TIP: Each and every copper layer is assumed to contain the same completed copper pounds unless in any other case specified in your fabrication notes. A 4-layer board with a defined bodyweight of 1oz, is assumed to possess a concluded copper thickness of 1.37mils (or more) on every copper layer. https://dominicklnqqr.onzeblog.com/31232902/top-latest-five-four-layer-inner-and-outer-layers-2oz-copper-thick-pcb-circuit-board-urban-news