Electronics Forum | Mon Mar 09 03:45:19 EDT 2009 | nagesh
I have a double sided assembly board having more no. of QFP's & IC's at both Top & bottom.Is there any concern about this??.COz. i have the profile set to be almost same for Top & Bottom.Worried whether bottom side IC's fall/ Shift during Top side re
Electronics Forum | Fri Mar 27 14:12:10 EDT 2009 | rgduval
Check with your paste manufacturer for a recommended baseling. The paste manufacturers generally have a database by oven that gives optimal performance for their paste. It's only a baseline, and does need to be adjusted based on the thermal foot pr
Electronics Forum | Thu Apr 09 21:15:43 EDT 2009 | qualityguy
Interesting, A north American Solder resist firm stated the same thing to a degree. They said altering the resist cure profile can effectively change the surface energy thus making the surface more conducive to conformal coat adhesion. At in coming
Electronics Forum | Wed May 20 17:00:56 EDT 2009 | dyoungquist
We just placed a 56 pin QFN, 1 per board, on 10 boards and had zero defects. A good paste job, proper placement and a correct oven profile are the keys. If these are set up correctly, on larger runs your defects won't be zero but they should be le
Electronics Forum | Thu May 14 06:55:59 EDT 2009 | davef
While you're waiting for others to reply: * Search the fine SMTnet Archives to find threads like http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=28544 * Checkout Daan Terstegge's excellent jump site http://www.smtinfo.net/Db/_Ball%20Grid%2
Electronics Forum | Thu Jun 04 14:35:11 EDT 2009 | floydf
We wound up using a ramp to spike profile with 50 sec. between 150C and 217C and 90 sec. above 217C. The idea being the flux is still active when it hits reflow, and it stays in reflow long enough for the weird alloy in the parts lead to wet. All par
Electronics Forum | Thu Jul 02 10:52:45 EDT 2009 | dyoungquist
For 0402s we use type 3 paste. We have .006 and .005 stencils. The .006 works okay but .005 seems to give us slightly better results. We use a 1:1 ratio for the aperture to match the pad, round pad not needed. With accurate placement and a correc
Electronics Forum | Tue Aug 25 07:13:20 EDT 2009 | davef
It sounds like the BGA balls are not melting. You're probably getting no collapse. Put a bare BGA on a hot plate. Heat it up until you get collapse. Adjust your reflow profile until you have that temperature on the BGA pads on the board. What is the
Electronics Forum | Mon Aug 24 03:59:26 EDT 2009 | hurr
Hallo Joanne, I had employed by producer of Ecofrec 303. We make many tests of corrosion and conductive test in our company. All results of this tests was OK . Vast majority correspond mil standarts. When I ask my labor assistent in BRY, white residu
Electronics Forum | Tue Sep 22 08:35:47 EDT 2009 | cman
Did you try pre-tinning your board on this suspect pad/s to see if it improved wetting/solderability prior to printing/SMT placement and reflow? Does the pad/s not soldering tie to a ground layer? I would connect a T/C to each pad of the same part an