Electronics Forum | Fri Jan 16 08:36:40 EST 2009 | davef
That the bubbling gets worse when you run the board through the oven indicates the issue is with the balance between releasing volatiles and cure. Try one of these ideas: * Adjust the atomization pressure, nozzle size, temperature or viscosity of th
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 | Tue Feb 03 11:42:54 EST 2009 | lmartenson
We use PVA and I have had bubbles that came from the pressure in the pressure pot being to high. Also the material filter was slightly clogged. I'm not sure of your setup hope this helps.
Electronics Forum | Fri Jan 16 10:54:21 EST 2009 | realchunks
Hi Steve, Make sure your spray head is all the way down. If so, try slowing your rate of speed over the part. Which head are you using to coat this part?
Electronics Forum | Mon Jan 19 09:10:17 EST 2009 | stevewilde
Thank you for all of the advice. I am using the extended spray for these cards. Humiseal have recommended using their own thinners 600 instead, so will run some trials with this and also the humiseal pre-mixed material (at the moment we mix our ow
Electronics Forum | Tue Feb 03 13:47:59 EST 2009 | grics
I would also suggest looking at your ramp rate in the cure oven. We noticed that accelerated heating increased the "gas out" of the solvent. We run 1A33 and and do not exceed a .5/degC ramp rate.
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 | Thu Jan 22 09:04:22 EST 2009 | mefloump
Humiseal recommends a 1 to 1 mix ratio of 1B31 and Thinner 521. I have for that I need to thin my ratio more to get humiseal to spray correctly in our PVA650. Also I am using Humiseal 1B73 but the tech data sheets say the same for spraying. Try thinn
winsouce.jpg)
.gif)
.gif)
