Bed leveling: the first layer has to sit right everywhere
Bed leveling is measuring or adjusting the distance between the nozzle and the build plate across the whole surface. It means the first layer has the same height everywhere and the part sticks.
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Contents
Why levelness matters
The first layer is only about 0.2 mm high. If the bed is tilted by a few tenths of a millimetre relative to the nozzle, then on one side the nozzle squashes the plastic into the plate and on the other it leaves it lying loose. On one side the part holds badly, and on the other the underside is squashed flat (first layer, adhesion).
That is why the distances are checked before printing to make sure they are equal. You will find more on the principle under FDM printing.
Manual and automatic
The manual way is to level the bed with four screws in the corners and a sheet of paper that should still slide between the nozzle and the bed with slight resistance. It is tedious and goes out of adjustment after the printer is moved.
Modern printers have a sensor that measures the surface of the bed on a grid of points, and the result is factored into the movement. The printer thus compensates for even a slightly warped bed. The exact height of the nozzle above the bed is fine-tuned with the Z-offset.
How it affects your order
- You do not have to do anything. Leveling is the printer's business, not the customer's.
- What you see of it. Good leveling gives an even underside on the part. Poor leveling shows as ripples, holes in the first layer or corners lifting (warping).
- Large parts. The bigger the area, the more levelness matters. A large flat part is more sensitive to it, and we photograph every batch before dispatch.
What to do if the underside is rough
If you do not like the underside after delivery, look for two signs. Regular ripples or stripes point to an uneven bed, while a glossy, wavy edge points to too much nozzle pressure. Both are machine settings, not a fault in your model.
The underside is also the hardest face to get right, so rotate the model so that the most important face points up. You will find more on that in the entry on model orientation. If a part does not fit, write to jakub.novak@boostello.com and send a photo.
Common questions
Does the bed have to be leveled before every print?
On printers with a sensor the measurement is done automatically before printing. With manual leveling, occasionally is enough, when something goes out of adjustment.
What is the difference between bed leveling and Z-offset?
Bed leveling finds out how flat the surface is. Z-offset is the fine adjustment of the nozzle height above it.
Why did my part come loose?
It can be poor leveling, a dirty plate or shrinkage of the material. When you order from us, you do not have to worry about it.
Related terms
Z-offset
Z-offset is a setting that moves the print nozzle higher or lower above the build plate by fractions of a millimetre. It decides how firmly the first layer is pressed onto the plate.
Build plate
The build plate is the flat surface of a 3D printer onto which the first layer is printed and from which the finished part is removed once it has cooled. Its surface affects adhesion and the look of the part's underside.
First layer
The first layer is the first layer of plastic that the nozzle lays on the build plate. If it does not stick, the whole print fails.
Poor first-layer adhesion
Poor first-layer adhesion is when the first layer of plastic does not stick well enough to the build plate, so the part comes loose or shifts during printing, or only a clump of plastic forms.
Heated bed
A heated bed is a build plate with built-in heating that keeps the bottom layers of a part warm. The plastic sticks better and cools more slowly, so the part warps less.
PEI build plate
A PEI build plate is a flexible steel sheet with a polyetherimide surface that filament sticks to well when warm, and the part releases once it has cooled. It is the most common build surface today.
SourcesSources checked 1 November 2026, 2
- Fused filament fabrication, Wikipedia, checked 2026-11-01
- RepRap, Wikipedia, checked 2026-11-01
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No model? No problem, pick a ready one
These sites have thousands of free models. Download an STL or 3MF and upload it here. If you sell it or use it for business, check the model licence. How to pick a model and licence