Electronics Forum | Wed Mar 24 08:36:58 EST 2004 | Evtimov
Hi! What exatly you do? Do you reflow the both sides of the board at the same time or you reflow your second side? I think in both cases you should decrease you bottom zones. If you reflow both sides - with 10-20C(F) If you reflow the second side - w
Electronics Forum | Mon Oct 29 20:19:44 EST 2001 | davef
DON'T do it!!! The two problems you'll have are: 1 Poor manufacturing process control, resulting in weak solder connections. 2 Weak solder connections are stressed, when the board is straightened upon installation in the "box". There's several hits
Electronics Forum | Thu Apr 05 22:27:06 EDT 2001 | davef
As a band-aid, consider running your chip wave when soldering these boards [Similar to Cals "dance with me babe" suggestion.] If the problem is as broad based as you say and the radial components have a tight fit, consider increasing the holes by a
Electronics Forum | Mon Oct 29 18:21:43 EST 2001 | slthomas
We recently have received a lot of warped (bowed and/or twisted behond IPC 600 specs.) bare boards (some our fabricator's fault, some ours by design) and I can't help but figure that long term reliability will suffer when building product with them.
Electronics Forum | Sat Dec 11 12:15:21 EST 1999 | Steve Thomas
We have a pretty challenging board (2-up panel, 15"x20", 48 20mil pitch QFP 100's and 2 25mil QFP128) that gives us LOTS of lead bridging on the 20 mil parts. There is typically very poor wetting on these parts also, and some joints just flat aren't
Electronics Forum | Thu Sep 02 16:06:33 EDT 1999 | Earl Moon
| Has anyone done or seen any studies done documenting what may be the affect of hardware such as screws in the parimeter vicinity of BGAs on a circuit board? | | What I'm really after is anything describing how close a screw/washer/nut combination
Electronics Forum | Thu Sep 02 16:37:23 EDT 1999 | R Scheller
| | Has anyone done or seen any studies done documenting what may be the affect of hardware such as screws in the parimeter vicinity of BGAs on a circuit board? | | | | What I'm really after is anything describing how close a screw/washer/nut combin
Electronics Forum | Mon Dec 13 05:43:27 EST 1999 | Wolfgang Busko
Hi Steve, 20 mil pitch shouldn�t be that problem nowadays. In your case bridging and poor wetting seem to go hand in hand. For the poor wetting try to eliminate it by using different paste (higher activated) and work on your profile. Coplanarity also
Electronics Forum | Mon Dec 13 09:43:28 EST 1999 | Chris May
As Wolfang says about slightly bent legs, handling is of the essence. Are these devices decanted into another tray for your machine. It may be worthwhile doing a "movement" chart for these components. Do not explain why or when you are doing it beca
Electronics Forum | Thu Sep 02 16:52:31 EDT 1999 | Earl Moon
| | | Has anyone done or seen any studies done documenting what may be the affect of hardware such as screws in the parimeter vicinity of BGAs on a circuit board? | | | | | | What I'm really after is anything describing how close a screw/washer/nut
