I’ve been looking for a PCB manufacturer that does hobby-size orders and supports [edge castellation, so finally I just bit the bullet and sent in an order to [SeeedStudio with a castellated design, just to see how it ended up. I specified the castellations by creating square vias (16 mil drill) along the edge of the board with the dimension layer drawn straight through the middle of them. I also put pads on the bottom of the board just to increase the bottom surface area, but that probably isn’t necessary. This board is a 1.27mm pitch for the castellation contacts.
I just figured I’d post my results here in case anybody else was interested in doing the same thing. SeeedStudio doesn’t mention castellations anywhere on their page, so I figured this may help somebody else. YMMV, especially for different size pads, different pitch, different PCB thickness (mine were 0.8mm thick), etc. but there ya go. Here’s it is, mounted on the target board:
One thing I should note is that the edge plating only exists in the hole wall of the original via, they did not extend the edge plating to the edge of the square pads. But still, I’m very happy with it.
On a related note, I tried the same thing at OSHPark, with 20mil holes @1mm pitch, and they did NOT turn out. So OSHPark seems to be a no-go on castellations. However, there are at least 3 variables there, the manufacturer, the hole size, and the board thickness, so it could have been any of those…
Just an update: turns out I managed to order these boards right after the person responsible for checking board files quit, so I lucked out. I tried another order and they emailed me to say they didn’t allow castellations due to the additional cost of the extra processing required. They did allow me to proceed with the order, but only after charging me an additional $25. I asked if I would be allowed to order boards with castellations in the future if I was willing to pay the extra charge, and they said that I could, but the order would be placed on hold and they would email me asking if I wanted to pay the extra charge. So, it will require an extra manual step in the ordering process, and they may change their minds in the future, YMMV…
You could email Laen at OSH Park and see if there is any secrets to get them done. I may do that myself. I haven’t needed castellations, but ya never know in the future.
http://i.imgur.com/7uTFY4X.jpg
http://i.imgur.com/J6cYUao.jpg](http://www.seeedstudio.com/depot/fusion-pcb-service-2-layers-p-835.html?cPath=70_71)](pcb design - Feasibility of PCB edge plating? - Electrical Engineering Stack Exchange)