Electronics Forum | Tue Jul 28 02:28:48 EDT 1998 | Bob Willis
The causes for solder on gold are: Paste wash offs Dirty stencils Dirty under stencil cleaning cloths/no solvent Poor handling The most common reason is wash offs when there is a couple of balls left on the tabs and they reflow. With correct profile
Electronics Forum | Tue Jul 18 10:16:49 EDT 2006 | russ
Clean up!, check all conveyors for paste, the printer, oven. If you are splattering in the oven than you need a better profile or better paste, one of the two, maybe both. Hope was helpful Russ
Electronics Forum | Mon Feb 05 20:43:27 EST 2001 | davef
1 Solder on gold fingers comes from: 1a About 70 % of the time it's caused by poor cleaning of screen printer, staging area (table), conveyor, reflow oven chain or belt, and keeping boards separate from cleaning process 1b After loading paste onto
Electronics Forum | Wed Dec 28 16:03:53 EST 2005 | Chris
I have lots of experience with thermosonic gold ball bonding. You can read the literature and you will probably find some papers that say you can do it. I have never been able to do it. We gold ball bond all day long with little problems at all bu
Electronics Forum | Sun Jan 23 03:23:09 EST 2000 | Rob Steltman
Hi We use a U-channel piece of high temperature silicon which is just pushed over the gold tabs before the soldering process. The silicon can be used over and over again. The advantages are that there is no mask on the board during the SMT process a
Electronics Forum | Tue Jul 01 17:38:24 EDT 2003 | jartman
I've faced this several times in the past, and the only real solution is to wirebond before SMT assembly. Everything leaves a residue, and trying to clean a residue off later is basically hopeless. This may require some trickery in your SMT process
Electronics Forum | Mon Jul 27 17:09:20 EDT 1998 | Rin
| We are trying to reduce the number of units fail at system test due to flux on gold finger. We know so far that the flux is deposited onto the | goldfinger during touch-up or rework and to reduce the contamination we are | planning to imp
Electronics Forum | Tue Aug 20 18:15:02 EDT 2002 | davef
Haaaaa!!!! Soldering to plastic!!!! An apt analogy!!! I like to compare it to soldering to dirt. Some thing. In fact, you are soldering on nickel, when soldering on many things. It�s just that the gold, er Pd, flash enables the wetting mechanism
Electronics Forum | Tue May 19 12:29:59 EDT 1998 | Richard Jackson
| Richard, | You may be encountering solder paste contamination | on the assembly during the printing process. Solder | will reflow on tin/lead plated lands therefore invisible. | If you are washing the assembly prior to inspection | then you are
Electronics Forum | Sat Jan 23 16:07:20 EST 1999 | Steve Gregory
| hi, | i am working towards developing a no-clean process for a customer at contract manufacturing facility. the assemblies have gold fingers on them. these are masked to prevent from any damage to them during reflow soldering. the earlier proces
