Electronics Forum | Fri Dec 18 09:07:24 EST 2009 | tommyg_fla
dave, where I work they are having the same problems with 1B31 acrylic. The coating thickness is 6-8 mils dried so that have to do several passes with an air dry between them and a final oven cure. They think that it might be related to the heating r
Electronics Forum | Thu Nov 19 20:05:14 EST 2009 | davef
Density. There is a difference between lead (.410 lbs. per cubic inch) and tin (.254 lbs. per cubic inch). The same volume of tin-based solder, therefore, weighs approximately 1/4 less than a lead-based material. This adds up to more joints per pound
Electronics Forum | Sat Nov 21 12:28:00 EST 2009 | flipit
There is evidence of lead being used in soldering 5000 years ago in Mesopotamia. Not a big issue for most people doing SMT but the poster should also understand why percent metal is adjusted for different solder paste alloys. You print by volume b
Electronics Forum | Fri Nov 20 09:07:43 EST 2009 | Sean
Hi all, Another thing that I would like to discuss here is that I used to come across few reports that mention about the flux residue has great impact on the PCBA impedance, especially when everything become smaller and smaller...I mean, when mother
Electronics Forum | Fri Nov 20 11:21:37 EST 2009 | patrickbruneel
In 90% humidity it’s easy to get condensation. Condensation will create electrical failure when the board isn’t conformal coated. In your case the failure disappears when the humidity level drops so to me it’s unlikely that the flux has anything to d
Electronics Forum | Sat Nov 21 09:39:01 EST 2009 | patrickbruneel
Dave, I would only agree with you when you talk about low residue (water based) fluxes. In low residue (alcohol based) fluxes you can use non water soluble acids, so in the event you still have flux residues on the board water has no effect on them.
Electronics Forum | Sun Nov 22 09:36:17 EST 2009 | patrickbruneel
Dave, A low residue/No residue flux does exist that when an excessive amount of flux is applied it would only create a cosmetic problem not a reliability issue. The active ingredients are neutralized by the heat applied in the soldering machine and
Electronics Forum | Tue Nov 24 19:07:12 EST 2009 | gregoryyork
I agree Patrick many people blame the assembly fluxes when it is some other hygroscopic chemistry left on the bare PCB such as surfactents from the HASL process these will do exactly what the guy reported in his post fail then cool down and pass ever
Electronics Forum | Mon Dec 21 11:28:47 EST 2009 | lynn_norman
We used Loctite 3609 and never had problems. If memory serves me isn't 3606 a screen print adhesive? First thing I would check is the cure profile of the adhesive. If it doesn't develop full adhesion, could be problems. Nuther question is are you
Electronics Forum | Wed Dec 02 14:54:52 EST 2009 | jdumont
Hi all, just wondering what type of brushes you all are using to manually touch up/apply your conformal coatings? We use an solvent based acrylic and do minor touch ups as they are processed. Occasionally we will have a bristle or two come off the
