Electronics Forum | Wed Nov 05 13:17:58 EST 2008 | mrmaint
Take a look at your profile. Early on in the development of our leadfree process we saw excessive voids on BGA'S. We tweeked our reflow profile and were able to bring our voids down to about 9% or less. Also found that some paste mfgs. worked better
Electronics Forum | Wed Nov 05 13:34:24 EST 2008 | ed_faranda
Exactly what should I look at in my reflow profile? Soak Times, TAL, Peek?!? I am right in the middle of the manufacturing specifications as far as my profile goes.
Electronics Forum | Wed Nov 05 15:42:58 EST 2008 | mrmaint
Ed, Send me an email to skipjack20@yahoo.com and contact info. I can give more detailed info. Mark
Electronics Forum | Thu Nov 06 15:26:55 EST 2008 | mrmaint
IPC only allows 25% max voiding. We are able to run at levels much lower than 25% by using a heller 1800 reflow oven. Have not been able to eliminate voids completly. Not even the worst case have we been above 20%.
Electronics Forum | Thu Nov 06 07:45:10 EST 2008 | davef
Try here: * http://forum.allaboutcircuits.com/showthread.php?t=15575 * http://www.uoguelph.ca/~antoon/gadgets/555/555.html * http://www.williamson-labs.com/555-tutorial.htm
Electronics Forum | Mon Nov 10 12:29:59 EST 2008 | joeherz
Dave, You've got me worried - All of the boards we've tested to this point are LF HASL. Why do you say "can't be ENIG"? Am I missing something? We have not sectioned soldered boards as yet but plan to shortly. Thanks.
Electronics Forum | Mon Nov 10 19:45:51 EST 2008 | davef
Joe On the earlier ENIG comment: No, you're not missing anything. ENIG board are less likely to have copper dissolution issues that other solderability protection.
Electronics Forum | Mon Nov 10 22:29:31 EST 2008 | fctassembly
Hello Hoss Voidin/blow holes can also be exacerbated by residual flux. Have you experimented with dwell times and separation speed parameters with your selective ? What related parameters are you currently running processing under ? regards Jim
Electronics Forum | Wed Nov 12 10:58:56 EST 2008 | ck_the_flip
Jim, We are experiencing voids, also at Selective, on a transformer with known flux residue issues. The supplier told us they were using a OA, or RMA flux which has to be cleaned, and we accepted these parts anyway. How does the "separation speed
Electronics Forum | Wed Nov 12 17:36:43 EST 2008 | gregoryyork
If its an OA flux then this too acts similar to HASL flux in that they are very hygroscopic and would attract moisture and that would blow out the solder causing a void. Remember these fluxes have very high boiling solvents that do not get volatised
