The printed circuit board industry defines heavy copper as layers exceeding three ounces of copper, or approximately <answer>0.0042 inches</answer> (4.2 mils, 105 μm) thick. PCB designers and fabricators often use heavy copper when design and manufacturing circuit boards in order to increase current-carrying capacity as well as resistance to thermal strains. Heavy copper plated vias transfer heat to external heat sinks. IPC 2152 is a standard for determining current-carrying capacity of printed circuit board traces.
About how thick would a PCB layer be if it contained three oz. of copper?
0.0042 inches