PA11 vs PA12: Which Type of Nylon to Choose for 3D Printing?

• 1
  PA11 vs PA12 at a glance
• 2
  What actually separates PA11 from PA12
• 3
  Choose PA11 when the part has to survive impact
• 4
  Choose PA12 when geometry and stability matter more
• 5
  How the printing process changes the answer
• 6
  What tolerance to expect, and when to machine instead
• 7
  How each material fails in the field
• 8
  Cost, lead time, and the prototype-to-production path

Both materials are polyamides, so both absorb water from the air and both soften when hot. The difference sits in the carbon chain. PA11 is polymerized from 11-aminoundecanoic acid, which comes from castor oil. PA12 is built from butadiene, a petrochemical route, and its repeat unit is a little longer.

That longer, more regular chain is why PA12 crystallizes more predictably in a laser sintering bed. The powder melts and re-solidifies with less internal stress, so thin walls and long flat sections stay put. PA11 crystallizes a bit less tightly, which is exactly why it bends further before it breaks.

Moisture is the variable engineers underestimate. A PA11 part can pick up 1.5–2% of its own weight in water in a humid room. Water acts like a plasticizer: elongation goes up, stiffness and strength drop, and the part grows. PA12 takes on roughly 0.5–1%, so the same room moves it less.

Neither difference makes one material better. It makes one material better for a given part. Decide which property your design cannot lose, then pick.

PA11 is the pick when a part will be dropped, snapped, or hit while cold. Think latches, living hinges, cable clips, drone arms, and guards on handheld tools. Its higher elongation at break means a crack opens slowly instead of running straight through the wall.

Notched Izod values for PA11 sit above PA12 in most published grades, and the gap widens at low temperature. If your part sees −20 °C in winter shipping, PA11 keeps more impact margin. That margin is worth real money when a field failure costs a service call.

The trade is dimensional. On a 150 mm long PA11 bracket, 1% moisture uptake is 1.5 mm of growth. If a mating bore is controlled to ±0.1 mm, that bracket will not fit after a week in a humid plant.

PA11 also costs more per kilogram, and used powder loses flow faster, so the price gap on a printed part is usually 15–30%. Pay it only when you need the ductility.

PA12 wins on housings, ducts, manifolds, brackets, and anything with a long flat face or a thin wall. It sinters with less curl, so you can print longer unsupported spans and still hold flatness. Build orientation matters less, which makes nesting easier and the build cheaper.

Moisture uptake around 0.5–1% still moves a part, just less. A 150 mm PA12 bracket grows roughly 0.75–1.5 mm at full saturation, and most of that happens in the first 48 hours. If you measure parts straight off the machine and again three days later, you will see the shift.

PA12 also survives powder reuse better. In an MJF or SLS cell, the refresh ratio for PA12 is lower, so the effective material cost drops. For repeat orders of the same housing, that compounds.

Pick PA12 unless you have a specific impact requirement that it cannot meet. For most enclosures and structural brackets, it is the default.

The same polymer behaves differently in SLS, MJF, and FDM. In powder bed processes, the part is surrounded by unsintered powder that supports it, so overhangs are cheap and orientation is flexible. In FDM, you print a bead, so layer adhesion becomes the weak link and PA11's ductility matters less than your nozzle temperature and chamber control.

For FDM nylon, dry the filament to below 0.2% moisture before printing. Wet filament foams at the nozzle, leaves voids, and turns a tough part brittle. A 4-hour dry at 80 °C in a desiccated dryer is a normal starting point.

Powder bed parts are also porous. An SLS PA12 duct at 100% density in CAD might be 96–98% dense in the part, and air or fluid can weep through a wall. If the part has to seal, plan for a machined face, an impregnation step, or a different process.

Chamber temperature matters as much as material. A cold chamber gives you warped PA12 and delaminated PA11. This is a machine setting problem, not a polymer problem.

Printed nylon is not a precision process. SLS and MJF typically hold ±0.3 mm on small features and add roughly 0.1–0.15 mm per 100 mm of length. That is fine for a housing, not fine for a bearing bore.

GreatLight machines nylon to ±0.005 mm on 5-axis centers when the part needs it. For a PA12 or PA11 part with a bearing seat, a sealing groove, or a thread that must torque to spec, the practical route is print the body and machine the critical features, or machine the whole part from PA stock.

The hybrid route is often the cheapest. You get the organic geometry from printing and the fits from turning or milling in one setup. Inspect after machining, not after printing, because moisture will still move the part.

If you need both impact toughness and a tight bore, tell us the fit and we will machine the PA11 body on a 4-axis mill with the printed blank as stock. 100% inspection before shipment and reports on request cover that path.

PA11 fails by yielding. A latch arm bends, whitens, and eventually tears. That is a warning before failure, which is useful for a safety-relevant clip. PA12 fails more sharply: less yielding, then a crack.

Both materials lose strength when hot. At 80 °C, a PA12 bracket that held 40 MPa at room temperature keeps a fraction of that. If your part sits near a motor or an exhaust path, run the numbers at the service temperature, not at 23 °C.

UV exposure is the quiet killer. Unstabilized nylon yellows and embrittles outdoors. For an outdoor bracket, specify a UV-stabilized grade or plan a coating. A printed part left in sunlight for a season behaves like a different material.

Water and glycol attack nylon over time. PA12 resists them a little better. For a part that sees coolant or brake fluid, test the actual fluid before committing to a production run.

PA12 powder costs less per kilogram and reuses better, so a PA12 part is usually cheaper than the same PA11 part. On small prototype quantities the gap is mostly material price; on repeat runs the powder reuse ratio widens it.

Lead time is driven by build scheduling, not by the polymer. GreatLight quotes and returns a free DFM analysis within 12 hours, and production can start within 24 hours for a confirmed order. Printed parts typically ship in 3–5 days.

There is no minimum order quantity. One prototype and a 10,000-part run go through the same quoting path, which matters when you are validating a design and do not want to commit to a tool.

If the part needs certification, note which standard applies. GreatLight holds ISO 9001:2015, IATF 16949:2016, ISO 13485:2016, and ISO 27001:2022. Uploads are secure and confidential, and an NDA is available on request.

One more cost line people forget: post-processing. Dyeing, tumbling, and vapor smoothing each add a step and a day. Budget for it before you compare quotes.