Electronics Forum | Tue Feb 19 12:41:20 EST 2008 | patrickbruneel
Yes dendrites can cause electrical shorts. The first stage of dendritic growth is a dark fern like pattern which reduce surface insulation between anode and cathode. In a more advanced stage the ferns transfer the plating metals of the conductors and
Electronics Forum | Fri Feb 22 14:22:07 EST 2008 | stevek
Are you using nocleans, especially when you get to SMT? Years ago, I had OA wave flux get into vias that were plugged from the top under parts. It is really difficult to clean small, high aspect ratio vias. Cross sections showed that the copper in
Electronics Forum | Tue Feb 26 05:10:17 EST 2008 | adetuc
Thanks for the reply Hege, I calibrate the machines every 3 months and have checked that the board carrier to nozzle parralelism is ok. Have tried many different profile settings using a MOLE for readings but still collapsing on one corner. I did
Electronics Forum | Tue Feb 26 21:23:21 EST 2008 | davef
Several methods are available for singulating or extricating individual flexible circuits from a processed panel; this discussion of the topic applies to all types of flexible circuits. In general, the methods for singulating flex circuits can be bra
Electronics Forum | Thu Mar 13 16:37:48 EDT 2008 | darburch
The only time the customer is going to care about the standards is when it costs them money. Unsophisticated customers will continue the practice of providing little or no useful information, poorly designed boards and ridiculous mods until there is
Electronics Forum | Tue Apr 22 03:46:19 EDT 2008 | fowlerchang
It is CSP reliability issue, which is the mobile CPU from Spreadtrum. All the tests passed and shipped to customer. They assembly them and tested but failed. After they reflow this CSP with hot air gun, some of the boards passed. We got some board
Electronics Forum | Wed Apr 16 11:29:31 EDT 2008 | mmjm_1099
Per Tony SMT Here are more photos: Q15, Q16, Q17 represent good transistors on a 1 up board with the transistor locations that are in question. Q13 is a good transistor on a bad 2up board. Right next to it is Q14 a bad transistor on a bad 2 up boa
Electronics Forum | Mon Apr 28 19:50:09 EDT 2008 | boardhouse
My guess is that either the board house did not cool the boards down properly coming out of the lamination oven. Typically after they come out of the heat chambers they go into a cool down chamber for x amount of time, if they cool to fast or are pu
Electronics Forum | Fri May 02 16:20:35 EDT 2008 | rwyman
We've never, to my knowledge, sent out Pb-free BGAs to be reballed for use on an SnPb assembly. In fact, we developed an in-house reballing process and we haven't felt the need to do that either (for salvaging an occasional reworked part, maybe).
Electronics Forum | Fri May 09 12:08:19 EDT 2008 | sliebl
Last year I had my doctor do a lead test during one of my regular blood tests. My exposure at work is similar to most of you, I'm sure. I've been doing this for 13 years now. We do predominantly leaded solder processing through SMT and wave. I wash m
