Materials / Compare
PCB Laminate FR-4 vs. Wood
Compare PCB Laminate FR-4 vs. Wood strength, stiffness, weight and thermal properties.
| Try it on a partA sample part to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | not given (tensile used) | not given (tensile used) |
| Ultimate tensile strength | 246–385MPasourcetypical, in-plane: cross direction .. length direction (ASTM D3039) | 99MPasourcemodulus of rupture (no direct tensile value) |
| Compressive strength | not sourced | 46.6MPasourcecompression parallel to grain (maximum crushing strength), 12% MC |
| Flexural strength | 531–621MPasourcetypical: cross direction .. length direction (IPC-TM-650 2.4.4B) | 99MPasourcemodulus of rupture (static bending), 12% MC |
| Elongation at break | not sourced | not sourced |
| Young's modulus (stiffness) | 21.9–25.8GPasourcetypical, in-plane: cross direction .. length direction (ASTM D790-15e2) | 12.5GPasourcebending MOE, parallel to grain |
| Density | 1,920kg/m³sourcetypical, 50% resin content; another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR | not sourced |
| Strength to weight | 164kN·m/kg | not sourced |
| Stiffness to weight | 12.4MN·m/kg | not sourced |
| Poisson's ratio | 0.171–0.177sourcetypical, in-plane: cross direction .. length direction | 0.35sourcemu_LR (red oak group, ~12% MC) |
| Shear modulus | 10.2GPa2.19x stiffer in shear | 4.63GPa |
| Bulk modulus | 12.2GPa | 13.9GPa |
| Speed of sound | 3,525m/s | not sourced |
| Thermal | ||
| Thermal conductivity | 0.4W/m·Ksourcetypical (ASTM E1952); direction not stated by the sheet | 0.18W/m·Ksourceacross grain, 12% MC (Table 4-7, approximate) |
| Thermal expansion | 13–14µm/m·Ksourcetypical, in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C) | 3.1–4.5µm/m·Ksourceparallel to grain, ovendry wood, range across species |
| 100 mm part over a 50 °C swing | 67.5µm growth | 19µm growth3.55x less |
| Specific heat | 1,200–1,400J/kg·Ksourcetypical (ASTM E1461); another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR | 1,700J/kg·Ksourcesolid wood (all species), 12% MC, 27 C |
| Heats up and cools (diffusivity) | 0.16mm²/s | not sourced |
| Thermal shock resistance | 324W/m33% more resistant | 244W/m |
| Glass transition | 180°Csourcetypical, DSC (IPC-TM-650 2.4.25C) | not sourced |
| Max service temperature | 130°CsourceUL Relative Thermal Index (UL 796) | not sourced |
| Values for | Isola 370HR FR-4 laminate (Polyclad PCL-FR-370HR, 180 C Tg multifunctional epoxy, E-glass fabric), copper removed; Isola data sheet Revision C, last updated April 15, 2021. Woven-glass laminate: the sheet gives in-plane values per weave direction (length / cross) and the Z-axis CTE separately; the solver is isotropic per material. | Northern red oak (Quercus rubra), clear straight-grained specimens at 12% MC, parallel to grain unless stated; USDA FPL Wood Handbook FPL-GTR-282 (2021) Ch. 4 and Ch. 5 |
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 PCB Laminate FR-4 stronger than Wood?
PCB Laminate FR-4 is stronger: its tensile strength is 315 MPa against 99 MPa for Wood (3.19x).
Which is stiffer, PCB Laminate FR-4 or Wood?
PCB Laminate FR-4 is stiffer: Young's modulus 23.9 GPa against 12.5 GPa for Wood, so the same part in PCB Laminate FR-4 deflects less under the same load.
Which conducts heat better, PCB Laminate FR-4 or Wood?
PCB Laminate FR-4 conducts heat better: 0.4 W/m·K against 0.18 W/m·K for Wood.
Which expands less with temperature?
Wood expands less: 3.8 µm/m·K against 13.5 µm/m·K for PCB Laminate FR-4.