PET vs RPET
Polymer · grade comparison
PET and RPET are both polymer grades. PET is the stronger of the two: yield strength 80 MPa (11.6 ksi) against 52 MPa (7.54 ksi) for RPET, about 54% more; tensile strength follows at 82 MPa (11.9 ksi) vs 55 MPa (7.98 ksi). In exchange, RPET is the more ductile: elongation 60% versus 20% for PET. PET is stiffer (3.1 GPa vs 2.6 GPa) and PET runs hotter in service (100°C vs 65°C continuous). On the shop floor, PET machines more easily (very good vs good), RPET welds better (very good vs fair), and RPET sits in a lower cost tier (budget, $) than PET (standard, $$).
PETChoose it when strength drives the design, or when the part sees heat.
RPETChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
PET vs RPET: 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
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Hardness, Rockwell R
Same in both: Poisson's Ratio 0.4
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Light Transmission
Same in both: Refractive Index 1.575
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
Vicat Softening Point (B50)
Limiting Oxygen Index
Max Service Temperature (short-term)
Electrical
Conductivity and insulation.
Dielectric Strength
Dissipation Factor (1 MHz)
Comparative Tracking Index (CTI)
Same in both: Electrical Resistivity 1×10¹⁴ Ω·m3.94×10²¹ µΩ·in · Dielectric Constant (1 MHz) 3.2 · Volume Resistivity 1×10¹⁶ Ω·cm · Surface Resistivity 1×10¹⁵ Ω
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
Formability (cold)
Mold Shrinkage
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Melt Flow Rate
Same in both: Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
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 | PET | RPET |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Injection molding | Yes | — |
| Default condition | Unfilled | — |
| Relative cost | $$ Standard | $ Budget |
| Min. machined wall | 0.5 mm | — |
| Best machined surface | Ra 0.8 µm | — |
| Chrome Plating (Plastic) | Yes | — |
| EMI Shielding Coating | Yes | — |
| Painting | Yes | — |
| Soft Touch Coating | Yes | — |
| Spray Painting | Yes | — |
| UV Coating | Yes | — |
PET vs RPET — frequently asked
Is PET stronger than RPET?
Yes. PET has a typical yield strength of 80 MPa (11.6 ksi) against 52 MPa (7.54 ksi) for RPET — about 54% more. Tensile strength is 82 MPa (11.9 ksi) vs 55 MPa (7.98 ksi).
Which is cheaper, PET or RPET?
RPET is the lower-cost material: it sits in the budget tier ($) while PET 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, PET or RPET?
PET. Its machinability rates very good (78/100) against good (60/100) for RPET; for welding the order is RPET first (very good, 70/100) then PET (fair, 45/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in PET and RPET 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.