Electronics Forum | Tue Oct 29 21:27:21 EDT 2019 | aqueous
It depends on the flux type. If it's water soluble, it should be cleaned soon after reflow because OA flux remains active after reflow. If it's rosin or no-clean (low-residue), then the only concern is the longer wait time, the more difficult it will
Electronics Forum | Wed Oct 30 02:12:39 EDT 2019 | jags
yes and thanks for this feedback. we clean with degreaser ( strong) and flux is rosin with 10% in the paste (koki). we clean after second reflow . the gap time from bottom to topside completion is 10 hours. cleans with this time. my even after 20 h
Electronics Forum | Tue Oct 29 04:40:42 EDT 2019 | jags
how long i can keep pcba after bottom reflow soldering to top side reflow soldering. like 12 hours or 24 hour or 48 hours........Enig board. leadfree soldering with 10% flux
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 | Fri Aug 27 00:26:14 EDT 2004 | charly
hi, encounter few cases PCB was delam after reflow, and the supplier was refuse that this is a PCB manufacturing defect as the fallout is low within one lot. the cost for this scrap is high after PCBA level, my query here are 1) is there any way
Electronics Forum | Fri Aug 27 04:51:43 EDT 2004 | rose
I suggest you to do some EDX ananlysis or maping and make a comparsion between the delam part and the good one. maybe some contamination or element used in the board manufacturing process stayed under the coating layer. If there is some difference be
Electronics Forum | Fri Apr 21 09:03:59 EDT 2006 | choppy
I guess the first thing to look at is the temperature. We had to heat more for QFP256 on sample boards and we saw discoloration on some small parts. Just try to sense around when profiling to see what's there.
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 | Fri Sep 18 07:32:53 EDT 2009 | karthikthebest
I agree with Graham cooper's input. Also note that the brownish color is incremental w.r.t to number of days you hold after the thermal cycle(example: after the reflow)so try to complete all thermal cycles ASAP to lessen the discoloring.
Electronics Forum | Tue Jan 30 02:38:50 EST 2001 | arul2000
This BGA could have gone through the reflow cycle two times as we understand from the BGA manufacturer, during the BGA ball attachment process. (If any ball is found missing, they replace the missed ball manually after applying flux manually and refl
