First Layer Mastery

If a print is going to fail, it usually fails in the first layer. A good first layer is flat, evenly squished, and firmly stuck to the bed. A bad one curls, lifts, or doesn't stick — and everything built on top inherits the problem.

The goal is simple: every line of the first layer should be slightly squished into the bed so it bonds, with the lines just touching their neighbors to form a solid sheet — not round spaghetti sitting on the surface, and not a translucent smear.

First-layer quality is almost entirely about the gap between the nozzle and the bed. Too high and the lines stay round and barely stick; too low and the nozzle drags, starves the flow, and leaves a rough, see-through layer.

Dial it in with a Z-offset adjustment (live, while the first layer prints on many machines):

• Lines look round and separate → nozzle too high, lower the Z-offset
• Lines look transparent or ridged → nozzle too low, raise it
• Lines are flat-topped and fused with no gaps → perfect

Print a large single-layer test square and adjust until the whole square is one uniform sheet.

A perfect Z-offset only helps if the bed is actually flat relative to the nozzle. Manual-leveling printers need the four corners and center trammed so the gap is equal everywhere. Auto-leveling printers (CR-Touch, inductive probes, lidar) measure a mesh and compensate — but still need a correct Z-offset baseline.

If one corner is always loose and another always tight, that's a tramming problem, not a Z-offset one. Fix the mechanical level before chasing the offset.

Print the first layer slower than the rest (15–25 mm/s) to give each line time to bond, and use the correct bed temperature for your material (60°C for PLA, 70–80°C for PETG, 90–100°C for ABS/ASA).

A clean bed is just as important as the right numbers — fingerprints and dust are the most common cause of "it won't stick" when everything else looks right. Wipe the plate with isopropyl alcohol before a critical print.