... cloth. The fiberglass cloth is then impregnated with epoxy resin, and the copper foil material is adhered through an electroplating process ... power convertors, and so on Design Guide for Heavy Copper PCB Typical conductor width/spacing/thickness tolerance is +/-20%, ... . The fiberglass cloth is then impregnated with epoxy resin, and the copper foil material is adhered through an electroplating process ...