Electronics Forum | Mon Dec 12 13:09:46 EST 2005 | Kris
do you intend to use Immersion tin as a PCB surface finish ? Then Whisker concern is as below if you do not past your test pads, the pads will be stressed when probed on a ICT or a flying probe tester. This is a POTENTIAL for whiskers There is a lo
Electronics Forum | Wed Nov 28 02:43:00 EST 2007 | philip_yam
Hi all, For leadfree HASL finish, is there any specification or guidelines for contamination level, esp Cu% to refer? How can we ensure the HASL finish composition is reliable for assembly? Thanks..
Electronics Forum | Fri Nov 16 10:53:30 EST 2001 | Carol Stirling
Hello Everyone, Our board supplier changed our board surface finish on a prototype to flat solderable tin (FST) because of the PWB thickness (.125"). The pads seem to be contaminated, particularly on second side pass through reflow. The solder appea
Electronics Forum | Sat Dec 10 18:17:19 EST 2005 | Sergei
http://www.smtnet.com/Forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=9595&#Message38364
Electronics Forum | Thu Nov 22 08:30:59 EST 2001 | krs
I have heard of this but do not have direct experience. Immersion tin is susceptible to moisture absorption particularly after washing off solder paste. So it sounds like your boards are picking up the solvent off the screen. Water rinse or degrease
Electronics Forum | Sat Dec 10 08:13:53 EST 2005 | davef
We believe imm tin suppliers say that their product does not whiskey, oops whisker, because they use 'white tin' not the 'gray tin' that causes whiskers. But as soon as you alloy their tin with SAC or any other high tin content solder, all bets are
Electronics Forum | Mon Dec 12 09:39:39 EST 2005 | Amol Kane
thank you devef....My point is this....If you solder all the areas that have Imm Sn on them, there wont be any whisker formation DUE TO THE IMM TIN COATING.....whiskers could still potentially form as a result of COMPONENT FINISHES and effective miti
Electronics Forum | Mon Nov 19 20:15:39 EST 2001 | davef
Now, that is one thickass board!!! The rant first: If our �board supplier changed our board surface finish on� anything without our approval, the board supplier would be an �X�. Life has enough surprises. And of all the flat finishes available, h
Electronics Forum | Mon Dec 12 11:18:59 EST 2005 | muse95
OK, I feel the need to jump in here. Bright Tin has the tendency to easily whisker, and is almost never used, except on some through-hole connectors, I believe. Matte Tin is much less susceptible to whiskering, although under the right stress cond
Electronics Forum | Wed Nov 28 22:33:24 EST 2007 | davef
There is no specification for lead-free HASL. You can use any lead-free solderability protection that meets your customer requirements. Use IPC-9701 �Performance Test Methods and Qualification Requirements for Surface Mount Solder Attachments� to ass
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