PA6 vs PA66
Polymer · grade comparison
PA6 and PA66 are both polymer grades, both engineering plastic. PA66 is the stronger of the two: yield strength 80 MPa (11.6 ksi) against 75 MPa (10.9 ksi) for PA6, about 7% more. In exchange, PA6 is the more ductile: elongation 60% versus 40% for PA66. PA66 runs hotter in service (100°C vs 90°C continuous). On the shop floor, PA6 sits in a lower cost tier (budget, $) than PA66 (standard, $$).
PA6Choose it when the part is bent, formed or impact-loaded, or when cost is the deciding factor.
PA66Choose it when strength drives the design, or when the part sees heat.
PA6 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.
Shear Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Rockwell M
Hardness, Rockwell R
Same in both: Elastic (Young's) Modulus 3 GPa0.44 Msi · Bulk Modulus 5 GPa0.65 Msi · Poisson's Ratio 0.39 · Flexural Strength 105 MPa15.2 ksi · Hardness, Shore D 81 Shore D
Physical
Density and transition temperatures.
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Same in both: Density 1.14 g/cm³0.04 lb/in³ · Refractive Index 1.53
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)
Min Service Temperature
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
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Same in both: Electrical Resistivity 1×10¹² Ω·m3.94×10¹⁹ µΩ·in · 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).
Corrosion Resistance
Same in both: 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.)
Same in both: Mold Temperature (typ.) 80°C176 °F
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 5%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Same in both: Specific Stiffness (E / density) 2.6 MN·m/kg · 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 | PA66 |
|---|---|---|
| Default condition | Unfilled | Unfilled |
| Relative cost | $ Budget | $$ Standard |
| Min. machined wall | 0.5 mm | 0.5 mm |
| Best machined surface | Ra 0.8 µm | Ra 0.8 µm |
Both are offered for CNC machining, Sheet metal and Injection molding. Both take the same 6 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Painting, Soft Touch Coating, Spray Painting, UV Coating.
PA6 vs PA66 — frequently asked
Is PA66 stronger than PA6?
Yes. PA66 has a typical yield strength of 80 MPa (11.6 ksi) against 75 MPa (10.9 ksi) for PA6 — about 7% more. Tensile strength is 82 MPa (11.9 ksi) vs 80 MPa (11.6 ksi).
Which is cheaper, PA6 or PA66?
PA6 is the lower-cost material: it sits in the budget tier ($) while PA66 is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which welds better, PA6 or PA66?
PA66. Its weldability rates very good (70/100) against good (62/100) for PA6.
Ready to make it?
Upload a CAD file and FabDigit prices the part in PA6 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.