Materials / Compare
Plastic PMMA vs. Zinc Zamak 3
Compare Plastic PMMA vs. Zinc Zamak 3 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 | not given (tensile used) | 221MPasourcetypical |
| Ultimate tensile strength | 80MPasourcetypical, 23 °C | 283MPasourcetypical |
| Compressive strength | 110MPasourcecompressive yield stress, typical | not sourced |
| Flexural strength | 115MPasourcetypical | not sourced |
| Elongation at break | 5.5%sourcetypical | 10%sourcetypical, in 2 in. |
| Young's modulus (stiffness) | 3.3GPasourcetypical, short-term | 85.5GPasourcetypical |
| Density | 1,190kg/m³sourcetypical5.55x lighter | 6,600kg/m³sourcetypical |
| Strength to weight | 67.2kN·m/kg2.01x higher | 33.5kN·m/kg |
| Stiffness to weight | 2.77MN·m/kg | 13MN·m/kg4.67x higher |
| Poisson's ratio | 0.37sourcetypical | 0.27sourcetypical, Zamak 3 hot-chamber die cast |
| Shear modulus | 1.2GPa | 33.7GPa27.9x stiffer in shear |
| Bulk modulus | 4.23GPa | 62GPa |
| Speed of sound | 1,665m/s | 3,599m/s |
| Thermal | ||
| Thermal conductivity | 0.19W/m·Ksourcetypical | 113W/m·Ksourcetypical595x more heat through a fin |
| Thermal expansion | 70µm/m·Ksource0-50 °C | 27.4µm/m·Ksourcetypical |
| 100 mm part over a 50 °C swing | 350µm growth | 137µm growth2.55x less |
| Specific heat | 1,470J/kg·Ksourcetypical | 419J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 0.109mm²/s | 40.9mm²/s376x faster |
| Thermal shock resistance | 41.5W/m | 7,782W/m188x more resistant |
| Melting point | not sourced | 381–387°Csourcemelting range |
| Max service temperature | 80°Csourcemax. permanent service temperature | not sourced |
| Values for | Röhm PLEXIGLAS GS 0F00 cast acrylic sheet, typical values at 23 °C / 50 % RH (Röhm Technical Information Ref. No. 211-1) | Zamak 3 (ASTM B86 die cast), Nathan Trotter (zinc alloy producer) technical data sheet, 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.
Questions
Is Plastic PMMA stronger than Zinc Zamak 3?
Zinc Zamak 3 is stronger: its yield strength is 221 MPa against tensile strength 80 MPa for Plastic PMMA (2.76x).
Which is lighter, Plastic PMMA or Zinc Zamak 3?
Plastic PMMA is lighter: 1,190 kg/m³ against 6,600 kg/m³ for Zinc Zamak 3.
Which is stiffer, Plastic PMMA or Zinc Zamak 3?
Zinc Zamak 3 is stiffer: Young's modulus 85.5 GPa against 3.3 GPa for Plastic PMMA, so the same part in Zinc Zamak 3 deflects less under the same load.
Which is lighter for the same job, Plastic PMMA or Zinc Zamak 3?
For the same stiffness or strength: Plastic PMMA is lighter for a stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Zinc Zamak 3 is lighter for a stiff rod or tie (tension).
| Part that must be | Plastic PMMA | Zinc Zamak 3 |
|---|---|---|
| Stiff rod or tie (tension) | 4.67x heavier | lighter |
| Stiff beam (bending) | lighter | 9% heavier |
| Stiff panel or plate | lighter | 1.87x heavier |
| Strong rod or tie | lighter | 2.01x heavier |
| Strong beam | lighter | 2.82x heavier |
| Strong panel or plate | lighter | 3.34x 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).
Which conducts heat better, Plastic PMMA or Zinc Zamak 3?
Zinc Zamak 3 conducts heat better: 113 W/m·K against 0.19 W/m·K for Plastic PMMA.
Which expands less with temperature?
Zinc Zamak 3 expands less: 27.4 µm/m·K against 70 µm/m·K for Plastic PMMA.