Hi all,
Whenever I’ve routed my boards, I’d often first start with the thinnest track, do the routing, and then I’d thicken the tracks wherever there was space for it - even when you do photoresist, if there is a lot of metal to be removed from the board (as on the board right on pic below), then depending on UV light or acid freshness, one might end up waiting long enough for the exposed metal to be removed, so the acid starts eating into the tracks. Which is why I’ve always thought - the less metal to be removed from a PCB, the better, which is why I’d try to widen the tracks on a design.
This time, however, I might try a PCB mill. As I’ve understood, that one has a tiny drill that removes copper, and thus removing a flat piece of copper from a board (if the design demands it) seems unreasonable. So, I thought, even more of a reason to widen tracks - in fact, widen them so much, so that there is only the border left, which the drill would remove.
I tried looking up something that would do this as a technique for PCB design, but I couldn’t really find anything (such as a specific technique name). Then I remembered I read something in the past about “Voronoi cells”, so I looked that up, and only found this as related:
… with Java software at:
In fact, they have a very nice picture that explains it:
The same printed circuit board manufactured
three different ways: by traditional photochemical process (right); by
mechanical etch with standard outline toolpaths (middle); by mechanical
etch with Voronoi toolpaths (left). The board on the right has also had
additional processing: it has been drilled and tin-plated.
So, apparently, a mechanical etch system would itself calculate the board outlines where it has to drill (as on middle board) - if it is fed a more traditional track design (as on left board).
In pcbnew, I know that I can do a sort-of a track widening with zones - in that I just add a rectangle for a Zone; say what net it belongs to; and then I fill it - and even if it contains tracks for other nets, IIRC the zone fill algo will automatically add outlines, so the zone doesn’t touch those other tracks.
My question is: is there any other approach/algorithm in pcbnew, which could start from a finished/routed design with thin tracks - and then expand them, until there’s just outlines left?
EDIT: Here is a good discussion of pros/cons (mostly cons) of using Voronoi as such: