Aspect Ratio in PCB

In PCB fabrication the aspect ratio is the thickness of a PCB divided by the diameter size of a drilled hole. It’s importance relates to the plating process — plating solutions must flow through the hole efficiently in order to achieve acceptable copper plating. Hole sizes that are small compared with the board thickness can result in unsatisfactory plating.


The larger the aspect ratio, the more difficult it is to achieve reliable plating.