On Sat, 02 Dec 2006 17:47:01 +0100, DJ Delorie <
dj@...> wrote:
> My next project is probably going to require a solder paste stencil.
> So, I've been pondering what to do. I could buy one, but that's
> expensive, adds delays, and isn't as much fun as doing it myself ;-)
> I've tried drilling a transparency sheet (plastic) but the holes were
> very rough. Plus, I don't have drills small enough for the SMD pads
> I'll be using (11 mils wide). So I thought of etched brass, since the
> toner transfer kits say they can be used for that.
> After a little research and some thought, there seem to be two
> common techniques:
> 1. TT on one side, paint the other side, etch in FeCl or H2O2, clean.
> 2. TT on both sides for faster etching and cleaner edges.
> But I thought of a third, based on how pcb-pool makes PCBs. I have no
> idea if this would work, but it goes like this:
> ∗ TT on both sides, with toner ∗only∗ where you want paste.
> I.e. little dots of toner all over the place.
> ∗ Electroplate some tin or other metal onto the sheet.
> ∗ Remove the toner, leaving exposed brass where the paste goes.
> ∗ Etch.
> Not sure if this has any practical advantages over original option #2,
> though, and it's probably a lot more work to set up correctly.
> But anyway, has anyone had success etching their own paste stencils?
> DJ
Someone recently posted PICs about using CNC drilled brass for stencils.
The holes are of course round but that is not a problem.
How much are you going to do? You know you can just bulk-paste a row of
pins with a bead over all of them?
ST