Poor first-layer adhesion does not immediately justify changing Z offset. Describe the lines, how they join and the affected areas first, then check the surface, filament and profile. The cited Prusa i3 calibration provides visual reference points; it is not a procedure for every printer.
Start with an observation
Before another attempt, record the machine, nozzle, exact material, surface and profile. Note whether the issue starts with the first lines or after several passes, everywhere or in one area. Take an overview and a close-up if possible. This record avoids comparing prints made under several different conditions.
Do not reuse G-code of unknown origin or compatibility for a quick test. Slice your own small model using the correct machine profile and retain the same project for comparisons.
Read the first-layer clues
| Observation | Check to consider | What it does not prove |
|---|---|---|
| Separate, still rounded lines | Nozzle-to-bed distance may be too large | Offset is not necessarily the only cause |
| Ridges and heavily flattened lines | Distance may be too small | Stop before nozzle-to-bed contact; follow the printer manual |
| Joined lines with an even surface | Appearance sought in the Prusa example | Later layers are not thereby validated |
| Defect confined to one area | Compare the surface and the appropriate calibration procedure | Do not adjust the entire bed from one detail |
The first three clues come from the documented i3 calibration. The last row is an observation method, not remote hardware diagnosis. Stop if the nozzle scrapes or damage appears, and follow the machine manual.
Check the surface and material combination
Prusa’s first-layer documentation stresses cleanliness and preparation compatibility. Glue can act as a separation layer, not just an adhesion aid. PETG may adhere excessively to smooth PEI; do not automatically apply a PLA procedure.
- Identify the exact surface, not just its colour.
- Read its permitted cleaning procedure.
- Check whether this filament needs a separation agent.
- Find the calibration procedure for the machine and installed surface.
- Repeat a short test under the same conditions and compare.
Do not borrow a solvent recipe from another plate: smooth, textured and satin PEI have different instructions. See the PETG profile.
Make one check at a time
A tracking sheet can record the initial defect, check performed, precise change, observed result and decision to retain or undo it. No universal Z offset is suggested here. Automatic probing and manual calibration require different procedures.
When to broaden the investigation
If the first layer becomes even but gaps or strings remain later, consult the defect diagnosis guide. To distinguish layer height, extrusion and cooling, see FDM parameters. This guide organizes documented checks; it reports no physical tests by LayerBench3D.
Sources consulted
- First Layer Calibration (i3) — Prusa Research
Accessed - First layer issues — Prusa Research
Accessed