Electronics Forum | Fri Aug 22 10:01:52 EDT 2008 | robinj
I have seen this problem before. If the color is yellow usually it is caused by moisture left on the boards from poor drying after immersion silver. One of the ways to get rid of this is by dipping in acid cleaner solution. If the board supplier uses
Electronics Forum | Thu Aug 28 04:07:46 EDT 2008 | kelson
Hi robinj As you have mentioned, if the color is yellow usually it is caused by moisture left on the boards from poor drying after immersion silver. However, our boards were received from the supplier and the changes happened in our side. So, what di
Electronics Forum | Tue Aug 26 07:44:06 EDT 2008 | davef
Industry-wide, there is no current requirement for baking of bare boards. It adds no value. * IPC-HDBK-001 has guidelines olden times. * IPC-TM-650 has several test methods to determine moisture resistance to both liquid immersion and absorption from
Electronics Forum | Mon Sep 08 10:34:37 EDT 2008 | blnorman
Because of our high volume production, we use no clean flux. We have experienced leakage currents with leadless QFNs. One problem is the part isn't being utilized as it should, but another is the flux residue. There is ionic residue in no-clean fl
Electronics Forum | Fri May 15 13:17:18 EDT 2009 | tomsmiley
We implemented an inexpensive home dishwasher solution last year for cleaning assemblies. It works very well for both lead free and tin/lead cleaning. DI water at room temp is all we do and the boards come out squeaky clean. We had to use the least
Electronics Forum | Wed Jun 10 22:47:17 EDT 2009 | davef
You're correct that JEDEC J-STD-033 defines baking condidtions for moisture sensitive components. Why do you want to bake assemblies after cleaning? Search the fine SMTnet Archives for threads like: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Me
Electronics Forum | Fri Jul 24 07:43:56 EDT 2009 | davef
Your customer is correct. You are doing something wrong in your hand soldering process. Solder balls are a process indicator. Areas to assess are: * Moisture content of the bare board * Thickness of the copper plating in the through holes * Temperatu
Electronics Forum | Tue Aug 25 08:04:26 EDT 2009 | davef
Trapped moisture can be a problem, and one standard recommends baking a PCB for a minimum of 4 hours at 93+/- 5.5ºC before conformally coating. [NASA-STD-8739.1, “Workmanship Standard for Staking and Conformal Coating of Printed Wiring Boards and Ele
Electronics Forum | Tue Sep 08 07:07:55 EDT 2009 | davef
We think the idea is to avoid boiling-off the moisture and let it 'cook-off' at a lower temperature to decrease the potential damage to components. If you heat a pan of water on the stove below, but close to the boiling point of water, the water in t
Electronics Forum | Tue Aug 25 20:01:26 EDT 2009 | davef
We don't use bags like you describe. All of our bags are ESD shield bags that have dissipative and antistatic attributes. We'd be uneasy about the zip lock closure thing. Use your static field meter to determine the charge generated by opening and
