Electronics Forum | Mon Aug 07 09:04:09 EDT 2006 | molos21
Hi everyone, I am starting to use the lead free process and I had a few wetting problems (solder did not reach top side) at the wave soldering process once the pcb had passed our smt line (one heat pass). From what I understand, I have had a problem
Electronics Forum | Wed Aug 09 08:06:07 EDT 2006 | davef
See "IPC-4554 Specification for Immersion Tin Plating for Printed Circuit Boards" 3.2.1 Immersion Tin Thickness. The most common reason for solderability issues with the white tin surface coating during multiple thermal excursions is a thin white ti
Electronics Forum | Mon Nov 25 16:12:52 EST 2002 | russ
there is a good article by AIM solder regarding tin. In a nut shell, if you do not apply flux or heat to tin finish you will never degrade it! I agree with the others that you need to check the thickness of the pure tin layer. We have forbidden ti
Electronics Forum | Mon Jan 08 03:16:12 EST 2007 | oswald5087
hi' i need advise on immersion gold PCb shelf life. 1) what is the issue shelf life or expire for Immersion gold PCB? 2) How long we can keep the PCB? (with vacuum seal and without vacuum seal) 2) iF PCB expire, can we bake the immersion PCB? what t
Electronics Forum | Fri Dec 16 08:00:26 EST 2005 | jax
What you are most likely dealing with: Insufficient Pure Sn layer ( multiple causes ) Because elevated temperatures accelerate the diffusion process, the thickness of the Pure Sn layer will reduce during every thermal cycle... ( bakeing PCBs, S
Electronics Forum | Tue Mar 01 10:21:55 EST 2005 | davef
IPC Plating Committee is presently working on a specification for immersion tin [IPC-4554 Specification for Immersion Tin Plating for Printed Circuit Boards] as a solderable surface finish. Immersion tin is normally deposited at 30 to 60 microinches.
Electronics Forum | Sat Mar 05 22:44:44 EST 2005 | gpaelmo
You can also try the Florida Circtech website or call them direct. There is a min. thickness requirement and if the board house does not follow it you will end up with scrap boards after the second pass (from experience). I even sent blank boards to
Electronics Forum | Sun Sep 15 21:44:41 EDT 2002 | jason
Hi Dave, Immersion Ag has poor surface appearances after reflow or rather tarnished, while Immersion Tin requries higher temp. Probably that's why Immersion Ag is more preferred.
Electronics Forum | Fri Jun 14 14:30:36 EDT 2002 | davef
Assuming you are talking about solderable surfaces: People specify various materials to protect the solderability of the pads on the board. Gold, actually, Electroless Nickel - Immersion Gold [ENIG], is popular. * Board fabricators like it because
Electronics Forum | Fri Dec 16 03:47:46 EST 2005 | gpaelmo
Anyone have problems wave soldering white tin finish? We are an ems and our customer provides us the pcb's. SMT and TH components on the board. SMT is fine but when we wave solder, wetting to top side is very poor (solder only flows half way up). We
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