PCB Board FR-4, 2 copper planes vs. PCB Laminate FR-4

Compare PCB Board FR-4, 2 copper planes vs. PCB Laminate FR-4 strength, stiffness, weight and thermal properties.

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PCB Board FR-4, 2 copper planesComposite

Mechanical
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Yield strength	not given (tensile used)	not given (tensile used)
Ultimate tensile strength	246–385MPasourcethe bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D3039)	246–385MPasourcetypical, in-plane: cross direction .. length direction (ASTM D3039)
Flexural strength	not sourced	531–621MPasourcetypical: cross direction .. length direction (IPC-TM-650 2.4.4B)
Elongation at break	not sourced	not sourced
Young's modulus (stiffness)	21.9–25.8GPasourcethe bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D790-15e2); the copper planes are left out	21.9–25.8GPasourcetypical, in-plane: cross direction .. length direction (ASTM D790-15e2)
Density	not sourced	1,920kg/m³sourcetypical, 50% resin content; another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR
Strength to weight	not sourced	164kN·m/kg
Stiffness to weight	not sourced	12.4MN·m/kg
Poisson's ratio	0.171–0.177sourcethe bare laminate's (fr4-370hr), in-plane: cross direction .. length direction	0.171–0.177sourcetypical, in-plane: cross direction .. length direction
Shear modulus	10.2GPa	10.2GPa
Bulk modulus	12.2GPa	12.2GPa
Speed of sound	not sourced	3,525m/s
Thermal
Thermal conductivity	not sourced	0.4W/m·Ksourcetypical (ASTM E1952); direction not stated by the sheet
Thermal expansion	13–14µm/m·Ksourcethe bare laminate's (fr4-370hr), in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)	13–14µm/m·Ksourcetypical, in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)
100 mm part over a 50 °C swing	67.5µm growth	67.5µm growth
Specific heat	not sourced	1,200–1,400J/kg·Ksourcetypical (ASTM E1461); another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR
Heats up and cools (diffusivity)	not sourced	0.16mm²/s
Thermal shock resistance	not sourced	324W/m
Glass transition	not sourced	180°Csourcetypical, DSC (IPC-TM-650 2.4.25C)
Max service temperature	not sourced	130°CsourceUL Relative Thermal Index (UL 796)
Values for	A whole circuit board read as one orthotropic plate: the JEDEC high-K thermal test board (JESD51-7, "2s2p"), 0.062 in (1.575 mm) thick with two internal solid copper planes 0.0014 in (1 oz) thick, as Texas Instruments SZZA017A Table 1 gives it. Copper C110 and the Isola 370HR laminate from this library; the layers conduct in parallel along the board and in series through it (boardStackup.ts). Its two 0.0028 in trace layers cover little of the board and are left out; vias are ignored. Mechanical values are the bare laminate's.	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.

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 Board FR-4, 2 copper planes stronger than PCB Laminate FR-4?

PCB Board FR-4, 2 copper planes is stronger: its tensile strength is 315 MPa against 315 MPa for PCB Laminate FR-4 (0%).

Which is stiffer, PCB Board FR-4, 2 copper planes or PCB Laminate FR-4?

PCB Board FR-4, 2 copper planes is stiffer: Young's modulus 23.9 GPa against 23.9 GPa for PCB Laminate FR-4, so the same part in PCB Board FR-4, 2 copper planes deflects less under the same load.

Which expands less with temperature?

PCB Board FR-4, 2 copper planes expands less: 13.5 µm/m·K against 13.5 µm/m·K for PCB Laminate FR-4.

Among 73 materials

Stiffness against density

Strength against density