PA12 nylon 3D printing for parts that work under load, heat, and fluid
Nylon 3D printing in PA12 gives you a material for demanding applications: it keeps its strength in every direction, comes out of the build watertight, and takes heat and load at the same time. It's certified for skin contact and tested for electrical properties, so a part can go from the printer into service without a second material behind it.
AT A GLANCE
Tensile strength (6,960 psi), the same in XY and Z.
A 1.25 mm (0.049 in) wall holds 3 bar (44 psi) in HP's testing.
Tested for irritation, acute systemic toxicity, and implantation, alongside US FDA guidance for devices on intact skin.
Heat deflection temperature at 0.45 MPa (66 psi), and 95°C (203°F) at 1.82 MPa (264 psi).
THE MATERIAL
What is PA12 nylon?
PA12 nylon, also called polyamide 12, is an engineering thermoplastic used for functional prototypes and end-use parts. Printed on HP Multi Jet Fusion, it produces dense parts with balanced mechanical properties, resistance to oils, greases, aliphatic hydrocarbons, and alkalies, and watertightness with no coating applied.
Picking a material usually means giving something up: enough stiffness to carry load, and the part cracks where it needs to flex. PA12 carries the load and still takes the snap fit, and it resists oils and unleaded petrol without a coating to protect it, which is why a part validated as a prototype can go into production in the same material.
Tensile modulus (261 ksi): stiff enough to carry load, and it still takes a snap fit.
Reused powder in every build.
UNDER LOAD
PA12 3D printing properties
PA12 on MJF is near isotropic: tensile strength, modulus, and flexural properties come out the same in XY and Z.
| Property | XY | Z | Test method |
|---|---|---|---|
| Tensile strength | 48 MPa(6,960 psi) | 48 MPa(6,960 psi) | ASTM D638 |
| Tensile modulus | 1,800 MPa(261 ksi) | 1,800 MPa(261 ksi) | ASTM D638 |
| Elongation at break | 20% | 15% | ASTM D638 |
| Flexural strength (@ 5%) | 70 MPa(10,150 psi) | 70 MPa(10,150 psi) | ASTM D790 |
| Flexural modulus | 1,800 MPa(261 ksi) | 1,800 MPa(261 ksi) | ASTM D790 |
| Notched Izod impact (3.2 mm / 0.126 in, 23°C / 73°F) | 3.6 kJ/m² | 3.5 kJ/m² | ASTM D256, Method A |
| Shore D hardness | 80 | 80 | ASTM D2240 |
| Heat deflection @ 0.45 MPa (66 psi) | 175°C(347°F) | 175°C(347°F) | ASTM D648, Method A |
| Heat deflection @ 1.82 MPa (264 psi) | 95°C(203°F) | 95°C(203°F) | ASTM D648, Method A |
| Part density | 1.01 g/cm³(0.036 lb/in³) | ASTM D792 | |
| Powder melting point (DSC) | 187°C(369°F) | ASTM D3418 | |
| Particle size | 60 µm(0.002 in) | ASTM D3451 | |
Typical values from HP's PA12 technical datasheet (4AA6-4895ENA), published as representative averages, not as specification values.
IN SERVICE
Watertight 3D printing
A part that passes on the bench still has to hold up where it gets installed, and that's usually next to a motor, beside a live connector, or in the path of a fluid. PA12 parts hold liquid as printed, which lets you design parts with internal channels for fluid to run through, or an electronics enclosure that has to stay sealed.
Pressure is a design question more than a material one. Wall thickness, shape, temperature, and the fluid itself set the limit, and the rounder the vessel, the more pressure it holds before the wall gives.
| Fluid | Effect |
|---|---|
| Diluted alkalis | No effect |
| Concentrated alkalis | No effect |
| Chlorine salts | No effect |
| Alcohol | No effect |
| Esters | No effect |
| Ethers | No effect |
| Ketones | No effect |
| Aliphatic hydrocarbons | No effect |
| Aromatic hydrocarbons | No effect |
| Toluene | No effect |
| Motor oil | No effect |
| Unleaded petrol | No effect |
| DOT 3 brake fluid | No effect |
| Hot water | Moderate effect |
| Chlorinated hydrocarbons | Moderate effect |
| Trichloroethylene | Moderate effect |
Fluid resistance testing on PA12, HP white paper 4AA7-2720ENW. Download the full test (PDF) ↗
Heat and electrical insulation
Heat and current are the other two conditions the same part meets once it's installed. PA12 holds its shape under load up to the temperatures in the properties table, with the lighter load reaching further than the heavier one, and it insulates rather than conducts, which is what UL evaluated under 746A.
