Electronics Forum | Tue Nov 27 14:24:13 EST 2001 | mparker
Short term fixes can be: have the vias "plugged" with solder by the fab house. This works if your fab is HASL finish. Tent the vias with solder mask, top side only. You may get a flux entrapment issue in the vias with this manner. Long term fix can
Electronics Forum | Mon Apr 22 15:05:47 EDT 2002 | tim_easterling
Depending on the volume of boards you are manufacturing, the most cost effective solution would be to epoxy plug the vias prior to LPI soldermask application. The technique is common practice and most suppliers can provide it will little or no cost a
Electronics Forum | Sun Dec 15 22:31:43 EST 2002 | craigj
Has anyone heard of vias cracking (barrel from pad) when being wave soldered. Was told this was a big problem by contract pcb designer, he always tent vias because of this. The reason was that the solder filling the vias caused stressing and then sep
Electronics Forum | Fri Jan 21 16:50:33 EST 2005 | Board House
I work for a board house and our proceedure for this process is the following, We cover the via pads leaving the hole open and then apply the surface finish and then go back and Cover the Via with a second operation. By doing this you do not entrap
Electronics Forum | Thu Apr 15 10:09:55 EDT 2010 | davef
Dross formation rates for SnCu and SAC are roughly 2.5 times the rate for SnPb (Hwang et al., 2004) Methods for reducing dross are: * Lower pot temperature * Run pump speed slower and only when soldering * Check solder contaminants to BS219, ASTM
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 | Mon Jul 26 18:05:18 EDT 1999 | ScottM
| Presently protos of micro-bgas (80i/o) pitch .030/.031 | 12BGA per assembly | | The board is a (.062, 4 layers) FR-4 using Dry film | Pads .014inch | Vias within footprint .020inch | Vias to be filled by bottom side(solder side) only .030in dia. F
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 | Wed Feb 16 21:51:29 EST 2000 | Dave F
Kurt: Lots of choices, not many of them good, yano. 1 So LPI has taken over the market pretty nearly 100%, but it won't "tent" reliably, because it is not very viscous when applied and drops into the hole. So then, tenting/plugging with LPI is bad
Electronics Forum | Wed Feb 16 21:51:29 EST 2000 | Dave F
Kurt: Lots of choices, not many of them good, yano. 1 So LPI has taken over the market pretty nearly 100%, but it won't "tent" reliably, because it is not very viscous when applied and drops into the hole. So then, tenting/plugging with LPI is bad
