PC-FR vs PC-Si
Polymer · grade comparison
PC-FR and PC-Si are both polymer grades. PC-FR is the stronger of the two: yield strength 62 MPa (8.99 ksi) against 58 MPa (8.41 ksi) for PC-Si, about 7% more; tensile strength follows at 64 MPa (9.28 ksi) vs 60 MPa (8.7 ksi). In exchange, PC-Si is the more ductile: elongation 120% versus 100% for PC-FR. PC-FR is stiffer (2.4 GPa vs 2.2 GPa). On the shop floor, PC-Si welds better (very good vs good).
PC-FRChoose it when strength drives the design.
PC-SiChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
PC-FR vs PC-Si: 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
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Hardness, Rockwell R
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Refractive Index
Same in both: Water Absorption (24 h) 0.15% · Water Absorption (Saturation) 0.35%
Thermal
How each material carries heat and how hot it can run.
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 0.2 W/m·K0.12 BTU/hr·ft·°F · Specific Heat Capacity 1,200 J/kg·K0.29 BTU/lb·°F
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Dissipation Factor (1 MHz) 0.01 · Volume Resistivity 1×10¹⁶ Ω·cm · Surface Resistivity 1×10¹⁵ Ω · Comparative Tracking Index (CTI) 250 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: UV / Weathering Resistance 40 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Polishability
Melt Flow Rate
Processing Melt Temperature (typ.)
Same in both: Formability (cold) 60 / 100 · Mold Shrinkage 0.6% · Mold Temperature (typ.) 90°C194 °F
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 | PC-FR | PC-Si |
|---|---|---|
| 3D printing | Yes | — |
| Default condition | — | — |
| Relative cost | $$$ Premium | $$$ Premium |
| Min. machined wall | — | — |
| Best machined surface | — | — |
| Conductive Coating | Yes | — |
| Dyeing (Nylon) | Yes | — |
| EMI Shielding Coating | Yes | — |
| Painting | Yes | — |
| Primer Coating | Yes | — |
| Soft Touch Coating | Yes | — |
| Tinted Coating | Yes | — |
| UV Coating | Yes | — |
| Vacuum Metallization | Yes | — |
| Waterproof Coating | Yes | — |
PC-FR vs PC-Si — frequently asked
Is PC-FR stronger than PC-Si?
Yes. PC-FR has a typical yield strength of 62 MPa (8.99 ksi) against 58 MPa (8.41 ksi) for PC-Si — about 7% more. Tensile strength is 64 MPa (9.28 ksi) vs 60 MPa (8.7 ksi).
Which is cheaper, PC-FR or PC-Si?
Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, PC-FR or PC-Si?
PC-FR, by a small margin. Both rate good for machinability — 65/100 against 60/100 for PC-Si; for welding the order is PC-Si first (very good, 70/100) then PC-FR (good, 60/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in PC-FR and PC-Si 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.