Electronics Forum | Wed May 09 17:13:06 EDT 2007 | zanolli
Re: 63/37 paste reflow Is there a standard reccomended time (ball park) above liquidus? What are the negative ramifications if the TAL is too short or too long? Thanks in advance
Electronics Forum | Fri May 25 13:38:15 EDT 2007 | mfgengr
TAL Too Long - dull solder joints, dewetting. TAL Too Short - cold solder, insufficient wetting. You want TAL to be as short as possible (but not lower than 30 seconds), but long enough for every solder joint to be above TAL for at least 30 seconds.
Electronics Forum | Fri May 18 12:09:20 EDT 2007 | ed_faranda
I have been TAL around 45 to 90 seconds. I prefer the longer TAL so, I set my profiles around 80 seconds. In the old days (Before RoSH), the longer times would help with wetting. But, since Lead-Free, well. We all know the story about wetting now
Electronics Forum | Thu May 10 08:05:22 EDT 2007 | pjc
30 to 90 seconds TAL is typical.
Electronics Forum | Mon May 28 09:37:02 EDT 2007 | davef
Look here: http://www.aimsolder.com/techarticles/Time%20Above%20Liquidus.pdf We have no relationship, nor receive benefit from the company referenced above.
Electronics Forum | Thu May 10 08:09:52 EDT 2007 | davef
There is no standard for time above liquidus. It is described rather broadly by the solder paste supplier. Reflow Zone: If the temperature is too high, boards may char or burn. If the temperature is too low, cold and grainy solder joints will resul
Electronics Forum | Mon Jun 25 19:36:36 EDT 2007 | bga_kid
If you calculate CFM using the numbers you have provided you are pulling 1396CFM out of the oven. I am not sure what Hellers spec is but I know a Speedline OmniExcel Air machine should be set at 300CFM. I do know for a fact that to much exhaust can s
Electronics Forum | Fri Oct 06 15:43:33 EDT 2006 | Mario Scalzo, SMT CPE
What I usually do is keep the peak temperature about 5-10 deg C below the peak temperature of my lowest rated component, then set everything else up around that. Worse case scenario is to just extend the time above liquidus (TAL) in 5 second increme
Electronics Forum | Thu Oct 05 11:40:49 EDT 2006 | Mario Scalzo, SMT CPE
David, We have seeing this more and more in the recent weeks. In a nut shell, yes; we believe that the voids that you are seeing are from the trapped air in the via from printing over it. If you could remove the Kapton tape, this might help. Also
Electronics Forum | Fri Sep 09 21:09:20 EDT 2011 | hegemon
Wow, a lot of questions here...and you are definitely doing some "tough sledding". To the point. If you have 3 - 22" zones you'll have to calc your belt speed and temperatures to match the solder paste requirements with regard to flux activation an
