Electronics Forum | Thu Nov 29 22:38:05 EST 2007 | shy
Hi Dback, Yes, i'm open "dog bone" aperture for my chip component. this is to prevent solder ball issue. For fine pitch i'm opening square with full length and half width to prevent bridging. Btw, if "dog bone" is not for chip component, what is your
Electronics Forum | Wed Feb 07 16:14:54 EST 2001 | Antonio
I've recently read a posting here which said that the person was trying to reduce solder balls. One of the things the person had done was to adjust the reflow profile so as to be hotter and longer in the reflow state. Am I wrong here? I thought th
Electronics Forum | Thu Jul 19 08:00:03 EDT 2001 | doctord
Solder balls or mid chip beads? Remember IPC classification for Class 2 allows mid chip beads encapsulated in flux. Usually on R's and C's first thing I would do is verify .006 laser stencil 10% reduction and the most critical, The paste must be on t
Electronics Forum | Thu Feb 08 09:07:22 EST 2001 | Hussman
OK, without knowing the specifics, why does everyone blame the oven? Most solder balls occur around R's and C's in almost every shop I've been to. The best place to start looking is the screen printer - not the oven. Sure the oven is the last proc
Electronics Forum | Sat Aug 05 12:12:05 EDT 2000 | Ramon I Garcia C
Hello Friends: I'm new in SMT process, I have a problem with little balls of solder beside of the component, I'm tried reducing the apertures in the stencil and making home base, some times the balls desappear, but some time not, and some times
Electronics Forum | Thu Jul 05 09:27:05 EDT 2001 | blnorman
Our solder ball problem is linked to moisture. If the paste sits on the board too long (especially during our humid summer months) we experience the problem. As far as the problem being specific to components or areas of the board, maybe some of th
Electronics Forum | Thu Jul 12 10:32:59 EDT 2001 | Hussman
Wow, what a string of answers and nobody brought up the easiest way to eliminate solder balls. Yes, the paste being squished under the part does reflow and work it's way out to the side during reflow. I did a 5 week study on this (when I was a bori
Electronics Forum | Fri Jul 20 10:35:34 EDT 2001 | slthomas
David, I've thought about doing this also with no clean boards that were poorly cleaned following a misprint (and subsequently reprinted, populated, and reflowed) but have shyed away because of the potential for damage to components from the ultraso
Electronics Forum | Tue Jul 17 15:13:53 EDT 2001 | mparker
Dave - I agree that the U shape for QFP's sounds a bit whacked, for the reasons you state. It may work OK for larger pitchs but then again there are a myriad of fixes that work before resorting to U shapes. With the U shape removing paste from under
Electronics Forum | Thu Jul 12 20:50:37 EDT 2001 | davef
One possible reason no one brought-up "too much paste" is that suggestion has been proffered so many times that it�s in the archives like the layers of sediment making-up Kataden. Another thing [we can argue about this], using home plate apertures w
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