secured and that the nozzle wiper or brush is intact.
6. Adjust the Z offset in small steps and reprint the test: separate lines → bring the nozzle closer; transparent layer, ridges or no extrusion → move it away. On printers leveled with paper (Elegoo), the sheet should slide with slight resistance without being scratched.
7. Only after the steps above, change slicer settings: a slightly higher bed temperature, a slower and wider first layer, no part cooling on the first layers, a brim for parts with a small footprint.

Brand notes from official documentation

Bambu Lab: the P2S first-layer guide recommends always starting from calibration (automatic leveling and, where available, high-temperature leveling) and then adjusting the Z offset from the first-layer calibration menu: layer too high → decrease the offset, too low → increase it, in small steps (the guide’s example is 0.01 mm), printing a test after each change. Areas that are always high in the same spots usually indicate dirt on the plate. Acetone is forbidden on the textured plate; coating wear where the nozzle wipes before printing is normal, while wear inside the print area justifies using the other side or a new plate.

Prusa: the first layer is tuned with Live Adjust Z and, on machines that offer it, with the first layer calibration from the menu. Prusa warns not to compensate for poor adhesion by lowering the nozzle too much, as it can damage the sheet. Never use acetone on the textured sheet; on the smooth sheet acetone is allowed only occasionally when alcohol is not enough. When changing sheet type, on printers whose sensor requires it, the height must be recalibrated.

Creality: on the K1C the smooth plate (A) must be cleaned before each print with water or alcohol, or treated with the supplied glue stick, which is required for ABS; the textured plate (B) needs a bed about 10 °C hotter than the profile. For the Ender-3 V3 series Creality recommends enabling calibration before every print and softening residue by heating the bed before removing it: careful, the surface is hot.

Elegoo (Neptune 4): reset the Z offset and re-level, clean the PEI with alcohol or water and dry it, slow the first layer and, if needed, raise the bed 5–10 °C above the filament's recommended value. Anycubic (Kobra S1 Max): check extrusion first, then cleaning, preheating the bed for 5–10 minutes, automatic leveling and a brim for parts with a small footprint.

When replacing the plate makes sense

A new plate does not fix a wrong Z offset, a wrong slicer profile or a greasy surface: even a new plate loses grip once touched with fingers. Replacement is justified when, after washing, calibration and the correct profile, worn, scratched or lifted areas remain inside the print zone and the test print always fails in the same spots. Try the other side first if the plate is double-sided: Bambu Lab lists exactly this step, and contacting support if the plate is under warranty.

If the nozzle has scraped the plate, re-run leveling before printing again so the damage does not get worse.

How to verify the result

Record the model and variant, material, slicer profile and change made. Repeat the same test and compare the result with a photo taken before the adjustment. Keep the change only if it improves the defect without introducing others. Use your model’s instructions for temperatures, calibration and disassembly; this guide is not based on our own hands-on tests.