PCB Boards: What makes a good fiducial mark?

Accountants may have a fiduciary responsibility, but that really has nothing to do with PC board assembly. Change the “ry” to a “ls”, however, and you get fiducials, which does have something to do with PCB assembly.

A fiducial is essentially an alignment mark for surface mount assembly machines. High volume assembly requires them to ensure accurate registration and parts placement. Low volume assembly, like we do here at Screaming Circuits, doesn't necessarily require them. (Some low volume shops do, so ask before assuming). Even if they aren't required, they still help and are always a pretty decent idea.

Source: Screaming Circuits