Electronics Forum | Wed Aug 22 22:07:53 EDT 2007 | mdm4ua
Easy fix is put a drop of washable mask on the side of part before reflow. The mask dries before the solder reflows and holds the part in place. After reflow it washes away.
Electronics Forum | Wed Aug 22 21:44:04 EDT 2007 | davef
Questions are: * Do these boards meet IPC-A-600? * What does your supplier say is the source of this color variation? * What steps is your supplier taking to make the boards more acceptable?
Electronics Forum | Thu Sep 13 13:36:46 EDT 2007 | russ
switch pastes and see what happens, Kester had issues with their fluxes a little while ago and you may have gotten one of the bad batches. R
Electronics Forum | Tue Oct 09 08:30:22 EDT 2007 | davef
As a starting point, follow the guidance of your paste supplier: http://www.aimsolder.com/tds/WS%20353%20Sn62%20&%20Sn63%20Solder%20Paste.pdf
Electronics Forum | Mon Nov 05 14:26:24 EST 2007 | hussman
Maybe the "other" company runs a different wave, or flux, or pallet, or touches up every board. Assumptions are like brains - every claims they have one, but very few use em.
Electronics Forum | Thu Nov 08 08:56:51 EST 2007 | hussman
Sorry Matt, Just hate when people use this site as their engineering bed. I believe you can weigh your board before and after reflow. It would have to be a sensitive scale though. From there you can calculate weight to volume ratios.
Electronics Forum | Sat Nov 10 23:10:13 EST 2007 | mika
Hi Real Chunks, Nice to meet you. Well, I certainly not agree with you. Sorry. Can You be a little more specific about your claims, about my statements? Do you know what you are talking about? I wish no polemic about this. Best Regards, Mika
Electronics Forum | Mon Jul 07 17:25:04 EDT 2008 | thughes
I'm curious to know what the pitch of the outer pads is/was on your device. Also, is this a general formula you use on all of your QFN devices or was this for one specific device?
Electronics Forum | Mon Nov 26 15:42:20 EST 2007 | realchunks
Good luck. Being most machines use the edge of the board to locate pads, you'll always be adjusting. Now when someone comes out with fiducial recognition, you'll have something. Not impossible, but will cost a little.
Electronics Forum | Thu Dec 06 09:44:19 EST 2007 | darburch
If you are looking for fiducial recognition the RPS automation sytems have a very useful vision sytem, however they are built by engineers for engineers.
