PA12 (Polyamide 12)
polymersemi-crystalline thermoplastic polyamide
Nylon 12PA 2200 (EOS)HP 3D HR PA 12Polyamide-12Lauryl lactam polymer
Mechanical & thermal properties — 2 conditions
| Property | SLS as-built (isotropic, 50:50 refresh) | MJF as-built (HP, 30% refresh) |
|---|---|---|
| Elastic modulus | 2–2 GPa | 2–2 GPa |
| Yield strength (0.2%) | 44–52 MPa | — |
| Ultimate tensile strength | 44–52 MPa | 47–54 MPa |
| Elongation at break | 8.0–25.0 % | 12.0–25.0 % |
| Hardness (HV) | 68–82 HV10 | — |
| Density | 0.88–0.96 g/cm³ | 0.97–1.01 g/cm³ |
| Thermal conductivity | 0.2 W/m·K | — |
| Specific heat | 1700 J/(kg·K) | — |
| Glass transition (Tg) | 45–55 °C | — |
| As-built surface Ra | 9.0–20.0 µm | — |
Values shown as min–max where a spread is reported, otherwise as typical ± unit. Ranges reflect inter-source variation, not single-sample scatter. All values are for AM-processed specimens unless noted.
Engineering considerations
- Powder refresh ratio is the most important process control variable. For structural parts, enforce ≤50% recycled powder. For cosmetic parts, ≤30%. Run tensile coupon qualification tests at each production batch.
- Wall thickness: minimum functional wall 0.8 mm (SLS), 1.0 mm (MJF) for structural parts. Thin walls below 1.5 mm show higher property scatter. Avoid sharp internal corners (min fillet R = 0.5 mm) to prevent stress concentrations.
- Thermal annealing after printing (150°C/2h) can improve crystallinity by 3–5%, increasing stiffness and reducing elongation scatter. Not always beneficial — evaluate for each application.
- Vapour smoothing: acetone-amine vapour (IPA + isopropylamine) produces Ra <1 µm and seals inter-particle porosity. Enables pressure-tight parts and food-contact surfaces (with FDA-compliant PA12 grade). Removes ~50–100 µm material — account for in final dimensions.
- Dyeing: SLS PA12 parts accept industrial dyes uniformly (surface to 0.5 mm depth). Black dye provides UV protection and is standard for automotive parts. Colour consistency requires controlled powder age.
- Moisture pre-conditioning: if mechanical properties at equilibrium moisture are needed for design, pre-condition specimens per ISO 1110 (70°C/62% RH) before testing. Dry-as-moulded properties are not representative of service.
- Biocompatibility: EOS PA 2200 is CE-marked for non-implantable medical devices (Class I/IIa). HP PA12 is also biocompatible. Implantable devices require ISO 10993 testing and regulatory approval beyond material compliance.
- Fire: untreated PA12 burns — does not pass UL94 V-0 without flame-retardant additives. Use PA12-FR grades or surface coatings for electrical enclosures and aerospace interior parts.
Advantages
- Near-isotropic properties — support-free powder bed process eliminates the layer delamination weakness of FDM
- No support structures required — complex internal channels, interlocking parts, and undercuts are all feasible
- Well-established process: widest machine ecosystem of any AM process (EOS, Farsoon, Sinterit, HK, Formlabs Fuse, HP MJF)
- Good chemical resistance to oils, greases, weak acids, and many solvents
- Low moisture absorption (0.25% water uptake vs 1.5% for PA6) — more stable in humid environments
- Biocompatible grades available — CE-marked medical device applications
- Excellent surface finish achievable post-process: vapour smoothing, tumbling, electroplating, dyeing
- Design freedom: undercuts, lattices, and complex internal channels without supports
Limitations
- Powder reuse critically affects properties — elongation and surface quality degrade rapidly above 50% recycled ratio
- UV degradation: PA12 yellows and loses strength in prolonged UV exposure — stabiliser or coating required for outdoor use
- Moisture sensitivity in service: PA12 absorbs water (0.25%) which acts as plasticiser, reducing modulus ~10–15% at equilibrium
- Low maximum service temperature: HDT ~163–175°C but continuous-load limit ~60–80°C. Not suitable for elevated-temperature environments
- Limited strength and stiffness vs. engineering polymers — POM, PEEK, or filled PA achieve higher mechanical performance
- As-built surface is porous (SLS, 3–8%) — not suitable for pressure-tight components without post-infiltration
- Powder handling and storage: PA12 powder must be kept dry (desiccant storage) and below oxidation temperature; process atmosphere is N₂
- Dimensional accuracy: ±0.3% typical (minimum ±0.3 mm) — not suitable for high-precision applications without post-machining
Typical applications
Functional prototypes and end-use parts for automotive interiorsAir ducts, fluid manifolds, and complex flow-path geometriesSnap-fit assemblies, living hinges, and flex-jointsMedical device housings and surgical guides (biocompatible grades)Consumer product enclosures and electronic device housingsJigs and fixtures for manufacturing and assemblyAthletic equipment and customised sports insolesAerospace interior parts (non-structural)Complex interlocking assemblies printed-in-placeLow-volume production runs where tooling cost is prohibitive
Industries
automotiveaerospaceindustrialconsumermedical
Standards & certifications
ASTM-E8established
Tensile testing per ASTM D638 (preferred for polymers — ASTM-E8 is for metals; note: polymer labs typically use D638)
aerospaceautomotiveconsumer
ASTM D638 is the correct polymer tensile standard. D638 Type I specimens. Some labs cross-reference ASTM E8 for comparability with metal data.
ISO-52904established
Process quality assurance for safety-critical PBF parts (applies to SLS/MJF polymers for medical applications)
medicalaerospace
Compatible AM processes (2)
Other polymer materials
Related calculators
PackingBuild-chamber utilisation, virgin powder consumption, refresh cost, and cost/part for SLS and MJF. EOS P396, HP MJF 5200/4200, Farsoon 403P presets.RoughnessTheoretical Ra and Rz from layer thickness and surface angle (staircase effect). Upward, downward, and vertical faces. LPBF, SLS, FDM, SLA, DED. Per Grimm et al.Build Time EstimatorPer-process build time from part volume, layer count, and machine throughput. LPBF, SLS, FDM, SLA, DED, binder presets included.Shrinkage CompensationPer-axis scale factors for sintering (binder jet, MIM-AM) and resin cure (SLA/DLP) shrinkage. Inputs: green density, target density, material class.
Last reviewed: 2026-05-04 · v1 · Sources: eos-pa2200-2023, hp-pa12-2023, zarringhalam-2006-pa12, wegner-2011-pa12, stichel-2017-pa11, debroy-2018-review