Electronics Forum | Fri Feb 13 08:54:43 EST 1998 | justin medernach
| Hi , | I have not been able to find any good description on how to perform double sided reflow on PCBs.The best would of course be to avoid reflowing the bottom side again but in real life this is not possible. | So when double sided reflow sol
Electronics Forum | Mon Feb 16 16:28:25 EST 1998 | Brian Stumm
Dear Brian, I came across your question on the SMT Net and thought I better reply to this one. Perhaps you might remember me. My name is Brian Stumm and I work for ETS, Energy Technology Systems. I believe we met in Anaheim, CA during last years Nepc
Electronics Forum | Tue May 31 22:40:24 EDT 2011 | bejrananda
HI All, Please kindly advice me, I have project that it has DPAK part (MPN:SUD25N15-52 E3 Plating:100% Sn matte)which locate on bottom side (1st reflow), Good wetting for 1st reflow.. but .. when I run Top side (2nd reflow).I found that this D
Electronics Forum | Mon May 13 10:37:56 EDT 2002 | fmonette
The other important issue relates to moisture sensitive devices (MSD). If you have MSDs on the first side, you need to track the remaining floor life of the components on the partially assembled boards between the first and second reflow. Contrary to
Electronics Forum | Fri Apr 09 09:08:40 EDT 2010 | cast2010
Hello, I produce two types of board. - 100% Thru Hole - 50% thru hole and 50% SMT For the second, I have a bad wetting after the reflow on the top. The pcb board have Au-Ni pad. I use a water soluble paste. I clean the board with a solution with
Electronics Forum | Wed Feb 08 07:52:21 EST 2006 | davef
'TAL' is a poor measure of solder connection heating. In a reflow process, what you need is about 5 seconds at liquidus for the specific solder plus: * 20*C when soldering to Cu. * 35*C when soldering to Ni. This time over temperature is measured
Electronics Forum | Mon Jun 18 10:11:52 EDT 2007 | dyoungquist
Almost every board/panel we build is double sided and we use an MPM SPM screen printer with no problems. The screen printer is not the cause. We have seen heavier parts fall off the first side when going through the reflow for the second side. We
Electronics Forum | Mon Feb 03 18:00:49 EST 2003 | slthomas
I know that the accepted (by some, although some say it may be too conservative) rule is anything less than or equal to 30 grams/square inch of surface contact area should stay on the bottom side during the second pass. How is that surface area meas
Electronics Forum | Tue Nov 20 09:50:07 EST 2007 | rgduval
Only on the bottom side? Run that side first . We usually determine our run process based on the heaviest components, and propensity for falling off during the second reflow process. If there's only the one BGA on that side of the board, we'd tend
Electronics Forum | Tue May 14 21:07:03 EDT 2002 | ianchan
Hi mates, Yes, the lighter mass is a valid reasoning. in addition to the "lighter (mass) than thou" point of view, 1) the first reason for mounting active Parts (eg. IC, QFP, LGA...) is to minimize the temperature exposure of the Parts to a single
