Skip to content

First Layer Guide

Diagnose a problem

First Layer Not Sticking: A Safe Diagnostic Sequence

Separate a dirty surface, an incorrect nozzle gap and unsuitable starting temperatures without random tuning.

,
15–30 minLint-free towel, dish soap if approved, first-layer test
FDM printer laying plastic filament onto the build plate

Quick diagnosis

If the extruded line stays round, follows the nozzle or separates into loose strands, the nozzle is usually too far from the surface, the surface is contaminated, or the first-layer conditions are unsuitable.

Most likely causes

  1. Surface contamination. Finger oils can prevent adhesion even when the plate looks clean.
  2. Nozzle gap too large. The line should be gently flattened with neighboring lines touching.
  3. Old mesh or unstable plate. Contact changes across the bed.
  4. Temperature or speed outside the useful range. Marginal lines are pulled free.

1. Clean the cool build surface

Follow the plate manufacturer’s method. For many smooth PEI plates, warm water and a small amount of unscented dish soap remove oil effectively. Dry with a clean lint-free towel and avoid touching the print area. Some coatings require different products, so do not assume alcohol or solvents are universally safe. If you are deciding between build surfaces rather than just cleaning the one you have, see PEI vs glass build plate.

2. Print a single-layer patch

Use a square that reaches the problem area. If the lines remain separate, reduce the Z offset in small increments supported by the printer, such as 0.02 mm. If the surface becomes rough, translucent or the nozzle drags, increase the gap.

3. Confirm stable temperatures

Let the bed reach its target before movement starts. For PLA with a 0.4 mm nozzle, many profiles begin near 205–215 °C at the nozzle and 50–60 °C at the bed, but the filament and plate documentation define the safe range.

4. Slow only the first layer

A starting speed around 15–25 mm/s can make a marginal contact easier to observe. If slowing is the only thing keeping a visibly round line attached, fix the gap or surface rather than treating speed as the root cause.

Safety: Keep fingers and cleaning cloths away from a hot nozzle and moving bed. Pause the printer before any physical check.

Before the next print

  • Plate is cool, clean and dry.
  • Nozzle tip is free of old filament.
  • Current mesh is loaded.
  • First lines are continuous and gently flattened.
  • Only one adjustment changed during the test.

If a small or oddly shaped base keeps lifting despite a clean, level, correctly gapped first layer, a brim can add real holding force that these checks alone will not. See the skirt vs brim guide to decide whether one is worth adding before reprinting.

Your next print can be better

Describe the symptom. Start with the most likely fix.

The troubleshooting hub narrows the library by print stage, material and the action you are comfortable taking.

Diagnose my print