3D Printed Living Hinge: Best SLS and MJF Material

A 3D printed living hinge can work, but material choice decides whether it lasts dozens of cycles or snaps on the first bend.

What's the Best Material for a 3D Printed Living Hinge That Has to Flex Repeatedly?

In SLS or MJF, pick PA11 if you can, or MJF PA12 as the next choice, and stay away from glass-filled grades. PA11 is the more ductile nylon, while glass-filled powders tend to snap instead of bend.

Where the question came from

An r/3Dprinting thread asked which filament makes the best living hinge. That's the FDM version of the question. For powder bed parts the answer comes down to a short list of nylons.

What the sources say

They don't fully agree, which is worth knowing. Protolabs' living hinge guide names MJF PA12 as the most suitable nylon, with SLS PA11 Black also workable and SLS PA12 white less preferred. It specifically says to avoid PA12 40% glass filled because it will snap rather than bend. It also says TPU is technically possible for a hinge.

Proto3000's page on HP 3D High Reusability PA 11 points the other way. It lists living hinges and snap fits among PA11's uses and gives elongation at break of 50% in XY and 35% in Z, which makes it the more forgiving choice for a hinge that flexes a lot.

Either way, treat a printed hinge as a limited-life feature. Design it for the cycle count you need and test it before you commit to a run.

Designing the hinge

Protolabs sets hinge thickness at the process's minimum feature size: 0.508 mm for MJF and 0.762 mm for SLS in their guide. Thinner than that and the hinge may not print. For length, their rule for a 180° bend is L = πR, where R is the bend radius.

Wide hinges should be split. Their example breaks a 20.32 mm hinge into three 5.08 mm sections with 2.54 mm gaps.

Repeated flexing also wears down retention in snap features, which we covered in why a printed nylon snap-fit loses retention force. If you're weighing printed nylon against a machined part, see snap-fit design in MJF nylon vs machined Delrin. Humidity shifts nylon stiffness too; see nylon moisture absorption in PA12 parts.

At DigiForge

Our materials page lists MJF Nylon 11 for ductile printed parts and living hinges, along with MJF Nylon, SLS Nylon PA12 and Thermoplastic Polyurethane (TPU). We'd skip MJF Glass-Filled Nylon and SLS PP GB Glass Filled for a hinge. If you need a cycle count, ask us when you quote.