PA12 Nylon
WORKHORSEThe default SLS material and the best all-round engineering plastic we print. Tough, chemically resistant, dimensionally stable, and suitable for live hinges and thin flexible walls.
48–50 MPaLive hingesChemical resistant
MATERIAL · NYLON
Nylon PA12 — The Engineering Plastic That Needs No Supports
PA12 is the workhorse of selective laser sintering: 1.01 g/cm³, 48–50 MPa tensile with useful elongation, indifferent to oils and fuels, and it prints with no support structures at all because the surrounding powder holds the part up. For functional parts with complicated geometry, it is usually the best combination of strength, freedom and price on offer.
1.01 g/cm³Density
48–50 MPaTensile strength
0Supports required
~120 °CWorking temperature
OVERVIEW
What PA12 actually is
PA12 is a polyamide — a nylon — built from laurolactam, which gives it a long, flexible carbon chain between the amide groups that do the hydrogen bonding. That structure is why PA12 is the SLS default rather than PA6 or PA66: the longer chain means lower water absorption, a lower melting point, and a much wider processing window, so it sinters into a dense, dimensionally stable part instead of warping. It absorbs roughly 0.4–0.7 % moisture at equilibrium, an order of magnitude less than PA6, and that stability is the whole reason your part fits the next day and the next month.
Mechanically it behaves like a tough engineering plastic rather than a brittle one: around 48–50 MPa tensile with 15–25 % elongation, which is why SLS nylon parts survive being dropped, bolted, flexed and used. Thin sections act as living hinges and outlast the assembly they are in. It resists oils, greases, fuels, alkalis and most solvents, and it has no UV post-cure step, so there is no cure-related dimensional drift and the parts keep indefinitely.
What it is not: a cosmetic material. The laser fuses powder particles, so the surface keeps a fine granular texture, and the natural colour is grey or white with limited depth when dyed. Fine detail is coarser than SLA. The parts are slightly porous as they come out of the machine and need sealing if they have to hold water or air. And it is not food-safe or implant-grade without a specific certified material, whatever the colour looks like. Used inside those limits, SLS nylon is the most useful material most clients order a second time.
PROPERTIES
Mechanical, Thermal & Chemical Data
Typical values for SLS PA12. The two figures that decide most applications are the elongation and the water absorption — both are why PA12 took over from earlier nylons.
Density1.01 g/cm³
Tensile strength48 – 50 MPa
Elongation at break15 – 25 % — it deforms before it fractures, which is why it survives handling
Tensile modulus~1.6 – 1.8 GPa — flexible in thin sections, stiff enough in thick ones
Impact behaviourTough. Unnotched impact strength is high; the material is not sensitive to stress concentrations in the way a brittle plastic is.
Working temperature~120 °C heat deflection; melting point around 178 – 184 °C
Water absorption~0.4 – 0.7 % at saturation — low for a nylon, and the reason PA12 holds dimensions where PA6 would not
Chemical resistanceGood against oils, greases, fuels, alkalis and most solvents. Attacked by concentrated acids, phenols and some chlorinated hydrocarbons.
UV resistanceModerate. Unprotected parts yellow and embrittle outdoors over months; an opaque dye, paint or a UV-stable coating extends life.
PorositySlightly porous as built. Sealing or impregnation is required for anything that has to hold water, air or pressure.
MachinabilityMachines like a soft engineering plastic. Tapping works, but heat-set inserts give more reliable threads.
Number of finishesBead blasting, dyeing, vapour smoothing, sealing, painting and machining are all available — see the finishing section.
Food contact / medicalNot food-safe or implant-grade as a default material. A specifically certified grade is needed for either, and we will say so rather than imply it.
RecyclabilityUn-sintered powder is recovered and re-used in governed proportions; the printed part itself is not routinely recycled.
GRADES & VARIANTS
Nylon Grades & Variants
Four grades cover almost everything. The choice is nearly always between stiffness and toughness, and occasionally hardness.
PA12 Glass-Filled
STIFFRigid and dimensionally stable under load — for brackets, mounts and structural parts where plain nylon flexes too much. Slightly more abrasive surface and a little less elongation.
High stiffnessStructuralLow creep
PA11 Nylon
TOUGHBio-based nylon with better impact resistance and elongation than PA12. Preferred for parts that get knocked around and for snap-fits that are cycled repeatedly.
Impact resistantHigh elongationBio-based
TPU / Flexible
ELASTICPowder-based elastomer for gaskets, grips, shock absorbers and living parts that need to bend and return. Shore hardness options available — tell us the stiffness you need.
FlexibleGasketsGrips
PA11, PA12 glass-filled and TPU are all run in-house. If your application needs a specifically certified food-contact or medical grade, say so at enquiry stage — that is a material qualification question, not a colour choice.
FINISHING
Finishing SLS Nylon
An SLS part comes out functional but unfinished. These are the operations that turn it into something an end user can hold.
Depowdering & bead blasting
Loose powder is blasted out of every cavity and the surface is cleaned to a uniform matte finish. Standard on every SLS order, and the step that makes the part feel finished.
Vapour smoothing
A controlled solvent vapour melts the surface micro-texture, giving a sealed, near-glossy skin and better water resistance. Watch for slight dimensional loss on fine features — tell us if a tight fit matters.
Dyeing
Parts dyed black or a custom colour. Grey and white are the natural states; dyeing is what gives a uniform appearance for a customer-facing unit.
Sealing & impregnation
A sealant or resin impregnation makes the part watertight and paint-ready. Essential for anything that holds fluid or pressure.
Tapping & threading
Threads are usually cut rather than printed — we tap the printed boss, or install a metal insert for anything that will be assembled more than once.
