Nothing is more annoying in 3D printing than coming back to a ten-hour print job and finding a twisted, messy failure. Usually, the problem is simple: the print lost its hold on the build plate during the first few layers. To fix this, slicing programs offer tools to help prints stick to the bed, like skirts, brims, and rafts. While each tool has its purpose, the brim is one of the best and most efficient options you can use. This guide focuses only on the brim, explaining what it is, why it works so well, and how to use it properly. By the end, you will know when to use a brim, how to set it up, and how to remove it for a clean, professional result.
What is a 3D Printing Brim?
A brim is a single layer of plastic printed on the build plate that extends outward from the bottom of your 3D model. It connects directly to the first layer of your print.
Think of a classic top hat. The wide, flat part that goes around the bottom is the brim. In 3D printing, it works the same way, creating a wider base for your object.
The main job of a brim is to make the first layer bigger. This larger contact area greatly improves how well the print sticks to the build plate, keeping the print firmly in place during the important first stages of printing. This simple addition often makes the difference between a successful print and a failed one.
Key Problems Solved
A brim is more than just extra plastic; it's a focused solution to some of the most common 3D printing problems. By understanding what problems it solves, you can use it more effectively.
Problem 1: Warping
Warping happens when plastic filament cools and shrinks unevenly. As the top layers of a print cool down, they shrink and pull on the layers below them. This cooling and shrinking creates strong forces that can lift the corners and edges of the model off the build plate. Materials like ABS, ASA, and PETG are especially likely to do this. A brim acts like a physical anchor. By making the first layer bigger and holding it down across a wider area, the brim fights against these lifting forces, keeping the bottom of your model flat and secure.
Problem 2: Poor Bed Adhesion
Some models are naturally hard to print because they have very little surface area touching the build plate. Think of a statue standing on its feet or a part with small support points. These "tippy" models have a weak grip and can easily be knocked loose by the nozzle moving around. A brim provides the extra surface area needed to create a strong, reliable bond with the build surface, making sure the print stays in place from start to finish.
Problem 3: Print Instability
For models that are tall and thin, staying stable is a major concern. As the print gets taller, any small wobble at the bottom gets much worse at the top. This can cause layers to shift or the print to fall over completely. A brim provides a much wider and more stable base, similar to how outriggers help stabilize a boat. This added stability keeps the model perfectly upright throughout the printing process, resulting in a cleaner, more accurate final part.
Choosing Your Adhesion Tool
Understanding the difference between the three main adhesion helpers—brim, skirt, and raft—is important for making the right choice for your print job. Each serves a different purpose.
The Skirt: Priming the Nozzle
A skirt is one or more outlines printed around the model but not connected to it. Its main job has nothing to do with adhesion. Instead, a skirt is used to get the extruder ready, making sure that the filament is flowing smoothly and consistently before the printer starts on the actual model. It's a pre-print check that helps prevent gaps or blobs on your model's first layer.
The Brim: The Adhesion Anchor
As we've discussed, a brim is attached directly to the model's bottom. Its only purpose is to improve adhesion and prevent warping. It is the best choice for parts with small bases, sharp corners that tend to lift, or when using materials that warp easily. It offers a big adhesion boost with minimal material use and relatively easy cleanup afterward.
The Raft: The Ultimate Foundation
A raft is a thick grid of filament that is printed on the build plate first. The entire model is then printed on top of this raft, not on the build plate itself. A raft is the most aggressive adhesion solution. It's used for materials that warp severely, for prints with extremely complex or tiny bottom surfaces, or when printing on a build plate that is uneven or damaged. While highly effective, rafts use a lot of filament and require more intensive cleanup, often leaving a rougher finish on the model's bottom surface.
Decision-Making Table
To make your choice easier, use this comparison table:
| Feature | Skirt | Brim | Raft |
|---|---|---|---|
| Purpose | Nozzle priming, flow check | Bed adhesion, warp prevention | Foundation for severe adhesion/warp issues |
| Attachment | Not attached to model | Attached to base of model | Model prints on top of raft |
| Filament Usage | Very Low | Low to Medium | High |
| Post-Processing | None | Easy to Medium removal | Difficult removal, affects bottom finish |
| Best For | Quick nozzle check before every print | Tall parts, warping materials (ABS, PETG), small contact points | Very uneven beds, extremely difficult materials, complex bases |
Mastering Slicer Settings
Turning on a brim is a simple process in all modern slicer software available in 2025. Whether you use popular slicers like Cura, PrusaSlicer, or others, you will find the bed adhesion settings typically located under the "Build Plate Adhesion" or a similarly named section. While enabling it is often a single click, understanding the key settings allows you to fine-tune how well it works.
Key Settings Explained
Brim Width / Brim Line Count
This setting controls how wide the brim is. It can be set either by a distance in millimeters (e.g., Brim Width) or by the number of rings around the model (e.g., Brim Line Count). A wider brim provides more surface area and greater holding power. A good starting point is a width of 4-8mm or a line count of 10-20 lines. For materials that warp easily like ABS, or for very tall and unstable models, you may need to increase this to 10-15mm or more.
Brim Separation Gap / Brim Distance
This is the most important setting for balancing strong adhesion with easy removal. This value sets the tiny horizontal gap between the brim and the first layer of the model itself. A smaller gap (e.g., 0.1mm) creates a stronger connection, offering maximum resistance to warping, but makes the brim harder to peel away cleanly. A larger gap (e.g., 0.2mm) makes removal much easier but provides slightly less holding force. We recommend starting with a small, conservative value like 0.1mm or 0.12mm and adjusting based on your results. A well-calibrated printer can often produce an easily removable brim even with a small gap.
