FabDigit

ACM vs AEM and 2 more: properties

ACMAEMEPDMSilicone

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

0.01 GPa8.7×10⁻⁴ Msi
0.01 GPa0 Msi
0.01 GPa8.7×10⁻⁴ Msi
0 GPa3.19×10⁻⁴ Msi

Shear Modulus

0 GPa2.9×10⁻⁴ Msi
0 GPa2.9×10⁻⁴ Msi
7.5×10⁻⁴ GPa1.09×10⁻⁴ Msi

Bulk Modulus

2 GPa0.29 Msi
2 GPa0.29 Msi
2 GPa0.22 Msi

Poisson's Ratio

0.5
0.49
0.5
0.49

Tensile Strength (Ultimate)

11 MPa1.6 ksi
13 MPa1.9 ksi
12 MPa1.7 ksi
8 MPa1.2 ksi

Elongation at Break

220%
250%
400%
500%

Hardness, Shore A

70 Shore A
70 Shore A
70 Shore A
50 Shore A

Hardness, Shore D

22 Shore D
22 Shore D
22 Shore D

Tear Strength

22 kN/m126 lbf/in
30 kN/m171 lbf/in
25 kN/m143 lbf/in
25 kN/m143 lbf/in

Compression Set (22 h, 70 °C)

20%
18%
20%
20%

Shear Strength

9 MPa1.3 ksi

Physical

Density and transition temperatures.

Density

1.25 g/cm³0.05 lb/in³
1.2 g/cm³0.04 lb/in³
1.15 g/cm³0.04 lb/in³
1.15 g/cm³0.04 lb/in³

Glass Transition (Tg)

-25°C-13 °F
-33°C-27 °F
-55°C-67 °F
-125°C-193 °F

Water Absorption (24 h)

1%
1.5%
0.5%
0.3%

Refractive Index

1.41

Light Transmission

88%

Thermal

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

Thermal Conductivity

0.2 W/m·K0.12 BTU/hr·ft·°F
0.22 W/m·K0.13 BTU/hr·ft·°F
0.3 W/m·K0.17 BTU/hr·ft·°F
0.22 W/m·K0.13 BTU/hr·ft·°F

Specific Heat Capacity

1,800 J/kg·K0.43 BTU/lb·°F
1,900 J/kg·K0.45 BTU/lb·°F
2,000 J/kg·K0.48 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
200 µm/m·K111 µin/in·°F
180 µm/m·K100 µin/in·°F
270 µm/m·K150 µin/in·°F

Max Service Temperature (continuous)

150°C302 °F
150°C302 °F
120°C248 °F
200°C392 °F

Min Service Temperature

-25°C-13 °F
-40°C-40 °F
-50°C-58 °F
-60°C-76 °F

Limiting Oxygen Index

20%
20%
19%
26%

Max Service Temperature (short-term)

175°C347 °F
175°C347 °F
160°C320 °F
250°C482 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10⁸ Ω·m3.94×10¹⁵ µΩ·in
1×10⁹ Ω·m3.94×10¹⁶ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in
1×10¹³ Ω·m3.94×10²⁰ µΩ·in

Dielectric Strength

15 kV/mm381 V/mil
18 kV/mm457 V/mil
25 kV/mm635 V/mil
22 kV/mm559 V/mil

Dielectric Constant (1 MHz)

5.5
6
3
3

Dissipation Factor (1 MHz)

0.05
0.06
0.007
0.002

Volume Resistivity

1×10¹⁰ Ω·cm
1×10¹¹ Ω·cm
1×10¹⁴ Ω·cm
1×10¹⁵ Ω·cm

Comparative Tracking Index (CTI)

600 V
600 V

Surface Resistivity

1×10¹⁴ Ω

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

75 / 100
80 / 100
85 / 100
90 / 100

UV / Weathering Resistance

85 / 100
90 / 100
95 / 100
97 / 100

Manufacturability

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

Machinability

30 / 100
25 / 100
30 / 100
20 / 100

Formability (cold)

70 / 100
85 / 100
90 / 100
95 / 100

Mold Shrinkage

2%
2.2%
2.5%
2.5%

Mold Temperature (typ.)

180°C356 °F
180°C356 °F
175°C347 °F
180°C356 °F

Weldability

12 / 100
15 / 100
20 / 100

Processing Melt Temperature (typ.)

95°C203 °F
100°C212 °F
25°C77 °F

Polishability

20 / 100
85 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

110 MJ/kg47,292 BTU/lb
125 MJ/kg53,740 BTU/lb
95 MJ/kg40,843 BTU/lb
110 MJ/kg47,292 BTU/lb

Embodied Carbon (primary production)

5 kg CO₂/kg
5.5 kg CO₂/kg
4 kg CO₂/kg
6.5 kg CO₂/kg

Embodied Water

200 L/kg24 gal/lb
150 L/kg18 gal/lb
250 L/kg30 gal/lb

Typical Recycled Content

0%
0%
5%
0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

9 kN·m/kg
11 kN·m/kg
10 kN·m/kg
7 kN·m/kg

Thermal Shock Resistance Index

2
2
3
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 scaleEPDMSilicone

Manufacturing and finishing

CapabilityACMAEMEPDMSilicone
Injection moldingYesYes
Default conditionSolidMedical Grade
Relative cost$$$ Premium$$$$ High$$ Standard$$$ Premium
Min. machined wall
Best machined surface
Chrome Plating (Plastic)YesYes
EMI Shielding CoatingYesYes
Soft Touch CoatingYesYes
Spray PaintingYesYes
UV CoatingYesYes

Ready to make it?

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