Materials / Compare
Plastic POM/Acetal vs. Plastic TPU
Compare Plastic POM/Acetal vs. Plastic TPU 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 | 69MPasourcetypical (single ASTM D638 tensile strength) | not given (tensile used) |
| Ultimate tensile strength | 69MPasourcetypical | 23.7MPasourcetypical, stress at break |
| Compressive strength | 124MPasourcecompressive stress at 10% deformation | not sourced |
| Flexural strength | 99MPasourceflexural yield strength, typical | 4.1MPasourcetypical |
| Elongation at break | 75%sourcetypical | not sourced |
| Young's modulus (stiffness) | 2.8GPasourcetypical41.8x stiffer | 0.067GPasourcetypical |
| Density | 1,420kg/m³sourcetypical (DuPont product information for Delrin 100 NC010; 'The data listed here fall within the normal range of product properties') | 1,220kg/m³sourcetypical |
| Strength to weight | 48.6kN·m/kg2.5x higher | 19.4kN·m/kg |
| Stiffness to weight | 1.97MN·m/kg35.9x higher | 0.0549MN·m/kg |
| Poisson's ratio | 0.35sourcetypical | not sourced |
| Shear modulus | 1.04GPa | not sourced |
| Bulk modulus | 3.11GPa | not sourced |
| Speed of sound | 1,404m/s | 234m/s |
| Thermal | ||
| Thermal conductivity | 0.4W/m·Ksourcetypical | not sourced |
| Thermal expansion | 122µm/m·Ksourcemean, 29 to 60 °C | not sourced |
| 100 mm part over a 50 °C swing | 610µm growth | not sourced |
| Specific heat | 1,465J/kg·Ksourceaverage -18 to 100 °C, Delrin acetal resins (not grade-specific) | not sourced |
| Heats up and cools (diffusivity) | 0.192mm²/s | not sourced |
| Thermal shock resistance | 52.5W/m | not sourced |
| Melting point | 175°Csourcecrystalline melting point | 217°Csourcetypical |
| Max service temperature | 125°CsourceHDT 1.8 MPa (annealed) | 50.3°CsourceHDT 0.455 MPa (printed specimens) |
| Values for | DuPont Delrin 100 acetal homopolymer, Table 2 'Typical Properties of Delrin Acetal Resins' (ASTM methods), Delrin Design Guide Module III hosted on delrin.com | Ultimaker TPU 95A, 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 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.
Plastic TPU is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Plastic POM/Acetal stronger than Plastic TPU?
Plastic POM/Acetal is stronger: its yield strength is 69 MPa against tensile strength 23.7 MPa for Plastic TPU (2.91x).
Which is lighter, Plastic POM/Acetal or Plastic TPU?
Plastic TPU is lighter: 1,220 kg/m³ against 1,420 kg/m³ for Plastic POM/Acetal.
Which is stiffer, Plastic POM/Acetal or Plastic TPU?
Plastic POM/Acetal is stiffer: Young's modulus 2.8 GPa against 0.067 GPa for Plastic TPU, so the same part in Plastic POM/Acetal deflects less under the same load.
Which is lighter for the same job, Plastic POM/Acetal or Plastic TPU?
For the same stiffness or strength: Plastic POM/Acetal 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 POM/Acetal | Plastic TPU |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 35.9x heavier |
| Stiff beam (bending) | lighter | 5.55x heavier |
| Stiff panel or plate | lighter | 2.98x heavier |
| Strong rod or tie | lighter | 2.5x heavier |
| Strong beam | lighter | 1.75x heavier |
| Strong panel or plate | lighter | 47% 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).