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 Feb 24 10:26:50 EST 2014 | rgduval
Jimmy, The higher population board will actually be 7 feeders. Smallest parts are 0805 and SOT-23's. cheers, ..rob
Electronics Forum | Tue Apr 01 13:17:49 EST 2003 | cyber_wolf
The problem is that there are also SOT23's present. I would use a .004 or a .005 stencil, but I don't think that the dots are going to contact the bottom of the larger packages on a thinner stencil. ...Thanks for the input.
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 | Thu Feb 03 22:02:11 EST 2022 | stephendo
Another long shot. Are there any irregularities in the shape of the body or leads of the parts that are skewed? Any flash from the molding process for example? Almost all SOT-23s that I have seen are basically perfect but I seem to remember seeing so
Electronics Forum | Wed Oct 06 10:31:05 EDT 1999 | Chris May
Hopefully, everybody suffers from solderability of SOT-23 devices and I would like to know how everybody else resolves this problem. Historically, here, we have always gone for 6 thou stencils. I found that going to an 8 thou stencil improved the sit
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 | Tue Oct 03 16:40:28 EDT 2006 | slthomas
It's a consignment kit and we already have the parts. Otherwise I'd tell them to panelize the thing and we could build all 30 in one pass. I may be able find a 25 mil QFP on a stencil and hand print that one part if the apertures are long enough. D
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 | Thu May 10 15:32:45 EDT 2012 | 14367
We are having a lot of tomb stoning with this no clean solder paste. It's limited to larger, complex boards, affecting 0603 ferrite beads, capacitors and SOT23s. It was suggested that paste removed from a stencil should not be put back in it's origin
