2
\$\begingroup\$

I'd like to know how I can create fiducials with gEDA. Some PCB manufacturers, such as Eurocircuits proscribe zero-aperture drill holes so I can't just whack in a via or pad and set its diameter to zero. BTW I tried that and gEDA PCB doesn't even allow a null-diameter for a via.

I also tried clearing a round-sized track but the solder mask doesn't clear. Hence my question: how am I supposed to create fiducials with gEDA?

\$\endgroup\$
3
\$\begingroup\$

I finally found the answer. Copper can be cleared by converting a track into an element, then clearance can be set. The link is about poly's but actually refers to tracks.

\$\endgroup\$
2
\$\begingroup\$

I don't know how it's done with that particular software, but the fiducials I always use are just a small dot of copper with the solder mask and silk screen cleared in its immediate vicinity. This must be possible with any competent software.

I use Eagle, and there it's just a filled circle in the top copper layer, with a larger filled circle of solder mask at the same coordinate. In Eagle, drawing in the solder mask layer (tStop) removes the solder mask. I then place these in convenient places at rounded coordinates as pretty much the last step in designing the board. I therefore manually ensure there is no silkscreen within the solder mask hole.

I just checked, and my standard fiducial is a 20 mil diameter copper dot within a 50 mil diameter solder mask hole. I have had several different manufacturers make boards with these fiducials on them, and never received any complaints. You need to have at least two in opposite corners. For large boards I usually put one in each corner.

\$\endgroup\$
  • \$\begingroup\$ That's indeed one reasoning I had figured out. The "how" is unknown to me so far with gEDA. I can only clear around pads, not copper "tracks" like this. In gEDA there's actually no way to draw inside the solder mask as it is non selectable. But I might have missed something, I guess. \$\endgroup\$ – user59864 Oct 20 '15 at 14:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy