PLA first layer: bed, surface and adhesive

Quick answer

PLA sticks best to smooth or textured pei at a bed temperature of about 60 C. No adhesive is needed on a clean plate.

Bed temperatures and surface preparation are conventions drawn from manufacturer guidance. Your build plate maker knows your plate better than any general table.

PLA first layer reference
SettingValue
Bed temperature, first layer60 C
Bed temperature, later layers50 to 60 C
Nozzle temperature190 to 220 C
SurfaceSmooth or textured PEI
AdhesiveNone needed on clean PEI
EnclosureOptional
Warping tendencylow

What a correct first layer looks like

The lines should be slightly wider than they are on later layers and just touching each other, giving a continuous surface with no gaps and a faintly matte finish. Distinct round strands with gaps between them mean the nozzle is too high. A glossy surface with ridges pushed up between the lines means it is too low.

Slight squish. The first layer should look joined, not shiny and round.

PLA specifics

Stiff, easy, and the default for anything that will not live in a hot car.

PLA is forgiving enough that a first layer problem is usually genuinely the first layer: offset, plate cleanliness, or bed temperature. Clean the plate with isopropyl alcohol first, since finger oils are the single most common cause of a part that will not stick.

Build surfaces and adhesion

Common questions

What bed temperature for PLA?

About 60 C for the first layer, then 50 to 60 C for the rest of the print. Running the first layer slightly hotter helps it key into the plate, and dropping back afterwards reduces the chance of the lower part of a tall print softening and bulging, which is sometimes called elephant foot.

Do I need glue for PLA?

Not on a clean plate. PLA bonds well to PEI at temperature without help, and adding glue usually makes removal harder rather than adhesion better. Clean the plate with isopropyl alcohol when parts stop sticking, since skin oils are almost always the cause.

How do I set the Z offset?

Print a single layer patch, let it cool, peel it off and measure it with calipers. If you asked for 0.2 mm and measured 0.28 mm, lower the nozzle by 0.08 mm. Change the offset in small steps and confirm the direction on your machine first, because a few invert the sign and a large blind adjustment can gouge the plate.

Why did it stick last week and not now?

Plate contamination is the usual answer, and it builds up gradually so the failure seems sudden. Oils from handling parts transfer to the surface every time you touch it, and they repel plastic long before the plate looks dirty. Wash with warm water and dish soap, or wipe with isopropyl alcohol, and adhesion usually returns immediately.