Electronics Forum | Tue Nov 05 12:34:54 EST 2013 | rgduval
3-6 months, say, depending on the environment), I might consider a ramp-soak-spike profile to allow sufficient time for the flux to clean any potential contaminants. Cheers, ..rob
Electronics Forum | Tue Mar 25 11:25:18 EDT 2014 | horchak
The first impression I get is that the mask was applied over dirty or contaminated copper. What is the trace and land finish on the PCB? You also appear to have a wetting problem.
Electronics Forum | Tue Mar 25 11:43:48 EDT 2014 | sara_pcb
It is Solder Mask on Bare copper, The land finish is HASL as per MIL-PRF-55110G which accepts trace of HASL as acceptable. Wetting is acceptable. regards, R.Saravanan
Electronics Forum | Fri Apr 18 18:06:47 EDT 2014 | davef
Methods that can reduce the wettability of OSP: * Previous heat cycles * Previous cleaning cycles * IPC-1601 "Printed Board Handling and Storage Guidelines" says do not bake prior to soldering * Using improper handling methods BR ... davef
Electronics Forum | Tue Aug 25 11:19:00 EDT 2015 | cyber_wolf
Adam, We have very recently experienced poor wetting on immersion silver as well. I would be very interested to talk to you offline, however I do not see the option to private message forum members.
Electronics Forum | Sat Sep 12 09:49:38 EDT 2015 | davef
If the boards were still "wet" after DI wash, your [I assume] low res flux could be reacting with the moisture on the board and causing the white spots. The preheater in the wave could have more dryification than the preheater on the selective solde
Electronics Forum | Mon Dec 21 17:31:06 EST 2015 | dyoungquist
If your goal is for the solder bridge to be there, then I do not see any defect. Looks like the pins and pad are wetted properly.
Electronics Forum | Thu Apr 28 09:19:21 EDT 2016 | vchauhan
Would you use dry wipe or wet wipe procedure for your Stencil Printing process? Whichever you use would you please let me know the benefits of it? Thank you in advance.
Electronics Forum | Thu Apr 28 13:27:29 EDT 2016 | duchoang
We use WET, then DRY and VACCUM for 2 or 3 boards. Do not know if your printer has those options.
Electronics Forum | Fri May 06 08:47:05 EDT 2016 | davef
You're correct. This design will have a record amount of 0402 rework for tombstoning and misalignments. Suggest that the pads on each end of all components be the same size in order to balance wetting forces during reflow.
