Electronics Forum | Thu Dec 07 14:19:07 EST 2006 | russ
You have two options 1. Get some real solder mask form board supplier (not touchup pens) and repaint the trace and heat cure. 2. Fill the via with solder before reflowing new part, this usually works but sometimes it doesn't. We use Method 1 Russ
Electronics Forum | Thu Aug 21 08:33:09 EDT 2008 | davef
There is no standard as such. It's easy to see why. It's too complicated and has such a small payoff. Standoff is comprised of: * Package height * Solder thickness between the pad and the component lead * Delta of pad thickness and solder mask For p
Electronics Forum | Fri May 01 07:22:56 EDT 2009 | kareal
In my project of flip chip PGA production , I found serious delamination in interface of solder mask and first layer copper trace of substrate after UHAST 96hrs( 130C, 85%RH) reliability test. The delamination are always around one type solder bump,
Electronics Forum | Wed Feb 13 14:01:37 EST 2013 | davef
Things that come mind are: * Not sure why you want to do this, since probing solder gives a longer probe life than probing copper. * I've never tried it, but I see no reason why you couldn't probe Kapt0n or blue painters tape. * Fabs [or you] can pri
Electronics Forum | Mon Jul 08 14:52:40 EDT 2013 | hegemon
The smaller ball "missing" from the lower left is from solder migrating down into the adjacent via. The solder mask may have been damaged or missing prior to mounting the BGA device. The larger balls at the top right are due to uneven heating during
Electronics Forum | Mon Sep 19 21:35:54 EDT 2016 | shriram
Appreciate your suggestion. NSMD pads are used for this design, the anomalies we found are 1. the trace running between pads has a lesser solder mask height compared the other area of the pads. 2. the NSMD pads doesnot have a trench close to pad e
Electronics Forum | Mon Aug 10 12:58:04 EDT 2020 | SMTA-64386637
We have found Acrylic CC under QFNs is a failure mechanism in thermal cycling. The coating acts as a wedge and causes solder joint cracks. We do not coat QFNs. To enhance reliability we have the vias plugged with solder mask. This eliminates some
Electronics Forum | Wed Feb 09 21:19:03 EST 2005 | Mrduckmann2000
Russ, We can not use a wave pallet, already went that route. We have parts next to the thru-hole pins and between thru-hole pins. I am going to try an experiment in the next day or so with solder mask. I plan to solder SMT parts on the back of se
Electronics Forum | Wed Jan 27 21:02:53 EST 1999 | Dave F
| i am working with the noclean process and getting white residues on the bottomside of the board probably due to the | wave soldering flux.i am using a no-clean solder paste and a noclean wave solder flux.The boards passed the accelerated temperatu
Electronics Forum | Thu Jan 28 08:58:10 EST 1999 | Peet
| | i am working with the noclean process and getting white residues on the bottomside of the board probably due to the | | wave soldering flux.i am using a no-clean solder paste and a noclean wave solder flux.The boards passed the accelerated tempe
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