Electronics Forum | Fri Nov 23 03:40:09 EST 2001 | ianchan
Hi All, agree 100% on product characteristics SPC, and do find process indicators such as paste Volume, useful to monitor via SPC, the printing process, as printing constitutes "70% cases of SMT defects". We juz purchased a 2nd hand CyberOptics 3D
Electronics Forum | Tue Nov 20 12:48:40 EST 2001 | tony_sauve
We recently experienced a problem w/voids (up to 65%) in uBGA solder joints. The only joints that have the problem correlated to pads which had blind 0.006" via's in them. The via's only extend down 2 layers, of the 18. 21 BGA's on the PCB, only expe
Electronics Forum | Tue Nov 20 20:58:43 EST 2001 | davef
Very coo!!! [You have done an outstanding job of describing your situation.] I guess the via are connected to a BIG chunk of copper that affects your profile on that pad / ball. At the same time, run a profile each on a: * Void pad * Nonvoid pad
Electronics Forum | Thu Nov 22 12:56:12 EST 2001 | tony_sauve
Thanks for the comments & suggestions. Here's some info garnered from a telecon w/the PCB Fab house: -the blind via's extend from layer 2-17...this was a revelation. The info from our customer was that the via's only extended down 2 layers. Did I men
Electronics Forum | Sat Nov 24 22:15:16 EST 2001 | Glenn Robertson
Tony, I'm not sure if even baking will stop the voids if you have gaps in the plating. It probably doesn't take much moisture or even trapped air. I'm not speaking from a lot of direct experience here, so please run the tests and let us know wh
Electronics Forum | Fri May 02 09:37:23 EDT 2003 | Jerry Magera
Via in pad is the most efficient use of space. Blind via seems to be blamed for this. Cross-sections (send me some) will probably show a void still existing in the via or spherical voids aligned near the component pad side. One can estimate the vo
Electronics Forum | Tue Nov 27 10:16:07 EST 2001 | davef
Oooo, I get it. We do that trick on the wave solder side of boards. On the bare board, during design / layout, the basic shape of the jumper is a 125 thou disc of copper [that of course is eventually covered with whatever solderability preservative
Electronics Forum | Sun Nov 25 22:54:20 EST 2001 | ianchan
Hi All, We juz purchased a 2nd hand CyberOptics 3D paste inspection machine (what a mouthful...) and am seeking info : 1) what formulae is applicable, to calculate the deposited solder paste volume onto the pre-defined PCB pads? 1.a) from our obse
Electronics Forum | Tue Dec 11 13:56:38 EST 2001 | Damian Holzmann
Regarding your comment "technology doesn't seem to have improved". Actually, technology has improved significanty. Cyber Optics uses a line measurement, a new unit from Germany uses sine wave differential measurement. The Gridmeter unit captures a vi
Electronics Forum | Sun Dec 09 22:54:20 EST 2001 | dburr
It sound you have already discovered to root cause, flux entrapment in the via holes. Short of changing the desing, here are sone suggestions. The main thing is you have to dry out the via holes of the wet flux. Some things to try are: slow down t
