Your Guide to SLS: Advantages, Materials, and Best Practices
Selective Laser Sintering for complex, functional prototypes and end-use parts. Advantages, materials, design guidelines, and faster production.
Read the ArticlePA12-AF 3D Printing Material
Selective Laser Sintering (SLS) · Composites
Aluminum-filled nylon with a metallic look and high stiffness.
What Is PA12-AF?
Aluminum-filled PA12 (often called Alumide) blends fine aluminum powder into nylon for high stiffness, thermal stability, and a distinctive metallic-gray appearance. It suits demanding engineering parts, tooling, and components where a metal-like finish and rigidity are valued.
Aluminum-Filled Nylon PA12 (Alumide) - SLS, printed with Selective Laser Sintering (SLS). Every order is reviewed by our engineering team - no minimum order quantity.
When to choose PA12-AF
Choose PA12-AF (Alumide) when your part needs the highest stiffness available in SLS nylon and the metallic-gray appearance adds functional or aesthetic value. At 3,517 MPa flex modulus and 180 °C HDT, Alumide is the stiffest and most heat-resistant filled nylon in this catalog.
The metallic look sets Alumide apart: tumbled and polished Alumide parts resemble light die-cast metal. For prototypes that must look and feel metallic without the cost of CNC machining, Alumide delivers. It is widely used for automotive show parts, motorsport components, and demonstration models.
If metallic appearance does not matter and you need stiffness at lower weight, PA12-GF is lighter (1.30 vs 1.35 g/cm³) and nearly as stiff (3,300 MPa). If your part needs toughness alongside stiffness, neither filled nylon delivers - unfilled PA12 or PA11 are tougher. Alumide is brittle (3–5% elongation) and will crack under impact.
Material Properties
Representative values - process- and orientation-dependent. Full technical datasheet available on request.
Process
Selective Laser Sintering (SLS)
Tensile strength
43 MPa
Elongation at break
3–5%
Flexural modulus
3,517 MPa
Heat deflection (HDT)
180 °C @ 0.45 MPa
Density
1.35 g/cm³
Max build size
≈ 350 × 350 × 550 mm
Min wall thickness
1.0 mm
Resolution / layer
≈ 110 µm
Relative cost
$$$ (1 = lowest, 4 = highest)
Design Guidelines
Plan features to print reliably and assemble cleanly in PA12-AF. Need DFM help?
Min wall
1.0 mm - 1.5 mm+ for load
Min feature
0.8 mm - fine detail limit
Min hole Ø
1.5 mm - prevents powder entrapment
Surface
Metallic gray - can be polished
Dimensional tolerances
Typical tolerance is ±0.3 mm or ±0.3%. The aluminum fill provides very good dimensional stability - thermal contraction is lower than unfilled PA12 or PA12-GF. Large flat parts remain notably flat. Post-machining is available; the aluminum content does not significantly affect machinability - standard HSS tooling works, though carbide produces better surface finish.
Printing notes
PA12-AF (Alumide) parts are produced on industrial SLS systems. The process uses standard laser sintering with aluminum-powder-blended nylon. The aluminum content (approximately 30–40% by weight) significantly increases part density and changes thermal behavior during sintering. Laser parameters are adjusted for the metal fill. Cooling cycles must be controlled - aluminum's thermal conductivity means heat dissipates differently than pure nylon. Surface finish is characteristically metallic-gray and slightly granular. Tumbling and polishing bring out a noticeable metallic sheen. No supports are needed - powder bed self-supports all geometry.
How PA12-AF Compares
PA12-AF alongside related materials.
| PA12-AF | PA12-GF | PA12 (SLS) | ULTEM 9085 | |
|---|---|---|---|---|
| Tensile strength | 43 MPa | 38 MPa | 48 MPa | 42–69 MPa |
| Heat deflection (HDT) | 180 °C @ 0.45 MPa | 175 °C @ 0.45 MPa | 154 °C @ 0.45 MPa | 153 °C @ 1.82 MPa |
| Flexural modulus | 3,517 MPa | 3,300 MPa | 1,730 MPa | 2,050–2,300 MPa |
| Elongation | 3–5% | 3–5% | 15–20% | 5–6% |
| Density | 1.35 g/cm³ | 1.30 g/cm³ | 1.01 g/cm³ | 1.34 g/cm³ |
| Relative cost | $$$ | $$$ | $$$ | $$$$ |
When to Use PA12-AF
Where PA12-AF fits, where it doesn't, and what to use instead.
