In this quick 3D printing guide, let's discuss the difference between skirt, raft, and brim. They are methods used for improving build bed adhesion, and each method has its time and place based on the design.
What is a skirt
The skirt is the outline of the first layer of the part, and its main purpose is to prime the extruder by unifying the flow of the filament from the nozzle and prevent any unwanted extrusion in order to improve the build plate adhesion.
The skirt method can also help detect if the bed isn't leveled.
What is a brim
The brim is a special type of skirt adhesion method.
Its main use is to draw the outline of the first layer to hold down the edges of the part to prevent warping.
Typically it's printed with an increased number of outlines to increase the surface area to the bottom of the part, in order to better build parts that start with many details. The skirt method only builds a couple of thin layers.
What is an raft
The raft is a much more popular option over the brim, and its main purpose is to build a uniform layer under the part instead of just outlines to significantly increase the bed adhesion. When using a raft, the printer builds the part on top of the raft instead of directly on the bed.
Major differences
| Bed Surface Build Area | Adhesion | Time | |
| Brim | Thicker around the part | Good | Long |
| Raft | Large | Very strong foundation | Medium |
| Skirt | Very small | For small part | Short |
Brim
Pros
- Prints faster
- Like the shirt method
- Use brim for parts that are generally look have small bed surface area
- Separate part from the main part easily
- Add brim to every print the designers think should have to ensure bed adhesion
- Use for narrow base
Cons
- Requires sanding after (Not too bad)
- Removing brim may break the main part attached
Raft
Pros
- Good for ABS material to prevent warping
- Stabilizes models with small prints before the upper layers
- Good for building parts with a large surface area
- Much higher chance of successful prints
Cons
- Uses more filament for the raft layer depend on the object size
- Takes more time
Skirt
Pros
- Primes the nozzle, basically warming up the print first before working on the main part
- Use this technique before committing a large amount of material for the rest of the part
- Detect uneven print bed
Cons
- Poor layer adhesion for serious projects
- Takes up space if printing multiple parts on the same printer, and the print bed is small.