Silicone vs TPU
Polymer · grade comparison
Silicone and TPU are both polymer grades. TPU is the stronger of the two: tensile strength 40 MPa (5.8 ksi) against 8 MPa (1.16 ksi) for Silicone, about 5.0 times as much. TPU is stiffer (0.03 GPa vs 0 GPa) and Silicone runs hotter in service (200°C vs 80°C continuous). On the shop floor, TPU welds better (excellent vs poor) and TPU sits in a lower cost tier (standard, $$) than Silicone (premium, $$$).
SiliconeChoose it when the part sees heat.
TPUChoose it when strength drives the design, or when it will be welded.
Silicone vs TPU: 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)
Elongation at Break
Hardness, Shore A
Tear Strength
Compression Set (22 h, 70 °C)
Hardness, Shore D
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Refractive Index
Light Transmission
Melting Temperature (Tm)
Water Absorption (Saturation)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Limiting Oxygen Index
Max Service Temperature (short-term)
Vicat Softening Point (B50)
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume Resistivity
Surface Resistivity
Same in both: Comparative Tracking Index (CTI) 600 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Polishability
Mold Shrinkage
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Melt Flow Rate
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Typical Recycled Content
Same in both: Embodied Water 250 L/kg30 gal/lb
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Thermal Shock Resistance Index
Same in both: Specific Stiffness (E / density) 0 MN·m/kg · Thermal Diffusivity 0.1 mm²/s
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 | Silicone | TPU |
|---|---|---|
| CNC machining | — | Yes |
| Sheet metal | — | Yes |
| 3D printing | — | Yes |
| Default condition | Medical Grade | Shore A 85 |
| Relative cost | $$$ Premium | $$ Standard |
| Min. machined wall | — | 0.5 mm |
| Best machined surface | — | Ra 0.8 µm |
| Conductive Coating | — | Yes |
| Dyeing (Nylon) | — | Yes |
| Painting | — | Yes |
| Primer Coating | — | Yes |
| Tinted Coating | — | Yes |
| Vacuum Metallization | — | Yes |
| Waterproof Coating | — | Yes |
Both are offered for Injection molding. They share 5 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Soft Touch Coating, Spray Painting, UV Coating.
Silicone vs TPU — frequently asked
Is TPU stronger than Silicone?
Yes. TPU has a typical tensile strength of 40 MPa (5.8 ksi) against 8 MPa (1.16 ksi) for Silicone — about 5.0 times as much.
Which is cheaper, Silicone or TPU?
TPU is the lower-cost material: it sits in the standard tier ($$) while Silicone is premium ($$$). 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, Silicone or TPU?
TPU, by a small margin. Both rate poor for machinability — 25/100 against 20/100 for Silicone; for welding the order is TPU first (excellent, 85/100) then Silicone (poor, 20/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Silicone and TPU 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.