Electronics Forum | Tue Sep 16 16:45:44 EDT 2008 | trynders
Thanks for the response! I thought is was odd the component vendor chose SAC for a lead frame finish. I am in the Military world, and things have been difficult to control from a lead-free standpoint. I have not been able to find any studies on SAC
Electronics Forum | Fri Feb 20 12:04:29 EST 2009 | markhoch
Okay, after taking an actual minute to think about my suggestion, it has dawned on me that filling a metal cavity with molten solder to make a solder connection is not a good idea. By doing so I wouldn't be giving the metal cavity sufficient time to
Electronics Forum | Wed Aug 19 18:18:02 EDT 2009 | smt_guy
Thanks Sir Dave. Yeah my apologies. To clarify, we built the product PCB whcih has a Lead-Free HASL Finish using a Sn63/Pb37 Solder paste. My major concern regarding reliability is that my profile whish is between 215'C-225'C was insufficient to ref
Electronics Forum | Fri Sep 18 09:18:06 EDT 2009 | ysutariya
Also, it wouldn't hurt to perform SERA testing to determine the amount of free tin to begin with. From what I remember, I think you need 30 microinches of free tin to ensure success. XRF won't give you an accurate thickness reading as it counts the
Electronics Forum | Tue Apr 13 08:21:05 EDT 2010 | esca
Hi manchella, After ATC test, two different failure modes can be present: solder FATIGUE (into bulk) or BRITTLE INTERMETALLIC fracture. So, first you have to verify this. Moreover, which brand of SMT paste have you used ? The crack into solder joint
Electronics Forum | Mon May 03 11:20:43 EDT 2010 | mikesewell
A good guideline is keep it similar to your wave solder process, for example 2-3 sec. This assumes you're preheating the assembly. While polyimide boards are fairly robust at some point you will begin to see copper dissolution - the solder side pad
Electronics Forum | Fri Sep 17 03:03:29 EDT 2010 | grahamcooper22
Hi Gani, looking at the HASL icture and the poor wetting of the solder over the pads I would imagine that the HASL coating is very thin on the pads and in actual fact isn't 'solder' but is tin /copper intemetallic and this has poor solderability. It
Electronics Forum | Tue Oct 05 08:01:57 EDT 2010 | scottp
Have you confirmed in an SEM that the break is in the solder and not in the termination? If not in the termination, is it in the intermetallic rather than the bulk solder? It's unusual for the break to be in the solder joint when chips are knocked
Electronics Forum | Fri Jun 24 09:32:53 EDT 2011 | kahrpr
Looking at the appearance of pads and solder joint is pretty subjective. Especially lead free people are all over the map on the physical appearance of pads and joints. The true test is solderabilty testing, weather it’s just looking for good wetti
Electronics Forum | Thu Oct 25 13:33:18 EDT 2012 | cyber_wolf
Ken, The photo looks like results I have seen because the gold flash was too thick on the board. This causes a condition known as gold imbrittlement. You may want to get an analysis of the plating thickness. I'm not real experienced with immersion si
