FabDigitFabDigit

C578 Type IX vs XPS 400

Polymer · grade comparison

C578 Type IX and XPS 400 are both polymer grades. XPS 400 is the stronger of the two: tensile strength 0.6 MPa (0.087 ksi) against 0.35 MPa (0.0508 ksi) for C578 Type IX, about 71% more. C578 Type IX is lighter (0.03 g/cm³ vs 0.04 g/cm³ for XPS 400) and XPS 400 is stiffer (0.02 GPa vs 0.01 GPa). On the shop floor, C578 Type IX forms better (fair vs not recommended).

C578 Type IXChoose it when weight is the constraint.

XPS 400Choose it when strength drives the design.

C578 Type IX vs XPS 400: properties

C578 Type IXXPS 400

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

0.01 GPa8.7×10⁻⁴ Msi
0.02 GPa0 Msi

Shear Modulus

0 GPa4.06×10⁻⁴ Msi
—

Poisson's Ratio

0.1
0.25

Tensile Strength (Ultimate)

0.35 MPa0.05 ksi
0.6 MPa0.09 ksi

Compressive Strength

0.19 MPa0.03 ksi
0.42 MPa0.06 ksi

Compressive Modulus

0.01 GPa7.98×10⁻⁴ Msi
0.02 GPa0 Msi

Flexural Strength

0.55 MPa0.08 ksi
0.75 MPa0.11 ksi

Shear Strength

0.16 MPa0.02 ksi
0.28 MPa0.04 ksi

Yield Strength (0.2% offset)

—
0.4 MPa0.06 ksi

Elongation at Break

—
2.5%

Flexural Modulus

—
0.02 GPa0 Msi

Compression Set (22 h, 70 °C)

—
2%

Physical

Density and transition temperatures.

Density

0.03 g/cm³0 lb/in³
0.04 g/cm³0 lb/in³

Water Absorption (24 h)

1.5%
0.2%

Water Absorption (Saturation)

4%
0.5%

Same in both: Glass Transition (Tg) 100°C212 °F

Thermal

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

Thermal Conductivity

0.03 W/m·K0.02 BTU/hr·ft·°F
0.03 W/m·K0.02 BTU/hr·ft·°F

Specific Heat Capacity

1,400 J/kg·K0.33 BTU/lb·°F
1,450 J/kg·K0.35 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

65 µm/m·K36.1 µin/in·°F
70 µm/m·K38.9 µin/in·°F

Min Service Temperature

-80°C-112 °F
-50°C-58 °F

Max Service Temperature (short-term)

95°C203 °F
85°C185 °F

Vicat Softening Point (B50)

—
98°C208 °F

Same in both: Max Service Temperature (continuous) 75°C167 °F · Limiting Oxygen Index 25%

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹⁴ Ω·m3.94×10²¹ µΩ·in
1×10¹³ Ω·m3.94×10²⁰ µΩ·in

Dielectric Constant (1 MHz)

1.04
1.08

Volume Resistivity

1×10¹⁶ Ω·cm
1×10¹⁵ Ω·cm

Same in both: Dissipation Factor (1 MHz) 3×10⁻⁴

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

UV / Weathering Resistance

20 / 100
15 / 100

Corrosion Resistance

—
70 / 100

Manufacturability

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

Machinability

85 / 100
92 / 100

Weldability

20 / 100
15 / 100

Formability (cold)

45 / 100
10 / 100

Mold Shrinkage

0.6%
—

Processing Melt Temperature (typ.)

—
205°C401 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

3.4 kg CO₂/kg
8 kg CO₂/kg

Embodied Water

200 L/kg24 gal/lb
—

Typical Recycled Content

5%
10%

Same in both: Embodied Energy (primary production) 100 MJ/kg42,992 BTU/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

12 kN·m/kg
14 kN·m/kg

Specific Stiffness (E / density)

0.2 MN·m/kg
0.4 MN·m/kg

Thermal Diffusivity

0.8 mm²/s
0.5 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 scaleXPS 400

Manufacturing and finishing

CapabilityC578 Type IXXPS 400
Default condition——
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——

C578 Type IX vs XPS 400 — frequently asked

Is XPS 400 stronger than C578 Type IX?

Yes. XPS 400 has a typical tensile strength of 0.6 MPa (0.087 ksi) against 0.35 MPa (0.0508 ksi) for C578 Type IX — about 71% more.

Which is cheaper, C578 Type IX or XPS 400?

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

Which is easier to machine, C578 Type IX or XPS 400?

XPS 400, by a small margin. Both rate excellent for machinability — 92/100 against 85/100 for C578 Type IX; for welding the order is C578 Type IX first (poor, 20/100) then XPS 400 (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in C578 Type IX and XPS 400 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.