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AEM vs Silicone

Polymer · grade comparison

AEM and Silicone are both polymer grades. AEM is the stronger of the two: tensile strength 13 MPa (1.89 ksi) against 8 MPa (1.16 ksi) for Silicone, about 63% more. In exchange, Silicone is the more ductile: elongation 500% versus 250% for AEM. Silicone is lighter (1.15 g/cm³ vs 1.2 g/cm³ for AEM) and AEM is stiffer (0.01 GPa vs 0 GPa). On the shop floor, Silicone sits in a lower cost tier (premium, $$$) than AEM (high, $$$$).

AEMChoose it when strength drives the design.

SiliconeChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

AEM vs Silicone: properties

AEMSilicone

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

0.01 GPa0 Msi
0 GPa3.19×10⁻⁴ Msi

Tensile Strength (Ultimate)

13 MPa1.9 ksi
8 MPa1.2 ksi

Elongation at Break

250%
500%

Shear Strength

9 MPa1.3 ksi
—

Hardness, Shore A

70 Shore A
50 Shore A

Hardness, Shore D

22 Shore D
—

Tear Strength

30 kN/m171 lbf/in
25 kN/m143 lbf/in

Compression Set (22 h, 70 °C)

18%
20%

Shear Modulus

—
7.5×10⁻⁴ GPa1.09×10⁻⁴ Msi

Bulk Modulus

—
2 GPa0.22 Msi

Same in both: Poisson's Ratio 0.49

Physical

Density and transition temperatures.

Density

1.2 g/cm³0.04 lb/in³
1.15 g/cm³0.04 lb/in³

Glass Transition (Tg)

-33°C-27 °F
-125°C-193 °F

Water Absorption (24 h)

1.5%
0.3%

Refractive Index

—
1.41

Light Transmission

—
88%

Thermal

How each material carries heat and how hot it can run.

Specific Heat Capacity

1,900 J/kg·K0.45 BTU/lb·°F
1,300 J/kg·K0.31 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

200 µm/m·K111 µin/in·°F
270 µm/m·K150 µin/in·°F

Max Service Temperature (continuous)

150°C302 °F
200°C392 °F

Min Service Temperature

-40°C-40 °F
-60°C-76 °F

Limiting Oxygen Index

20%
26%

Max Service Temperature (short-term)

175°C347 °F
250°C482 °F

Same in both: Thermal Conductivity 0.22 W/m·K0.13 BTU/hr·ft·°F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10⁹ Ω·m3.94×10¹⁶ µΩ·in
1×10¹³ Ω·m3.94×10²⁰ µΩ·in

Dielectric Strength

18 kV/mm457 V/mil
22 kV/mm559 V/mil

Dielectric Constant (1 MHz)

6
3

Dissipation Factor (1 MHz)

0.06
0.002

Volume Resistivity

1×10¹¹ Ω·cm
1×10¹⁵ Ω·cm

Surface Resistivity

—
1×10¹⁴ Ω

Comparative Tracking Index (CTI)

—
600 V

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

80 / 100
90 / 100

UV / Weathering Resistance

90 / 100
97 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

25 / 100
20 / 100

Weldability

12 / 100
20 / 100

Formability (cold)

85 / 100
95 / 100

Mold Shrinkage

2.2%
2.5%

Processing Melt Temperature (typ.)

95°C203 °F
25°C77 °F

Polishability

—
85 / 100

Same in both: Mold Temperature (typ.) 180°C356 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

125 MJ/kg53,740 BTU/lb
110 MJ/kg47,292 BTU/lb

Embodied Carbon (primary production)

5.5 kg CO₂/kg
6.5 kg CO₂/kg

Embodied Water

—
250 L/kg30 gal/lb

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

11 kN·m/kg
7 kN·m/kg

Thermal Shock Resistance Index

2
3

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.

0.1110100123Density (g/cm³)Yield strength (MPa) — log scaleSilicone

Manufacturing and finishing

CapabilityAEMSilicone
Injection molding—Yes
Default condition—Medical Grade
Relative cost$$$$ High$$$ Premium
Min. machined wall——
Best machined surface——
Chrome Plating (Plastic)—Yes
EMI Shielding Coating—Yes
Soft Touch Coating—Yes
Spray Painting—Yes
UV Coating—Yes

AEM vs Silicone — frequently asked

Is AEM stronger than Silicone?

Yes. AEM has a typical tensile strength of 13 MPa (1.89 ksi) against 8 MPa (1.16 ksi) for Silicone — about 63% more.

Which is cheaper, AEM or Silicone?

Silicone is the lower-cost material: it sits in the premium tier ($$$) while AEM is high ($$$$). 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, AEM or Silicone?

AEM, by a small margin. Both rate poor for machinability — 25/100 against 20/100 for Silicone; for welding the order is Silicone first (poor, 20/100) then AEM (not recommended, 12/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in AEM and Silicone 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.