FabDigitFabDigit

BMI vs DAIP

Polymer · grade comparison

BMI and DAIP are both polymer grades. BMI is the stronger of the two: tensile strength 72 MPa (10.4 ksi) against 55 MPa (7.98 ksi) for DAIP, about 31% more. BMI is the more ductile: elongation 2% versus 0.6% for DAIP. BMI is lighter (1.3 g/cm³ vs 1.8 g/cm³ for DAIP) and DAIP is stiffer (11 GPa vs 4 GPa). On the shop floor, BMI machines more easily (50 vs 40 out of 100).

BMIChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

BMI vs DAIP: properties

BMIDAIP

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

4 GPa0.58 Msi
11 GPa1.6 Msi

Shear Modulus

1.5 GPa0.21 Msi
—

Poisson's Ratio

0.35
0.34

Tensile Strength (Ultimate)

72 MPa10.4 ksi
55 MPa8 ksi

Elongation at Break

2%
0.6%

Compressive Modulus

4.1 GPa0.59 Msi
—

Flexural Strength

120 MPa17.4 ksi
105 MPa15.2 ksi

Flexural Modulus

4 GPa0.58 Msi
11.5 GPa1.7 Msi

Shear Strength

55 MPa8 ksi
—

Fracture Toughness (K_IC)

0.6 MPa·√m0.55 ksi·√in
—

Izod Impact, Notched

18 J/m0.34 ft·lbf/in
75 J/m1.4 ft·lbf/in

Hardness, Rockwell M

115 HRM
108 HRM

Same in both: Compressive Strength 200 MPa29 ksi

Physical

Density and transition temperatures.

Density

1.3 g/cm³0.05 lb/in³
1.8 g/cm³0.07 lb/in³

Glass Transition (Tg)

290°C554 °F
190°C374 °F

Water Absorption (24 h)

0.35%
0.25%

Water Absorption (Saturation)

4%
0.7%

Thermal

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

Thermal Conductivity

0.21 W/m·K0.12 BTU/hr·ft·°F
0.42 W/m·K0.24 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

40 µm/m·K22.2 µin/in·°F
30 µm/m·K16.7 µin/in·°F

Max Service Temperature (continuous)

230°C446 °F
205°C401 °F

Min Service Temperature

-70°C-94 °F
-65°C-85 °F

Heat Deflection Temp. @ 1.8 MPa

280°C536 °F
290°C554 °F

Limiting Oxygen Index

38%
34%

Max Service Temperature (short-term)

300°C572 °F
260°C500 °F

Same in both: Specific Heat Capacity 1,150 J/kg·K0.27 BTU/lb·°F · Heat Deflection Temp. @ 0.45 MPa 300°C572 °F

Electrical

Conductivity and insulation.

Dielectric Strength

20 kV/mm508 V/mil
16 kV/mm406 V/mil

Dielectric Constant (1 MHz)

3.4
4.4

Dissipation Factor (1 MHz)

0.008
0.01

Comparative Tracking Index (CTI)

200 V
400 V

Same in both: Electrical Resistivity 1×10¹³ Ω·m3.94×10²⁰ µΩ·in · Volume Resistivity 1×10¹⁵ Ω·cm · Surface Resistivity 1×10¹⁴ Ω

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

UV / Weathering Resistance

35 / 100
70 / 100

Same in both: Corrosion Resistance 85 / 100

Manufacturability

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

Machinability

50 / 100
40 / 100

Weldability

0 / 100
3 / 100

Formability (cold)

5 / 100
3 / 100

Polishability

60 / 100
45 / 100

Mold Shrinkage

0.4%
0.35%

Processing Melt Temperature (typ.)

130°C266 °F
105°C221 °F

Mold Temperature (typ.)

190°C374 °F
165°C329 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

190 MJ/kg81,685 BTU/lb
105 MJ/kg45,142 BTU/lb

Embodied Carbon (primary production)

9.5 kg CO₂/kg
5.5 kg CO₂/kg

Embodied Water

300 L/kg35.9 gal/lb
180 L/kg21.6 gal/lb

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

55 kN·m/kg
31 kN·m/kg

Specific Stiffness (E / density)

3.1 MN·m/kg
6.1 MN·m/kg

Thermal Diffusivity

0.1 mm²/s
0.2 mm²/s

Same in both: 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.

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

Manufacturing and finishing

CapabilityBMIDAIP
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

BMI vs DAIP — frequently asked

Is BMI stronger than DAIP?

Yes. BMI has a typical tensile strength of 72 MPa (10.4 ksi) against 55 MPa (7.98 ksi) for DAIP — about 31% more.

Which is cheaper, BMI or DAIP?

Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, BMI or DAIP?

BMI, by a small margin. Both rate fair for machinability — 50/100 against 40/100 for DAIP.

Ready to make it?

Upload a CAD file and FabDigit prices the part in BMI and DAIP 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.