Materials / Compare

Plastic PEEK vs. Plastic PLA

Compare Plastic PEEK vs. Plastic PLA strength, stiffness, weight and thermal properties.

Plastic PEEKBulk polymer (molded or machined)
Plastic PLA3D printed (FDM)
MechanicalPlastic PEEKPlastic PLA
Yield strength98MPa11.87x stronger52.5MPa2
Ultimate tensile strengthnot stated (yield given)52.5MPa2
Compressive strength125MPa1not sourced
Flexural strength165MPa196.8MPa2
Elongation at break25%13.21x more ductile7.8%2
Young's modulus (stiffness)4GPa123% stiffer3.25GPa2
Density1,300kg/m³11,240kg/m³2
Strength to weight75.4kN·m/kg1.78x higher42.3kN·m/kg
Stiffness to weight3.08MN·m/kg17% higher2.62MN·m/kg
Poisson's ratio0.383not sourced
Shear modulus1.45GPanot sourced
Bulk modulus5.56GPanot sourced
Speed of sound1,754m/s8% faster1,619m/s
1k10k0.1110100Density (kg/m³)Young's modulus (GPa)Plastic PETGPlastic ABSPlastic TPUPlastic NylonWoodAluminumSteelIronTitaniumSteel AISI 1018Stainless Steel 304Stainless Steel 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110Copper C10100Copper C12200GlassSteel AISI 1045Steel AISI 4340Steel A992Stainless Steel 303Stainless Steel 17-4PHAluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic POM/AcetalPlastic Nylon PA6Plastic Nylon PA66Plastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM PAHT-CFFDM HIPSSLA Resin StandardSLA Resin Tough 2000SLS PA12 NylonDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelConcretePCB Laminate FR-4SiliconCeramic Alumina 96%Ceramic Aluminum NitrideAluminum A380Aluminum 6063-T6Aluminum 1100-OAluminum 3003-OAluminum ADC12Magnesium AZ91DSolder SAC305Plastic PBT GF30Plastic PPS GF40Plastic LCP GF30Plastic PEEKPlastic PLA
Stiffness against densityHigher and further left: stiffer for its weight
1k10k101001kDensity (kg/m³)Yield strength (MPa)Plastic PETGPlastic ABSPlastic TPUPlastic NylonRubberWoodAluminumSteelIronTitaniumSteel AISI 1018Stainless Steel 304Stainless Steel 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110Copper C10100Copper C12200GlassSteel AISI 1045Steel AISI 4340Steel A992Stainless Steel 303Stainless Steel 17-4PHAluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic POM/AcetalPlastic Nylon PA6Plastic Nylon PA66Plastic PTFEPlastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM PAHT-CFFDM HIPSSLA Resin StandardSLA Resin Tough 2000SLA Resin Elastic 50ASLS PA12 NylonDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelBrickPCB Laminate FR-4SiliconCeramic Alumina 96%Aluminum A380Aluminum 6063-T6Aluminum 1100-OAluminum 3003-OAluminum ADC12Magnesium AZ91DSolder SAC305Plastic PBT GF30Plastic PPS GF40Plastic LCP GF30Plastic PEEKPlastic PLA
Strength against densityHigher and further left: stronger for its weight
ThermalPlastic PEEKPlastic PLA
Thermal conductivity0.29W/m·K12.23x more heat through a finbase material0.13W/m·K4
Thermal expansion55µm/m·K1not sourced
100 mm part over a 50 °C swing275µm growthnot sourced
Specific heat2,200J/kg·K51.83x higherbase material1,200J/kg·K4
Heats up and cools (diffusivity)0.101mm²/s16% faster0.0874mm²/s
Thermal shock resistance80.1W/mnot sourced
Melting point343°C1191 °C higher152°C2
Glass transitiononset143°C183.9 °C higher59.1°C2
Max service temperatureUL 746B RTI240°C1HDT 0.455 MPa58.8°C2
1k10k0.1110100Density (kg/m³)Thermal conductivity (W/m·K)Plastic PETGPlastic ABSPlastic NylonRubberWoodAluminumSteelIronTitaniumSteel AISI 1018Stainless Steel 304Stainless Steel 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110Copper C10100Copper C12200GlassSteel AISI 1045Steel AISI 4340Steel A992Stainless Steel 303Stainless Steel 17-4PHAluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic POM/AcetalPlastic Nylon PA6Plastic Nylon PA66Plastic PTFEPlastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM HIPSSLA Resin StandardDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelConcreteBrickPCB Laminate FR-4SiliconCeramic Alumina 96%Ceramic Aluminum NitrideAluminum A380Aluminum 6063-T6Aluminum 1100-OAluminum 3003-OAluminum ADC12Magnesium AZ91DSolder SAC305Plastic PBT GF30Plastic PPS GF40Plastic LCP GF30Plastic PEEKPlastic PLA
