DMLS 316L Stainless Steel vs. Plastic Polycarbonate

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

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DMLS 316L Stainless Steel3D printed metal (DMLS)

Plastic PolycarbonateBulk polymer (molded or machined)

Mechanical
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Yield strength	530MPasourcetypical, as manufactured, horizontal	65MPasourcetypical, tensile yield
Ultimate tensile strength	640MPasourcetypical, as manufactured, horizontal	65MPasourcetypical, stress at break
Flexural strength	not sourced	97MPasourcetypical, flexural strength
Elongation at break	40%sourcetypical at break, as manufactured, horizontal	125%sourcetypical, strain at break
Young's modulus (stiffness)	185GPasourcetypical, as built, horizontal (XY); EOSINT M280-400W / M290-400W, 316L_Surface 1.0, 20 µm (2014 sheet)	2.4GPasourcetypical
Density	7,900kg/m³sourcepart density (ISO 3369, not labelled min or typical), EOS M 290, 40 µm FlexLine	1,200kg/m³sourcetypical
Strength to weight	67.1kN·m/kg24% higher	54.2kN·m/kg
Stiffness to weight	23.4MN·m/kg11.7x higher	2MN·m/kg
Poisson's ratio	0.3sourcebase material: austenitic stainless steels incl. 1.4404 (316L), design value	0.38sourcetypical, polycarbonate family (Covestro Part and Mold Design guide, Table 3-1)
Shear modulus	71.2GPa81.8x stiffer in shear	0.87GPa
Bulk modulus	154GPa	3.33GPa
Speed of sound	4,839m/s	1,414m/s
Thermal
Thermal conductivity	16.2W/m·Ksourcebase material: wrought 316/316L (Cleveland-Cliffs), at 100 °C	0.2W/m·Ksourcetypical, through-plane, 23 C
Thermal expansion	15.7µm/m·Ksourcemean 25-100 °C, ASTM E228	65µm/m·Ksourcetypical, 23-55 C, parallel and normal
100 mm part over a 50 °C swing	78.6µm growth4.13x less	325µm growth
Specific heat	500J/kg·Ksourcebase material: wrought 316/316L (Cleveland-Cliffs), 0-100 °C	1,172J/kg·Ksourcetypical (guide value), Bayer ASTM datasheet for Makrolon 2405, ASTM D 2766
Heats up and cools (diffusivity)	4.1mm²/s28.8x faster	0.142mm²/s
Thermal shock resistance	2,067W/m40x more resistant	51.7W/m
Glass transition	not sourced	144°Csourcetypical, DSC 10 C/min
Max service temperature	not sourced	125°CsourceUL 746B RTI, tensile strength, 1.5 mm
Values for	EOS StainlessSteel 316L (powder 9011-0032), EOS M 290, ParameterSet 316L 20µm Surface M290/400W, as manufactured, horizontal; ISO 6892-1	Covestro Makrolon 2405 general-purpose PC (MVR 19), Covestro technical datasheet version 2026-09-28, typical values

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 is 3D printed: its properties depend on build direction and print settings; these are typical values.

Questions

Is DMLS 316L Stainless Steel stronger than Plastic Polycarbonate?

DMLS 316L Stainless Steel is stronger: its yield strength is 530 MPa against 65 MPa for Plastic Polycarbonate (8.15x).

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

Plastic Polycarbonate is lighter: 1,200 kg/m³ against 7,900 kg/m³ for DMLS 316L Stainless Steel.

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

DMLS 316L Stainless Steel is stiffer: Young's modulus 185 GPa against 2.4 GPa for Plastic Polycarbonate, 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 Polycarbonate?

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 Polycarbonate is lighter for a stiff panel or plate, strong beam, strong panel or plate.

Part that must be	DMLS 316L Stainless Steel	Plastic Polycarbonate
Stiff rod or tie (tension)	lighter	11.7x heavier
Stiff beam (bending)	lighter	33% heavier
Stiff panel or plate	1.55x heavier	lighter
Strong rod or tie	lighter	24% heavier
Strong beam	1.63x heavier	lighter
Strong panel or plate	2.31x 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 Polycarbonate?

DMLS 316L Stainless Steel conducts heat better: 16.2 W/m·K against 0.2 W/m·K for Plastic Polycarbonate.

Which expands less with temperature?

DMLS 316L Stainless Steel expands less: 15.7 µm/m·K against 65 µm/m·K for Plastic Polycarbonate.

Among 59 materials

Stiffness against density

Strength against density