How do I design non-plated through holes/slots? ← Have a problem with PCB design? To ensure that the mechanical or mounting holes/slots are not plated, there should not be any copper around the hole in the design files. Plated holes/slots:Circuit layer: holes have copper Solder mask layer: holes have openingsNon-plated holes/slots:Circuit layer: holes have no copperSolder mask layer: openings don't matter