Thermal conductivity against densityHigher and further left: spreads more heat for its weight
0.111010010100Thermal conductivity (W/m·K)Thermal expansion (µm/m·K)Plastic PETGPlastic ABSPlastic NylonWoodAluminumSteelIronTitaniumSteel AISI 1018Stainless Steel 304Stainless Steel 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110Copper C10100Copper C12200GlassSteel AISI 1045Steel AISI 4340Steel A992Stainless Steel 303Stainless Steel 17-4PHAluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic POM/AcetalPlastic Nylon PA6Plastic Nylon PA66Plastic PTFEPlastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM HIPSSLA Resin StandardDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelConcreteBrickPlywoodPCB Laminate FR-4SiliconCeramic Alumina 96%Ceramic Aluminum NitrideAluminum A380Aluminum 6063-T6Aluminum 1100-OAluminum 3003-OAluminum ADC12Magnesium AZ91DSolder SAC305Plastic PBT GF30Plastic PPS GF40Plastic LCP GF30Plastic PEEK
Thermal expansion against thermal conductivityLower and further right: warps less when heated
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Sources5 documents: Victrex, UltiMaker, NatureWorks
Plastic PEEK
Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07)
Plastic PLA
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.
  1. 1
    VICTREX PEEK 450G Technical Data SheetVictrexPlastic PEEK · Yield strength: typical, tensile yieldPlastic PEEK · Compressive strength: typical, 23 CPlastic PEEK · Flexural strength: typical, flexural stress at yield, 23 CPlastic PEEK · Elongation at break: typical, at breakPlastic PEEK · Young's modulus (stiffness): typical (nominal)Plastic PEEK · Density: typical (crystalline)Plastic PEEK · Thermal conductivity: typical, average, 23 CPlastic PEEK · Thermal expansion: average of flow/cross-flow, below Tg (<143 C)Plastic PEEK · Melting point: typical, DSCPlastic PEEK · Glass transition: onset (midpoint 150 C)Plastic PEEK · Max service temperature: UL 746B RTI, mechanical strength (continuous use index)
  2. 2
    Ultimaker PLA Technical Data Sheet, v5.00UltiMakerarchived copyPlastic PLA · Yield strength: typicalPlastic PLA · Ultimate tensile strength: typical, peak stress (= stress at yield)Plastic PLA · Flexural strength: typicalPlastic PLA · Elongation at break: typicalPlastic PLA · Young's modulus (stiffness): typicalPlastic PLA · Density: typicalPlastic PLA · Melting point: typicalPlastic PLA · Glass transition: typicalPlastic PLA · Max service temperature: HDT 0.455 MPa (printed specimens)
  3. 3
    VICTREX PEEK for Use in Fluid Management (2020)VictrexPlastic PEEK · Poisson's ratio: typical
  4. 4
    Engineering Properties of Ingeo BiopolymerNatureWorksarchived copyPlastic PLA · Thermal conductivity: base material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °CPlastic PLA · Specific heat: base material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C
  5. 5
    VICTREX PEEK 450G Technical Data Sheet (2012)Victrexarchived copyPlastic PEEK · Specific heat: typical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012)

Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "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

Mechanical

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 bePlastic PEEKPlastic PLA
Stiff rod or tie (tension)lighter17% heavier
Stiff beam (bending)lighter6% heavier
Stiff panel or platelighter2% heavier
Strong rod or tielighter1.78x heavier
Strong beamlighter45% heavier
Strong panel or platelighter30% 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 is more ductile, Plastic PEEK or Plastic PLA?

Plastic PEEK stretches further before it breaks: 25% elongation at break against 7.8% for Plastic PLA.

Thermal

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.

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