How to Embed Magnets into 3D Prints

3D printing opens up a world of creative possibilities, and embedding magnets into your prints can take your projects to the next level. Whether you’re designing modular storage, magnetic closures for boxes, or even articulated toys, magnets add functionality and flair. In this tutorial, we’ll walk you through the process of embedding magnets into 3D prints—from design considerations to finishing touches. Let’s dive in!

Why Embed Magnets in 3D Prints?

Magnets bring a unique interactivity to your creations. Imagine a snap-together model, a fridge-mounted tool holder, or a jewelry box with a satisfying magnetic clasp. Embedding magnets during or after printing ensures they’re securely integrated, saving you from messy glue jobs or weak attachments. Plus, it’s just plain cool!

What You’ll Need

Before we start, gather these materials and tools:

● 3D Printer and Filament: Any FDM or resin printer works; PLA, PETG, or ABS are great filament choices.

● Magnets: Neodymium magnets (small, strong, and widely available) are ideal. Common sizes are 6mm x 2mm or 10mm x 3mm discs.

● CAD Software: Fusion 360, TinkerCAD, or Blender for designing your print with magnet slots.

● Calipers: For precise measurements of your magnets.

● Tweezers or Pliers: To handle small magnets safely.

● Superglue (Optional): For securing magnets post-print if needed.

● Sandpaper or File: To fine-tune slots if tolerances are off.

● Safety Gear: Gloves and goggles (magnets can snap together unexpectedly).

Step 1: Choose Your Magnets

TRYMAG Small Strong 6 Different Sizes 255Pcs Rare Earth Magnets for Crafts

The first step is selecting the right magnets for your project. Neodymium magnets are the go-to choice due to their strength-to-size ratio. Measure their diameter and thickness with calipers—accuracy here is key. For example, a 6mm x 2mm disc magnet is 6mm wide and 2mm thick. Buy a few extras; they’re cheap and easy to lose (or accidentally stick to your fridge).

Tip: Check the magnet’s polarity. Magnets attract or repel based on their poles, so plan how they’ll align in your design. Mark one side with a marker if needed.

Step 2: Magnet Size and Popular Magnet Sizes

The size of your magnets will dictate both their strength and how they fit into your design. Neodymium magnets come in various shapes—discs, cubes, spheres, and even rings—but discs are the most popular for 3D printing due to their simplicity and availability. Here’s a breakdown of magnet sizes and some commonly used options:

● Small Magnets (3mm x 1mm to 6mm x 2mm):

○ Use Case: Perfect for lightweight applications like jewelry clasps, small figurines, or delicate snap-together parts.

○ Strength: Moderate—enough to hold light objects but not overpowering.

○ Example: A 6mm x 2mm disc is a hobbyist favorite for its balance of size and strength.

● Medium Magnets (8mm x 3mm to 10mm x 3mm):

○ Use Case: Ideal for tool holders, modular containers, or medium-sized enclosures.

○ Strength: Strong enough to grip securely without being unwieldy.

○ Example: 10mm x 3mm discs are widely used for magnetic lids or wall-mounted organizers.

● Large Magnets (15mm x 5mm and up):

○ Use Case: Heavy-duty projects like furniture connectors, levitating displays, or industrial prototypes.

○ Strength: Very powerful—use with caution to avoid pinching or breaking prints.

○ Example: A 20mm x 5mm disc can hold significant weight but requires thicker walls in your design.

● Popular Sizes:

○ 6mm x 2mm: A versatile all-rounder for small to medium projects.

○ 10mm x 3mm: The sweet spot for most 3D printing applications—strong yet manageable.

○ 5mm x 5mm Cube: Great for unique designs where height equals width.

○ 3mm x 1mm: Tiny but mighty for intricate work.

When choosing a size, consider your project’s scale, the force needed, and the space available in your print. Larger magnets are stronger but harder to embed discreetly, while smaller ones are subtle but may lack holding power. Test a few sizes to find your perfect match!

Step 3: Design Your 3D Model

Eyeglasses Case with embedded magnets lock

Now, fire up your CAD software. You’ll need to create slots or cavities in your model where the magnets will sit. Here’s how:

1. Measure and Model the Slot:

○ Add 0.2–0.4mm to the magnet’s diameter and thickness for a snug fit (e.g., a 6mm x 2mm magnet gets a 6.3mm x 2.3mm slot). This accounts for printer tolerances.

