Electronics Forum | Wed Nov 21 15:02:46 EST 2007 | jlawson
From info I have been told from design standpoint, via in pads helps with managing EMC issues with working design, in particular for high speed digital/dense populated type PCB's. We had a manufacturing customer that had very low yield because of th
Electronics Forum | Mon Nov 05 02:51:48 EST 2007 | omidjuve
our boards have many smd pads that has vias under them so when the screen printer wants to print the solder paste on it , it will penetrate through the via to the bottom side of the board and cause many problem for us . i want to know that is it sta
Electronics Forum | Mon Nov 05 06:27:23 EST 2007 | grantp
Hi, We are also interested in this, and I have heard you can get the PCB's with the via's plugged. Also, if the via's are small, the solder should not penetrate? Anyone have any further info? Grant
Electronics Forum | Tue Nov 20 12:31:12 EST 2007 | kelz
In my past experience, having via's under or attached to SMD lands produces risk. Solder will not consistently wick the same if it is being drawn into a via. This has also caused issues from solder wetting through the via to the other side causing a
Electronics Forum | Fri Nov 23 15:46:06 EST 2007 | mika
Question: We have an issue right know on a prototype batch with via in the pad on an very small pcb 50x50mm (in a panel of course). The designer has no room to move the vias as they said. The pcb is to packed with components also 8-layers. It is also
Electronics Forum | Fri Nov 23 16:32:05 EST 2007 | davef
There a several things you can do to prevent the solder wicking down the hole with the current design, and that's where you should focus. Cost goes up as you go down the list, but in neither case do you need to respin the board, have solder starvatio
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 | Wed Nov 14 14:44:10 EST 2007 | grantp
Hi, Those via's sure do sound large, and I think the designer must have made a mistake in the PCB design do you think? From looking at our PCB designs, if we moved to via in pad, it would really reduce the size of the PCB, so this is an important i
Electronics Forum | Tue Nov 13 08:11:16 EST 2007 | grantp
Hi, What is this unacceptable? Designed the PCB is much easer if this is possible, so it would be really good to know why via in pad is a problem in production. Grant
Electronics Forum | Tue Nov 13 09:32:28 EST 2007 | kpm135
For the simple fact that the via in the middle of the pad causes the solder to wick into the hole instead of flowing out across the pad and part. Thus cause insufficient solder issues.
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