The first layer will not stick to the bed — 6 causes and how to fix them

Symptom: the first lines will not hold onto the plate. The material trails behind the nozzle like spaghetti, the skirt outline rolls up into a ball, and after a few minutes the whole print is being dragged around the bed by the head. Sometimes the layer sticks only in the middle while the corners lift straight away.

The first layer plays by different rules from the rest of the print. Every later layer bonds to plastic that is still warm and chemically similar. The first one has to grip a cold, smooth, foreign surface, and it holds on purely mechanically — the nozzle presses molten material into the micropores of the plate and leaves it there. If there is no pressure, if the plate is greasy or too cold, nothing will hold that layer down. That is why the fault almost always lies with first-layer geometry and the state of the surface, not with the filament.

The most common causes and their fixes

1. The nozzle is too far from the bed (Z-offset set wrong)

This is cause number one and accounts for most reports. If the gap between nozzle and plate is even 0.05 mm too large, the material is not pressed into the surface but simply laid loosely on top of it. A layer like that has a round cross-section, the lines do not touch each other, and you can see the plate between them.

How to check: look at the skirt from the side, at eye level. A correct first layer is slightly flattened, and neighbouring lines merge into one continuous sheet with no gaps. If the lines look like separate little sausages, the nozzle is too high.

What to do: correct the distance live, while the first layer is printing. In Marlin that is Tune → Babystep Z, in Klipper the Z-offset slider in the web interface, and on enclosed printers usually the Z-offset item in the current print menu. Lower it in steps of 0.025 mm and watch the line. Stop the moment the gaps disappear but before the line starts forming ruffles at its edges. Save the value permanently, otherwise it is lost on restart.

Note: overdoing it in the other direction gives you elephant's foot and splayed model bases.

2. The bed is not level or the plate is warped

You will recognise this because the problem affects only part of the surface: on the left the layer is perfect, on the right it will not stick. Even printers with automatic probing (BLTouch, inductive, strain gauges) only correct what they manage to measure — if the mechanical levelling screws are out by a millimetre, mesh compensation will not make that up.

How to check: print a first-layer test sheet that covers the whole bed. The spots where the material lifts will point you to the corner that needs adjusting.

What to do: level mechanically with the bed hot and the nozzle hot — aluminium and springs move with temperature, so levelling cold is useless. Only then run the automatic mesh probe. If the plate is permanently warped (typical with cheap 3 mm aluminium plates), turn on mesh compensation in the slicer or replace the plate with a thicker one.

3. The print surface is greasy or does not suit the material

Grease from your fingers is the most effective release agent there is. One grab of a PEI sheet with a bare hand is enough for the print to stop holding at that spot. The second version of this problem is a mismatched material-surface pairing: PETG melts into smooth PEI so strongly that removing it tears flakes out of the sheet, so many users start applying a release agent and then overshoot in the other direction.

What to do: wash the plate with warm water and washing-up liquid and dry it with a paper towel. Isopropanol removes fresh grease but smears an older layer of residue around, so treat it as a quick clean-up, not a deep clean. Textured (powder-coated) PEI works well for PLA and PETG; for ABS and ASA, glass with a thin layer of glue stick. With HT PETG the manufacturer explicitly recommends using glue — this material prints at temperatures where ordinary surfaces do not forgive mistakes.

4. The bed temperature does not match the material

A plate that is too cold will not hold material that shrinks as it cools. Too hot and yes, the material will stick, but the base of the model will spread and you will get elephant's foot, or a model you cannot get off at all. The differences between families of plastics are enormous here: PLA prints even on a cold bed, while HT PETG needs more than 100 °C.

What to do: set the temperature to the manufacturer's figures, and if you are in the lower half of the range and the layer still lifts, raise it by 5 °C at a time up to the top of the range. Do not go above it.

Porima material	Bed temperature	Enclosure	First-layer note
PLA	0–60 °C	open	Holds even on a cold plate
Tough PLA	0–60 °C	open	Same as PLA
Hyper PLA+	0–60 °C	open	Same as PLA
Silk PLA	0–60 °C	open	The glossy coating keys into the plate less well
PLA/CF	50–70 °C	open	Requires a hardened nozzle
PETG	60–80 °C	open	Sticks very hard, avoid bare PEI
PETG Transparent	60–80 °C	open	Same as PETG
HT PETG	100–120 °C	enclosed or open	The manufacturer recommends glue on the plate
ABS	80–110 °C	enclosed, 50 °C	Without an enclosure the corners will lift
ASA	90–120 °C	enclosed, 50 °C	Same as ABS
PA (nylon)	90–120 °C	enclosed, heated	Drying before printing is mandatory
TPU Flex 98A	40–60 °C	open	Print slowly, this material forgives little

Source: the official FDM technical data table from the manufacturer, Porima. The full set of 25 materials: print temperature table.

5. The first layer is running too fast

Freshly extruded plastic needs a few moments of contact with the plate to take up its temperature and flow into the micropores of the surface. At something like 60 mm/s the nozzle simply does not have time to press it down, and on top of that sharp accelerations tear away the line that has only just been laid.

What to do: set the first-layer speed to 20–25 mm/s, and go lower still for TPU. Check the first-layer accelerations too, because in many factory profiles they stay at the values used for the rest of the model, and it is those, not the speed, that tear the line on corners.

6. The first layer is too thin or too narrow

A thin layer has no way of filling in the unevenness of the plate. Even a well-levelled bed has local deviations, and a 0.12 mm layer has no spare material to even them out. You get the same effect from an under-set flow or an extrusion width smaller than the nozzle diameter.

What to do: for a 0.4 mm nozzle set the first-layer height to 0.2–0.3 mm and its width to 0.45–0.5 mm. This is the one place where slight over-extrusion helps rather than hurts. Remember that PLA Wood and PLA Star require a 0.6 mm nozzle — on a 0.4 mm nozzle the filler will block the flow on the very first outline.

Quick checklist

Wash the plate with water and washing-up liquid and do not touch it with your fingers.
Level the bed hot, then run the automatic mesh probe.
Set the Z-offset live, watching the skirt from the side.
Check the bed temperature in the table above and raise it by 5 °C if you are at the bottom of the range.
Slow the first layer to 20–25 mm/s and lower its accelerations.
Raise the first-layer height to 0.2–0.3 mm.
Add a brim if the model has a small contact area with the plate.

The overriding rule: change one parameter at a time. Three fixes made at once will not tell you which one worked.

When it is not the settings

If the same printer and the same profile worked yesterday and do not work today, stop changing the slicer. First check whether the plate has simply been touched by hand or sprayed with some cleaning product. The second typical cause is a change of conditions in the room — an open window above the printer can chill one corner of the bed enough that with ABS the first layer lifts in that one place. The third is a clogged nozzle: if the material comes out unevenly, no Z-offset will fix it, because the problem is the amount of plastic, not the distance. It is also worth remembering that wet filament foams in the nozzle and lays down a porous line of varying volume — with PETG, nylon and TPU that is a common scenario.

Last of all comes the material itself. Variation in diameter changes the volume of plastic delivered every second, and the first layer is the most sensitive thing to it. Porima filaments are produced to a ±0.03 mm tolerance, which keeps the flow steady from the first metre of the spool to the last.