Elephant's foot in 3D printing: when the bottom layer bulges
are explained briefly when you hover over or tap them.
With elephant’s foot, the bottom layers of a print are wider than the rest. A small lip that sticks out forms at the base. For decorative items this hardly matters, but for parts that have to fit exactly it does: lids jam, parts cannot be pushed together, edges look untidy.
How do you recognise elephant’s foot?
- The bottom edge sticks out like a narrow bulge.
- A measured dimension is right at the top but a few tenths of a millimetre too large at the bottom.
- The lip is even all the way round. If it is only on one side, it is more likely a levelling problem.
Do not confuse it with warping: there the corners lift off the bed. With elephant’s foot everything is stuck down, just too wide. More about lifting is in Warping.
Why does it happen?
The first layer is deliberately pressed onto the bed a little so that it holds well. In the process it becomes wider than the layers above. Heat from below adds to this: the heated bed keeps the bottom layers soft for longer. The weight of the layers above then pushes them even further outwards.
A little elephant’s foot is therefore normal with almost every print. It becomes a problem when several causes come together.
The causes, sorted by frequency
1. Z offset too low
If the nozzle is too close to the bed in the first layer, the material is squashed flat and bulges out sideways. This is the most common cause.
Solution: raise the Z offset in small steps of about 0.02 mm. The first layer should look slightly flattened, and the lines should touch but not fuse into a shiny, bulging film. What a good first layer looks like is covered in First layer does not stick.
2. Bed too hot
A hot bed keeps the lower layers soft for a long time. With PLA, 55 to 60 °C is usually enough. If you use 70 °C or more with PLA, you will almost certainly get elephant’s foot. With PETG the problem also occurs if bed and nozzle run at the upper end of the manufacturer’s range.
Solution: lower the bed temperature in 5-degree steps as long as adhesion is still good. A nozzle temperature 5 to 10 °C lower in the first layer can also help. You will find guide values in the article on your material, for example PLA or PETG.
3. Too much material in the first layer
Some profiles print the first layer with increased flow or wider lines so that it adheres better. If this is too much, the material bulges out sideways. A flow value that is too high overall makes it worse.
Solution: check in the slicer whether a separate flow value is set for the first layer, and take it back to 100 %. If the flow is generally too high, a flow calibration helps, see Over-extrusion.
4. Little cooling in the first layers
Most profiles leave the part cooling fan off in the first layers so that adhesion is right. With PLA it can help to switch the fan on fully from layer 2 or 3 instead of later.
Slicer option: elephant’s foot compensation
Most slicers have a setting that deliberately shrinks the first layer inwards. The lines still bulge outwards, but end up at the target size.
| Slicer | Where to find it | Note |
|---|---|---|
| PrusaSlicer | Print Settings, Advanced, Elephant foot compensation | active by default in the Prusa profiles, guide value 0.2 mm with a 0.4 mm nozzle |
| Bambu Studio | Process, Quality, Elephant foot compensation | shrinks the first layer automatically |
| OrcaSlicer | Process, Quality, Precision | additionally adjustable over how many layers the compensation runs |
A starting value of 0.1 to 0.2 mm suits most prints with a 0.4 mm nozzle. Very fine structures in the first layer can disappear or adhere poorly because of too much compensation. Current versions of PrusaSlicer detect thin lines and shrink them less strongly.
Important: the compensation only masks the result. If the Z offset is clearly too low, fix that first.
Preventing it in the model itself
If you design the part yourself, there is a simple trick: give the bottom edge a small chamfer, for example 0.5 mm at 45 degrees. The squeezed-out layer then fills the chamfer instead of sticking out. For fits, you can also model the bottom 0.2 to 0.4 mm slightly smaller on purpose.
What has already been printed can be reworked with a deburring tool or a sharp knife. For visible parts, however, this is manual work that you would rather avoid.
Quick checklist
- Lip the same all the way round? Then it is elephant’s foot, not a levelling problem.
- First layer squashed too much? Raise the Z offset by 0.02 mm.
- Bed temperature at the lower end for the material?
- First layer without increased flow?
- Elephant’s foot compensation active in the slicer, starting value 0.1 to 0.2 mm?
- With your own models: plan a small chamfer on the bottom edge.
Continue with: Over-extrusion, if the walls above are also too thick.