Electronics Forum | Tue Jul 11 20:13:05 EDT 2006 | davef
We agree with Chunks. You need to turn-up the heat [slow the conveyor] because you have significantly changed the melting point of the solder alloy by adding so much gold. Relative to ENIG you should expect: * Similarly smooth surface, possibly a l
Electronics Forum | Tue Jun 28 16:41:07 EDT 2005 | mattkehoe
Yes, .062 fr4. Like I said before, we run a lot of gold boards, as many as 25% of what goes through the shop, and we've never adjusted anything before??? Many of these are bigger by 2 X and much more dense. Reflow is not as shiny as HASL but always u
Electronics Forum | Tue Jun 28 09:13:46 EDT 2005 | russ
It appears that the reflow profile was incorrect or the paste was in bad shape on these boards from what I can see. I personally have never seen a board finish cause this symptom.
Electronics Forum | Tue Jun 28 10:41:57 EDT 2005 | GS
I am not an expert but just for my understanding: - solder paste used ? NC ? other ? - reflow in Air or N2 ? - temp ramp up before soack (�C/second) ? Tnks GS
Electronics Forum | Tue Jun 28 13:23:56 EDT 2005 | Bob Gilbert
Matt, Try a cooler profile by simply speeding up the conveyor by 10%. The difference may be the temperature the pads are reaching between the HASL boards and the Au boards. Are they the same thickness?
Electronics Forum | Tue Jun 28 17:38:13 EDT 2005 | mdang
We got the same problem. To solve it, we have to tint the pads first and do the normal reflow process. It works but take a lot of time to tint the pads. Any thoughts? Thanks, -Michael
Electronics Forum | Tue Jun 28 18:40:36 EDT 2005 | Bob Gilbert
Matt, Try putting a soldering iron to a pad to see if you get reflow. If it reflows, your oven is too cool. If no reflow, your oven may be too hot. Regards, Bob
Electronics Forum | Wed Jun 29 18:37:41 EDT 2005 | russ
I guess it's it's a good thing that they didn't work out. It might have been interesting when all of the boards failed down the road. I knew I should have asked if it was enig instead of assuming that it was.
Electronics Forum | Fri Jul 08 06:38:51 EDT 2005 | mattkehoe
I did not get that info. We sent them back and the vendor ran them through HASL finish. They processed very well after that. Thanks to everyone for the help. mk
Electronics Forum | Wed Jun 29 06:57:20 EDT 2005 | mattkehoe
Hi Bob, We tried flowing the pads with a soldering iron. The pad at the tip of the iron went shiny but as soon as the iron was taken away, the pad returned to the dull finish. You could actually move the tip around the pad and it would shine up then
