PETG First Layer Not Sticking? Start Here.

PETG usually has strong bed adhesion, so a first layer that will not stick is a useful clue. The most common causes are a dirty plate, incorrect Z offset, first-layer speed that is too high, temperature mismatch, poor extrusion, or a build surface that needs a different preparation method.

1. Clean the build plate correctly

Finger oils can ruin otherwise good PETG adhesion. Use the cleaning method recommended for your specific build surface and avoid touching the print area afterward. A plate can look clean and still be contaminated enough to cause inconsistent first-layer grip.

2. Check Z offset and first-layer height

PETG needs solid contact with the surface, but forcing the nozzle too close can create ridges, nozzle buildup, or poor flow. Compare the line shape rather than blindly moving Z in large steps.

• Round line with visible gaps: nozzle likely too high.
• Overly flattened, rough, translucent, or nozzle scraping: likely too low.
• Even connected lines with a smooth top: close to the target.

3. Slow the first layer down

A slower first layer gives the filament more time to bond before the nozzle changes direction. If corners peel loose during fast travel or small features will not anchor, reduce first-layer speed before changing many other variables.

4. Verify nozzle and bed temperatures

Start with the filament and build-plate manufacturer's recommended ranges. If extrusion looks weak or stringy at the first layer, the nozzle may be too cool. If the part releases immediately from a cool bed, a modest bed-temperature increase may help. Make small changes and compare.

5. Make sure extrusion is consistent

Partial clogs, wet filament, a slipping extruder, or an incorrect flow setup can create thin first-layer lines that never develop enough contact area. If extrusion looks inconsistent in free air, solve that before tuning adhesion.

6. Watch for drafts and rapid cooling

A strong fan, HVAC vent, or cold room can cool the first few layers unevenly. Keep first-layer cooling modest unless your printer or filament profile specifically requires more.

7. Confirm your plate preparation is PETG-safe

PETG can bond extremely strongly to some smooth surfaces. On certain plates, a release layer or manufacturer-recommended adhesive is used not just to improve sticking but to prevent damage when removing the print. Follow the plate maker's guidance.

If the first layer sticks but corners lift later

That is a different problem. If the print starts flat and warps later, move away from first-layer tuning and look at part cooling, drafts, bed temperature, brim use, and geometry.