Plastic HDPE vs. SLA Resin Standard

Compare Plastic HDPE vs. SLA Resin Standard strength, stiffness, weight and thermal properties.

Plastic HDPEBulk polymer (molded or machined)

SLA Resin Standard3D printed (SLA resin)

Mechanical	Plastic HDPE	SLA Resin Standard
Yield strength	24MPa1	not given (tensile used)
Ultimate tensile strength	not stated (yield given)	60MPa2
Flexural strength	not sourced	105MPa2
Elongation at break	not sourced	8%2
Young's modulus (stiffness)	0.9GPa1	2.75GPa23.06x stiffer
Density	950kg/m³127% lighter	1,210kg/m³3
Strength to weight	25.3kN·m/kg	49.6kN·m/kg1.96x higher
Stiffness to weight	0.947MN·m/kg	2.27MN·m/kg2.4x higher
Poisson's ratio	base material0.4–0.454	not sourced
Shear modulus	0.316GPa	not sourced
Bulk modulus	2GPa	not sourced
Speed of sound	973m/s	1,508m/s1.55x faster

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	Plastic HDPE	SLA Resin Standard
Thermal conductivity	base material0.4–0.49W/m·K4	0.54W/m·K5
Thermal expansion	base material120µm/m·K4	mean -30 to 140 °C114µm/m·K5
100 mm part over a 50 °C swing	600µm growth	571µm growth5% less
Specific heat	base material2,250J/kg·K425% higher	1,800J/kg·K5
Heats up and cools (diffusivity)	0.208mm²/s	0.248mm²/s19% faster
Thermal shock resistance	56.9W/m	not sourced
Max service temperature	not sourced	HDT 1.8 MPa59°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

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Sources5 documents: LyondellBasell, Formlabs, INEOS Olefins & Polymers USA

Plastic HDPE: LyondellBasell Hostalen 23050 B high density polyethylene, typical ISO values
SLA Resin Standard: Formlabs Clear Resin V5 (FLGPCL05), TDS Rev. 01 March 20, 2024; printed on Form 4 at 100 µm, washed 5 min in >=99% IPA, post-cured 15 min at 60 °C in Form Cure. Orientation not stated.

1
Hostalen 23050 B Product DataLyondellBasellPlastic HDPE · Yield strength: typical, tensile stress at yield 23 °C, 50 mm/min ISO 527Plastic HDPE · Young's modulus (stiffness): typical, tensile modulus 23 °C ISO 527Plastic HDPE · Density: typical, ISO 1183
2
Clear Resin V5 Technical Data Sheet (2024)Formlabsarchived copySLA Resin Standard · Ultimate tensile strength: typicalSLA Resin Standard · Flexural strength: typicalSLA Resin Standard · Elongation at break: typicalSLA Resin Standard · Young's modulus (stiffness): typicalSLA Resin Standard · Max service temperature: HDT 1.8 MPa
3
Clear Resin V5 Technical Data Sheet (web edition)FormlabsSLA Resin Standard · Density: typical, post-cured (same for 5 min ambient and 15 min at 60 °C), ASTM D792
4
Typical Engineering Properties of High Density PolyethyleneINEOS Olefins & Polymers USAarchived copyPlastic HDPE · Poisson's ratio: base material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)Plastic HDPE · Thermal conductivity: base material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)Plastic HDPE · Thermal expansion: base material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)Plastic HDPE · Specific heat: base material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)
5
Thermal Properties of Selected Formlabs SLA ResinsFormlabsSLA Resin Standard · Thermal conductivity: typical, post-cured, ASTM E1530SLA Resin Standard · Thermal expansion: mean -30 to 140 °C, post-cured (5 min ambient cure), TMA ASTM E831SLA Resin Standard · Specific heat: typical, 25 °C, post-cured (5 min ambient cure), DSC ASTM E1269

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.

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

Questions

Mechanical

Is Plastic HDPE stronger than SLA Resin Standard?

SLA Resin Standard is stronger: its tensile strength is 60 MPa against yield strength 24 MPa for Plastic HDPE (2.5x).

Which is lighter, Plastic HDPE or SLA Resin Standard?

Plastic HDPE is lighter: 950 kg/m³ against 1,210 kg/m³ for SLA Resin Standard.

Which is stiffer, Plastic HDPE or SLA Resin Standard?

SLA Resin Standard is stiffer: Young's modulus 2.75 GPa against 0.9 GPa for Plastic HDPE, so the same part in SLA Resin Standard deflects less under the same load.

Which is lighter for the same job, Plastic HDPE or SLA Resin Standard?

For the same stiffness or strength: SLA Resin Standard 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 HDPE	SLA Resin Standard
Stiff rod or tie (tension)	2.4x heavier	lighter
Stiff beam (bending)	37% heavier	lighter
Stiff panel or plate	14% heavier	lighter
Strong rod or tie	1.96x heavier	lighter
Strong beam	45% heavier	lighter
Strong panel or plate	24% 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).

Thermal

Which conducts heat better, Plastic HDPE or SLA Resin Standard?

SLA Resin Standard conducts heat better: 0.54 W/m·K against 0.445 W/m·K for Plastic HDPE.

Which expands less with temperature?

SLA Resin Standard expands less: 114 µm/m·K against 120 µm/m·K for Plastic HDPE.