Electronics Forum | Mon Jul 24 11:35:42 EDT 2006 | Jimk@ics-inc.org
We have experienced a problem with tin leaching or discoloration of lead terminals on random parts on solder side of a paste/paste operation. The profile has been used on previous production runs and there doesn't appear to be any heat damage to othe
Electronics Forum | Thu Apr 20 22:14:51 EDT 2006 | raquel
hello! need ur inputs... if the Matte Sn pbfree finish of the component discolors AFTER having been exposed to bake, or, after reflow, will the base leadframe have any potential contribution to it? i know most likely suspects would be the plating pro
Electronics Forum | Mon Aug 29 16:21:20 EDT 2011 | rjlasko
Greetings...I have a customer that has an assembly that is conformal coated with Humiseal 1A33. This assembly has some components (resistors and FET's) that heated up during operation and has discolored the conformal coating around their location.
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 | Fri Mar 27 10:04:51 EDT 2009 | ericthered
We have been having problems with proper wetting when running mainly lead free but also leaded solder in our Ersa Hotflow 3. Solder either often looks grainy or doesn't flow over the whole pad. This is generally the case when my profile is 170 firs
Electronics Forum | Mon Aug 29 22:48:09 EDT 2011 | davef
Rich Here's what Humiseal says: Thermal Properties The coating must be able to withstand localized thermal 'hot spots' generated by components. High temperatures can cause short-term changes in coating characteristics, such as softening and lowered e
Electronics Forum | Thu May 14 22:45:46 EDT 2009 | davef
You're correct. It's a peculiar looking defect. With measling, we expect to see discrete white spots or crosses just below the surface of the base material. We don't see that here. We do see a similar condition at almost every PTH in the picture, a
Electronics Forum | Mon Jun 18 19:57:40 EDT 2001 | Gil Zweig
Dave: You pose a very good question. We have been in the electronics x-ray inspection business for 18-1/2 years and, to date, we have not received a single report of damage associated with x-ray exposure. However... we do see signs of long term x-ra
Electronics Forum | Tue Aug 22 16:13:08 EDT 2000 | Dr. Ning-Cheng Lee
FR-4 will be OK for small products such as cellular phones. Here the temperature gradient across the board may be 3-4C only, and the board temperature can be well controlled. At temperature above around 245C, the discoloration and delamination may be
Electronics Forum | Thu May 05 12:31:27 EDT 2005 | russ
Not in this case, these BGAs were lead free and the profile used was for a lead part. I guess I will give you the whole story. These boards were sent to us from a customer to have the BGAs replaced for an unknown to us reason. We removed the parts
