Electronics Forum | Thu Mar 19 15:20:19 EDT 2020 | emeto
We are trying to picture it here. Which side doesn't have traces connected to it? Which one does? An X-ray picture will be best. Gerber screenshot will be second best.
Electronics Forum | Thu Mar 19 20:12:32 EDT 2020 | slthomas
Stephen, you are spot on with your description. Here's a .jpg with paste layer, copper, and solder mask.
Electronics Forum | Mon Mar 23 16:38:09 EDT 2020 | emeto
Steve, On 16mil pitch I would try 12mil diameter on 5mil stencil, unless the BGA ball size is something unexpectedly huge.
Electronics Forum | Fri Mar 27 03:42:17 EDT 2020 | sssamw
Did you try 0.12 or 0.1mm nano coated stencil @ 10 mil aperture? A soak time type profile with long reflow time could help.
Electronics Forum | Thu Mar 19 16:06:29 EDT 2020 | stephendo
Imagine a circle. Now imagine a line attached to that circle. A line almost as wide as the circle. Or look at a regular BGA pattern now imagine if the traces were almost as wide as the pads. I have not seen any quite as bad as he describes but I have
Electronics Forum | Tue Mar 24 10:34:03 EDT 2020 | slthomas
My experience with our process is that those parameters would result in a big bridging problem. I'm working with a stencil designer at our fabricator on an asymmetrical aperture design that hopefully balances forces enough to keep the parts centered.
Electronics Forum | Wed Mar 18 11:27:24 EDT 2020 | slthomas
I am about to order a stencil and I can already see that I'm going to have issues. I'm hoping someone has a recipe for this scenario that we haven't tried yet. The parts are 16 mil pitch bga's, the pads are NSMD (10 mil dia. with 12.6 mil mask open
Electronics Forum | Tue May 06 10:53:03 EDT 2008 | realchunks
Yes, all quality directors are fat and heavy - but not all heavy coveyors are fat.
Electronics Forum | Tue May 06 09:28:31 EDT 2008 | realchunks
When looking at conveyors, you need to look at how heavy the equipment is. Heavy means it won't move when your fat quality director leans against it. Alignment can be a pain if the conveyor is light weight. Obviously heavy mean a little more expen
Electronics Forum | Tue Jun 24 13:46:21 EDT 2008 | bschreiber
I know it is not what you want to hear, but first and foremost, you must consult your local regulating agencies and here is why: Solder paste contains heavy metals. We are all familiar with the problems associated with lead, but lead free solder pas