In the world of industrial 3D printing , fiber-reinforced filaments are a premium choice for producing strong, stiff, and lightweight parts. The debate often centers on PA12CF vs PA12CKF (carbon-fiber-loaded filament versus carbon-aramid—or carbon-Kevlar—loaded filament). Both are based on PA12, a polyamide with excellent mechanical and chemical properties, but they differ in reinforcement type: PA12CF is loaded exclusively with carbon fiber, whereas PA12CKF combines carbon fiber with aramid (Kevlar) fibers.
Below you’ll find a table comparing the main mechanical properties reported in the technical data sheets, referencing typical values for 3D printing (where available) and injection molding.
Mechanical Properties Comparison Table
| Property | PA12 CF (3D Printing) | PA12 CF (Injection Molding) | PA12 CKF (Injection Molding) |
|---|---|---|---|
| Density [g/cm³] | 1.08 (theoretical) | 1,051 | 1,07 |
| Charpy Impact Strength (unnotched) | 55 kJ/m² | 60 kJ/m² | 35 kJ/m² |
| Charpy Impact Strength (notched) | 14 kJ/m² | 16 kJ/m² | 8 kJ/m² |
| Elongation at Break [%] | 7 | 4,9 | 5,4 |
| Tensile Strength at Break [MPa] | 50 | 125 | 70 |
| Tensile Modulus [MPa] | 3650 | 8900 | 4500 |
| Recommended Extrusion Temperature [°C] | 220 - 250 | – | 200 - 220 (filament) |
| Recommended 3D Printing Temperature [°C] | 220 - 240 | – | 250 - 255 |
| Material Drying [h °C] | 4 h @ 90°C | – | 4 h @ 80°C (filament) |
Data Analysis in Table
- Density: Both filaments have very similar density values, around 1.07 – 1.08 g/cm³. This means that the weight of printed parts varies little between PA12CF and PA12CKF, making both suitable where a low specific weight is required.
- Charpy Impact Resistance: PA12CF (injection-molded and 3D-printed) exhibits higher values, indicating good resilience. The aramid contribution in PA12CKF does not necessarily enhance impact resistance significantly, yet it can positively affect the part’s tribological properties and elasticity.
- Elongation at break: I valori sono abbastanza simili (4,9% – 7% per PA12CF e 5,4% per PA12CKF). Il PA12CF 3D dimostra un allungamento leggermente più elevato rispetto all’iniezione, indicando che il processo di stampa 3D può favorire un minore orientamento delle fibre e quindi una maggiore duttilità.
- Tensile strength at break: Injection molding and 3D printing are distinct manufacturing methods, so the values must be interpreted with caution. For PA12CF, the peak of 125 MPa in injection molding highlights the maximum potential of the formulation, whereas in 3D printing it drops to 50 MPa. PA12CKF in injection molding settles at 70 MPa, an intermediate value: the aramid addition slightly dampens the pure tensile strength of the carbon fiber, yet delivers other benefits (e.g., reduced wear).
- Elastic modulus: Injection moulding aside, in 3D printing PA12CF settles at around 3650 MPa, enough to give the part good stiffness. PA12CKF reaches 4500 MPa when injection-moulded, showing higher rigidity than a standard PA12 but lower than injected PA12CF (8900 MPa).
- Printing conditions: Both require drying to prevent moisture-related defects. The recommended extrusion temperatures for PA12CF (220-240°C) and for PA12CKF (250-255°C) fall within a typical range for technical filaments. It is always recommended to use a hardened steel nozzle given the abrasiveness of the fibres.
When to Choose PA12CF and When to Choose PA12CKF
- PA12CF (carbon-fiber-filled filament): ideal for those seeking high stiffness and good impact resistance. Recommended for mechanical and structural applications where weight must be kept low, such as automotive components or drone parts.
- PA12CKF (carbon- and aramid/Kevlar-loaded filament): delivers an attractive balance of stiffness and enhanced wear resistance thanks to the aramid content. If you need an aramid filament for applications where friction and abrasion are critical factors, this option can give you an edge.
Conclusion
In short, the choice between carbon- and kevlar-filled filament (PA12CKF) and carbon-filled filament (PA12CF) depends on project priorities: if maximum stiffness and good impact performance are required, PA12CF is an excellent option; if greater versatility in terms of wear resistance and good machinability is needed, carbon kevlar may be the most suitable solution.
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