Electronics Forum | Thu Aug 23 16:28:14 EDT 2007 | grics
I want to get a collective opinion from the forum... I was always under the impression that Humidity at SMT can be a disaster and can cause solder balls... But what about at the Wave/Selective solder? If every board or almost every board has solder
Electronics Forum | Thu Sep 27 10:40:46 EDT 2007 | rgduval
Joris, Yep, very common to have those small blow holes in lead-free alloys. We used to get them very consistently on white-tin finished boards, and less frequently with gold finished boards, for what ever that is worth. IPC-610 actually allows t
Electronics Forum | Tue Aug 28 23:53:31 EDT 2007 | crashoveride
dedicated fixture works best if the board is very much populated. But if the parts to be inserted are less than 300components, adjustable fixtures may be used. But the secret of good insertion is a precisely measured tooling pin to prevent the boards
Electronics Forum | Fri Sep 07 12:19:20 EDT 2007 | guqing
We are having problem to develop lead-free (SAC305) reflow profile for big SMT electrolytic caps. The delta T of the joint of the cap with the rest of the board is too big to fit in the tighter lead-free window. Any suggestions regarding the total pr
Electronics Forum | Wed Sep 19 17:36:16 EDT 2007 | slthomas
Like davef mentions, there are guidelines for both design and fabrication, not to mention assembly (which from the original post doesn't appear to come into play here). Not that I could improve on what dave has already shared, but it would be nice t
Electronics Forum | Thu Sep 20 13:06:37 EDT 2007 | hussman
Acualy same supplier, but they have 7 different facilities. Changes in prepreg thickness from lot to lot is the big deal, since internal shorting occurs form time to time. Just wondering if there was a spec I could use to force them to use the same
Electronics Forum | Thu Sep 20 15:05:20 EDT 2007 | jax
You can specify the prepreg thickness in the stackup. Once you have specified it somewhere, make your PCB manufacturer build to it... and prove it through cross-section analysis. Depending on the Board cost, we require a cross-section and analysis d
Electronics Forum | Fri Sep 21 10:31:44 EDT 2007 | russ
this would be meaniung that somewhere in your documantation it should have spec called "repeatability" what this means is that when the vision aligns the stencil/board, the board will always be within "x" amount of the njominal xy "T" position, some
Electronics Forum | Tue Sep 25 08:55:43 EDT 2007 | stepheniii
It's a test technology. It's quite different from either ICT or functional. It's also called boundary scan. The board has to be designed for it. You basically plug the J-tag tester into a port built into the board. It has it's own special niche b
Electronics Forum | Wed Oct 10 13:59:49 EDT 2007 | petep
I have always understood that on boards (or circuits) operating over 900 MHz, No Clean fluxes are to be avoided. Apparently the residues left behind, while non-conductive and non-corrosive, will change impedence of the circuit. It may be a possibil
