Examid® PA-CF — carbon-fiber polyamides (carbon nylons) for structural applications
Examid® PA-CF for structures where stiffness, low weight and geometric repeatability are critical
PA-CF is worth designing into a project for assemblies where specific stiffness, low CLTE, deflection stability, dimensional accuracy and the mass-to-size efficiency of a molded part become decisive.
In PA-CF, the fiber percentage is only a starting parameter. The real behavior of the part is shaped by the matrix, the residual fiber length after plastication, flow orientation, interfacial adhesion, moisture, temperature and the geometry of the assembly.
The buttons are placed after the key PA-CF explanation so the reader can jump straight to the section they need.
PA-CF — a short-fiber structural composite with its own logic of design, molding and assembly calculation
In unfilled polyamide the matrix itself plays the key role: crystallinity, melting temperature, moisture absorption, melt viscosity and load-bearing capability. In PA-CF part of the load is transferred to the carbon fiber, shrinkage becomes lower and more anisotropic, and the modulus increases severalfold.
The designation CF20, CF30 or CF40 is meaningful only together with the matrix and the processing context. The same CF content in different polyamides yields different levels of shrinkage, creep, impact endurance, electrostatic profile and dimensional stability after molding.
Before selecting PA-CF, the geometry, loads and melt flow path must be analyzed even before choosing a grade
Carbon fiber increases modulus and reduces deformation, but in a molded part the result is determined by the flow path through the mold, fiber orientation, weld-line zones and the actual loading regime.
CF30 in the grade name: which parameters actually determine part performance
Matrix
PA6, PA66, PA610 and PPA set different levels of heat resistance, moisture absorption, chemical resistance, creep and processability.
Interphase
Reinforcement efficiency depends on load transfer across the “polyamide–CF” interface. With insufficient adhesion, a high fiber content is not realized in the modulus, strength and service life of the part.
Residual fiber length
During compounding and molding the fiber is shortened. Excessive shear in the screw or in narrow channels can reduce reinforcement efficiency.
What carbon fiber actually changes in polyamide
The key value of PA-CF lies in higher specific stiffness, lower thermal expansion, less deflection under load, tighter control of geometry and the ability to build an electrostatic or conductive profile within a polyamide matrix.
| Material / grade | Reinforcement type | Actual modulus for comparison | Engineering meaning |
|---|---|---|---|
| Examid® PA6 GF30 | 30% glass fiber | 8 800 MPa · flexural modulus | The baseline glass-filled polyamide: good price, processability and sufficient stiffness for many housing parts. |
| Examid® PA6 GF50 R10 | 50% glass fiber | ~16 500 MPa · flexural modulus | High stiffness on a PA6 base without switching to a CF system; rational when price and familiar processing matter more than minimal CLTE. |
| Examid® PA6 GF20/CF10 | 20% GF + 10% CF | 12 000 MPa · flexural modulus | A hybrid option: part of the CF advantage in geometry and stiffness with softer economics and better impact behavior. |
| Examid® PA6 CF30 | 30% carbon fiber | 17 000 MPa · flexural modulus | The processing-friendly entry into PA-CF: high stiffness, low shrinkage, dark surface and a conductive profile, but higher demands on the mold and equipment. |
| Examid® PA66 CF30 family | 30% carbon fiber | 17 500–18 800 MPa · flexural modulus | The core structural zone for load-bearing molded parts where PA6 CF30 is no longer sufficient in heat resistance or stability. |
| Examid® PA66 CF40 J6 | 40% carbon fiber | 24 000 MPa · tensile modulus | The top stiffness of PA66-CF in this line. Use it where deflection is more critical than impact ductility and processing simplicity. |
| Examid® PA610 CF30 | 30% carbon fiber | 20 000 MPa · flexural modulus | CF stiffness with lower moisture drift than PA6/PA66; useful for precision fits and parts operating near moisture. |
| Examid® PPA CF33 / PA CF33 X | 33% carbon fiber | 20 800 MPa · flexural modulus | A higher temperature and dimensional level: when PA6/PA66 are already close to their limit in heat, moisture or geometric stability. |
Actual moduli of reinforced Examid® polyamides
PA6 CF30 versus PA6 GF30 and other reinforced polyamides: where carbon fiber delivers an engineering advantage
This block does not show “the best material overall”. It compares glass-filled, hybrid and carbon-fiber-filled polyamides by task profile: deflection, mass, dimensional accuracy, moisture, heat, impact, wear, molding and economics. The starting comparison shows PA6 CF30 versus PA6 GF30, and a third material can be added manually.
