PET vs PLA
Polymer · grade comparison
PET and PLA are both polymer grades. PET is the stronger of the two: yield strength 80 MPa (11.6 ksi) against 48 MPa (6.96 ksi) for PLA, about 67% more; tensile strength follows at 82 MPa (11.9 ksi) vs 50 MPa (7.25 ksi). PET is the more ductile: elongation 20% versus 5% for PLA. PLA is lighter (1.24 g/cm³ vs 1.39 g/cm³ for PET) and PLA is stiffer (3.4 GPa vs 3.1 GPa). On the shop floor, PET machines more easily (very good vs good), PLA welds better (very good vs fair), and PLA sits in a lower cost tier (budget, $) than PET (standard, $$).
PETChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
PLAChoose it when weight is the constraint, or when it will be welded.
PET vs PLA: 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
Poisson's Ratio
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
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Refractive Index
Same in both: Light Transmission 88%
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 -20°C-4 °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
Formability (cold)
Polishability
Mold Shrinkage
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Melt Flow Rate
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 | PLA |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| Injection molding | Yes | — |
| 3D printing | — | Yes |
| Default condition | Unfilled | Standard |
| Relative cost | $$ Standard | $ Budget |
| Min. machined wall | 0.5 mm | — |
| Best machined surface | Ra 0.8 µm | — |
| Chrome Plating (Plastic) | Yes | — |
| Conductive Coating | — | Yes |
| Dyeing (Nylon) | — | Yes |
| Primer Coating | — | Yes |
| Spray Painting | Yes | — |
| Tinted Coating | — | Yes |
| Vacuum Metallization | — | Yes |
| Waterproof Coating | — | Yes |
They share 4 finishes: EMI Shielding Coating, Painting, Soft Touch Coating, UV Coating.
PET vs PLA — frequently asked
Is PET stronger than PLA?
Yes. PET has a typical yield strength of 80 MPa (11.6 ksi) against 48 MPa (6.96 ksi) for PLA — about 67% more. Tensile strength is 82 MPa (11.9 ksi) vs 50 MPa (7.25 ksi).
Which is cheaper, PET or PLA?
PLA 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 PLA?
PET. Its machinability rates very good (78/100) against good (60/100) for PLA; for welding the order is PLA 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 PLA 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.