FDM Polycarbonate vs. Plastic PETG

Compare FDM Polycarbonate vs. Plastic PETG strength, stiffness, weight and thermal properties.

Mechanical	FDM Polycarbonate	Plastic PETG
Yield strength	53.3MPa115% stronger	46.2MPa2
Ultimate tensile strength	53.3MPa115% stronger	46.2MPa2
Flexural strength	89.4MPa113% stronger in bending	78.9MPa2
Elongation at break	9.2%121% more ductile	7.6%2
Young's modulus (stiffness)	2.39GPa123% stiffer	1.94GPa2
Density	range1,180–1,200kg/m³1	1,270kg/m³2
Strength to weight	44.8kN·m/kg23% higher	36.4kN·m/kg
Stiffness to weight	2.01MN·m/kg32% higher	1.53MN·m/kg
Poisson's ratio	base material0.383	not sourced
Shear modulus	0.867GPa	not sourced
Bulk modulus	3.33GPa	not sourced
Speed of sound	1,418m/s15% faster	1,236m/s

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	FDM Polycarbonate	Plastic PETG
Thermal conductivity	base material0.2W/m·K4	base material0.21W/m·K5
Thermal expansion	base material65µm/m·K4	base material51µm/m·K527% less
100 mm part over a 50 °C swing	325µm growth	255µm growth27% less
Specific heat	not sourced	base material1,300J/kg·K5
Heats up and cools (diffusivity)	not sourced	0.127mm²/s
Thermal shock resistance	42.5W/m	not sourced
Glass transition	108°C130.3 °C higher	77.4°C2
Max service temperature	HDT 0.455 MPa105°C128.3 °C hotter	HDT 0.455 MPa76.2°C2

Thermal conductivity against densityHigher and further left: spreads more heat for its weight

Thermal expansion against thermal conductivityLower and further right: warps less when heated

Try it on a partA bracket to run stress or thermal on, free in your browser	Open in LessCAD	Open in LessCAD

Sources5 documents: UltiMaker, Covestro, Eastman

FDM Polycarbonate: Ultimaker PC, 3D-printed specimens, XY (flat); 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 (file v5.00), April 20, 2022.
Plastic PETG: Ultimaker PETG, 3D-printed specimens, XY (flat); 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 v1.00, April 29, 2022.

1
Ultimaker PC Technical Data Sheet, v5.00UltiMakerarchived copyFDM Polycarbonate · Yield strength: typicalFDM Polycarbonate · Ultimate tensile strength: typical, peak stress (= stress at yield)FDM Polycarbonate · Flexural strength: typicalFDM Polycarbonate · Elongation at break: typicalFDM Polycarbonate · Young's modulus (stiffness): typicalFDM Polycarbonate · Density: rangeFDM Polycarbonate · Glass transition: typicalFDM Polycarbonate · Max service temperature: HDT 0.455 MPa (printed specimens)
2
Ultimaker PETG Technical Data Sheet, v1.00UltiMakerarchived copyPlastic PETG · Yield strength: typicalPlastic PETG · Ultimate tensile strength: typical, peak stress (= stress at yield)Plastic PETG · Flexural strength: typicalPlastic PETG · Elongation at break: typicalPlastic PETG · Young's modulus (stiffness): typicalPlastic PETG · Density: typicalPlastic PETG · Glass transition: typicalPlastic PETG · Max service temperature: HDT 0.455 MPa (printed specimens)
3
Engineering Polymers Part and Mold Design: Thermoplastics, A Design GuideCovestroarchived copyFDM Polycarbonate · Poisson's ratio: base material: polycarbonate family typical (Covestro Part and Mold Design guide, Table 3-1)
4
Makrolon 2405 Technical Data SheetCovestroFDM Polycarbonate · Thermal conductivity: base material: Covestro Makrolon 2405 injection-molding PC, typical, through-plane, 23 °CFDM Polycarbonate · Thermal expansion: base material: Covestro Makrolon 2405 injection-molding PC, typical, 23-55 °C, parallel
5
Eastar Copolyester 6763 Product Data SheetEastmanPlastic PETG · Thermal conductivity: base material: Eastman Eastar Copolyester 6763 (PETG), typicalPlastic PETG · Thermal expansion: base material: Eastman Eastar Copolyester 6763 (PETG), typicalPlastic PETG · Specific heat: base material: Eastman Eastar Copolyester 6763 (PETG), DSC at 60 °C (lowest temperature listed)

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.

FDM Polycarbonate and Plastic PETG are 3D printed: their properties depend on build direction and print settings; these are typical values.

Questions

Mechanical

Is FDM Polycarbonate stronger than Plastic PETG?

FDM Polycarbonate is stronger: its yield strength is 53.3 MPa against 46.2 MPa for Plastic PETG (15%).

Which is lighter, FDM Polycarbonate or Plastic PETG?

FDM Polycarbonate is lighter: 1,190 kg/m³ against 1,270 kg/m³ for Plastic PETG.

Which is stiffer, FDM Polycarbonate or Plastic PETG?

FDM Polycarbonate is stiffer: Young's modulus 2.39 GPa against 1.94 GPa for Plastic PETG, so the same part in FDM Polycarbonate deflects less under the same load.

Which is lighter for the same job, FDM Polycarbonate or Plastic PETG?

For the same stiffness or strength: FDM Polycarbonate 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	FDM Polycarbonate	Plastic PETG
Stiff rod or tie (tension)	lighter	32% heavier
Stiff beam (bending)	lighter	19% heavier
Stiff panel or plate	lighter	14% heavier
Strong rod or tie	lighter	23% heavier
Strong beam	lighter	17% heavier
Strong panel or plate	lighter	15% 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, FDM Polycarbonate or Plastic PETG?

FDM Polycarbonate stretches further before it breaks: 9.2% elongation at break against 7.6% for Plastic PETG.

Thermal

Which handles higher temperatures, FDM Polycarbonate or Plastic PETG?

FDM Polycarbonate does: 105 °C against 76.2 °C for Plastic PETG, both HDT 0.455 MPa (printed specimens).

Which conducts heat better, FDM Polycarbonate or Plastic PETG?

Plastic PETG conducts heat better: 0.21 W/m·K against 0.2 W/m·K for FDM Polycarbonate.

Which expands less with temperature?

Plastic PETG expands less: 51 µm/m·K against 65 µm/m·K for FDM Polycarbonate.