Brim Only on Outside
This setting is useful for models that have internal holes or cutouts, like a washer or a hollow cylinder. When enabled, the slicer will only create a brim on the outermost edge of the model. When disabled, it will also create brims on the inside edges of any holes that touch the build plate. For most applications, keeping this enabled is preferred, as removing an internal brim can be difficult and is often unnecessary for adhesion.
Removing the Brim Flawlessly
A successful print doesn't end when the printer stops. Proper brim removal is the final step to achieving a clean, professional-looking model. The goal is to detach the brim without leaving a rough, ugly mark along the base of your part.
Technique 1: The Flex and Peel
The simplest method often works best, especially with a well-tuned Brim Separation Gap. Once the print has cooled, gently flex the brim upwards or downwards. This can often start a clean break right along the intended separation line. You can then carefully peel the entire brim away from the model in one or two pieces. This works best with flexible build plates and less brittle materials like PLA or PETG.
Technique 2: The Deburring Tool
For a faster, cleaner, and more consistent result, a deburring tool is an invaluable asset. This tool features a small, curved, swiveling blade designed to remove sharp edges from metal and plastic. Hold the tool at a shallow angle and run the blade along the bottom edge where the brim was attached. The swivel head follows the shape of your model, cleanly slicing off the thin remnant of the brim. This is the preferred method for achieving a smooth, chamfered edge with minimal effort.
Technique 3: The Hobby Knife
A sharp hobby knife or craft blade can also be used for precise trimming. However, this method requires extreme caution. Always place the model on a stable cutting mat and cut away from your body and hands. Use gentle, controlled slicing motions to shave off the brim's edge rather than trying to cut it off in one pass. This method offers high precision but carries the highest risk of injury if not performed carefully.
Final Touches: Sanding and Filing
For a perfect, showroom-quality finish, you may want to do some final touch-ups. A set of small needle files can remove any stubborn bits in tight corners. A light pass with fine-grit sandpaper (400 grit or higher) can smooth the bottom edge completely, erasing any trace that a brim was ever there.
Pro-Level Techniques
Once you've mastered the basics, you can start using brims in more advanced ways to solve complex printing challenges and improve your workflow.
Combining with Other Techniques
A brim is powerful, but for extremely challenging materials like ABS or Nylon, it may not be enough on its own. The best strategy for preventing warping in these cases is to combine a wide brim with a draft shield or a full printer enclosure. The brim anchors the part physically, while the enclosure maintains a stable, elevated ambient temperature, reducing the thermal stresses that cause warping in the first place.
Brims for Multi-Part Prints
When printing a batch of many small, individual parts on the build plate, each one is a potential point of failure. You can dramatically increase the reliability of the entire batch by using a single, unified brim that connects all the parts. This effectively turns the collection of small parts into one large, stable object for the crucial first layers, ensuring nothing gets knocked over or detached during printing. Most slicers have a setting to control the distance at which brims will merge.
The "Mouse Ear" Technique
Sometimes, a full brim is overkill. If you have a large, rectangular object that only tends to lift at the sharp corners, you can use a technique called "mouse ears." Instead of letting the slicer generate a brim, you manually add small, thin discs (like a mouse's ears) to your model in your CAD software at the exact corner locations. This targets the problem areas directly, providing the necessary hold-down force while saving a significant amount of filament and print time compared to a full brim.
Troubleshooting Common Issues
Problem: Brim is impossible to remove or fuses to the part.
Solution: This is almost always caused by the nozzle being too close to the build plate (Z-offset is too low) or the Brim Separation Gap being set to zero or a very small value. First, recalibrate your Z-offset to ensure you have the correct first-layer "squish." If the problem persists, increase the Brim Separation Gap in your slicer in small increments (e.g., from 0.1mm to 0.14mm).
Problem: The brim itself is peeling or warping.
Solution: If the brim can't stick, your model has no chance. This points to a fundamental bed adhesion issue. The first step is to thoroughly clean your build plate with isopropyl alcohol. Ensure your bed temperature is appropriate for the material you are using. If it still fails, you may need to use a bed adhesion promoter or consider that the issue is severe enough to warrant using a raft instead.
Problem: Brim leaves a rough, ugly edge ("elephant's foot").
Solution: This artifact, where the first few layers bulge out, is known as elephant's foot. It's typically caused by the Z-offset being too low, which squishes the initial layers outwards. It can also be a sign of over-extrusion on the first layer. Calibrate your Z-offset carefully and consider reducing your first-layer flow rate by a few percent in your slicer settings.
Your Final Checklist
The brim is a simple yet powerful tool. It's a low-cost insurance policy against warping and adhesion failures, saving you time, material, and frustration. When used correctly, it can transform difficult prints into routine successes.
- A Brim increases surface area to improve bed adhesion and prevent warping.
- Use a brim for tall/unstable models, parts with small contact points, or materials like ABS and PETG.
- Choose a Brim over a Skirt for adhesion; choose it over a Raft to save material and time when extreme measures aren't needed.
- Fine-tune Brim Width and Brim Separation Gap in your slicer for a balance of adhesion and easy removal.
- Use a deburring tool or careful trimming for clean, professional post-processing.
We encourage you to experiment with these settings. Don't be afraid to add a brim to any print you feel might be challenging. It's a small investment that pays huge dividends in print success and peace of mind.