Electronics Forum | Fri Jan 21 08:00:09 EST 2005 | Lloyd
I recently saw a brief presentation on selective cleaning using Co2. In basic terms a fine jet of Co2 is blasted onto the desired area of the PCB removing the contamination and supposedly causing no damage to PCB or components. I think it's quite a n
Electronics Forum | Wed Oct 09 20:52:27 EDT 2002 | davef
Russ, Be careful on how you determine your liquidous point. Sure 205-210�C is fine if your paste and the solderability protection on pads and component leads are near eutectic solder and things worked according to plan, but in real life it doesn't
Electronics Forum | Mon Oct 07 09:05:41 EDT 2002 | russ
thnaks everyone for the the input. I have been noticing that a lot of comments are referring to 230 deg. C and such. has something changed in the industry lately? It has been to my knowledge previously to peak the reflow at 215 or so. I have many B
Electronics Forum | Sat Oct 19 11:48:39 EDT 2002 | davef
Good points, John. Continuing to track on the voiding issue, why remove voids anyhow? * Voids are primarily process indicators. There is experimental evidence that voids retard crack propagation locally around the void on at least on a temporary bas
Electronics Forum | Wed Oct 09 16:59:35 EDT 2002 | davef
Russ, as I told Eric the other day ... The steadfast rule of thumb is: In order to get reliable reflow, you need to be at or higher than [liquidus + 20�C] for about 5 to 10 seconds, rather than those old "60 seconds above 183�C" guideline. This prov
Electronics Forum | Mon Sep 30 09:26:04 EDT 2002 | itempea
Russ, first step would be to get IPC-7095 on BGAs. A few notes: There can be voids in solder balls, or at the solder joints to the BGA, or at the solder joints to the PCB. Various sources or reasons can be responsible for these voids. Voids can be
Electronics Forum | Thu Oct 30 00:12:13 EST 2003 | Grant Petty
Hi, Another option we have used here in house is to remove the unwanted BGA balls with solder wick, and then to manually place them on the PCB foot print. This eliminates the pick and place machine's optical centering freaking out because the balls
Electronics Forum | Mon Mar 30 16:39:04 EST 1998 | Tony Arteaga
Hello there, I am currently doing BGA repair and basically I am applying the same process as Mike sujested. It is actually the way to go when creating a profile. The next process is re-balling your package, that is if you whant to use the same compon
Electronics Forum | Sun Oct 20 12:49:11 EDT 2002 | johnw
Dave, I've had a few intersting conversations with Dr Lee, now there's a guy who know's stuff, but as it turn's out even he doesn't have all the answers on why things void. Many of his papers point towards oxides or contamination on the ball, so age
Electronics Forum | Thu Sep 01 12:07:35 EDT 2016 | pavel_murtishev
Is there any field proven spray cleaning technique able to remove flux residues under OSRAM LEDs? Is it possible in principle? The problem is that OSRAM LEDs are low standoff ones and I absolutely have no idea how cleaning agent could get there. Mo
