PA6/66 vs PA66
Polymer · grade comparison
PA6/66 and PA66 are both polymer grades. PA66 is the stronger of the two: yield strength 80 MPa (11.6 ksi) against 72 MPa (10.4 ksi) for PA6/66, about 11% more; tensile strength follows at 82 MPa (11.9 ksi) vs 76 MPa (11 ksi). In exchange, PA6/66 is the more ductile: elongation 60% versus 40% for PA66. PA66 is stiffer (3 GPa vs 2.8 GPa) and PA66 runs hotter in service (100°C vs 90°C continuous).
PA6/66Choose it when the part is bent, formed or impact-loaded.
PA66Choose it when strength drives the design, or when the part sees heat.
PA6/66 vs PA66: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Flexural Strength
Flexural Modulus
Shear Strength
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Hardness, Rockwell R
Bulk Modulus
Compressive Modulus
Fracture Toughness (K_IC)
Same in both: Poisson's Ratio 0.39
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Refractive Index
Thermal
How each material carries heat and how hot it can run.
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Vicat Softening Point (B50)
Limiting Oxygen Index
Max Service Temperature (short-term)
Same in both: Thermal Conductivity 0.25 W/m·K0.14 BTU/hr·ft·°F · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Dielectric Strength
Dissipation Factor (1 MHz)
Same in both: Electrical Resistivity 1×10¹² Ω·m3.94×10¹⁹ µΩ·in · Dielectric Constant (1 MHz) 3.4 · Volume Resistivity 1×10¹⁴ Ω·cm · Surface Resistivity 1×10¹³ Ω · Comparative Tracking Index (CTI) 600 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 60 / 100 · UV / Weathering Resistance 30 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Polishability
Mold Shrinkage
Melt Flow Rate
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Same in both: Thermal Diffusivity 0.1 mm²/s · Thermal Shock Resistance Index 0
Strength versus weight
Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | PA6/66 | PA66 |
|---|---|---|
| CNC machining | — | Yes |
| Sheet metal | — | Yes |
| Injection molding | — | Yes |
| Default condition | — | Unfilled |
| Relative cost | $$ Standard | $$ Standard |
| Min. machined wall | — | 0.5 mm |
| Best machined surface | — | Ra 0.8 µm |
| Chrome Plating (Plastic) | — | Yes |
| EMI Shielding Coating | — | Yes |
| Painting | — | Yes |
| Soft Touch Coating | — | Yes |
| Spray Painting | — | Yes |
| UV Coating | — | Yes |
PA6/66 vs PA66 — frequently asked
Is PA66 stronger than PA6/66?
Yes. PA66 has a typical yield strength of 80 MPa (11.6 ksi) against 72 MPa (10.4 ksi) for PA6/66 — about 11% more. Tensile strength is 82 MPa (11.9 ksi) vs 76 MPa (11 ksi).
Which is cheaper, PA6/66 or PA66?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, PA6/66 or PA66?
PA6/66. Its weldability rates very good (78/100) against very good (70/100) for PA66.
Ready to make it?
Upload a CAD file and FabDigit prices the part in PA6/66 and PA66 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.