DMLS 316L Stainless Steel vs. Plastic PETG

Compare DMLS 316L Stainless Steel vs. Plastic PETG strength, stiffness, weight and thermal properties.

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DMLS 316L Stainless Steel3D printed metal (DMLS)

Mechanical
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Yield strength	530MPasourcetypical, as manufactured, horizontal	46.2MPasourcetypical
Ultimate tensile strength	640MPasourcetypical, as manufactured, horizontal	46.2MPasourcetypical, peak stress (= stress at yield)
Flexural strength	not sourced	78.9MPasourcetypical
Elongation at break	40%sourcetypical at break, as manufactured, horizontal	7.6%sourcetypical
Young's modulus (stiffness)	185GPasourcetypical, as built, horizontal (XY); EOSINT M280-400W / M290-400W, 316L_Surface 1.0, 20 µm (2014 sheet)	1.94GPasourcetypical
Density	7,900kg/m³sourcepart density (ISO 3369, not labelled min or typical), EOS M 290, 40 µm FlexLine	1,270kg/m³sourcetypical
Strength to weight	67.1kN·m/kg1.84x higher	36.4kN·m/kg
Stiffness to weight	23.4MN·m/kg15.3x higher	1.53MN·m/kg
Poisson's ratio	0.3sourcebase material: austenitic stainless steels incl. 1.4404 (316L), design value	not sourced
Shear modulus	71.2GPa	not sourced
Bulk modulus	154GPa	not sourced
Speed of sound	4,839m/s	1,236m/s
Thermal
Thermal conductivity	16.2W/m·Ksourcebase material: wrought 316/316L (Cleveland-Cliffs), at 100 °C	0.21W/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical
Thermal expansion	15.7µm/m·Ksourcemean 25-100 °C, ASTM E228	51µm/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical
100 mm part over a 50 °C swing	78.6µm growth3.24x less	255µm growth
Specific heat	500J/kg·Ksourcebase material: wrought 316/316L (Cleveland-Cliffs), 0-100 °C	1,300J/kg·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), DSC at 60 °C (lowest temperature listed)
Heats up and cools (diffusivity)	4.1mm²/s32.2x faster	0.127mm²/s
Thermal shock resistance	2,067W/m	not sourced
Glass transition	not sourced	77.4°Csourcetypical
Max service temperature	not sourced	76.2°CsourceHDT 0.455 MPa (printed specimens)
Values for	EOS StainlessSteel 316L (powder 9011-0032), EOS M 290, ParameterSet 316L 20µm Surface M290/400W, as manufactured, horizontal; ISO 6892-1	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.

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.

DMLS 316L Stainless Steel and Plastic PETG are 3D printed: their properties depend on build direction and print settings; these are typical values.

Questions

Is DMLS 316L Stainless Steel stronger than Plastic PETG?

DMLS 316L Stainless Steel is stronger: its yield strength is 530 MPa against 46.2 MPa for Plastic PETG (11.5x).

Which is lighter, DMLS 316L Stainless Steel or Plastic PETG?

Plastic PETG is lighter: 1,270 kg/m³ against 7,900 kg/m³ for DMLS 316L Stainless Steel.

Which is stiffer, DMLS 316L Stainless Steel or Plastic PETG?

DMLS 316L Stainless Steel is stiffer: Young's modulus 185 GPa against 1.94 GPa for Plastic PETG, so the same part in DMLS 316L Stainless Steel deflects less under the same load.

Which is lighter for the same job, DMLS 316L Stainless Steel or Plastic PETG?

For the same stiffness or strength: DMLS 316L Stainless Steel is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie; Plastic PETG is lighter for a stiff panel or plate, strong beam, strong panel or plate.

Part that must be	DMLS 316L Stainless Steel	Plastic PETG
Stiff rod or tie (tension)	lighter	15.3x heavier
Stiff beam (bending)	lighter	1.57x heavier
Stiff panel or plate	36% heavier	lighter
Strong rod or tie	lighter	1.84x heavier
Strong beam	22% heavier	lighter
Strong panel or plate	1.84x heavier	lighter

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, DMLS 316L Stainless Steel or Plastic PETG?

DMLS 316L Stainless Steel conducts heat better: 16.2 W/m·K against 0.21 W/m·K for Plastic PETG.

Which expands less with temperature?

DMLS 316L Stainless Steel expands less: 15.7 µm/m·K against 51 µm/m·K for Plastic PETG.

Among 59 materials

Stiffness against density

Strength against density