COC vs PAR
Polymer · grade comparison
COC and PAR are both polymer grades. PAR is the stronger of the two: yield strength 68 MPa (9.86 ksi) against 60 MPa (8.7 ksi) for COC, about 13% more; tensile strength follows at 72 MPa (10.4 ksi) vs 63 MPa (9.14 ksi). PAR is the more ductile: elongation 60% versus 5% for COC. COC is lighter (1.02 g/cm³ vs 1.21 g/cm³ for PAR) and COC is stiffer (3.1 GPa vs 2.1 GPa). On the shop floor, PAR welds better (good vs fair).
COCChoose it when weight is the constraint.
PARChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
COC vs PAR: 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Flexural Strength
Flexural Modulus
Izod Impact, Notched
Hardness, Rockwell M
Shear Modulus
Bulk Modulus
Compressive Strength
Compressive Modulus
Shear Strength
Hardness, Shore D
Hardness, Rockwell R
Same in both: Poisson's Ratio 0.4
Physical
Density and transition temperatures.
Density
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.
Thermal Conductivity
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)
Limiting Oxygen Index
Max Service Temperature (short-term)
Same in both: Min Service Temperature -50°C-58 °F
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Surface Resistivity
Comparative Tracking Index (CTI)
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Volume Resistivity 1×10¹⁶ Ω·cm
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
Weldability
Polishability
Mold Shrinkage
Melt Flow Rate
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Same in both: Formability (cold) 55 / 100
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)
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 | COC | PAR |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
COC vs PAR — frequently asked
Is PAR stronger than COC?
Yes. PAR has a typical yield strength of 68 MPa (9.86 ksi) against 60 MPa (8.7 ksi) for COC — about 13% more. Tensile strength is 72 MPa (10.4 ksi) vs 63 MPa (9.14 ksi).
Which is cheaper, COC or PAR?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, COC or PAR?
PAR. Its weldability rates good (60/100) against fair (50/100) for COC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in COC and PAR 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.