Electronics Forum | Fri Nov 02 03:26:40 EDT 2012 | spopov
Hello! We want to try Lead Free paste Sn42/Bi58. Can we use this paste with Lead fihish such as HASL. I am worry about low melting temperature of 138C.
Electronics Forum | Wed Nov 14 03:26:38 EST 2012 | spopov
Ryan, in some cases we use 2 pastes with different melting temperature (LF SAC and PbSn)for complex boards with components on two sides. And we want to try to replace LF SAC with low melting paste.
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 | 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 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 | Tue Nov 06 22:14:10 EST 2012 | nikyta
Hi Popov, can you tell us the reason for the use of Sn-Bi ?
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 | Fri Nov 02 14:46:18 EDT 2012 | ericrr
So how does this (lead free paste Sn42/Bi58) solder compare with the Sn-Ag-Cu (Tin-Silver-Copper) combination which does not flow as well (in the oven), needs higher oven temperature, (that can be adjusted by reducing the oven chain speed) and cost m
Electronics Forum | Wed Sep 30 10:54:31 EDT 1998 | Clifford Peaslee
Very unusual. It seems to work on some pages, and not on others. I will do some research to try and correct that problem. Cliff
.gif)
