Electronics Forum | Fri Apr 16 17:44:12 EDT 2021 | dwl
I'm concerned by the solder spheres in the via on the first picture. Are these boards mis prints that got washed and printed again? To me it almost looks like someone washed the board, but left a lot of solder paste on it. The lack of flux prevents
Electronics Forum | Mon Mar 15 09:55:53 EST 1999 | Justin Medernach
| After rmoving a BGA (plastic)to correct unexplained shorts | I installed another BGA using flux only. | Checking on an X Ray machine and found two shorts. | | can anyone give a good explenation ? | | Thanks | | Ron | Ron, It could be a number o
Electronics Forum | Wed Jan 30 17:23:07 EST 2013 | dyoungquist
In response to hegemon... This is not a recommended practice but..... We have added a few drops of water soluble flux to our water soluble solder paste when the paste is on the stencil. This was after the paste had "dried" out a bit. We have had
Electronics Forum | Thu Apr 05 08:44:45 EDT 2007 | ck_the_flip
"Guest" is right, actually. CSP's are essentially BGA's, but typically the pitch and ball diameters are much smaller and in some cases, the pads of the CSP's can not be screen printed. If that's the case, you'd have to have flux-dip capabilities on
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 | Wed Aug 14 16:44:54 EDT 2002 | dragonslayr
What is the surface finish? HASL, Entek? what? If HASL, ask your fab supplier for recommendations, maybe even rerun the boards through the HASL process. The fab house would have to strip off the old coating and reapply. Just a thought, depends on y
Electronics Forum | Fri Sep 10 09:39:32 EDT 2004 | Bryan Sherh
Dears, I've a board with OSP surface finish,and I planned to print solder paste on the test pad for easy ICT, because the probe can't reach the OSP covered pad.But to my surprise,after reflow there's much flux residue on top of test pad(or solder) an
Electronics Forum | Tue Sep 24 12:30:11 EDT 2002 | Claude_Couture
I'm just shooting ideas here, but maybe a via hole in the middle of the solder pad would drain the excess solder by capillary force? Or using a tin plated PCB and printing flux only, then place and reflow. depending on the thickness of the tin plati
Electronics Forum | Tue Dec 14 13:26:19 EST 2004 | Peter
I have a question regarding post cured property of SMT adhesive. If after component placement, the epoxy dot gets compressed and bridges between the 2 pads, what would the impact on the circuitry? Would it pose risk for flux entrapment? Could the cu
Electronics Forum | Wed Sep 19 21:04:57 EDT 2007 | wailiang81
Hi,davef, thanks for your concern. The condition was the pasted printed off with around 0.8~0.9mm from the land pattern. This will easy observe at QFP area. At fiducial, the stencil seens aligned accurately. Once solder bridge happend, its easy to
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