Thermal conductivity against densityHigher and further left: spreads more heat for its weightThermal expansion against thermal conductivityLower and further right: warps less when heated
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Sources2 documents: Isola, Park Electrochemical (Nelco)
PCB Board FR-4, 2 copper planes
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.
PCB Laminate FR-4
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.
1
370HR Laminate and Prepreg Data SheetIsolaarchived copyPCB Board FR-4, 2 copper planes · Ultimate tensile strength: the bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D3039)PCB Laminate FR-4 · Ultimate tensile strength: typical, in-plane: cross direction .. length direction (ASTM D3039)PCB Laminate FR-4 · Flexural strength: typical: cross direction .. length direction (IPC-TM-650 2.4.4B)PCB Board FR-4, 2 copper planes · Young's modulus (stiffness): the bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D790-15e2); the copper planes are left outPCB Laminate FR-4 · Young's modulus (stiffness): typical, in-plane: cross direction .. length direction (ASTM D790-15e2)PCB Board FR-4, 2 copper planes · Poisson's ratio: the bare laminate's (fr4-370hr), in-plane: cross direction .. length directionPCB Laminate FR-4 · Poisson's ratio: typical, in-plane: cross direction .. length directionPCB Laminate FR-4 · Thermal conductivity: typical (ASTM E1952); direction not stated by the sheetPCB Board FR-4, 2 copper planes · Thermal expansion: the bare laminate's (fr4-370hr), in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)PCB Laminate FR-4 · Thermal expansion: typical, in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)PCB Laminate FR-4 · Glass transition: typical, DSC (IPC-TM-650 2.4.25C)PCB Laminate FR-4 · Max service temperature: UL Relative Thermal Index (UL 796)
2
N4000-6 Laminate Data Sheet (2006)Park Electrochemical (Nelco)archived copyPCB Laminate FR-4 · Density: typical, 50% resin content; another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HRPCB Laminate FR-4 · Specific heat: typical (ASTM E1461); another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR
Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Mechanical
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.
Thermal
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.