materials.fr4

materials.fr4()

FR-4 woven-glass/epoxy laminate — the standard PCB substrate.

FR-4 is orthotropic and the solver is isotropic, so this entry takes the through-thickness thermal conductivity (0.29 W/(mK)) — the number that matters for getting heat out of a board — together with the in-plane elastic constants and in-plane CTE, which is what board-level warpage and stiffness depend on. In-plane conductivity is roughly 0.8–1.0 W/(mK) and the out-of-plane CTE above Tg is several times the in-plane value; model those explicitly if they drive your result. yield_strength holds the ultimate tensile strength: FR-4 is brittle and has no yield plateau, so a “safety factor” against it is a factor against fracture.

Sources: NEMA LI-1 / IPC-4101 FR-4 specifications; Isola 370HR and Rogers laminate datasheets; Sarvar, Poole & Witting, J. Electron. Mater. 19 (1990) on PCB thermal conductivity.

Returns

Name	Type	Description
	Material	A fresh Material with the familiar solder-mask green appearance.