Electronics Forum | Fri Jun 18 11:37:10 EDT 1999 | Earl Moon
| | | | first of all what is the technical term for the small amount of solder on a plated pad. we are getting poor screen printing gasketing on a 20 mil qfp due to this solder not being even or too high in spots and not covering the length of the pa
Electronics Forum | Thu May 10 16:17:59 EDT 2001 | davef
I am unaware of any industry standard for specifying apertures for SM stencils. I am aware of IPC-7525, Stencil Design Guidelines. You can obtain it from IPC [http://www.ipc.org]. Further, it seems like there is an article on stencil design ever
Electronics Forum | Tue May 18 15:36:18 EDT 1999 | Tony
| | | What is the best way to re-ball a BGA? Who has the best system for doing it? | | | | | I'm using our SRT rework stuff to reball in house - when necessary. Of course, we only do this for protos and test boards. We use a standard micro-stencil,
Electronics Forum | Tue Dec 14 17:02:04 EST 1999 | John Thorup
Hello Kris If you do have and OSP coating I'd say Curtis has nailed it. But you seem to have references to gold. Does this board have a standard nickle/gold finish. If so what sort of "solder on gold" problems were you having? Reading between the
Electronics Forum | Wed Mar 14 17:52:49 EST 2001 | davef
6 Work Life Test 6.1 Obtain a stencil with 15 to 20 rows of a series of 0.025 by 0.050 inch apertures spaced 0.050, 0.040, 0.025, 0.015, 0.010, 0.010, 0.025, 0.040, 0.050 inches apart. See Appendix 1. Source of supply: Metal Etching Technology.
Electronics Forum | Thu Nov 11 14:13:57 EST 1999 | Dave F
Thomas: From what you're telling us, you seem to be thinking correctly: 1 Paste should not spread appreciably in preheat 2 Something has changed, because you've not had this problem, until recently Two things to consider: 1 Has any thing changed
Electronics Forum | Fri Feb 19 09:14:52 EST 1999 | Justin Medernach
| During inspection and test we find leads which do not get soldered. Some are because of insufficient paste, but with others everything looks right. This will only happen on 1 to 2 pins, and it is not isolated to a specific type of ic or location o
Electronics Forum | Thu Dec 08 14:26:58 EST 2005 | chunks
Start with your board first. Do you have resist/mask between the fine pitch? Is the finish HASL or a flat surface? If there is no mask/resist between the fine pitch leads you may want to reduce the apertures 5%. If the board is HASL, that means yo
Electronics Forum | Tue Sep 19 13:09:48 EDT 2017 | slthomas
Thanks, all, for your responses. It's always helpful to know what everyone else is doing, whether to validate your own experience or to force you think in more detail. At this point we've determined that no amount of aperture design, material contr
Electronics Forum | Mon Mar 25 21:50:10 EST 2002 | davef
Some of this was copped from Fred. There are numerous package types that now fall under the rubric of land grid array [LGA]. Land grid devices [ie, Bumped Chip Carrier� [BCC], LGA, Quad Flat-pack No-lead [QFN], MicroLeadFrame�, etc] are essentially
