Electronics Forum | Thu Aug 27 11:35:07 EDT 2009 | davef
There are many possibilities: * Conformal coat is incompatible with surface residue on the board * Conformal coat is incompatible with solder mask on the board * Moisture is out-gassing from the board * Conformal coat is too thick and does not allow
Electronics Forum | Thu Aug 27 08:34:50 EDT 2009 | floydf
I am having trouble with little air bubbles in my conformal coat. It ranges from a few pin sized bubble to looking like spit. We are using Dow 2620 silicone conformal coat applied with a PVA sprayer machine. The conformal coat comes in bladder bags t
Electronics Forum | Fri Oct 09 16:07:30 EDT 2009 | dlabelle
We use Dow 2620 silicone conformal coat applied with PVA1000 sprayer machine. If used on a daily bases, we have no problem. If we let the machine sit idle for over a week, we will get bubbles in the conformal coating. Sometimes, purging the line w
Electronics Forum | Mon Jan 28 11:50:23 EST 2013 | johng
Good morning Mark, No issues around the masking at this point. The issue seem to be in open areas as well as between clad runs. We are using Humiseal 1A33 Conformal Coat.
Electronics Forum | Fri Jan 25 12:23:07 EST 2013 | dontfeedphils
By "they've been through the wash cycle twice" what do you mean? What kind of cleaning process do you use? What sort of chemistry? How do you handle the assemblies after wash and before coating? Do the operators where power free gloves? -Phil
Electronics Forum | Thu Sep 10 15:01:28 EDT 2009 | mefloump
I currently spray DOW 2620 with my PVA650 without any problems. I do not thin it but I do have a distance between the coating machine and IR oven to provide a flash off period. I notice bubbles only when the flash off time is too short and the coatin
Electronics Forum | Wed Sep 02 11:36:22 EDT 2009 | kpm135
Is this an established process that is just now exhibiting these problems, or is this a brand new process you're just setting up? What is the rest of your process like? What is done to the boards before you coat them? Water washed? Solvent washed? Sa
Electronics Forum | Mon Jan 28 08:44:21 EST 2013 | diamondmt
John, In addtion to the cleaning process you may wnat to look at the masking materials you are using as well. Are you using any temporary masking tape? If so, do the dewetted areas coincide? Some of these tapes use a silicone-based adhesive which wi
Electronics Forum | Fri Nov 21 18:56:41 EST 2003 | jsloot
Gun wash is another term used for acrylic laquer thinner. We use DuPont 3642SC. We have much success in its use.
Electronics Forum | Fri Jan 25 13:41:04 EST 2013 | dontfeedphils
You definitely have to be careful with unsealed components and markings/labels. The best you can do is check with datasheets or find an extra assembly to test it out on first. You can also try slowing down your inline to more like 1-2 ft/min and se
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