NFCore
Download
Back to guides

Hide an NFC Tag Inside a 3D Print or Resin Craft

Pause the print, drop in the tag antenna-side up, test it, and seal it. Here is how it works for FDM, resin prints and cast resin, plus what breaks the read.

Published

Quick answer

Yes, you can seal an NFC tag inside a 3D print or a resin piece, and it will still read. A passive tag has no battery. The phone powers it over a 13.56 MHz field, and the working distance is only a few centimetres, so the tag just needs to sit flat, close to the surface you will tap.

There are three routes. On an FDM printer you pause the print and drop the tag into a pocket. With a resin printer you design a snap-fit pocket or a slit and slide the tag in afterwards. For cast resin you press a sticker tag into the wet pour. If you make art objects, this pairs well with linking artwork to provenance.

Pick the tag before you design the pocket

The pocket follows the tag, so choose the tag first. An NTAG215 holds 504 bytes, which is plenty for a URL, a phone number or a contact card. The micro NTAG203 tag used in Adafruit's printed NFC ring holds 144 bytes and is small enough for jewelry. If the object will be tapped by iPhones, read which tags work with iPhone before you buy a batch.

Measure the tag and leave a little tolerance. Too tight? Add about 0.1 mm to the pocket and reprint.

Printed objects: pause and insert, or a snap-fit pocket

FDM: pause at the pocket

The method in PrintPal's guide is short:

  1. Model a pocket and add a pause in your slicer at the layer just below where the pocket gets covered.
  2. When the printer stops, place the tag flat in the pocket, antenna side up, with the antenna centered.
  3. Test the tag before you continue. Write it, or at least scan it, while it is still open.
  4. Resume. The next layers cover the tag.

Keep the tag flush with or below the pocket top so the nozzle does not hit it. The same guide says 1 to 2 mm of material over the tag reads best, and suggests PLA or PETG.

Resin printing: a snap-fit pocket or a slit

Resin printers make the pause trick harder, because you can't stop mid-layer as easily. PrintPal's advice is to design a snap-fit cavity instead. Adafruit's ring takes another route: a curved slit cut into the bridge of the ring, and the tag slid in with fine-tipped tweezers after printing. Either way the tag goes in after the print is done, so you can test before anything is closed.

Casting in epoxy resin

Cast resin is the loosest method of the three. One maker described pressing a sticker tag into a small epoxy figure while the resin was still wet, and the figure worked after it hardened. That is one maker's report, not a guarantee, so pour a scrap piece first. Keep the tag flat, close to the surface you will tap, and away from anything metal such as foil flakes or metallic pigment.

Test, then write and seal

Write your data before the tag disappears. A URL is the safest payload because you can change where it points later, but only if the tag is not locked. If you plan to lock it, check whether a tag is locked first, since a locked tag inside a sealed print cannot be rewritten.

In NFCore, write the URL or record, scan it back to confirm, then seal the piece. Test with the phone you'll actually use, since antennas sit in different spots on different phones. Get NFCore on the App Store or Google Play.

Common problems and fixes

  • The phone will not read it. The tag may be too deep or the antenna misaligned. Thin the top wall or move the tag, as PrintPal suggests.
  • It reads weakly near metal. Nearby metal can cause eddy currents that quench the tag's antenna. Keep metal inserts, weights and steel parts of magnets away from it, and test.
  • The tag shifted during the print. Make the pocket a closer fit, then recheck it before resuming.

Frequently Asked Questions

Can you embed an NFC tag in a 3D print?

Yes. Pause the print at the pocket, place the tag flat with the antenna side up, test it, then resume so the next layers cover it.

How thick can the plastic over an NFC tag be?

Around 1 to 2 mm reads best according to one maker guide. Too much material over the tag is a common reason a phone cannot read it.

Does resin stop an NFC tag from working?

One maker reported that a sticker tag pressed into wet epoxy still worked after curing. Results vary, so test on a scrap piece.

Does metal near the tag matter?

Yes. Nearby metal can quench the tag's antenna, so keep metal away from it and test the finished piece.