Electronics Forum | Wed Mar 05 10:59:04 EST 2003 | jfb2003
Currently, my company's applies a PCB bake (5 hours @ 125C) for all SMT PCB's prior to surface mount assembly. Many of us believe this is a non-value added activity, and have concluded it can be eliminated. With today's PCB process controls coupled
Electronics Forum | Wed Mar 05 11:54:44 EST 2003 | ruggi
Hi JFB, I think this is an unnecessary activity, but it may depend on your RH. We are in the Spokane, WA area, and the RH avg year round is about 25-30%. We have never baked our PCBs in the 9 years I've been here across 800+ varieties, including
Electronics Forum | Thu Mar 06 22:34:55 EST 2003 | davef
O' Connor: Are you saying that: * You solder fine in the areas where you print paste * You solder poorly in the areas where you don't print paste Aside from that, the gold on these pads seems to be less bright than previous lots. [if that's not it
Electronics Forum | Sat Mar 08 21:45:59 EST 2003 | MA/NY DDave
Hi The other thing the Ni does is to create a time barrier for the underlying copper (Cu) migration into the joint. Degradation still occurs yet it is slowed significantly. Diffusion Equations under, electonic current pressures across time, are inv
Electronics Forum | Mon Mar 10 15:20:41 EST 2003 | MA/NY DDave
Hi Well I don't have all the titles right handy, yet let me give a few places for you to check. All my books aren't exactly at my finger tips. Author: Tumalla (??spelling) He is now at Georgia Tech Author: Lasky, Seraphim Author: Ning-Cheng Lee or
Electronics Forum | Thu Mar 06 18:21:29 EST 2003 | ppwlee
Mike, What is the most common method for monitoring and calculating machine capability for: - Reflow oven, I currently run a carrier monthly to monitor its temperature profile and would like to simplify the process. - P&P machines: We don't have a
Electronics Forum | Fri Mar 07 14:48:34 EST 2003 | gdstanton
Pretty much everything under the sun. For example if Company A wanted to hire Company B to build printed circuit cards designed by Company A; What type of T & C might Company B seek in their contract/agreement with Company A? The following things c
Electronics Forum | Thu Mar 13 15:22:47 EST 2003 | ruggi
Ditto on the profile/reflow oven...a couple years ago, we had a huge increase in the number of tombstones found post-reflow. Profiling the oven showed a decent curve with some innocuous minor deviations, and further investigation of the oven found 2
Electronics Forum | Fri Mar 14 04:42:24 EST 2003 | emeto
Hi, About Thombstone defects: 1.Placement accuracy-main reason 2.Soldering-should be right on pads.The print should have regular shape.The quontity of the solder on both pads on one component have to be equal. 3.Reflow: the profile have to be made v
Electronics Forum | Tue Mar 18 11:51:24 EST 2003 | slthomas
I like this answer! Part geometry, part mass, land pattern, print accuracy, reflow profile, placment accuracy, and aperture shape all play a role. If you use a homeplate to reduce solder balling, have high profile/low mass parts AND place more to
