Electronics Forum | Thu Sep 13 03:10:09 EDT 2012 | weyes
Optimize the pcb assembly layout can enhance the performance of the converter for switch-mode converters, excellent PCB layout is critical to the performance of the best system.If the pcb assembly layout is poorly designed, it may result in the fol
Electronics Forum | Fri Sep 14 12:32:25 EDT 2012 | mark25y2001
just check if the pad and component terminal was traces of solder, if have? try to reduce preheat temp and solder bath temp... reason why solder not adhere because of component lead type, if more heat you apply solder flows and not completely adhere.
Electronics Forum | Mon Sep 17 05:48:10 EDT 2012 | stivais
Hi Ben, Yes, this could be the reason but have you ever seen solderability issues for (new) boards with LF-HAL surface finish? I have seen this only if there are surface finish quality issues for bare boards (exposed copper etc.). In this case we di
Electronics Forum | Tue Sep 18 21:48:26 EDT 2012 | vergara1
Sorry. I don't see any solder balls. > > To me, it > looks like the solder wetted the pad and then > pulled back. It's called dewetting. It's a > defect. Ask your supplier for a SEM analysis. I'm > interested to know what he / she says. I see
Electronics Forum | Wed Sep 19 10:38:58 EDT 2012 | mark25y2001
It's both solderpaste or PCB pad problem... 1st it's possible that your PCB exposure problem or old stocks, remedy? try to bake your PWB. 2nd, it's possible that PWB coating (wax) are more ticked so that solder paste flux are cannot penetrate to clea
Electronics Forum | Tue Sep 18 12:47:33 EDT 2012 | mbnetto
Hi, Regarding to thermocouple placement, you should use a precision thin drill. Drill through the bottom of the board to the top as follows: One hole in the center of the part, preferably into one of the center balls, if available. One hole into the
Electronics Forum | Mon Sep 17 14:45:57 EDT 2012 | kkay
We are experiencing voiding on one of our lead-free assemblies on every part. The voiding only occurs underneath the parts and not in the solder fillet (see pic). We have tried baking, curing, washing, multiple pastes and everything else we can think
Electronics Forum | Tue Sep 25 12:00:21 EDT 2012 | kkay
Thanks for fixing the picture. What you are looking at is a pad that the part was pried off of after reflow. The right side of the pad shows a good solder joint and underneath the part is where the voids occur. The outter solder joints show no voids
Electronics Forum | Wed Oct 03 09:23:21 EDT 2012 | kkay
Well what we have seen so far is that the voiding occurs on nearly every part, but only underneath the terminations. When we run a board with no parts we do not see any voiding as there are no terminations to trap the out-gassing from the pads. Next
Electronics Forum | Sun Oct 21 22:17:19 EDT 2012 | eadthem
We have had this issue on several parts in the past, typically we use a grid of squares of solder paste on large flow areas, This helps reduce but not eliminate all voiding. I would be very interested in hearing what you come up with. O and what is
