Homebrew PCBs

Stephanie, the parts I'm looking at are about BGAs with 400-500 
balls.
 You seem to know a lot more than me about the process. Any tips you 
can share are much appreciated.

 timbomcnuckle: what king of PCBs have you done with your reflow 
oven ? What kind of parts have you done ? Have you done BGAs, or 
0.5mm TQFP ? Did you do two layers PCBs ?
 Please share your successes.



--- In Homebrew_PCBs@yahoogroups.com, "Stephanie Ann Thompson" 
<setlahs@...> wrote:
>
> I don't believe a simple hot air gun setup will work for a BGA 
part 
> with 500 pads. You need to preheat the board, and use a bottom 
heater 
> to ramp up the heat as well as a top heater. And with more 
products 
> going Lead Free, it will take a lot more heat and a lot more 
complex 
> heating profile to properly reflow the parts.
> I had worked on a BGA machine before, the big expensive automatic 
> type... Even then it would take a LONG time to properly create a 
> reflow profile to get maybe 95% success rate. (of course we were 
> working with like 1000+ pads) I can give you some tips and 
pointers, 
> but for only doing 1-2 a year, it can get pretty expensive 
> (especially with FPGA's) and frustrating when you fail at 
reflowing 
> the part.
> --- In Homebrew_PCBs@yahoogroups.com, "timbomcnuckle" <jaydag71@> 
> wrote:
> >
> >  hey!, I haven't used a hot-air station yet but I have done the
> > over-reflow a bunch fo times and I would take the time 
investment 
> into
> > making your own rather than the alternative- especially if you 
are
> > only oding a few boards per year! Elektor did a great version of 
the
> > taoster oven re-flow controlled with an AVR I think, lcd display,
> > programmable curves, precision control (within reason),, I think 
the
> > only complaint was lack of insulation, but you can always stuff 
with
> > rockwool or something.
> > 
> >  I have used old style black&decker toaster-oven without any
> > modification a few times but I got a better one now that I still 
> need
> > to finish. gluk.
> >