Electronics Forum | Fri Dec 10 12:24:46 EST 2010 | davef
Causes of dewetting in conformal coating. Factors that influence dewetting usually involve non-ionic contamination such as: * Residues from board manufacture including silicone surfactants from solder resist & HASL rinse contamination * Component res
Electronics Forum | Fri Sep 24 09:49:53 EDT 1999 | C.K.
Hi Folks: We've been having bridging problems on our fine-pitch QFP's, despite thorough inspection of paste height, volume, and placement accuracies....profiles look good also. The bridging is happening after coming out of reflow...one last thing t
Electronics Forum | Tue Jul 06 11:58:44 EDT 2010 | baildl632
What type of finish are the PCB's? HASL, tin immersion, silver immersion,........we've seen all the above problems with HASL finished boards. Usually either reheating w/ a soldering iron or "burnishing" with a scotch brite pad has worked for us.
Electronics Forum | Wed Dec 22 12:36:36 EST 2004 | rlackey
Hi Mark, Look on the bright side, if you want to change from HASL you've got the lead free issue which will allow you to evaluate all other finishes, and find the best one for you. Dave, have you seen any unleaded HASL finishes & any issues arising
Electronics Forum | Fri Jan 16 16:36:07 EST 2009 | boardhouse
i would not try to chemically clean the finish, you would just be asking for other problems. 1) I would ask your supplier their Hasl mix. Standard Lead hasl is 63/37 - it almost sounds like your boards have a higher content of Tin and your experien
Electronics Forum | Wed Jan 26 17:36:22 EST 2011 | ck_the_flip
had a quick question regarding compatibility of Sn100C HASL finish and regular Sn63 solder paste. Does the thermal profile have to reach Sn100C eutectic temps. in order for the Sn 100C HASL to coaelesce with the Sn63 Solder paste? How reliable is t
Electronics Forum | Wed Oct 18 09:44:38 EDT 2000 | mike weekes
we're considering PWB finishes other than HASL - the uneven plating contributed to defects and the residues exceed our goal for PWB cleanliness. What success have any of you had with CuOSP, Immersion Silver, Gold or other finishes? Did you have to
Electronics Forum | Mon Apr 28 11:13:21 EDT 2008 | ck_the_flip
Here's a crude wettability test. Take a PCB - both types of finish - print them, and reflow with no components using your standard profile. Observe the wetting spread and flow of the solder paste. This rules in/out that it's PCB solderability.
Electronics Forum | Fri Jun 17 10:06:13 EDT 2005 | Doug
We have had some experience with the immersion tin. The appearance can be "bright" or "dull". Don't discount the fact that it is "bright" doesn't necessarily make it HASL. Furthermore, I personally have never heard of a board manufacturer "stripping
Electronics Forum | Thu Aug 28 11:31:17 EDT 2008 | patrickbruneel
Matt solder mask finishes gives the widest process window in view of potential amount of residues when using No-Clean. Shiny (glass like) finishes are more sensitive to residues due to lower surface area compared to matt finish. If the shiny finish i
