Electronics Forum | Sat Oct 06 08:36:04 EDT 2001 | davef
Your point about thermosets getting soft in the preheater of the wave is well taken. But an adhesive that is used past its expiry or other up-front lack of process control represent 99 & 44/100 percent of the reason for �glued parts falling off in
Electronics Forum | Tue Feb 08 12:36:28 EST 2000 | Charlie
I'm looking for information from both those who do cure glue and reflow past with the same profile and those who have tried and decided against it. What were the problem? What are the limitations?
Electronics Forum | Mon Dec 22 14:15:41 EST 2008 | ck_the_flip
As Emil says, it's 100% the glue! Your paste is not designed to hold parts on at wave solder. Reflow is MUCH hotter than glue, so I doubt you're not adequately heat-curing it. Possibly, the glue cure is "too hot" and maybe making the material brit
Electronics Forum | Mon Dec 22 12:06:27 EST 2008 | evtimov
Hi, it seems like a glue problem to me. If you don't have enough glue on SOT23, you have no contact and the part is holded only by the paste, which results bad in the waver machine. So first I would check is the glue amount under the SOT. The second
Electronics Forum | Mon Dec 22 14:52:18 EST 2008 | wrongway
We run our process like that all the time paste then glue we use same profile as if we were just reflowing paste once in a while we have A plastic bodied part that has that problem we asume it was some mold relase still on the part basicly comtamena
Electronics Forum | Wed Dec 24 20:29:45 EST 2008 | xianhua_tang
Oh,I consider the process is wrong,it is stencil print paste-mount-reflow -apply glue-reflow,then wave solder. it must pass twice reflow,also the first reflow profile is different and the second .
Electronics Forum | Mon Dec 22 11:09:21 EST 2008 | mfcat
We changed paste manufacturers rather recently and are now seeing SOT23s falling off after wave solder. These parts have a dual process... we stencil print paste, apply glue, populate then reflow. Only SOT23s fall off, chips are fine. We do not be
Electronics Forum | Mon Dec 22 20:16:17 EST 2008 | davef
The first question in solving the "ol' SMT component loss after second-side wave operation" problem is: So, what makes you think the components actually came-off in the wave and not during some previous 'handling'? Putting that aside, we'll play thi
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 Feb 08 14:49:23 EST 2000 | Travis Slaughter
I have never tried this and wouldn�t really even want to consider it. Epoxy generally cures at around 160c in a fairly short amount of time, solder paste requires much more time and a peek temperature of about 210c or more in some cases. Curing you
.gif)