Prototypes that must look like die-cast metal
Tumbled Alumide closely resembles light die-cast aluminum in color and heft - lets design teams present functional prototypes with a metallic look at a fraction of CNC cost.
AutomotiveStiff tooling, drill jigs, and assembly fixtures
3,517 MPa flex modulus - the highest in our SLS nylon catalog - resists deflection under clamping and drilling forces through hundreds of production cycles.
EngineeringHeat-exposed brackets and motor mounts
180 °C HDT - 5 °C above PA12-GF - provides the best thermal stability of any filled nylon for parts near heat sources and exhaust paths.
AutomotiveMotorsport and show-car prototype parts
Metallic-gray surface with real heft (1.35 g/cm³) convinces stakeholders during review, while delivering functional stiffness for intake manifold prototypes and cooling duct brackets.
AutomotiveThermoforming molds and soft tooling
Survives 150–170 °C forming cycles with enough stiffness to hold mold cavity shape through 50–200 pulls before wear becomes significant.
EngineeringStrengths
- Highest stiffness in the SLS nylon catalog at 3,517 MPa flex modulus - 6% stiffer than PA12-GF (3,300 MPa) and 2x unfilled PA12
- Distinctive metallic-gray surface that polishes to a genuine aluminum sheen - the only 3D-printed material that convincingly simulates die-cast metal
- 180 °C HDT - the highest thermal stability of any filled nylon - combined with SLS design freedom for complex geometry
Keep in mind
- Brittle at 3–5% elongation, like PA12-GF - will crack under impact or snap-fit loads; unfilled PA12 or PA11 are required for toughness
- Heaviest nylon in the catalog at 1.35 g/cm³ (vs 1.01 for PA12) - the aluminum fill adds 34% density; use PA12-GF at 1.30 if weight matters more than appearance
- Not electrically or thermally conductive despite the aluminum fill - the aluminum particles are dispersed, not connected; use solid metal for conductive requirements
Not the right fit?
Lighter weight at similar stiffnessPA12-GF (SLS)Impact toughnessPA12 (SLS)
Actual metal strengthCNC Machined Aluminum
Finishes & Colors
Finishing options and in-stock colors for PA12-AF.
Standard
De-powdered metallic-gray matte finish.
Best for: Engineering parts
Polished / Tumbled
Brings out the metallic sheen.
Best for: Display and finished parts
In-Stock Colors
Metallic Gray
Black
Custom colors and dyeing available on request. Contact us for options.
PA12-AF FAQ
No - it is nylon filled with aluminum powder. It looks and feels metallic and is stiffer than plain nylon, but it is not a structural metal. For true metal parts, ask about CNC machining.
Yes. Tumbling and polishing bring out the aluminum sheen for a more finished, metallic appearance.
Choose Alumide when you want the metallic look and maximum stiffness (3,517 MPa vs 3,300 MPa). Choose PA12-GF when weight matters (1.30 vs 1.35 g/cm³) and appearance is secondary. Both are brittle - neither is suitable for impact-prone parts.
Yes, but many applications use the natural metallic-gray finish as-is or with polishing. If you need a specific color, the material accepts primer and paint like other SLS nylons. The metallic substrate can show through thin coats, which some customers use as a design feature.
Alumide is widely used for jigs, fixtures, and soft tooling. Its stiffness and heat resistance make it suitable for low-volume thermoforming molds, drilling jigs, and assembly fixtures that must hold dimensional accuracy under repeated use.
Alumide is roughly 50% the density of solid aluminum and far less strong (43 MPa vs 250+ MPa for 6061-T6). It is not a metal replacement for structural loads. Its value is in complex geometry, fast delivery, and the metallic look - at a fraction of the cost of CNC machining for low volumes.
We hold ±0.3 mm or ±0.3%. Alumide has very good dimensional stability due to the aluminum fill. Large flat surfaces stay notably flat compared to unfilled nylon. Post-machining is available for critical fits.
Alumide has slightly higher thermal conductivity than unfilled nylon due to the aluminum particles, but it is not thermally or electrically conductive in any meaningful engineering sense. For conductive parts, use metal.
Technical Documents
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