Electronics Forum | Thu Oct 08 15:15:49 EDT 2015 | huske
BGA's are by far much easier to process correctly and inspect. As for LGA's you'll never get 100% of the materiel out from under it during the cleaning process. The voiding issue is magnified with and LGA, the low standoff is the reason for the v
Electronics Forum | Wed Jul 03 10:32:05 EDT 2002 | davef
First, we have talked about drying / baking / demoisturizing / whatevering bare board previously. Search the fine SMTnet Archives to get started on recipes. Second and more importantly, you gotta fix this delamination problem. If it is delaminatio
Electronics Forum | Wed Feb 09 21:29:28 EST 2000 | Dave F
Charlie: People cure glue using their paste reflow profile all the time. And most of them are happy. Personally, I�m with Dean and Travis. It�s possible to as you suggest, it�s appealing not to mess with your oven profile, but it just doesn�t s
Electronics Forum | Tue Mar 30 20:04:19 EST 2004 | Ken
If speed is truly an issue, migrate to no-clean. However, this is not always an option. Why bake after 1st smt pass? Because you are probably not drying completely under the BGA components, and/or you are pushing water into the parts/boards/ vias
Electronics Forum | Mon Apr 12 22:22:01 EDT 2004 | davef
Large voids are common in via in pad [seach the fine SMTnet Archives for earlier laments], especially in blind via. Observations on your via out gassing theory: * If the copper plating on your via is GT 1 thou, there will be no outgassing from the
Electronics Forum | Fri Apr 22 10:12:14 EDT 2005 | davef
Common RTV does out-gas causing corrosion. NASA allows use of non/low-out-gassing RTV. Try the following companies: * Ablestik Electronic: Materials, 20021 Susana Road, Rancho Dominguez, California 90221 U.S.A., 310-764.4600, F 310-764-2545 * Arlon
Electronics Forum | Tue Nov 11 19:41:06 EST 2008 | gregoryyork
Thats the problem residual residue from HASL fluxes Lead free especially are worse.Very hygroscopic and out gass and produce dewetting as well over wave soldered boards especially. Leave iron on blown joint and will after several seconds fizz and pop
Electronics Forum | Wed Sep 09 09:38:53 EDT 2009 | patrickbruneel
Dave is correct (as usual). Baking the boards might reduce blowholes but will definitely not eliminate the problem. Back in my hay days we had a huge problem with blowholes and we baked boards 24/7 with very little success in reducing blowholes (ev
Electronics Forum | Fri Jul 27 09:47:20 EDT 2018 | davef
Adding to Rob's suggestions ... One of the theories about voiding in thermal / ground pads of BTC is: Solder starts melting at the edge of the pad and moves inward towards the center of the solder mass. This traps flux volatilizes. So, there needs t
Electronics Forum | Mon Dec 06 14:44:41 EST 2021 | dwl
1 to 1 stencil aperture to pad should be fine on the gull leads, and yield 100% coverage with leaded solder. The thermal pad is going to be a challenge though, if you truly need 100% coverage. There will be out gassing from the flux and this will nee
