Frequently Asked Questions
What size vias should I be using?
[ PCB Design / Design for Manufacture ]
Choosing the correct size for vias is not always easy.
There isn't a straight forward answer to this as it depends on the type of board you are designing and the density of it, the current carried by the tracks, and so on.
The general rule is that you need at least 10 thou /0.025 mm more than the drill size for the pad land diameter.
Also remember that vias in the design should be specified as vias and you shouldn’t use free pads as vias. This is essential otherwise the Design Rules Check (DRC) will not recognise them, and you may get the wrong results when producing solder mask plots. If you've already got some free pads which should be vias, right click on them and you'll see a menu entry to convert free pads to vias.
Under [Tools] [Design Calculators] is a utility for calculating the resistance of vias based on the board parameters. If a via is likely to be carrying significant current, this can be helpful. You can also choose to include vias in any resist plots which prevents them from being covered so they would be filled if the board were flow soldered. In exceptional cases you could include them in the paste mask definition if the board is being reflow soldered, again to ensure they are filled to minimise the resistance.
If you are in any doubt, then check with your manufacturer before proceeding too far.