Dielectric strength (71 V/mil), certified under UL 746A
Volume resistivity, certified under UL 746A
TOLERANCES
PA12 tolerances by size and axis
These are our PA12 tolerances by nominal dimension and by axis, at a measured capability of Cpk 1.33, the minimum automotive and aerospace set for production.
| Nominal dimension | XY | Z |
|---|---|---|
| 0–30 mm (0–1.18 in) | ±0.25 mm(0.010 in) | ±0.42 mm(0.017 in) |
| 30–50 mm (1.18–1.97 in) | ±0.30 mm(0.012 in) | ±0.50 mm(0.020 in) |
| 50–80 mm (1.97–3.15 in) | ±0.37 mm(0.015 in) | ±0.60 mm(0.024 in) |
| Gap between mating faces | 0.4 mm (0.016 in), ±0.2 mm (0.008 in) per part | |
| Hole for a threaded insert | ±0.2 mm(0.008 in) | |
The three dimensional bands are measured capability. The last two rows are design recommendations and carry no capability index.
Two of the conditions behind them are fixed on every order: the refresh ratio that keeps the powder bed stable, and natural cooling. The orientation that produced a part stays on file, so the second batch is built the way the first one was. Geometry still moves the result.
Design decides whether your part lands comfortably inside these tolerances.
How to design for tolerance: MJF design guide ↗CERTIFICATIONS
PA12 nylon certifications
| Certification | Scope |
|---|---|
| USP Class I-VI | Biocompatibility of the material: irritation, acute systemic toxicity, and implantation |
| US FDA guidance | Intact skin surface devices |
| UL 94 | HB at 0.75 mm (0.030 in) |
| UL 746A | Short-term property evaluation for electrical end products |
| RoHS | EU and 11 additional regions |
| EU REACH | Compliant |
| PAHs | Polycyclic aromatic hydrocarbons: none of those tested were detected in printed parts |
APPLICATIONS
What PA12 nylon 3D printing builds
Aerospace and drones
Lightweight housings, fairings, and interior components.
Automotive and transportation
Clips, brackets, housings, and interior components.
Complex and moving assemblies
Hinges, snap fits, and interlocking parts printed in one piece.
Consumer and sports products
Eyewear frames, buckles, and components for bicycles and gym equipment.
Electronics and electrical
Enclosures, connector housings, and covers for sensors and control units.
Fluid handling
Manifolds, internal channels, and sealed housings that carry liquid and resist oils and unleaded petrol.
Industrial and manufacturing
Jigs, fixtures, assembly tools, and machine components that stay on the line.
Medical and orthotics
Orthotic and prosthetic components and other devices that sit on intact skin.
Finishing options for nylon 3D printing in PA12
Black dye
Colors the part through its surface rather than on top of it, so a batch of end-use parts leaves in one consistent black.
Shot peening
Evens out the as-printed texture and removes the last of the loose powder, with nothing added to the part.
Cerakote
A thin-film ceramic coating applied in a single layer, bringing scratch and abrasion resistance, UV stability, and chemical resistance to the part, in a wide range of colors.
Heat-set inserts
Brass threads set with heat, for joints assembled and taken apart frequently for service or repair.
FAQ
Nylon 3D printing in PA12: common questions
The figures that matter are heat deflection, not the melting point: 175°C (347°F) at the lighter test load and 95°C (203°F) at the heavier one. UL's abnormal heat resistance test on the material came back at 172°C (342°F).
HP tested it to USP Class I-VI and to US FDA guidance for intact skin surface devices, covering irritation, acute systemic toxicity, implantation, cytotoxicity per International Organization for Standardization (ISO) 10993-5, and skin sensitization per ISO 10993-10. That certifies the material, not a finished device, which its manufacturer validates for its intended use.
Up to 80% of the surplus powder from earlier builds goes back in, with the balance fresh, at the minimum refresh ratio specified for stable performance. Holding that ratio is what keeps nylon 3D printing consistent from one order to the next, which is why reuse doesn't get pushed further.
The table covers features up to 80 mm (3.15 in). Beyond that, the tolerance depends on the feature and on how the part sits in the build, and the design guide works through both. A part that doesn't fit the build gets split and bonded, and the seam is placed where it does the least harm to the part.
Tolerances by feature and size: MJF design guide ↗Yes, and it's one of the finishes we quote most. Brass inserts are set into the part with heat, and they're the right call where a joint gets taken apart frequently for service or repair. Insert size and how many each part takes are decided per part, so send the requirement with the file and it gets quoted manually.
Quote your PA12 parts
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