Electronics Forum | Tue Aug 01 10:09:52 EDT 2006 | cyber_wolf
Chunks, Make sure your aspect ratio is OK. Normally for an application like this, I would use a .005 foil. The foil material would be invar.The invar has better release characteristics. Crappy solder paste can also cause release issues. I am not sur
Electronics Forum | Tue Aug 01 10:29:43 EDT 2006 | slthomas
It's been a while since I've built with 16 mil pitch, but I have to second the recommendation to go to 5 mil stencils. Night and day as far as release characteristics. The increase in aspect ratio opens up the window a lot. (read = covers up a mult
Electronics Forum | Mon Oct 27 14:06:10 EST 2003 | russ
Search the archives, plug in 0402 OR aspect ratio and you will find everything you need to know about area and aspect ratio. These are the critical formulas for paste release. Russ
Electronics Forum | Mon Jul 31 12:59:19 EDT 2006 | slthomas
Nothing like making a handful of changes all at once to confuse an issue, huh? Did you (or whomever ordered the stencil) spec. the same stencil design parameters that you would normally have used? We've never done fine pitch of any sort on silver
Electronics Forum | Mon Jul 30 18:52:43 EDT 2001 | Brian W.
You did not provide the stencil thickness or your aspect ratio. If your aspect ratio (Aperture width/stencil thickness) is less than 1.5, the paste will not release correctly from the aperture, leaving paste in the aperture. For example, if your pa
Electronics Forum | Mon Jun 25 20:37:14 EDT 2001 | davef
You are 100% correctamundo that the pad on PCB should be the same as the pad on the BGA interposer, but let�s not expend that thinking to the aperture of your solder paste stencil, right away. Generally, paste on large pitch BGA is often 1:1, but as
Electronics Forum | Wed Aug 25 15:24:07 EDT 2010 | mikesewell
Whatever you would normally use to print that size part on the pcb should work. Same aspect ratio rules apply for release.
Electronics Forum | Tue Jul 31 00:48:55 EDT 2001 | Frank
Sorry I forgot to provide enough information. Stencil thickness is 6 mil Aperture width is 10 mil Aspect ratio (aperture area / wall area) = 0.72 Solder paste mesh size, type 3 (-325 +500) With this aspect ratio we can printing without any probl
Electronics Forum | Thu Mar 18 07:19:39 EDT 2021 | bukas
maybe. some machines require screen aspect ratio of 4:3 as CRTs are 4:3. If you find that 16:9 doesnt work try 4:3 if you have one, they are rare.
Electronics Forum | Thu Mar 03 18:09:06 EST 2005 | gpaelmo
We also use Indium NC-SMQ92J. We do the same as mentioned per Russ. We reduce apertures mostly on QFP's with pitch of 25 mil or less (we place down to 15 mil QFP). All other apertures we keep 1:1. We print resnet 0805 size with no problems. You might
