CAP vs CTA
Polymer · grade comparison
CAP and CTA are both polymer grades. CTA is the stronger of the two: yield strength 55 MPa (7.98 ksi) against 30 MPa (4.35 ksi) for CAP, about 83% more; tensile strength follows at 70 MPa (10.2 ksi) vs 32 MPa (4.64 ksi). In exchange, CAP is the more ductile: elongation 50% versus 25% for CTA. CAP is lighter (1.21 g/cm³ vs 1.3 g/cm³ for CTA) and CTA is stiffer (3.2 GPa vs 1.4 GPa). On the shop floor, CAP machines more easily (very good vs good).
CAPChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
CTAChoose it when strength drives the design, or when the part sees heat.
CAP vs CTA: 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
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Flexural Strength
Flexural Modulus
Shear Strength
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell R
Shear Modulus
Hardness, Rockwell M
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Refractive Index
Light Transmission
Thermal
How each material carries heat and how hot it can run.
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Vicat Softening Point (B50)
Max Service Temperature (short-term)
Same in both: Thermal Conductivity 0.21 W/m·K0.12 BTU/hr·ft·°F · Min Service Temperature -40°C-40 °F · Limiting Oxygen Index 19%
Electrical
Conductivity and insulation.
Dielectric Strength
Dissipation Factor (1 MHz)
Same in both: Electrical Resistivity 1×10¹² Ω·m3.94×10¹⁹ µΩ·in · Dielectric Constant (1 MHz) 3.4 · Volume Resistivity 1×10¹⁴ Ω·cm · Surface Resistivity 1×10¹³ Ω · Comparative Tracking Index (CTI) 600 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
Mold Shrinkage
Melt Flow Rate
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Same in both: Weldability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Carbon (primary production) 4.5 kg CO₂/kg
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Same in both: Thermal Diffusivity 0.1 mm²/s · 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 | CAP | CTA |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$ Premium | $$$ Premium |
| Min. machined wall | — | — |
| Best machined surface | — | — |
CAP vs CTA — frequently asked
Is CTA stronger than CAP?
Yes. CTA has a typical yield strength of 55 MPa (7.98 ksi) against 30 MPa (4.35 ksi) for CAP — about 83% more. Tensile strength is 70 MPa (10.2 ksi) vs 32 MPa (4.64 ksi).
Which is cheaper, CAP or CTA?
Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, CAP or CTA?
CAP. Its machinability rates very good (78/100) against good (65/100) for CTA.
Ready to make it?
Upload a CAD file and FabDigit prices the part in CAP and CTA 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.