How to Incorporate Magnets in Your 3D Printing Projects

Magnets are everywhere—on your fridge, in your bag, and inside devices like electric motors, microphones, and hard drives, where billions of tiny magnets store data. They’re equally valuable in 3D printing, offering both fun and functional uses. Magnets can enhance modular designs, enable quick swaps, or even assist with tasks like mesh bed probing.

Incorporating magnets into 3D prints requires careful planning to ensure they are securely and conveniently integrated into your designs. This article explores creative ways to use magnets in your 3D printing projects and outlines practical methods for embedding them seamlessly into your prints.

Ready to add some magnetic charm to your designs? Let’s get started!

Functions

Magnets are affordable, easy to find, and versatile, making them ideal for various applications. We'll explore both fun, decorative uses and more practical, engineering-focused ones next.

Enjoyable&Ornamental

Magnets are inherently fun! Remember the excitement of discovering them as a child? It’s no surprise we’ve created playful ways to use them. Here are a few examples of how magnets can be incorporated into enjoyable applications.

Refrigerator magnets

Want to create custom fridge magnets? You’ll definitely need magnets for that!

Makers have designed countless fridge magnets, with many available on 3D model repositories. From practical designs like a note holder to nostalgic items like a Tetris set, or even quirky creations like an articulated slug, there’s a fridge magnet to suit every taste and style. The variety is endless, making it easy to find or create something unique for your fridge.

Calm-Down Toys

Magnets are incredibly durable, and their attraction and repulsion properties make them perfect for fidget toys. For instance, a fidget switch uses repelling magnets to create satisfying clicks, while a magnetic sliding fidget offers another engaging design. You can find many more creative options by searching repositories like Printables or Thingiverse.

Functional & Engineering Uses

Configurable Structures

Magnets offer an easy way to customize or swap out modular components in functional designs. For instance, they can be used in a versatile dust collection coupling system that allows for quick adjustments. Additionally, magnets are ideal for creating cases and latches that snap shut securely, providing a satisfying and practical solution. Their ability to simplify design changes makes magnets a valuable tool in many engineering projects.

Bed Sensors

A magnet-based microswitch probe, like the Klicky Probe, uses magnets as conductors to create a low-cost, mechanical bed probing system. This method is highly repeatable, accurate, and not dependent on specific build surfaces. Unlike inductive probes, the Klicky Probe can detect all materials used for build surfaces.

The process works by the toolhead attracting the probe from its dock using magnets. These magnets are connected to pins on a microswitch. When the switch is pressed or released, the circuit either opens or closes. The magnets on the toolhead are connected to the mainboard’s ports, and the firmware detects the circuit’s state to accurately probe points on the bed. This efficient system provides reliable, versatile bed probing for 3D printing.

Magnetic Proximity Sensors

Some printers use Hall effect switches instead of microswitches or sensorless homing. A magnet is placed on the toolhead or gantry for homing. As the magnet approaches the sensor, the magnetic field intensifies, triggering the sensor to switch into an active state, enabling precise homing.

How can I accomplish this?

There are several ways to incorporate magnets into your 3D printed or other parts. Here are four effective methods, listed from less to more secure:

• Glued fit: The magnet is glued into an oversized hole.
• Compliant press fit: The magnet is held in place using friction.
• Screwed: A countersunk magnet is screwed into the part.
• Embedded: The magnet is permanently held inside the part.

The method you choose will depend on the specific requirements of your project, balancing ease of use with security and durability for your application.

Factors

Before using magnets in your project, there are a few key factors to consider when choosing the right one:

• Shape: Magnets are generally available in cylindrical or rectangular formats, with cylindrical magnets being more popular. They are easier to incorporate, allowing for a more convenient press fit, and are unidirectional. Cylindrical magnets can also be found in ring or countersunk shapes for a screwed fit. Depending on your needs, other shapes may also be suitable.
• Size: The size of the magnet determines its strength. Larger magnets have stronger magnetic fields. For applications where strength is crucial, choose a larger magnet. For thin parts requiring strength, a large diameter but short height (thin and wide) magnet might be ideal.
• Material: Neodymium magnets are popular due to their strength relative to size and weight. They can also withstand high temperatures, but it’s best to keep them below 70°C long-term to maintain their magnetism.

Also, be sure to insert magnets with the correct polarity!

1. Glued fit

A glued fit is the simplest and most convenient method for mounting magnets. By using superglue, epoxy, or similar adhesives, you can easily fix a magnet into an oversized hole. Although it’s the least secure method, it’s often strong enough for most applications.

When gluing magnets into your project, it’s crucial to design the holes slightly oversized. For example, if you’re using a circular magnet with a diameter of 6.00 mm and height of 3.00 mm, model the hole diameter to be 6.30 mm and the height to 3.30 mm.

Adjust these values based on your 3D printer’s tolerances. For tight tolerances, decrease the size; for looser tolerances, increase it. This ensures the magnet fits in and out of the hole easily.

After printing, apply a drop of glue and press the magnet firmly into place. Once the glue dries, your part is ready for use.

2. Compliant press fit

A compliant press fit takes advantage of the slight flexibility of plastic and design features to securely grip a magnet without the need for glue. However, adding a drop of glue can provide extra security.

In your design, model the hole to be the same size or slightly larger or smaller than the magnet, depending on your printer’s tolerances. The hole’s height should be slightly larger than the magnet’s height.

To enhance the grip, add fins or other compliant features that allow the hole to expand slightly. For a stronger hold, use fewer and stiffer fins, as the hole will expand less. However, this depends on your printer’s tolerances. If the hole is too small, the magnet might not fit at all, so careful calibration is key to a successful press fit.

Alternatively, you can design the hole to make it easier for the magnet to fit by adding more flexible fins, allowing the hole to flex. However, this results in a less secure hold.

In the image above, the left design shows a more secure, less compliant fit, while the right design illustrates a more flexible, compliant fit. Experiment with different fin styles to achieve your desired outcome.

After printing, firmly press the magnet into the compliant hole, adding a drop of glue for extra security if needed. This ensures a solid but adaptable magnet mounting.

3. Screwed

A screwed fit provides a very secure method of mounting magnets. Countersunk screws are used to firmly attach countersunk magnets to the desired part, often for applications where the magnet needs to be exposed (e.g., for electrical conductivity).

For example, the PCB Klicky Probe uses screwed magnets for added reliability, security, and conductivity. YouTuber YGK3D has a helpful video demonstrating the process.

To design a screwed magnet, create holes or features for the screw in your part. This can include self-tapping holes, heatset inserts, or nut slots. After printing, screw the magnet into place, and it’s ready for use.

4. Embedded

In this method, magnets are fully embedded into a printed part, making them secure and unable to be removed or altered after insertion. This prevents magnets from loosening over time, but the presence of plastic between the magnet and the attracted surface reduces its strength. Therefore, embedding magnets is particularly useful for parts where insulation is required.

To embed a magnet, pause the print at a specific height. Most modern slicers, like Cura, offer this option. Alternatively, you can monitor the print and pause manually at the correct height.

Here’s how to design and print for embedded magnets:

• Model a hollow hole inside your part for the magnet. Ensure the hole is slightly oversized in all dimensions for an easy fit.
• Set a pause height in your slicer where the hole is fully printed, like after completing layer 10.00 mm.
• Insert the magnet with the correct polarity, then resume printing to encapsulate the magnet.

Your result will be a part with a securely embedded magnet.

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