In the world of 3D printing,a thin horizontal layer called a raft is often laid down first to level the build plate, reduce warping and increase contact area. A skirt is a thin line of plastic extruded around the perimeter before the main model, priming the nozzle and ensuring consistent flow.. A brim, meanwhile,consists of multiple lines printed directly around the model’s edge,offering strong adhesion with less material waste than a raft.

RAFTS : The Heavy‑Hitters of Bed Adhesion

According to the source, rafts create a level foundation and help prevent prints from detaching, especially with warping‑prone ABS. They also give fragile bottom features extra support, but they consume more material and can leave a rough underside on the final print. Removing a thick raft can be difficult, and there is no universal setting—experimentation with gap size, raft thickness and outward extension is required.

SKIRTS: Nozzle Priming Without Attachment

The article explains that skirts are simply a thin line of plastic extruded around the perimeter of the print before the model starts. Their main job is to prime the nozzle , ensuring a smooth and consistent flow of material at the right temperature—much like preheating an oven. Skirts do not attach to the model and are easily removed, but they do add material waste.

BRIMS: The Best of Both Worlds

Brims combine the benefits of a raft and a skirt. They are printed directly around the edge of the model, directly connected to it, and help hold the print down firmly while combating warping. Brims use far less material than a raft and leave a cleaner bottom surface, though they may require a sharp tool to cut away. The source notes that brims are typically simpler to take off than rafts.

WHEN TO CHOOSE EACH METHOD

Choosing between a raft, skirt or brim depends on the material and geometry of the print. ABS, which is stronger but more warping‑prone, is highly recommended to be printed with a raft. PLA, less prone to warping,may still benefit from a raft depending on design geometry and support needs. Brims are often the best choice when you want strong adhesion without the material waste of a raft.

Trade‑Offs and Unknowns

While the source outlines the general benefits and drawbacks of each technique, it leaves unanswered questions about optimal settings for different printers and filaments. For instance, what specific gap sizes or raft layer thicknesses yield the best adhesion for a given printer model? How does the choice of brim width affect the ease of removal across different filaments? These variables remain open for experimentation.