My favorite, inexpensive off-shore PCB supplier seems to have lots of trouble keeping via holes properly aligned. The upshot of this is that some boards are going to have marginal vias that may fail later. Would the addition of alignment targets on the global layer (where the board outline is) assist this PCB fab house in doing a better job with vias?
Note that I have increased the annular ring of the via to help compensate for the misalignment per one of the excellent SFE tutorials.
Alignment targets probably won’t work as they probably don’t use an optical drilling system. Alignment marks are mostly for component placement machines that use optical processing to place components on finished boards.
You might want to email your question to your board house, if they can’t answer or don’t have an excuse, maybe you should find a higher quality board house? Getting 10 boards at half the cost when only 5 work isn’t much of a deal…
I agree with finding a better board house and I’m in the process of doing that. I should have said that I wanted to add fiduciary marks to the global layer of the board. These are circles with cross hairs and are usually placed at the upper left and lower right hand corners of the board for alignment purposes.
Yes, fiduciary alignment marks are used for optical systems, your overseas board house is probably using a pure CNC drilling system with no optical alignment, and it’s probably a cheap one.