Electronics Forum | Fri Sep 12 09:10:23 EDT 2003 | Norm Morikawa
Around 1989 I had this probelmm with a SMT CCA that would not solder in one area consistently. I had it cross sectioned by the bare board supplier and found that under their metallurgical microscope the thickness of this HASL bare board could not be
Electronics Forum | Tue Sep 09 18:07:18 EDT 2003 | davef
We would be very wary of allowing 50 uinches, because this will likely result in reduced shelf life due to intermetallic growth. As a guesstimate, at least 10 uinches of that 50 uinches, and maybe more, is already intermetallic when you receive the b
Electronics Forum | Wed Sep 10 12:56:09 EDT 2003 | davef
Intermetallic compounds [IMC]: * Form during the alloying process of some metals. In soldering these are Sn, Ni, Ag, Cu, Au. * Do not accept solder. * Increase in depth in logarithmic proportion to both time and temperature. [So during the solder
Electronics Forum | Thu Mar 02 13:04:22 EST 2006 | Chunks
0603 parts at .2mm spacing is pretty easy. But are there any other parts, like fine pitch QFPs? Is your board HASL or something else? Is there resist/mask between all pads? If it's just 0603's at .2mm, then you can probably go 7 mils and get good
Electronics Forum | Mon May 18 13:18:25 EDT 1998 | Chrys
I'm reviewing my board fab spec. It calls for a minimum SnPb thickness of 50 microinches on HASL PWB's. I've looked at other specs that call out anything from 30 to 80 microinches, and others that just say the copper pad must be covered and soldera
Electronics Forum | Tue Sep 16 15:47:17 EDT 2003 | davef
First and most important, it doesn't matter dip who is down-wind of the rendering plant. The customer said, "I want bla bla bla." The supplier said, "I want to supply to the customer's order for bla bla bla and will deliver to that specification on
Electronics Forum | Wed Nov 17 10:03:29 EST 2010 | scottp
Instead of a minimum thickness, we require no exposed copper or SnCu intermetallic. We've been having a lot of trouble lately with suppliers of SN100 HASL boards giving us pads with very irregular solder deposits with areas of exposed intermetallic.
Electronics Forum | Mon May 18 13:30:15 EDT 1998 | Earl Moon
| I'm reviewing my board fab spec. It calls for a minimum SnPb thickness of 50 microinches on HASL PWB's. I've looked at other specs that call out anything from 30 to 80 microinches, and others that just say the copper pad must be covered and solde
Electronics Forum | Thu May 21 09:54:07 EDT 1998 | Justin Medernach
| I'm reviewing my board fab spec. It calls for a minimum SnPb thickness of 50 microinches on HASL PWB's. I've looked at other specs that call out anything from 30 to 80 microinches, and others that just say the copper pad must be covered and solde
Electronics Forum | Thu Feb 23 13:56:21 EST 2006 | slthomas
I have dealt with it before and usually it's consistent, so you use some simple math to work around the issues. Now, if you have so much variability between different locations on your board for resist thickness, HASL thickness, etc., that it fouls
