he FR4 PCBs are composed of woven fiber glass and epoxy resin with copper foil on one side. FR is the short form of Flame Retardant, a halogenated material used as a non-conducive layer with strong adherence to copper. They serve as a self-extinguisher laminating layer.
Aluminum PCB and FR4 PCB (Glass Fiber Reinforced Epoxy Resin PCB) are two common types of PCBs with significant differences in terms of materials, performance, and applications. Copper-based PCBs have better thermal conductivity than aluminum-based PCBs.
The layout of an aluminum PCB is similar to other PCBs. It has one or more layers of copper, solder mask, and silkscreen on it. However, instead of fiberglass or plastic substrates, aluminum circuit boards have metal substrates.