Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 11:29pm 21 Apr 2021
Perhaps I have just been extremely lucky, but in all the years I have been having boards made for me by reputable companies, I have never once received a board back that was faulty due to a manufacturing stuff up.
But I can certainly see your point. Something like a very fine spiral track COULD have a copper bridge and a shorted turn, and it would not show up during automatic testing for continuity. It SHOULD have failed visual inspection before the solder mask was applied.
It may also be difficult to convince the board manufacturer that it is in fact faulty, unless a short is plainly visible. Don't really know the answer to that one.
But I can only go on my own personal experience, which seems to be rather different to your own.