Stencil Printer for Rework

So I needed to install a funky thing on a funky board that was already partially assembled. Typically no big deal but this part was silly - an SMT PCB module with parts already soldered on to it. Like WTF, Over? I really hate those, but typically they use castellated PCB's that are easily hand soldered. But no, these clowns used some whacky SMT ball things like the ones TI uses on some power supplies. I've done a lot of PCB design, and whenever any client has used these power modules that come in either a thru hole or funky SMT, the client always wants thru hole.

So this thing has a heavy part on the bottom... a BGA no less. Again WTF, Over? I guess some CM's can handle this... but I've talked to a few and they hate theses things as much as I do. And it easily could have been made thru hole by just NOT placing the silly ball things, but no it's too much work to NOT place something (I'm not getting this).

So it go me to thinking that I need to come up with some way to handle SMT rework stencils on PCB's that already have a shit ton of parts installed. No way to use a CM's stencil printer or the typical homebrew method that uses painters tape and a square. You need to use a custom small ass stencil and get down between what's already there, apply paste, and get the fuck out vertically to give good definition to the paste on the pads.

So this is what I came up with - an X-Y table from Little Machine Shop, a microscope camera holder, and some custom machined other stuff. I had to add gibs to the holder where it rides on the column - too much play in the azimuth. The C-Clamp is a stop for repeatable insertion (everyone likes repeatable insertions). The two large bars are dovetailed to hold upto a 1/8" PCB. I used a camera ball swivel to allow for alignment.

Silly I tell you...

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