Electronics Forum | Mon Jul 03 13:02:19 EDT 2023 | fuji_user_2014
There are some "rule of thumb" design approaches for circle apertures for BGA's. Does anyone use rule of thumb formulas for square/squircle apertures for BGA? If so, what are they?
Electronics Forum | Sat Jul 01 04:22:09 EDT 2000 | Sal
I have two questions 1. How do I control the skewing of FETs/power regulators ? ( the one's with the big rectangular pad and two smaller one's for the leads).If I go 1:1 with the apertures I seem to get solder balling and when I tryed to minimise th
Electronics Forum | Mon Jul 16 14:48:16 EDT 2001 | mparker
Just received "Circuits Assembly", July 2001 issue. An article regarding solder balls and aperture design, beginning on page 40. This DOE had aperture, reflow profile and no clean pastes (3 types) as attributes. It is advocated that a U-shaped a
Electronics Forum | Wed Aug 25 21:51:13 EDT 1999 | Jason Tomlinson
| Does anyone have any information on stencil aperture/pad ratios for noclean solder paste. In the past I have experienced severe solder ball problems when using the same size apertures from aqueous products as I do with the No-clean products. Cons
Electronics Forum | Tue Jun 17 08:52:39 EDT 2003 | russ
Aspect ratio = width of aperture divided by height. E.G. 6 mil stencil at 9 mil wide = aspect ratio of 1.5. Value should be 1.5 min. Area ratio - use when length and width of pad are roughly same dimension like for BGAs and 0805 and smaller R-nets
Electronics Forum | Mon Nov 13 08:24:03 EST 2000 | G. English
Richard, From your description of the IC, as Wolfgang indicates it sounds like a 20mil pitch device, the aperture design really depends upon your solder paste particle size, we use a type 3 solder paste with a mesh size of �325 / +500microns. This is
Electronics Forum | Tue Jan 16 09:23:26 EST 2001 | P.Gerits
Hello, Standard way to calculate stencil design can be done as follows: A normal ratio of aperture width/stencil thickness = 1.5 for pitches below 650u A normal ratio of stencil aperture width against pad width = 0.8-0.9 (or stencil aperture 10%-20
Electronics Forum | Tue Aug 17 10:41:13 EDT 1999 | Steve A
Wayne, Sounds like a gasketing problem. When the horizontal apertures are bleeding but not the vertical apertures. Could be poor underside support, HASL miniscus issues, masking or plugging issues, but what many people do not account for is that t
Electronics Forum | Fri Sep 21 14:03:45 EDT 2001 | jschake
I have observed solder balling for all aperture sizes tested. Solder balling levels appear to be better correlated against the amount of solder paste that is underneath the 0201 component terminations after placement rather than comparing this to th
Electronics Forum | Tue Sep 21 13:17:29 EDT 1999 | Dave F
snip | I've often been tempted to try something a little different when specifying QFP apertures. Like, for example, using long, tapered triangular apertures arranged in alternating directions. The objective being, get the maximum amount of paste do
