Materials / Compare
Plastic HDPE vs. Plastic POM/Acetal
Compare Plastic HDPE vs. Plastic POM/Acetal strength, stiffness, weight and thermal properties.
| Try it on a partA bracket to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | 24MPasourcetypical, tensile stress at yield 23 °C, 50 mm/min ISO 527 | 69MPasourcetypical (single ASTM D638 tensile strength) |
| Ultimate tensile strength | not sourced | 69MPasourcetypical |
| Compressive strength | not sourced | 124MPasourcecompressive stress at 10% deformation |
| Flexural strength | not sourced | 99MPasourceflexural yield strength, typical |
| Elongation at break | not sourced | 75%sourcetypical |
| Young's modulus (stiffness) | 0.9GPasourcetypical, tensile modulus 23 °C ISO 527 | 2.8GPasourcetypical |
| Density | 950kg/m³sourcetypical, ISO 1183 | 1,420kg/m³sourcetypical (DuPont product information for Delrin 100 NC010; 'The data listed here fall within the normal range of product properties') |
| Strength to weight | 25.3kN·m/kg | 48.6kN·m/kg1.92x higher |
| Stiffness to weight | 0.947MN·m/kg | 1.97MN·m/kg2.08x higher |
| Poisson's ratio | 0.4–0.45sourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 0.35sourcetypical |
| Shear modulus | 0.316GPa | 1.04GPa3.28x stiffer in shear |
| Bulk modulus | 2GPa | 3.11GPa |
| Speed of sound | 973m/s | 1,404m/s |
| Thermal | ||
| Thermal conductivity | 0.4–0.49W/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 0.4W/m·Ksourcetypical |
| Thermal expansion | 120µm/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 122µm/m·Ksourcemean, 29 to 60 °C |
| 100 mm part over a 50 °C swing | 600µm growth2% less | 610µm growth |
| Specific heat | 2,250J/kg·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE) | 1,465J/kg·Ksourceaverage -18 to 100 °C, Delrin acetal resins (not grade-specific) |
| Heats up and cools (diffusivity) | 0.208mm²/s8% faster | 0.192mm²/s |
| Thermal shock resistance | 56.9W/m8% more resistant | 52.5W/m |
| Melting point | not sourced | 175°Csourcecrystalline melting point |
| Max service temperature | not sourced | 125°CsourceHDT 1.8 MPa (annealed) |
| Values for | LyondellBasell Hostalen 23050 B high density polyethylene, typical ISO values | DuPont Delrin 100 acetal homopolymer, Table 2 'Typical Properties of Delrin Acetal Resins' (ASTM methods), Delrin Design Guide Module III hosted on delrin.com |
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.
Questions
Is Plastic HDPE stronger than Plastic POM/Acetal?
Plastic POM/Acetal is stronger: its yield strength is 69 MPa against 24 MPa for Plastic HDPE (2.88x).
Which is lighter, Plastic HDPE or Plastic POM/Acetal?
Plastic HDPE is lighter: 950 kg/m³ against 1,420 kg/m³ for Plastic POM/Acetal.
Which is stiffer, Plastic HDPE or Plastic POM/Acetal?
Plastic POM/Acetal is stiffer: Young's modulus 2.8 GPa against 0.9 GPa for Plastic HDPE, so the same part in Plastic POM/Acetal deflects less under the same load.
Which is lighter for the same job, Plastic HDPE or Plastic POM/Acetal?
For the same stiffness or strength: Plastic HDPE is lighter for a stiff panel or plate; Plastic POM/Acetal is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie, strong beam, strong panel or plate.
| Part that must be | Plastic HDPE | Plastic POM/Acetal |
|---|---|---|
| Stiff rod or tie (tension) | 2.08x heavier | lighter |
| Stiff beam (bending) | 18% heavier | lighter |
| Stiff panel or plate | lighter | 2% heavier |
| Strong rod or tie | 1.92x heavier | lighter |
| Strong beam | 35% heavier | lighter |
| Strong panel or plate | 13% 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, Plastic HDPE or Plastic POM/Acetal?
Plastic HDPE conducts heat better: 0.445 W/m·K against 0.4 W/m·K for Plastic POM/Acetal.
Which expands less with temperature?
Plastic HDPE expands less: 120 µm/m·K against 122 µm/m·K for Plastic POM/Acetal.