The first layer won’t stick, prints unevenly, or the nozzle scrapes the bed. Everything that follows depends on this layer, and most print failures trace back to it.
Read the First Layer Like a Diagnostic
The first layer tells you exactly what’s wrong if you know what to look for:
Filament doesn’t stick, rolls off the nozzle: Z-offset too high. The nozzle is printing into air.
Extruder clicking, first layer is thin and translucent: Z-offset too low. The nozzle is pressing into the bed, creating back-pressure. Back off 0.05mm at a time.
First layer sticks to the nozzle and gets dragged around: Bed not hot enough, or bed surface contaminated. Clean with IPA first before adjusting temperature.
First layer sticks in some spots but not others: Bed is not level, or the surface has high/low spots. Run a mesh bed leveling routine if the printer supports it.
Lines are too wide and squeeze into each other: Over-squished. Raise Z-offset slightly. The correct first layer has lines that are wider than the nozzle diameter but not flattened into each other so tightly they merge.
Z-Offset: The Most Important Setting
The goal is “squish” — the first layer line should be compressed about 20–30% of its original diameter. A 0.4mm nozzle at 0.2mm first layer height should leave lines approximately 0.48–0.52mm wide. Too thin = over-squished. Round and barely touching the surface = under-squished.
Live-adjust Z-offset during the first layer while watching. Move in 0.02–0.05mm steps. Stop when the lines look flat on the bottom and rounded on the top, with each line just touching the adjacent one.
Bed Temperature by Material
PLA: 55–60°C on textured PEI, 60–65°C on smooth PEI or glass. PETG: 75–80°C. ABS: 100–110°C. Let the bed fully soak for 3–5 minutes after reaching temperature before starting the print — the sensor hits target temperature before the entire plate surface does.
Clean the Bed Before Every Print
IPA (90%+ concentration) removes skin oils and filament residue that cause adhesion failure. One fingerprint on PEI is enough to cause a print to lift. Make this part of your print start routine rather than something you do when adhesion fails.
First Layer Speed
20–25mm/s for the first layer. Faster than 30mm/s doesn’t give the filament time to wet the surface and bond. This is not about how long the first layer takes — it’s about contact time per millimeter.
When to Use a Brim
Any part with corners under 30mm, any part with a small footprint relative to its height, and any ABS or ASA print regardless of size. A 6–8mm brim takes seconds to trim off and prevents hours of failed print.