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 | Fri Jan 25 12:14:18 EST 2013 | johng
I'm using urethane conformal coat and have fisheyes and dewetting after coating even though the PWAs have been through the wash cycle twice. I'm looking at using Ionox 13302 in an ultrasonic cleaner as a short term solution until root cause can be id
Electronics Forum | Fri Jan 25 12:15:04 EST 2013 | johng
I'm using urethane conformal coat and have fisheyes and dewetting after coating even though the PWAs have been through the wash cycle twice. I'm looking at using Ionox 13302 in an ultrasonic cleaner as a short term solution until root cause can be id
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
Electronics Forum | Fri Jan 25 15:51:26 EST 2013 | johng
Water soluble process, yes. The machine is old and fixed at 4 ft/min by someone way before me. Looking into ways to reverse that to allow for adjusting the conveyor. Trying to determine how the contamination gets onto the boards. So far testing has i
Electronics Forum | Fri Jan 25 13:07:31 EST 2013 | johng
Thank you for replying Phil. We use water only wash at 130°F and at 4 ft/min (about 2 min). They are mostly dried by the hot ait knife and left to air dry until next day. The operators do not wear gloves. When I run a bare board through the same pro
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