Materials / Compare
Plastic PEEK vs. Plastic PLA
Compare Plastic PEEK vs. Plastic PLA strength, stiffness, weight and thermal properties.
| Try it on a partA bracket to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | 98MPasourcetypical, tensile yield | 52.5MPasourcetypical |
| Ultimate tensile strength | not sourced | 52.5MPasourcetypical, peak stress (= stress at yield) |
| Compressive strength | 125MPasourcetypical, 23 C | not sourced |
| Flexural strength | 165MPasourcetypical, flexural stress at yield, 23 C | 96.8MPasourcetypical |
| Elongation at break | 25%sourcetypical, at break | 7.8%sourcetypical |
| Young's modulus (stiffness) | 4GPasourcetypical (nominal) | 3.25GPasourcetypical |
| Density | 1,300kg/m³sourcetypical (crystalline) | 1,240kg/m³sourcetypical |
| Strength to weight | 75.4kN·m/kg1.78x higher | 42.3kN·m/kg |
| Stiffness to weight | 3.08MN·m/kg17% higher | 2.62MN·m/kg |
| Poisson's ratio | 0.38sourcetypical | not sourced |
| Shear modulus | 1.45GPa | not sourced |
| Bulk modulus | 5.56GPa | not sourced |
| Speed of sound | 1,754m/s | 1,619m/s |
| Thermal | ||
| Thermal conductivity | 0.29W/m·Ksourcetypical, average, 23 C | 0.13W/m·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C |
| Thermal expansion | 55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C) | not sourced |
| 100 mm part over a 50 °C swing | 275µm growth | not sourced |
| Specific heat | 2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012) | 1,200J/kg·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C |
| Heats up and cools (diffusivity) | 0.101mm²/s16% faster | 0.0874mm²/s |
| Thermal shock resistance | 80.1W/m | not sourced |
| Melting point | 343°Csourcetypical, DSC | 152°Csourcetypical |
| Glass transition | 143°Csourceonset (midpoint 150 C) | 59.1°Csourcetypical |
| Max service temperature | 240°CsourceUL 746B RTI, mechanical strength (continuous use index) | 58.8°CsourceHDT 0.455 MPa (printed specimens) |
| Values for | Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07) | Ultimaker PLA, 3D-printed specimens, XY (flat) orientation; Ultimaker S5 Pro, engineering intent profile, 0.15 mm layer height, AA 0.4 print core, 100% infill, Cura 4.9, printed one-at-a-time, conditioned >=24 h at room temperature. TDS dated April 20, 2022. |
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Plastic PLA is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Plastic PEEK stronger than Plastic PLA?
Plastic PEEK is stronger: its yield strength is 98 MPa against 52.5 MPa for Plastic PLA (1.87x).
Which is lighter, Plastic PEEK or Plastic PLA?
Plastic PLA is lighter: 1,240 kg/m³ against 1,300 kg/m³ for Plastic PEEK.
Which is stiffer, Plastic PEEK or Plastic PLA?
Plastic PEEK is stiffer: Young's modulus 4 GPa against 3.25 GPa for Plastic PLA, so the same part in Plastic PEEK deflects less under the same load.
Which is lighter for the same job, Plastic PEEK or Plastic PLA?
For the same stiffness or strength: Plastic PEEK is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Plastic PEEK | Plastic PLA |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 17% heavier |
| Stiff beam (bending) | lighter | 6% heavier |
| Stiff panel or plate | lighter | 2% heavier |
| Strong rod or tie | lighter | 1.78x heavier |
| Strong beam | lighter | 45% heavier |
| Strong panel or plate | lighter | 30% heavier |
For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).
Which conducts heat better, Plastic PEEK or Plastic PLA?
Plastic PEEK conducts heat better: 0.29 W/m·K against 0.13 W/m·K for Plastic PLA.