Electronics Forum | Thu Oct 01 07:03:55 EDT 2009 | davef
We doubt that Humiseal 1A33 is causing opens in your assemblies. We'd guess the opens occur earlier in the process, but are not hard failures. So, you pass your tests. When applied, the conformal coat flows into the gap in the ball crack and insulate
Electronics Forum | Mon Oct 05 04:55:42 EDT 2009 | pengliang
we suggest as below : the first : check the soldering(solder ball and pad) by X-ray ; second: to do dye analyse (note:pls confrm is there have crack )
Electronics Forum | Wed Sep 30 11:32:45 EDT 2009 | pbarton
What type of conformal coating are you using and are you allowing the coating to migrate under the device in question? If you are allowing the coating unbder the BGA the problem could be CTE of coating is much greater than that of the BGA balls/sold
Electronics Forum | Thu Oct 08 08:15:39 EDT 2009 | kpm135
We've used both 1A33 urethane and 1B31 acrylic coating on our SMT assemblies with great success for many many years. This is with components of all shapes and sizes including a 9 ball micro-BGA. We apply the coating in every way imaginable and we hav
Electronics Forum | Thu Nov 19 22:48:22 EST 2009 | davef
Since the bubbles: * Are only on the solder connection, we'd guess there must be some compatibility issue between the flux residues and the conformal coat materials. * Occur after curing, we'd guess the cure recipe is too rapid and is entrapping voli
Electronics Forum | Sun Nov 22 18:40:47 EST 2009 | 89jeong
Hi The bubble shows only around component body after ir reflow. I think bubble means that there is a moisture. How do you dry the PCB(?) before IR reflow? Thanks Ju-young.
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 | Tue Dec 01 09:24:01 EST 2009 | sforman1
40 years. no cost to you. just trying to help Sam
Electronics Forum | Sun Nov 22 19:59:26 EST 2009 | prodivegsr
Hi Davef, The bubbles occurs at the body also...there's also a washing process before the conformal coating:-the Flux residue are removed after washing. ... The curing profile is also something that we are looking into during the initial troubles
Electronics Forum | Thu Nov 19 05:18:37 EST 2009 | prodivegsr
Hi All, Recently we are working on the conformal coating process using Humiseal chemical 1B73 and thinner 521. Bubbles on component body/joints are seen after gone through the IR Reflow Oven. During the conformal coating, only tiny bubbles seen af
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