Glossary · Setting

3D printing

Brim

A thin, flat edge that is printed around the print to help it stay on the plate better. It is peeled off afterwards.

Explained in more detail

Several lines in the first layer, usually 3 to 10 mm wide, directly adjoining the part. It enlarges the adhesion area and holds corners down, so it works well against warping and with small contact areas. Distinction: a skirt is an outline at a distance, only for priming the nozzle. A raft is a complete base under the part. Many slicers leave a tiny gap between brim and part so that it comes off cleanly.

Where does the term come from?

English "brim" means edge or rim, such as the brim of a hat. The brim lies flat around the bottom layer of the part in just this way.

In practice

• For PLA and PETG, a width of 3 to 5 mm is enough, and 5 to 10 mm is common for ABS, ASA, PA and PC.
• Set the gap to the part to 0 to 0.1 mm: a larger gap is easier to remove but holds less.
• Print the brim on the outside only; on inner contours such as holes it is hard to remove and adds little.
• Mouse ears, small round brim discs only at the corners, save material and keep straight edges clean.
• Peel off only after cooling and smooth any residue at the edge with a deburring tool.

Not to be confused

Not to be confused with the skirt, which runs around the part at a distance and does not help with adhesion, or the raft, a multi-layer platform under the part.

Frequently asked questions

How wide should a brim be?

3 to 5 mm for PLA and PETG, 5 to 10 mm for materials that shrink strongly such as ABS, ASA, PA and PC. Prusa recommends at least 3 mm, and the Bambu Lab default profiles use 5 mm.

Brim or raft, which is better?

Usually the brim: it needs little material and leaves the underside smooth. A raft is only worthwhile with a very small or irregular contact surface.