My imediate use for recessing has to do with ridged flex riged boards. In one example we have a circuit board that has for example a ridged section on the right that has a connector, this section has to have one level of thickness. connected to this ridged is a section of flex, on the other side of the section of flex these is a section of ridged material that has a flip chip a resistor and a few capacitors. This second ridged section has a different thickness then the first. It is thinner and we achieve this by having few layers. Continuing on we have another section of flex and then a final section of ridged. This last section of ridged has yet a third thickness then the other two ridged sections.
All of this is constructed in layers that are glued and pressed together. So we cut out different holes out of the different layers before aligning them and gluing them and pressing them. Problem is that the pads have to be on different layers. We over came this by pretending at layout that they were different boards and getting the shop to merge the gerbers. I think there is a second reason, (note the i think) in that some very high frequency devices have pins that stick streight out their sides so as to avoid bends. But that these devices also would like to be heat sinked to the ground plane. This is again an I think and I am looking for an example. Steve M. DJ Delorie wrote: >> Yes fab shops can cnc the layers before gluing and pressing them >> together. >> > > Drool. Yeah, you'd need the "layer types" patch to really manage > that, as you'd be able to tag multiple pcb layers as "outline" layers > and associate them with specific board layers or whatnot. > > You could do it now, except that they'd have all the pins' copper on > them as well as the outline. > > The only thing you can't do already is tell pcb to put elements on > inner layers. > > Of course, I'm curious *why* you need to recess parts... > > > _______________________________________________ > geda-user mailing list > geda-user@moria.seul.org > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > > _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user