Optimizing the IRIS+ Drone: Lightweight, Durable Arms with Onyx 3D Printing

In this third installment of our 3D‑printed drone series, we showcase the performance gains achieved by replacing the original injection‑molded kit arms with Onyx‑printed components. These arms are lighter, stronger, and feature a superior surface finish, thanks to Markforged’s advanced extrusion technology.

Earlier in the series we released the first 3D‑printed arm and detailed the electrical upgrades needed to fully customize the IRIS+ drone. Building on that foundation, this post focuses on how the new Onyx filament elevates arm design beyond the nylon/carbon‑fiber hybrid introduced in Episode 2.

From left to right, the original injection‑molded kit arms, the nylon/carbon‑fiber hybrid, and the Onyx variant. The Onyx arms are 13 g lighter than the kit and 5 g lighter than the hybrid, delivering a total weight savings of 20 % across all four arms.

Although Onyx is slightly denser than nylon, its superior stiffness allows us to use fewer carbon‑fiber reinforcement layers. The resulting structure provides ample strength while trimming mass, which is why each Onyx arm is 5 g lighter than its nylon counterpart.

Below is a close‑up of the drone’s underside, highlighting the precise wire tracks and the crisp definition of the motor vents—features notoriously difficult to print. Thanks to Onyx’s excellent surface finish, the complex geometries match the quality of the original injection‑molded arms.

The flat top of the Onyx arms eliminates the bulky superstructure required by the kit design. This not only reduces weight but also gives the drone a sleeker aesthetic, while the internal lattice provides the necessary rigidity.

Onyx’s refined surface finish is evident in this side‑by‑side comparison, where the printed arms appear virtually indistinguishable from the injection‑molded originals.

With the re‑assembled drone now ready for flight, we plan one final tweak before the maiden flight. Stay tuned for the next chapter in our 3D‑printed drone journey.