Property radar
higher = stronger positionHow to read the radar: PA6 GF30 and PA6 GF50 are often more rational in price and processing. PA-CF is needed when lower deflection, stable geometry, low CLTE, mass reduction and stiffer part behavior are critical. PA610 CF30 and PPA / PA CF33 make sense when moisture, temperature or elevated dimensional-stability requirements are added on top of stiffness.
The Examid® PA-CF range: matrix, reinforcement level, heat resistance, moisture risk and electrostatic profile
The Examid® PA-CF range should be viewed through the matrix, reinforcement level, modulus, moisture sensitivity, electrostatic profile and processing constraints. This makes it clear which task each grade addresses.
Examid® PPA CF33 J
PPA / CF33A semi-aromatic high-temperature platform for structural parts that require high modulus, thermal-cycling resistance, lower moisture drift and predictable mechanical behavior. Per TDS: 33% CF, density 1.29 g/cm³, flexural modulus 20 800 MPa, tensile modulus 24 000 MPa, HDT 180°C at 1.8 MPa.
Examid® PA CF33 X
PA/PPA blend / CF33A blend of PA66 and semi-aromatic PPA for parts that need higher stability than typical PA66 CF, with more controlled economics compared to a full PPA level. Technically close to high-stiffness CF33 solutions.
Examid® PA612 CF40-T588
PA612 / CF40A low-moisture PA612 platform with 40% Torayca® M60J for parts where water absorption and the associated dimensional drift are unacceptable. Focused on modulus and geometry stability in humid, cyclic or long-term service regimes.
Examid® PA610 CF30
PA610 / CF30A grade for precision parts that need CF30-level stiffness where the water absorption of PA6/PA66 creates a fit-drift risk. Per TDS: density 1.28 g/cm³, flexural modulus 20 000 MPa, flexural strength 280 MPa, HDT 215°C at 1.8 MPa.
Examid® PA66 CF40 J6
PA66 / CF40A high-stiffness PA66 CF level for structural parts, brackets, housings and metal replacement where deflection is more critical than impact ductility. Per TDS: 40% CF, density 1.31 g/cm³, tensile modulus 24 000 MPa, tensile strength 260 MPa.
Examid® PA66 CF30 family
PA66 / CF30The core PA66 CF30 family for load-bearing molded parts. The CF30W, CF30Y, CF30S and CF30J variants are differentiated by heat resistance, flowability, modulus level and behavior in series production. Within the TDS: flexural modulus 17 500–18 800 MPa, HDT 182–250°C, tensile strength up to 280 MPa.
Examid® PA66 CF20
PA66 / CF20A PA66 variant with 20% carbon fiber for parts that need increased stiffness, an electrostatic profile or lower CLTE, where CF30/CF40 may be excessive in cost, abrasiveness or brittleness.
Examid® PA6 CF30
PA6 / CF30A processing-friendly PA-CF compound for series molding of rigid parts when the moisture-stability and heat-resistance requirements do not push the project into the PA610 or PPA zone. Per TDS: 30% CF, density 1.30 g/cm³, MVR 30 cm³/10 min, flexural modulus 17 000 MPa.
Examid® PA6 GF20/CF10
PA6 / GF20+CF10A hybrid composite for parts that need a combination of structural stiffness, impact endurance and a more moderate cost compared to pure CF systems. The glass fiber provides the load-bearing stiffness, while the CF adjusts CLTE and reinforces geometric stability.
PA-CF selection starts with part function, load mode and permissible geometry drift
Excessive modulus can degrade impact endurance, complicate mold filling, increase anisotropy and raise cost without a corresponding design benefit.
The baseline structural zone: stiffness, processability, more accessible economics.
moderate temperatureseries moldingThe main zone for load-bearing parts: stiffness, heat resistance, ESD and metal replacement.
HDTESDbracketsWhen moisture and fit stability matter more than the lowest material price.
moistureprecise clearancesThe high-temperature level for assemblies where PA66 is already close to its limit.
high temperaturestabilityPA-CF applications by part function
PA-CF is most compelling in parts where modulus, weight, clearance stability, elevated-temperature operation, low CLTE or electrostatic-charge control are critical at the same time.
Brackets and supports
Load-bearing housings, sensor holders, mounting elements, functional covers.
Precision technical components
Parts with stable clearance, low CLTE and repeatable geometry.
Dimensional accuracy and electrical engineering
Housings, guides, fasteners and components adjacent to electronics.
A polymer alternative to metal
An alternative to aluminum or zinc die casting when stiffness at low weight is required.
UAV / robotics
Frames, brackets, holders and lightweight rigid elements with impact and vibration verification.
