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BMC vs UP

Polymer · grade comparison

BMC and UP are both polymer grades. UP is the stronger of the two: tensile strength 55 MPa (7.98 ksi) against 42 MPa (6.09 ksi) for BMC, about 31% more. UP is the more ductile: elongation 2% versus 0.5% for BMC. UP is lighter (1.2 g/cm³ vs 1.85 g/cm³ for BMC) and BMC is stiffer (11 GPa vs 3.4 GPa). On the shop floor, UP machines more easily (good vs fair) and UP sits in a lower cost tier (budget, $) than BMC (standard, $$).

BMCChoose it when the part sees heat.

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

BMC vs UP: properties

BMCUP

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

11 GPa1.6 Msi
3.4 GPa0.49 Msi

Shear Modulus

4.2 GPa0.61 Msi
1.3 GPa0.19 Msi

Poisson's Ratio

0.3
0.35

Tensile Strength (Ultimate)

42 MPa6.1 ksi
55 MPa8 ksi

Elongation at Break

0.5%
2%

Compressive Strength

160 MPa23.2 ksi
130 MPa18.9 ksi

Compressive Modulus

10 GPa1.5 Msi
3.4 GPa0.49 Msi

Flexural Strength

85 MPa12.3 ksi
95 MPa13.8 ksi

Flexural Modulus

10.5 GPa1.5 Msi
3.6 GPa0.52 Msi

Shear Strength

45 MPa6.5 ksi
48 MPa7 ksi

Izod Impact, Notched

75 J/m1.4 ft·lbf/in
16 J/m0.3 ft·lbf/in

Hardness, Rockwell M

100 HRM
98 HRM

Bulk Modulus

—
4 GPa0.57 Msi

Fracture Toughness (K_IC)

—
0.5 MPa·√m0.46 ksi·√in

Hardness, Shore D

—
85 Shore D

Physical

Density and transition temperatures.

Density

1.85 g/cm³0.07 lb/in³
1.2 g/cm³0.04 lb/in³

Glass Transition (Tg)

120°C248 °F
90°C194 °F

Water Absorption (24 h)

0.15%
0.25%

Water Absorption (Saturation)

0.6%
1.2%

Refractive Index

—
1.55

Light Transmission

—
85%

Thermal

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

Thermal Conductivity

0.6 W/m·K0.35 BTU/hr·ft·°F
0.19 W/m·K0.11 BTU/hr·ft·°F

Specific Heat Capacity

1,100 J/kg·K0.26 BTU/lb·°F
1,300 J/kg·K0.31 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

25 µm/m·K13.9 µin/in·°F
100 µm/m·K55.6 µin/in·°F

Max Service Temperature (continuous)

150°C302 °F
85°C185 °F

Heat Deflection Temp. @ 0.45 MPa

250°C482 °F
90°C194 °F

Heat Deflection Temp. @ 1.8 MPa

220°C428 °F
72°C162 °F

Limiting Oxygen Index

24%
19%

Max Service Temperature (short-term)

200°C392 °F
130°C266 °F

Same in both: Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Dielectric Strength

14 kV/mm356 V/mil
17 kV/mm432 V/mil

Dielectric Constant (1 MHz)

4.6
3.2

Surface Resistivity

1×10¹³ Ω
1×10¹⁴ Ω

Same in both: Electrical Resistivity 1×10¹² Ω·m3.94×10¹⁹ µΩ·in · Dissipation Factor (1 MHz) 0.02 · Volume Resistivity 1×10¹⁴ Ω·cm · Comparative Tracking Index (CTI) 600 V

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

70 / 100
50 / 100

UV / Weathering Resistance

60 / 100
40 / 100

Manufacturability

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

Machinability

35 / 100
55 / 100

Weldability

3 / 100
5 / 100

Formability (cold)

3 / 100
5 / 100

Polishability

40 / 100
65 / 100

Mold Shrinkage

0.15%
2%

Processing Melt Temperature (typ.)

35°C95 °F
—

Mold Temperature (typ.)

160°C320 °F
25°C77 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

55 MJ/kg23,646 BTU/lb
70 MJ/kg30,095 BTU/lb

Embodied Carbon (primary production)

3 kg CO₂/kg
3.4 kg CO₂/kg

Embodied Water

120 L/kg14.4 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)

23 kN·m/kg
46 kN·m/kg

Specific Stiffness (E / density)

5.9 MN·m/kg
2.8 MN·m/kg

Thermal Diffusivity

0.3 mm²/s
0.1 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

CapabilityBMCUP
Default condition——
Relative cost$$ Standard$ Budget
Min. machined wall——
Best machined surface——

BMC vs UP — frequently asked

Is UP stronger than BMC?

Yes. UP has a typical tensile strength of 55 MPa (7.98 ksi) against 42 MPa (6.09 ksi) for BMC — about 31% more.

Which is cheaper, BMC or UP?

UP is the lower-cost material: it sits in the budget tier ($) while BMC is standard ($$). 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, BMC or UP?

UP. Its machinability rates good (55/100) against fair (35/100) for BMC.

Ready to make it?

Upload a CAD file and FabDigit prices the part in BMC and UP 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.