Electronics Forum | Mon Jul 24 11:35:42 EDT 2006 | Jimk@ics-inc.org
We have experienced a problem with tin leaching or discoloration of lead terminals on random parts on solder side of a paste/paste operation. The profile has been used on previous production runs and there doesn't appear to be any heat damage to othe
Electronics Forum | Thu Jul 27 07:50:35 EDT 2006 | davef
Send us pix
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 | Tue Feb 27 13:21:24 EST 2001 | kmorris
We've recently identified that one of our wavesolder machines has a high tin content. It should be 63% and is greater than 1% above that. We are adding pure tin to adjust the ratio back to 63%. I'm wondering what defects might be expected as the ti
Electronics Forum | Wed Feb 08 04:08:35 EST 2006 | fctassembly
Hello Greg, I agree with you that the article in SMT Magazine should be studied very carefully as it contains many errors in respect to SN100C. The testing performed was a DOE and was not an optimized run. There is also a statement on dross generatio
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 | Fri Dec 16 08:16:41 EST 2005 | davef
Heat cycles deplete the pure tin layer. Each solder cycle reduces the tin thickness by ~0.1 micron (4 uin). So, if you start with a thin imm tin coating you'll have problems after multiple heat cycles. Steve Wentz says, "In almost every case I've
Electronics Forum | Fri Jul 18 10:46:43 EDT 2003 | davef
If you are saying that you have discolored white tin at in-bound inspection, you have bad boards. The boards are fabricated incorrectly. Your fabricator is deficient. That is the GREAT thing about imm coatings. You can look at them and determine
Electronics Forum | Sat Jun 04 01:39:39 EDT 2005 | adlsmt
It would appear that pure tin is backward compatible with leaded processes. This makes it a great finish, as if you migrate all your parts over time there is no issue mixing them. I am not aware of any finish that eliminates the possibility of tin wh
Electronics Forum | Mon Mar 01 15:28:30 EST 2010 | mikesewell
Pure tin finish? Tin whiskers?
