The Ultimate Guide to Using Brims 3D Printing

3D printing allows us to create almost any object we can imagine. However, some models are more challenging to print than others. Getting good bed adhesion is crucial for avoiding failed prints and wasted filament. That’s where brims come in.

What is a Brim in 3D Printing?

A brim is an additional layer of plastic printed around the base of your model. It extends just beyond the edges of the print, forming a smooth surface that adheres well to the build plate. This helps anchor the model during printing, preventing warping and detachment.

Brims provide a larger surface area for bed adhesion. They also give added stability against forces like cooling shrinkage and curling up at the edges. Brims act as a sacrificial barrier, protecting the main model from collisions if the nozzle gets too close on the first layer.

When Should You Use a Brim in 3D Printing?

Here are some situations where adding a brim is recommended:

Printing Small Models

Smaller prints have less contact area with the print bed. A brim gives them more surface adhesion to keep them planted. Brims are especially useful for delicate miniatures and jewelry pieces that could easily get knocked loose.

Models with a Small Footprint

Tall, thin models like towers and spikes have a high center of gravity. The brim keeps them standing upright instead of toppling over mid-print.

Overhangs and Steep Angles

Overhangs and steep slopes often start curling up from the bed during printing. A brim will hold them down until more of the model is complete.

Warping Prevention

Some materials like ABS are prone to warping due to shrinkage when cooling. A brim helps counteract forces that cause the corners to lift.

Draft Protection

Breezy conditions can blow lightweight, wispy prints away. A brim shields the model from drafts that could displace it.

Nozzle Collision Protection

The brim acts as a bumper that takes any heat/impact from the nozzle on the first layer instead of your model. This is useful for small, detailed prints.

Materials Prone to Curling

Some filaments like PETG are known to curl and peel up from the bed. A brim provides insurance against edges detaching.

Painting/Sanding Aid

The brim gives you some extra area to hold onto while painting or sanding the printed model.

Unsuitable Bed Surfaces

If your print surface doesn’t allow great adhesion, a brim can compensate and get prints to stick.

How to Add a Brim in Slicer Settings

Adding a brim is easy and only takes a couple quick settings changes in your slicer software (Cura, PrusaSlicer, Simplify3D, etc). Here’s how to do it:

1. Look for the “Platform Adhesion” or “Build Plate Adhesion” section in your slicer settings.
2. Check the box next to “Brim”. This activates the brim feature.
3. Adjust the “Brim Width” to increase or decrease how far out the brim extends from your model. 3-5mm is a good starting point.
4. Make sure the “Brim Only on First Layer” box is checked. This will only create the brim on the very first layer against the bed.
5. Consider increasing your first layer extrusion width and height for better adhesion.
6. Save your slicer profile and slice as normal. Your model will now generate with a brim attached!

Brim vs. Raft vs. Skirt

Brims, rafts, and skirts all assist bed adhesion, but work differently:

• Brim: Flat single layer outline extending just beyond print edges. Good for preventing warping.
• Raft: Thicker floating base layer under the print. Helps minimize warping on large surface area models.
• Skirt: Perimeter lines drawn around but not connected to the model. Primes the nozzle before printing.

Brims strike a balance of being lightweight yet adding surface area for adhesion. Rafts provide robust adhesion but use more material and leave thicker bumpy layers on the bottom of prints. Skirts don’t assist bed adhesion since they don’t touch the model.

Brim Tips and Tricks

Here are some pro tips for getting the most out of brims:

• For small models, use a wider brim of 5mm or more to maximize surface area.
• Keep brim widths under 10mm. Anything larger is overkill and wastes material.
• Set the number of brim lines to 3-6 for good adhesion withoutexcess material.
• Adjust the brim width and lines for the specific model shape and size. Wider/more lines for smaller contact patches.
• Increase extrusion widths to 105-120% for the brim only to get it to stick well.
• Raise temperatures and slow down the first layer speed for better brim adhesion.
• Set the brim height slightly lower than the first layer height to make it easy to detach.
• Remove brims soon after printing while the material is still warm and pliable.
• For tools like pliers and clamps, heat brim areas with a heat gun to soften before prying off.
• Cut away brims using flush cutters, hobby knives or small snips. File down any remains.
• Avoid using rafts and brims together. This is redundant and makes bottom finish cleanup more difficult.

Troubleshooting Poor Brim Adhesion

Here are some common problems with brim adhesion and how to fix them:

Not Sticking to the Bed

• Increase first layer temps, slow down speed
• Clean, level, and prepare the bed surface
• Use wider brim width or more lines
• Increase first layer extrusion width and height

Detaching from the Model

• Raise bed temperature
• Increase brim width to overlap more of the model
• Slow down print speed for the brim
• Check filament is dry and free of contaminants

Messy Brim Cleanup

• Set brim height lower than model first layer
• Remove brim soon after printing when still warm
• Re-slice model at an angle to eliminate brim on one face

Brim Not Removing Cleanly

• Heat brim area with hair dryer/heat gun to soften plastic
• Cut away bulk of brim with snippers, then file/sand remains

Final Thoughts

Adding a brim takes just a minute but can make the difference between a successful print and a failed one. While not required for every print, brims come in handy to boost adhesion for more challenging models. Dial in the right brim settings for your specific scenario. Then remove the brim cleanly afterwards so it doesn’t detract from your model’s appearance. Used properly, brims can help any 3D printer produce flawless results.CopyRetry