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How to best handle component fiducials?

EvanShultz
Note: This post has some elements in common with this post.

Component fiducials, assumed to be part of a symbol, can be either pins or vias.
-If they're pins, they can't be moved unless the UNFIXED_PINS property is added to the symbol. Sometimes, the fiducials have to move.
-If they're vias, they can be easily moved by the engineer if they need to be, but they can also be deleted accidentally. Either manually or when deleting all vias in the autorouter.

Putting the FIXED property on a via works, but I can't fix a pin in the symbol editor. It doesn't really matter, because the FIXED property doesn't "bubble up" to the board if the property is on a via.

I don't know of a way to fix an object with relation to another object, and I combed over the Allegro platform property reference without finding any useful properties. Manual work to unfix a fiducial is OK, since the vast majority of time the default fiducial location is fine.

So I see 2 options, both with limitations:
1. Use fiducial pins, but then I can't move them without putting all pins in danger of errant, umm, user adjustments.
2. Use fiducial vias, but those are too easy to delete.

Which leads me to my question: Have any of you smart folks come up with a rugged solution for component fiducials? Hopefully something that resolves the concerns I mentioned above.

  •  I use Option 1 when necessary. But...

    Times have changed. All these fiducial niceities are kind of out-dated. Assembly houses have got so much better in the last 5-7 years that they don't really require all these fiducials. Lately I've just placed 'extra' fiducials inside the board, around fine-pitch (e.g. less than 20mil) parts to facilitate manufacturing, if needed. To be a stickler for all the old requirements, is almost counter-productive anymore.

    Good day.

  •  Cadpro is correct. We are not using local fiducials for fine-pitch components without requirement. We are using only global fiducials and it works fine.

  •  Cadpro is correct. We are not using local fiducials for fine-pitch components without requirement. We are using only global fiducials and it works fine.

  • Good points. Thanks! We do PCB assembly in-house, and I'm following the recommendations from our manufacturing team. I'll see if we can eliminate some (or all) comp fiducials.
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