BMI vs DAP
Polymer · grade comparison
BMI and DAP 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 DAP, about 31% more. BMI is the more ductile: elongation 2% versus 0.6% for DAP. BMI is lighter (1.3 g/cm³ vs 1.8 g/cm³ for DAP) and DAP is stiffer (10.5 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 DAP: 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
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Rockwell M
Same in both: Compressive Strength 200 MPa29 ksi
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
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
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Limiting Oxygen Index
Max Service Temperature (short-term)
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Same in both: Electrical Resistivity 1×10¹³ Ω·m3.94×10²⁰ µΩ·in · Volume Resistivity 1×10¹⁵ Ω·cm · Surface Resistivity 1×10¹⁴ Ω · Comparative Tracking Index (CTI) 200 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
Formability (cold)
Polishability
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Same in both: Weldability 0 / 100 · Mold Shrinkage 0.4%
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
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.
Manufacturing and finishing
| Capability | BMI | DAP |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
BMI vs DAP — frequently asked
Is BMI stronger than DAP?
Yes. BMI has a typical tensile strength of 72 MPa (10.4 ksi) against 55 MPa (7.98 ksi) for DAP — about 31% more.
Which is cheaper, BMI or DAP?
Both sit in the same relative cost tier ($$$$, 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 DAP?
BMI, by a small margin. Both rate fair for machinability — 50/100 against 40/100 for DAP.
Ready to make it?
Upload a CAD file and FabDigit prices the part in BMI and DAP 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.