First Layer Test

This is one of the simplest and yet most revealing tests for FDM 3D printing 👇

A model measuring 100 mm x 100 mm with only 0.2 mm in height (a single layer) can tell you a lot about the quality of your first layer — which is undoubtedly the most important of the entire print.

How does it work?

By printing just one layer spread across a large area of the print bed, you can clearly see how the filament is being deposited in different regions. This allows you to identify problems that often go unnoticed in common parts.
 

What can be analyzed with this test:
 

• Bed leveling
If some areas are more squished and others are looser, it's a sign that the bed is not uniform.
 

• Nozzle distance ( Z-offset )
Very flattened lines indicate the nozzle is too close.
Loose, rounded, or failed lines indicate the nozzle is too high.
 

• Bed adhesion
If the material doesn't adhere well in certain areas, it could be a problem with cleanliness, temperature, or even airflow.
 

• Flow uniformity ( flow/extrusion )
Gaps, holes, or excessive material show that the flow is not well calibrated.

• Line width consistency
Well-joined lines with a homogeneous appearance indicate healthy extrusion.

Why is this test so efficient?

Because it “isolates” the most critical variable of printing: the first layer. No walls, no height, no complexity — just the behavior of the material on the base.

If the first layer is perfect, you have already eliminated a large part of the possible printing problems.