3D Printed Headphones

// overview

Overview

At Maker Faire Shenzhen I picked up a pair of headphones from HuaQiangBei — magnetically detachable ear cups, interchangeable back panels, impressive packaging. On the way home, at the airport, the headband snapped. Rather than discard them, I reverse-engineered the entire design, redesigned everything from scratch, printed all structural parts in PLA, and reassembled the headphones using the original PCB, speakers, magnets, and fasteners. The rebuild added a folding hinge the original never had.

// specs

Project Details

// background

The Problem

The original headband failed at the center — the curved geometry concentrated bending stress exactly at the weakest cross-section. The injection-molded plastic couldn't handle repeated flexing at that point. I documented the failure mode and used it to guide the redesign rather than just copying the same geometry.

The original — convincing packaging, magnetic ear cups, interchangeable panels

Failure point — stress concentrated at the curve's center

// design

Design Process

Attempt 1 — Direct Replica

My first approach was to recreate the original headrest geometry as closely as possible so the existing foam padding would fit. I designed it in Rhino, going through multiple iterations to capture the curves from manual measurements. The problem: measuring a curved, foam-padded component with calipers is imprecise, and FDM tolerances couldn't reliably match the injection-molded mating parts.

Rhino design iterations of the headrest — each round required new measurements and reprints

Attempt 2 — Full Redesign from Scratch

I abandoned the replica approach and instead designed the complete headphone around the components worth keeping — the PCB, speakers, ear cups, and magnetic hardware. The side housings required careful curve matching in Rhino so the original magnetic attachment geometry would still work. Once those were solid, I imported them into Fusion 360 and designed the rest of the assembly around them, including a new folding hinge mechanism.

Side housing in Rhino — geometry matched to the original magnetic attachment system

// build

Manufacturing & Assembly

All structural parts were printed in PLA. Most fasteners were salvaged from the original unit. The hinge mechanism required two additional M-size nuts and bolts — the only new hardware purchased for the project. The PCB, battery, speakers, magnets, and all ear cup components were transplanted directly.

One compromise: a single PCB LED had to be removed because it interfered with the 3D-printed button geometry. Everything else was retained.

Original PCB — reused entirely

All printed parts laid out before assembly

Internal layout — PCB, battery, and magnets positioned before closing

// result

Result

The rebuilt headphones work correctly — audio, button controls, and magnetic ear cup attachment all function as expected. The folding hinge adds real utility the original never had. They've been in daily use since assembly without issues.

Finished — fully functional, foldable, built almost entirely from original parts

Daily driving the rebuild