Insert installation
Heat-set brass inserts give reliable, re-usable machine-screw threads in a printed nylon boss.
Machining & facing
Mating faces, bores and seating surfaces machined flat where the printed tolerance is not enough on its own.
Painting & priming
Sealed and primed parts take a normal paint system, including colour matching to a client reference for visible enclosures.
WHERE IT FITS
Where Nylon Fits Best
Nylon is what we recommend when the part has to work, the geometry is complicated, or the quantity does not justify tooling. Here is where it wins and where it does not.
Strengths
- No supports and no support marks — complex geometry costs nothing extra
- Genuinely tough, functional parts that take load and impact
- Live hinges, snap-fits and thin flexible walls all work
- Multiple parts nest in one build, so per-part cost falls with quantity
- No tooling, so low volumes and one-offs are economical
- Chemically resistant to oils, greases, fuels and alkalis
- No UV post-cure, so no cure-related dimensional drift and a long shelf life
- Bead-blasted surface is easy to paint, dye or seal
Limits to know
- Surface is matte and granular, not glossy — SLS is not a cosmetic process
- Natural colour options are limited to grey, white and black; dyed depth is limited
- Parts are porous by default and need sealing to hold water or air
- Fine detail is coarser than SLA: 0.4 mm features are the practical limit
- Thin features can warp slightly as the part cools inside the powder bed
- Not food-safe or implant-grade without a specific certified material
- Absorbs a little moisture, so dimensions can drift by a fraction of a percent over the first days
Functional prototypes
A part you can bolt onto the real assembly and test — not a display model. This is the single most common reason clients use SLS.
Enclosures and electronics housings
Bosses, vents, snap-fit lids and internal ribs in one printed piece, with heat-set inserts for repeatable assembly.
Ducting and air routing
Smooth internal paths with no support material to dig out. Vapour smoothing or sealing makes the part airtight.
Gears, cams and living hinges
Tough nylon with natural lubricity, and thin sections that flex for millions of cycles without cracking.
Jigs, fixtures and end-effectors
Lightweight custom tooling and robot grippers, produced in days instead of weeks and easily modified for the next revision.
Drone and robot frames
Complex, weight-optimised structural parts with integrated cable routing, in a material that survives crashes.
Low-volume end-use production
When you need 20 to 500 units and injection tooling is not yet justified, SLS is the bridge.
Historic and replacement parts
Obsolete brackets and one-off components, printed from a scan or a reverse-engineered model.
COMPARISON
How PA12 Compares
PA12 sits between resin on detail and metal on strength, and it is the only material on this list that needs no supports at all.
| Material | Process | Density | Strength | Heat | Pick it when |
|---|---|---|---|---|---|
| Ti-6Al-4V | SLM | 4.43 g/cm³ | 900–1100 MPa | ~400 °C | Strength per gram, or biocompatibility |
| 316L stainless | SLM | 7.9 g/cm³ | 480–620 MPa | ~400 °C | Corrosion resistance and ductility |
| AlSi10Mg | SLM | 2.67 g/cm³ | 330–400 MPa | ~170 °C | Light, thermally conductive, machinable |
| Copper & Cu alloys | SLM | 8.9 g/cm³ | 210–400 MPa | ~200 °C | Electrical or thermal conductivity |
| PA12 nylon | SLS | 1.01 g/cm³ | 48–50 MPa | ~120 °C | Tough, complex geometry, no supports, low volume |
| Photopolymer resins | SLA | ~1.1–1.2 g/cm³ | 40–70 MPa | ~80 °C | Detail, smoothness, transparency |
The usual decision is PA12 against SLA resin. Resin wins on surface and fine detail; nylon wins on toughness, temperature and complexity, and it wins outright as soon as the part has to be used rather than looked at. Above a few dozen units SLS also starts winning on price, because parts nest in the build and complexity is free.
FAQ
PA12 nylon — Common Questions
Does SLS really need no supports?
Correct — the un-sintered powder bed supports the part on all sides. That is why overhangs, internal cavities and nested assemblies come out clean with no marks to sand away, and why geometry that would be awkward in another process is simply not a problem here.
How strong is a PA12 part?
PA12 comes out around 48–50 MPa tensile with 15–25 % elongation, so it behaves like a tough engineering plastic rather than a brittle one. Glass-filled grades trade some elongation for stiffness; PA11 trades a little strength for more impact resistance.
Why does my part look grainy?
That is the process signature — the laser fuses powder particles, and the surface keeps the texture of the un-melted powder around it. Bead blasting is included and evens it out; vapour smoothing makes it glossy if you need a cosmetic finish.
Are SLS parts waterproof?
Not out of the machine — they are slightly porous. We seal or impregnate them when watertightness matters, or vapour-smooth the surface to close it. Tell us what the part has to hold at enquiry stage so it is included in the quote rather than added afterwards.
Can I get a colour other than grey?
Yes. Grey and white are the natural states, black is the most common dye, and we can match a custom colour on request. Deep saturation is harder than on an injection-moulded part, so send us a reference and we will tell you honestly how close we can get.
Is PA12 food-safe?
Not as a default material. Food-contact use needs a specifically certified grade and a documented process, which is a different qualification exercise. If you need it, ask at enquiry stage and we will tell you what is and is not available rather than implying a general-purpose nylon is acceptable.
GET STARTED
Upload the Part, Not Just the Idea
Drop an STL, OBJ or 3MF for an instant indicative price, or send the assembly drawing and we will tell you whether nylon is right, whether it needs sealing or vapour smoothing, and what the alternatives cost.
Built for global product teams · Worldwide shipping via DHL / FedEx / UPS