Measurement systems
Components where shape stability under temperature, load and cycling is essential.
PA-CF limitations to account for before mold launch
PA-CF cannot be dropped into a design automatically in place of PA-GF, POM, PBT, PPA or metal. Higher modulus, conductivity and anisotropy change how the part behaves and raise the requirements for geometry, the molding process and tooling condition.
Sharp corners, thin webs, holes without radii and abrupt cross-section transitions require special attention.
Properties along and across the flow can differ substantially. This must be built into the geometry.
CF is abrasive. The condition of the screw, barrel, nozzle, hot runner and mold is important.
CF conductivity can be an advantage in antistatic parts, but in insulating assemblies it creates unwanted conductive paths.
CF compounds can be undesirable next to certain metals in humid or electrochemically active environments.
PA-CF is almost always black or dark. A light-colored decorative part is a weak scenario for CF.
PA-CF processing: drying, shear, fiber orientation and series stability
PA-CF start-up problems are usually linked to pellet moisture, excessive shear, an incorrect gating scheme, excessive residence time and anisotropic shrinkage. For carbon-fiber-filled polyamide composites, the molding regime directly shapes the properties of the finished part.
The matrix remains a polyamide, so moisture control is mandatory even for rigid carbon-fiber-filled grades. Moisture degrades the surface, provokes silver streaks, reduces the repeatability of mechanical properties and makes the process less stable.
The second critical topic is preserving the effective fiber length. Excessive screw speed, narrow channels, unnecessary back pressure or a long residence time can shorten the fiber and reduce the real stiffness of the part.
The third factor is flow direction. Maximum modulus values and minimum CLTE typically develop along the prevailing fiber orientation.
Practical takeaway
The temperature profile from the TDS is only a starting point. You need to stabilize pellet moisture, limit fiber breakage during plasticization, orient the flow relative to the critical load and verify the part after conditioning, thermal cycling or an assembly-level test.
dryingdew pointsheargateweld lineCLTEwarpagescrew wear
For precision parts, monitor the actual pellet moisture or work with a desiccant dryer.
The goal is a stable melt without unnecessary fiber breakage.
A controlled, fast flow front is required, without overheating or weak weld lines.
Hold pressure / hold time parameters are adjusted to compensate for volumetric shrinkage.
Barrel guideline: 220–280°C. Drying: 100°C / 2 h, moisture <0.2%.
Barrel guideline: 240–290°C. Drying: 4–6 h at <80°C for opened bags.
Typical range: 250–310°C depending on the grade. For CF40: mold 80–95°C.
High-temperature processing: 290–310°C. Drying: 130°C / 4 h, moisture <0.2%.
Guideline: 220–260°C, mold 60–80°C, pressure 80–130 MPa. Drying: 80–85°C down to 0.01% moisture.
Guideline: 300–325°C. Drying is critical: 80–100°C, 2–4 h, dew point ≤ −40°C.
CF is abrasive: wear-resistant screws, nozzles and hot runners are preferred, along with monitoring of the plasticizing unit condition.
Some grades allow up to 25% regrind, but the real limit depends on matrix degradation and fiber shortening.
Material Wizard selects PA-CF based on assembly geometry, environment and the processing route
In PA-CF projects, comparing TDS documents is only the starting point. A standard specimen demonstrates the potential of the compound, but it does not show the behavior of the specific part with its anisotropy, weld lines, inserts, wall thickness, temperature, moisture and load type.
Technical questions before launching PA-CF
When is PA-CF a better choice than PA-GF?
PA-CF makes more sense for specific-stiffness tasks, low CLTE and dimensional accuracy. PA-GF often remains the more rational choice for impact-loaded parts, a wider processing window, lower abrasiveness to tooling and better economics.
When can PA-CF replace aluminum?
Yes, if the function of the part is defined by stiffness at low weight, geometric stability and acceptable creep. If plastic deformation, thermal conductivity, the thread endurance of metal or very high operating temperatures are critical, a direct replacement requires separate validation.
Why can PA-CF warp despite low shrinkage?
The key factor is not the absolute shrinkage value but the difference along and across the flow. High fiber orientation can produce anisotropic shrinkage and local warpage.
Does PA-CF require drying?
Yes. The matrix remains a polyamide, so moisture control before molding is critical for the surface, mechanical repeatability, process stability and defect reduction.
Need a PA-CF grade for a specific part?
Send us the geometry, load mode, temperature, environment, dimensional-accuracy requirements and weight-reduction or metal-replacement targets. We will propose a starting Examid® PA-CF grade, flag the critical failure modes and outline the list of validation tests before series launch.