On Tue, 31 Jul 2018 18:02:05 -0700, you wrote:
I have done dual sided PC boards. As you have been told, in the
industry, the copper plating is extended through the hole, thus
connecting top and bottom layers.
Generally, without special equipment, that's not posible to do at
home.
You have two major possibilities. One is to sit a board sufficiently
off the motherboard that you can solder the pins on both sides. This
is generally a bit nasty to do.
Another would be to get single inline sockets for the daughterboard,
and plug in the daughterboard to that. The disadvantage is that the
daughterboard would sit higher than might be convenient. The
advantage is that you can unplug it.
Since this puts all the connections on the bottom, which is not always
convenient, I use a via (small hole intended to be plated though) to
connect the top and bottom. Since homebuilt boards do not have plated
through holes, I take some bare #26 copper wire (tinned), and stitch
the top and bottom of the board together at the vias only. Naturally,
this means that you cannot have a via under a chip, resistor,
capacitor, or anything that sits flat on either side of the board.
I solder both sides of a run (about a foot of wire), then clip them
off close (but not flush) to the board. If you want, crimping the
wire over on the board is reasonable.
Eyelets could be used, but they have to be copper plated, and you must
solder them well top and bottom. Since they take up additional space
(and should be staked), they are useful only for large boards. There
have been reliability problems with eyelets in the past, so while
possible, they are not really recommended.
Harvey
My project involved several proprietary breakouts attached to a main PCB.? They are physically mounted on the top of the board and the pins are? soldered on the B.Cu layer (as I believe is normal).? That's where I get lost!?
One of the proprietary breakouts is the Arduino Pro Mini - the brains of the operation - which has a footprint like this
Assume I have a two-layer PCB:? most of the pins of the Pro Mini are connected to traces on B.Cu but some must connect to traces on F.Cu.? As illustrated, this footprint is just a collection of standard pads.? How do they connect through the fibreglass of the board?
I guess this is a silly question to those of you in the know, but it has me stumped.? I cannot find anything on the Net or in any literature which explains this mystery.? I hope one or more of you can help.
Thanks
