PAI vs PSU
Polymer · grade comparison
PAI and PSU are both polymer grades, both high performance plastic. PAI is the stronger of the two: tensile strength 152 MPa (22 ksi) against 71 MPa (10.3 ksi) for PSU, about 114% more. In exchange, PSU is the more ductile: elongation 60% versus 15% for PAI. PSU is lighter (1.24 g/cm³ vs 1.42 g/cm³ for PAI) and PAI is stiffer (4.5 GPa vs 2.5 GPa). On the shop floor, PSU welds better (good vs not recommended) and PSU sits in a lower cost tier (high, $$$$) than PAI (specialty, $$$$$).
PAIChoose it when strength drives the design, or when the part sees heat.
PSUChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
PAI vs PSU: 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
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Yield Strength (0.2% offset)
Hardness, Rockwell R
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Refractive Index
Light Transmission
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
Limiting Oxygen Index
Max Service Temperature (short-term)
Vicat Softening Point (B50)
Same in both: Thermal Conductivity 0.26 W/m·K0.15 BTU/hr·ft·°F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume Resistivity
Surface Resistivity
Comparative Tracking Index (CTI)
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
UV / Weathering Resistance
Same in both: Corrosion Resistance 80 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Mold Shrinkage
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Melt Flow Rate
Same in both: Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Same in both: Thermal Diffusivity 0.2 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 | PAI | PSU |
|---|---|---|
| Default condition | Unfilled (Electrical) | Medical Grade |
| Relative cost | $$$$$ Specialty | $$$$ High |
| Min. machined wall | 0.5 mm | 0.5 mm |
| Best machined surface | Ra 0.8 µm | Ra 0.8 µm |
Both are offered for CNC machining, Sheet metal and Injection molding. Both take the same 6 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Painting, Soft Touch Coating, Spray Painting, UV Coating.
PAI vs PSU — frequently asked
Is PAI stronger than PSU?
Yes. PAI has a typical tensile strength of 152 MPa (22 ksi) against 71 MPa (10.3 ksi) for PSU — about 114% more.
Which is cheaper, PAI or PSU?
PSU is the lower-cost material: it sits in the high tier ($$$$) while PAI is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, PAI or PSU?
PSU, by a small margin. Both rate good for machinability — 65/100 against 60/100 for PAI; for welding the order is PSU first (good, 60/100) then PAI (not recommended, 10/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in PAI and PSU 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.