Electronics Forum | Wed Aug 17 13:57:27 EDT 2005 | ppwlee
We have encountered what appears to be mask discoloration after wave soldering. The areas of concern coincide with the areas that were exposed selectively by fixtures during wave soldering, dominated by one date code of PCB with a slightly different
Electronics Forum | Wed Aug 17 22:41:37 EDT 2005 | davef
Peter are you having fun with solder masks erwat? We saw this years ago with LPI solder masks. It shows occasionally with other masks. We agree with Russ. If nothing [eg, alcohol, flux thinner, acetonitrile, or water] dissolves the haze, then it
Electronics Forum | Tue Jun 06 14:31:42 EDT 2000 | Jeff Sanchez
I have 25#'s of bismuth in my shop. I wanted to add some to my 63/37 till it was eutectic. This would allow me to lower the waves temp. Can I do this and still meet standards? Also would it make the solder joints to brittle and would discoloration be
Electronics Forum | Tue Jul 27 13:48:45 EDT 2004 | Ralf
Hi Recently i have noticed that after reflow (hot air oven) on the solder lands without components but with solder(screen printing) there is discoloration. It looks like gasolin spilled on the wet road (rainbow). Any idea and reason Ralf
Electronics Forum | Wed Jul 28 17:34:27 EDT 2004 | Steve Stach
Hi Ralf, This discoloration may be re-oxidation. Fluxes are supposed to do three things (1) remove oxide, (2) promote wetting, and (3) protect surface from reoxidation. The solder paste possibly is not protecting from reoxidation. Best Regards, St
Electronics Forum | Mon Jun 12 22:00:51 EDT 2000 | Dave F
Could be. What are your profiles? 2) Au finish fail => Could be, but that the connections can be made with hand soldering makes this a low probability cause, assuming the activity of the flux used in hand soldering is not significantly different fr
Electronics Forum | Thu Feb 19 09:02:43 EST 2004 | russ
This is a pretty common sympton when wave soldering chip components. As a note IPC allows for this in wave process. The problem is in the pell off of the wave and you may not be able to fix. Is your back flow off of the wave only present when a bo
Electronics Forum | Thu Feb 19 18:07:57 EST 2004 | davef
We're inclined to buy Russ's stuff about peel from the wave. Look here, but shield your eyes first: [ http://www.thepdfshop.co.uk/ppm/defects/Wave/asp/50.asp ] [A respectful bow to BW for the pix] Could you tell us more about: * Board direction thro
Electronics Forum | Fri Feb 20 12:55:43 EST 2004 | russ
Ah, the old contour wave. I don't really know how to adjust those to get correct backflow to reduce your solder volume. I need to ask why you are worried about this. Do you have a QC requirement in excess of IPC class3 wich allows for this joint t
Electronics Forum | Mon Feb 23 20:19:15 EST 2004 | greg york
Has anyone ever seen a bulbous joint (on 1 side > of 1 designator) on every board? I checked the > preheat profile at the wave and have played with > dwell times but can't get rid of it. I checked > the archives and didn't find much. Any help wou
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