○ Decide if the magnet will be flush with the surface or recessed slightly for a cleaner look.

2. Placement:

○ Position slots where magnets will interact (e.g., on mating parts of a box lid and base).

○ Ensure at least 1–2mm of wall thickness around the slot to maintain structural integrity.

3. Pause Point (Optional):

○ If you want to insert magnets mid-print, calculate the layer height where the slot will be covered. Most slicers let you add a pause command (more on this later).

4. Test Fit:

○ Export a small test piece with a single slot and print it. Check if the magnet fits without forcing it—adjust your design if necessary.

Pro Tip: Add a small chamfer (angled edge) to the slot opening to guide the magnet in smoothly.

Step 4: Slice and Prepare Your Print

Magnet Slider Fidget Toy

Load your model into a slicer (like Cura, PrusaSlicer, or Simplify3D). Here’s how to set it up:

● Layer Height: Use 0.1–0.2mm for precision around the slots.

● Infill: 20–30% is usually fine unless your design needs extra strength.

● Pause Command (Optional):

○ If embedding mid-print, find the layer just above the slot’s top (e.g., if the slot is 2mm tall and your layer height is 0.2mm, pause at layer 11).

○ In Cura, use the “Post-Processing Scripts” > “Pause at Height” feature. Set the pause height and save the G-code.

Export your G-code and send it to your printer.

Step 5: Embedding Option 1 – Mid-Print Insertion

This method embeds magnets as the print progresses, sealing them inside.

1. Start Printing: Begin your print as usual.

2. Pause the Print: When the printer pauses (or you manually pause it), the slot should be fully formed but not yet covered.

3. Insert Magnets:

○ Use tweezers to place the magnet into the slot. Ensure correct polarity if pairing with another magnet.

○ Press gently—it should fit snugly but not deform the print.

4.Resume Printing: The printer will cover the magnet, locking it in place.

Caution: Don’t bump the print bed or nozzle—alignment is critical.

Step 6: Embedding Option 2 – Post-Print Insertion

Soot Sprite Magnets

If mid-print pausing feels tricky, insert magnets after printing:

1. Print the Model: Complete the print with open slots.

2. Test Fit: Push a magnet into a slot. If it’s too tight, sand or file the edges slightly. If too loose, proceed to the next step.

3. Secure the Magnet:

○ Add a tiny drop of superglue to the slot, then press the magnet in.

○ Wipe away excess glue immediately.

4. Let It Cure: Wait 10–20 minutes for the glue to set.

Alternative: For a glue-free fit, heat the magnet slightly with a hairdryer and press it into the slot. The plastic will soften and grip the magnet as it cools (works best with PLA).

Step 7: Finishing Touches

      ● Test Functionality: If your magnets pair with another part, check that they attract (or repel) as intended.

● Sand or Paint: Smooth any rough edges and add a finish if desired. Avoid thick paint over the magnet area—it can weaken the magnetic force.

● Adjust Polarity: If two parts don’t align correctly, pop out a magnet and flip it.

Common Mistakes to Avoid

Embedded Magnet Dispenser Tool for 3D Prints

Even with careful planning, it’s easy to stumble when embedding magnets. Here are some common pitfalls to steer clear of:

● Ignoring Polarity: Forgetting to check magnet orientation can leave you with parts that repel instead of attract. Always test polarity before embedding—mark one side with a marker to keep track.

● Slots Too Close to Edges: Placing a magnet slot near the edge of your print risks cracking or weak walls. Maintain at least 1–2mm of material around the slot for strength.

● Over-Sanding Slots: Sanding too much to fit a tight magnet can make the slot too loose, causing the magnet to fall out later. Go slow and test frequently.

● Overheating Magnets: Neodymium magnets lose strength above 80°C (176°F). Avoid excessive heat from hairdryers or hot glue guns when securing them.

● Skipping Test Prints: Jumping straight to a complex design without testing slot sizes often leads to wasted filament. Print a small prototype first to perfect your tolerances.

Avoiding these mistakes will save you time, material, and frustration—trust me, I’ve learned the hard way!

Troubleshooting

● Magnet Won’t Fit: Your slot is too small. Increase the size by 0.1mm and reprint the test piece.

● Magnet Falls Out: Slot’s too big. Reduce the size or use glue.

● Weak Attraction: Magnets might be too far apart—reduce the gap between slots in your design.