Can Markforged Onyx Filament Be Used For Functional Parts?

From a maker’s perspective, Onyx filament feels like cheating at functional prints. I run a YouTube channel testing 3D printed parts to destruction, and Onyx consistently outperforms standard engineering plastics. The interlayer bonding is so good that my hydraulic press struggles to split test cubes apart. Recently, I printed a motorcycle footpeg that survived a 200-mile ride without deformation—something PETG would’ve melted doing.

The matte black finish looks professional straight off the bed, which is rare for functional materials. I’ve used it for everything from robot chassis to custom wrench handles. While it doesn’t have the flexibility of TPU, the stiffness-to-weight ratio makes it perfect for structural components.

One thing beginners should know: Onyx hates moisture. Leave it out for a weekend, and you’ll hear it pop like rice krispies during prints. A drybox is mandatory. Also, layer lines can become stress concentrators—orient your prints to distribute loads across layers, not along them. For the price, I’d say it’s overkill for trinkets but unbeatable for load-bearing parts.

As someone who runs a small engineering workshop, I rely on materials that bridge the gap between prototyping and end-use parts. Markforged Onyx is one of those rare filaments that delivers both. The carbon fiber infusion gives it a tensile strength of around 580 MPa, which is nuts for a printed material. I’ve used it for custom jigs that withstand daily abuse in our metal shop, and the wear resistance is impressive.

What really sets Onyx apart is how it plays with Markforged’s continuous fiber reinforcement options. You can embed Kevlar or fiberglass layers for ballistic-level durability in specific stress points. I printed a hydraulic mount last month that’s still holding strong after 300+ hours of runtime. The downside? You’re locked into Markforged’s ecosystem, and the printers aren’t cheap. But for aerospace or automotive applications where failure isn’t an option, this filament is game-changing.

One pro tip: annealing Onyx parts boosts heat resistance up to 150°C, which opens doors for under-the-hood automotive applications. Just account for the 2-3% shrinkage during post-processing.

I've been 3D printing for years, and let me tell you, Markforged Onyx filament is a beast for functional parts. It's not just about looks—this stuff is reinforced with chopped carbon fiber, making it way tougher than standard nylon. I've printed gears, brackets, and even drone parts that hold up under serious stress. The layer adhesion is insane, and the surface finish is smooth enough for moving parts. Compared to PLA or ABS, Onyx feels like upgrading from a bicycle to a motorcycle. It’s pricey, but if you need parts that won’t snap under pressure, it’s worth every penny. Just make sure your printer can handle high-temp materials, because this isn’t your average filament.