Nozzle too high
Lines remain round, separate easily and leave gaps. Lower Z offset in very small steps after confirming the plate is clean.
FIRST LAYER DIAGNOSTIC
READ THE FIRST LAYER BEFORE CHANGING SETTINGS.
Use the visible shape of the line to separate nozzle height, surface contamination, temperature, flow and speed problems.
Z
OFFSET
OFFSET
Correct height
Adjacent lines touch with a smooth top and consistent width without a sharp ridge or transparent scraping.
Nozzle too low
Lines are overly transparent, ridged or scraped. Raise Z offset slightly and confirm flow is not excessive.
Fastest safe order
- Wash or clean the plate using the manufacturer-safe method.
- Confirm plate installation, mesh and mechanical stability.
- Adjust Z offset using a single-layer test.
- Only then change first-layer temperature or speed.
Common traps
- Using flow to hide a bad Z offset.
- Adding glue before cleaning contamination.
- Changing mesh, temperature and speed together.
- Ignoring a loose bed, nozzle or toolhead.
HOW TO READ THE RESULT
Line shape tells you which variable to test first.
Round lines or open gaps
Check nozzle height and mesh before increasing flow. A globally high nozzle and a local mesh error require different fixes.
Sharp ridges or scraping
Stop lowering the nozzle. A too-close first layer can look strongly attached while damaging surface quality and restricting extrusion.
Good line shape but weak adhesion
Move to surface cleanliness, plate/material compatibility, bed temperature and first-layer motion rather than forcing more squish.