Materials / Compare
Plastic PLA vs. Plastic POM/Acetal
Compare Plastic PLA 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 | 52.5MPasourcetypical | 69MPasourcetypical (single ASTM D638 tensile strength) |
| Ultimate tensile strength | 52.5MPasourcetypical, peak stress (= stress at yield) | 69MPasourcetypical |
| Compressive strength | not sourced | 124MPasourcecompressive stress at 10% deformation |
| Flexural strength | 96.8MPasourcetypical | 99MPasourceflexural yield strength, typical |
| Elongation at break | 7.8%sourcetypical | 75%sourcetypical9.62x more ductile |
| Young's modulus (stiffness) | 3.25GPasourcetypical16% stiffer | 2.8GPasourcetypical |
| Density | 1,240kg/m³sourcetypical | 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 | 42.3kN·m/kg | 48.6kN·m/kg15% higher |
| Stiffness to weight | 2.62MN·m/kg33% higher | 1.97MN·m/kg |
| Poisson's ratio | not sourced | 0.35sourcetypical |
| Shear modulus | not sourced | 1.04GPa |
| Bulk modulus | not sourced | 3.11GPa |
| Speed of sound | 1,619m/s | 1,404m/s |
| Thermal | ||
| Thermal conductivity | 0.13W/m·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C | 0.4W/m·Ksourcetypical |
| Thermal expansion | not sourced | 122µm/m·Ksourcemean, 29 to 60 °C |
| 100 mm part over a 50 °C swing | not sourced | 610µm growth |
| Specific heat | 1,200J/kg·Ksourcebase material: NatureWorks Ingeo biopolymer, amorphous sheet, 25 °C | 1,465J/kg·Ksourceaverage -18 to 100 °C, Delrin acetal resins (not grade-specific) |
| Heats up and cools (diffusivity) | 0.0874mm²/s | 0.192mm²/s2.2x faster |
| Thermal shock resistance | not sourced | 52.5W/m |
| Melting point | 152°Csourcetypical | 175°Csourcecrystalline melting point |
| Glass transition | 59.1°Csourcetypical | not sourced |
| Max service temperature | 58.8°CsourceHDT 0.455 MPa (printed specimens) | 125°CsourceHDT 1.8 MPa (annealed) |
| Values for | Ultimaker PLA, 3D-printed specimens, XY (flat) orientation; 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 dated April 20, 2022. | 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.
Plastic PLA is 3D printed: its properties depend on build direction and print settings; these are typical values.
Questions
Is Plastic PLA stronger than Plastic POM/Acetal?
Plastic POM/Acetal is stronger: its yield strength is 69 MPa against 52.5 MPa for Plastic PLA (31%).
Which is lighter, Plastic PLA or Plastic POM/Acetal?
Plastic PLA is lighter: 1,240 kg/m³ against 1,420 kg/m³ for Plastic POM/Acetal.
Which is stiffer, Plastic PLA or Plastic POM/Acetal?
Plastic PLA is stiffer: Young's modulus 3.25 GPa against 2.8 GPa for Plastic POM/Acetal, so the same part in Plastic PLA deflects less under the same load.
Which is lighter for the same job, Plastic PLA or Plastic POM/Acetal?
For the same stiffness or strength: Plastic PLA is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate; Plastic POM/Acetal is lighter for a strong rod or tie, strong beam.
| Part that must be | Plastic PLA | Plastic POM/Acetal |
|---|---|---|
| Stiff rod or tie (tension) | lighter | 33% heavier |
| Stiff beam (bending) | lighter | 23% heavier |
| Stiff panel or plate | lighter | 20% heavier |
| Strong rod or tie | 15% heavier | lighter |
| Strong beam | 5% heavier | lighter |
| Strong panel or plate | about equal | about equal |
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 is more ductile, Plastic PLA or Plastic POM/Acetal?
Plastic POM/Acetal stretches further before it breaks: 75% elongation at break against 7.8% for Plastic PLA.
Which conducts heat better, Plastic PLA or Plastic POM/Acetal?
Plastic POM/Acetal conducts heat better: 0.4 W/m·K against 0.13 W/m·K for Plastic PLA.