3D Printing Brims, Skirts, and Rafts: How to Use Them?

3D printing warping is a common problem in 3D printing. In order to effectively prevent warping at the bottom of the part and increase the adhesion of the build plate, 3D printing brims, skirts, and rafts are usually designed based on the printed object. So what are they and how to choose? This article will help you solve this problem.

Source: https://3dprintmentor.com/3d-printing-raft-vs-brim-vs-skirt/

What are brims, skirts, and rafts in 3D printing

3D printing brim is a series of lines printed around the bottom of the model, forming a large ring, similar to a brim. These lines increase the surface area of ​​the first layer and help to firmly fix the model to the build plate. Its purpose is to improve adhesion and minimize warping, and it is used for models with small bases or sharp corners that are prone to warping. The brim and the bottom of the model are parallel and can be easily removed after printing.

3D printing skirt is a contour printed around the model, but does not touch the model, so it has no effect on structural support. The purpose of the skirt is to test the nozzle, adjust the filament flow rate, and verify that the print bed is level to prevent warping problems.

3D printing raft is a flat, grid-like structure that is printed underneath a model. It provides a solid foundation, especially for models with uneven or small bases. The purpose of a raft is to provide a stable platform and enhance adhesion, making it best suited for large prints, materials that are prone to warping, or uneven build surfaces. Rafts are printed directly underneath a model, but are more difficult to remove than brims and skirts.

How to choose

Use a 3D printing brim when printing with materials like ABS or PETG that are prone to warping, or when your model has a small contact area with the build plate. Brims provide additional adhesion without complicating post-processing. For models that already have excellent adhesion, testing filament flow and consistency before starting a print, ensuring proper bed leveling, and 3D printing skirts are recommended for troubleshooting. Use a 3D printing raft when printing with materials like nylon or flexible filament TPU that require additional stability, or when working on build plates that have bonding issues or printing models with uneven or small bases.

Optimize settings

Brims

Brims can be understood as a special type of skirt in slicing software (set the distance of the skirt to 0 from the edge of the part). In most slicer settings, the default width of the brim is about 8 mm. Generally speaking, the wider the brim, the better the first layer adhesion, but it also consumes more material. After printing, the brim can usually be peeled off manually to minimize surface marks. If the edge removal leaves marks on the printed part, sanding can help smooth the edge.

Source: https://facfox.com/docs/kb/guide-and-slicer-setting-for-raft-brim-and-skirt

Skirts

Slicing programs provide a variety of skirt settings, including line count, distance, and number of layers. Increasing the number of lines helps to confirm the initial settings of the print, the skirt distance controls its separation from the part, and the number of layers is usually one layer, but multi-layer skirts are easier to remove. When printing, the skirt is used to pre-condition the nozzle and is easily removed after completion without being attached to the printed object. If removal is difficult, increase the number of skirt layers or use a scraper to assist.

Rafts

Most slicing software comes with a raft design function, and users do not need to create it manually. The key parameters of the raft include layer thickness, air gap, extra margin, and print speed. The bottom layer is the thickest to enhance adhesion, and the top layer thickness matches the printed layer. The extra margin increases the raft area, thereby improving stability, and reducing the print speed helps improve the adhesion of the raft. The air gap is critical for removing the raft. It is the air between the top layer of the raft and the bottom layer of the print, which weakens the adhesion between the two. If the raft is found to have fused to the print, it may be because the printing temperature is too high.

Source: https://www.flashforge.com.hk/blog/what-is-raft-in-the-3d-slicing-software

By properly selecting and optimizing the 3D printing brim, skirt and raft, the problem of printing warping can be reduced and the printing success rate can be significantly improved. If you need to print a complex model using a material that is prone to warping, JLC3DP's high-quality 3D printing service can help you solve possible problems in post-processing and provide full support for your creativity!