Electronics Forum | Thu Mar 29 15:50:35 EST 2001 | tomgervascio
We've think that with seen solder shorts under BGAs after wave soldering the boards. In addition, it seems to be related to a certain soldermask configuration over the topside BGA vias.. THere is one vendor,A, that is applying soldermask after HASL,
Electronics Forum | Fri Jul 09 16:32:35 EDT 1999 | John
Thanks everyone. I appreciate the help. John | Q #1) Is it more reliable to have the mask tent over the vias or risk getting vias half filled with solder? These are vias with an .020" hole and .040" or .050" pad. | | Q #2) When speaking of annular
Electronics Forum | Mon Sep 28 09:35:28 EDT 1998 | Clive Heke
I have had some field failures returned recently, the boards had flux contamination under the components in a sensitive area, Nothing really visible until the component was removed, and the board had no evidence of rework of any type. Is it possib
Electronics Forum | Thu Dec 15 11:06:05 EST 2005 | Samir Nagaheenanajar
You might wanna try a small reduction in your stencil aperture. For example, for a 30-mil pad go 26-mil square aperture with 8 to 10-mil radius on your corners. Also, look at your designs. Is there enough resist between your pad and ball? Another
Electronics Forum | Fri Nov 22 05:04:07 EST 2019 | SMTA-Matthew
We have some circuit boards where the solder mask seems clear instead of green on top of some of the tented via pads. No gold deposited during the ENiG process and no solder sticks to it but why is it clear and does it have any correlation to the thi
Electronics Forum | Wed Jun 16 07:35:28 EDT 2010 | scottp
Rather than tent the thermal vias, we use a small annular ring of soldermask around them and only print paste in the areas between the vias. Any way you go you're going to have voids under QFNs, so we just try to make it repeatable so our designers
Electronics Forum | Mon Mar 02 23:48:22 EST 2015 | vb7007
Hi We are using Universal carrier for a 2 sided PCB, where the bottom side goes for hand solder the switches after wave. Our issue is, we are getting micro solder balls all over PCB bottom after wave, whereas we got numerous vias, which also turns
Electronics Forum | Thu Feb 07 20:53:51 EST 2002 | davef
Regardless of the technique used for the mounting pad shape or definition, isolation of the plated through hole [PTH] from the mounting pad is important. If the PTH is contained within the mounting pad, solder will wick down the PTH. The amount of
Electronics Forum | Tue Dec 14 22:17:33 EST 1999 | Dave F
Armin: How ya doin� bud? CK gives good advice, but I'd like to take a bit of a different angle. Q1. For 0.7 mm (0.027in) diameter hole for vias, what�s the minimum annular ring for this hole diameter? Depends on what you�re trying to do. For in
Electronics Forum | Mon Oct 18 09:41:56 EDT 1999 | Wolfgang Busko
That should not happen. There are some threads concerning BGA and wavesoldering you could look for. It�s said that you should protect the vias in the BGA-area by soldermask or at least with tented vias to prevent rereflow of BGAs solderjoints what co
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