I 3D Printed a Musical Fidget That Plays Happy Birthday (Bambu Lab A1)

What if a birthday gift could be printed in an hour, cost less than a cup of coffee in filament, and actually play a song? That's exactly what this musical fidget does — flick your thumb across its printed tines and it plays Happy Birthday, music-box style.

Here's the full process, from slicer to song.

The Model

The musical fidget works like a tiny kalimba or music box comb: a row of tines with carefully tuned lengths, arranged so that strumming them in sequence plays a melody. This version is tuned to Happy Birthday, and the design even has "HAPPY BIRTHDAY" embossed on the body.

The print consists of two main comb plates plus a small connector piece. No supports needed — the parts print flat on the bed.

Download the model: Musical Fidget Generator on MakerWorld — it's a generator, so you can create fidgets tuned to different songs, not just Happy Birthday.

Slicing in Bambu Studio

I sliced the model in Bambu Studio with a single-colour setup. The numbers that matter:

Filament: PETG (red), 5.29 m / 15.91 g total

Print time: 54m 32s model time, about 1h 1m total including prep and timelapse

Plate: Bambu Textured PEI plate

One tip straight from Bambu's own Daily Tips panel: PETG (especially Bambu PETG Basic) has a higher shrinkage rate than PLA, which can cause slight dimensional deviations after cooling. For a model like this — where tine length literally determines the musical note — it's worth running shrinkage calibration first if your tuning sounds off.

Why PETG?

For a fidget that will be flicked, flexed, and strummed hundreds of times, PETG is the better choice over PLA:

Flexibility: PETG tines bend and spring back instead of snapping.

Durability: better layer adhesion means the thin tines survive repeated strumming.

Feel: slightly softer "twang" that actually sounds closer to a music box.

Printing on the Bambu Lab A1

The A1 handled this print without drama. The parts are mostly flat with fine repeating tine geometry, so the two things to watch are:

First layer adhesion — the tines are thin; a clean textured PEI plate did the job with no glue needed.

Stringing between tines — PETG loves to string. Good retraction settings (or just using the stock Bambu PETG profile) kept the gaps between tines clean, which matters because fused tines = dead notes.

After roughly an hour, both comb plates popped cleanly off the flexible plate.

Assembly

Assembly takes just a couple of minutes: the comb plates stack and lock together with the small connector piece, no glue or hardware required. The satisfying part is that the moment it clicks together, it's ready to play.

The Result: It Actually Plays Happy Birthday 🎂

Run your thumb across the tines at a steady speed and the melody comes out surprisingly recognisable. It's not going to replace a real music box, but for a printed-in-an-hour, 16-gram gadget? It's a genuinely delightful desk toy — and a perfect quick birthday gift.

Print Summary

Printer: Bambu Lab A1 Mini

Material: PETG (red)

Filament used: 5.29 m / 15.91 g

Print time: ~1h 1m (incl. prep)

Supports: None

Assembly: Snap-fit, use glue to make it stronger

Want more quick, practical 3D printing projects like this? Check the 3D Printing category or follow me on Instagram and YouTube for the video versions.